Rectal progesterone administration secures a high ongoing pregnancy rate in a personalized Hormone Replacement Therapy Frozen Embryo Transfer (HRT-FET) protocol: a prospective interventional study.

STUDY QUESTION: Can supplementation with rectal administration of progesterone secure high ongoing pregnancy rates (OPRs) in patients with low serum progesterone (P4) on the day of blastocyst transfer (ET)? SUMMARY ANSWER: Rectally administered progesterone commencing on the ET day secures high OPRs in patients with serum P4 levels below 35 nmol/l (11 ng/ml). WHAT IS KNOWN ALREADY: Low serum P4 levels at peri-implantation in Hormone Replacement Therapy Frozen Embryo Transfer (HRT-FET) cycles impact reproductive outcomes negatively. However, studies have shown that patients with low P4 after a standard vaginal progesterone treatment can obtain live birth rates (LBRs) comparable to patients with optimal P4 levels if they receive additionalsubcutaneous progesterone, starting around the day of blastocyst transfer. In contrast, increasing vaginal progesterone supplementation in low serum P4 patients does not increase LBR. Another route of administration rarely used in ART is the rectal route, despite the fact that progesterone is well absorbed and serum P4 levels reach a maximum level after ∼2 h. STUDY DESIGN, SIZE, DURATION: This prospective interventional study included a cohort of 488 HRT-FET cycles, in which a total of 374 patients had serum P4 levels ≥35 nmol/l (11 ng/ml) at ET, and 114 patients had serum P4 levels <35 nmol/l (11 ng/ml). The study was conducted from January 2020 to November 2022. PARTICIPANTS/MATERIALS, SETTING, METHODS: Patients underwent HRT-FET in a public Fertility Clinic, and endometrial preparation included oral oestradiol (6 mg/24 h), followed by vaginal micronized progesterone, 400 mg/12 h. Blastocyst transfer and P4 measurements were performed on the sixth day of progesterone administration. In patients with serum P4 <35 nmol/l (11 ng/ml), 'rescue' was performed by rectal administration of progesterone (400 mg/12 h) starting that same day. In pregnant patients, rectal administration continued until Week 8 of gestation, and oestradiol and vaginal progesterone treatment continued until Week 10 of gestation. MAIN RESULTS AND THE ROLE OF CHANCE: Among 488 HRT-FET single blastocyst transfers, the mean age of the patients at oocyte retrieval (OR) was 30.9 ± 4.6 years and the mean BMI at ET 25.1 ± 3.5 kg/m2. The mean serum P4 level after vaginal progesterone administration on the day of ET was 48.9 ± 21.0 nmol/l (15.4 ± 6.6 ng/ml), and a total of 23% (114/488) of the patients had a serum P4 level lower than 35 nmol/l (11 ng/ml). The overall, positive hCG rate, clinical pregnancy rate, OPR week 12, and total pregnancy loss rate were 66% (320/488), 54% (265/488), 45% (221/488), and 31% (99/320), respectively. There was no significant difference in either OPR week 12 or total pregnancy loss rate between patients with P4 ≥35 nmol/l (11 ng/ml) and patients with P4 <35 nmol/l, who received rescue in terms of rectally administered progesterone, 45% versus 46%, P = 0.77 and 30% versus 34%, P = 0.53, respectively. OPR did not differ whether patients had initially low P4 and rectal rescue or were above the P4 cut-off. Logistic regression analysis showed that only age at OR and blastocyst scoring correlated with OPR week 12, independently of other factors like BMI and vitrification day of blastocysts (Day 5 or 6). LIMITATIONS, REASONS FOR CAUTION: In this study, vaginal micronized progesterone pessaries, a solid pessary with progesterone suspended in vegetable hard fat, were used vaginally as well as rectally. It is unknown whether other vaginal progesterone products, such as capsules, gel, or tablet, could be used rectally with the same rescue effect. WIDER IMPLICATIONS OF THE FINDINGS: A substantial part of HRT-FET patients receiving vaginal progesterone treatment has lowserum P4. Adding rectally administered progesterone in these patients increases the reproductive outcome. Importantly, rectal progesterone administration is considered convenient, and progesterone pessaries are easy to administer rectally and of low cost. STUDY FUNDING/COMPETING INTEREST(S): Gedeon Richter Nordic supported the study with an unrestricted grant as well as study medication. B.A. has received unrestricted grant from Gedeon Richter Nordic and Merck and honoraria for lectures from Gedeon Richter, Merck, IBSA and Marckyrl Pharma. P.H. has received honoraria for lectures from Gedeon Richter, Merck, IBSA and U.S.K. has received grant from Gedeon Richter Nordic, IBSA and Merck for studies outside this work and honoraria for teaching from Merck and Thillotts Pharma AB and conference expenses covered by Merck. The other co-authors have no conflict of interest to declare. TRIAL REGISTRATION NUMBER (25): EudraCT no.: 2019-001539-29.

Psychological interventions improve quality of life despite persistent pain in endometriosis: results of a 3-armed randomized controlled trial.

PURPOSE: Despite standard medical treatment endometriosis is often associated with disabling pain and poor quality of life (QoL). Studies indicate that psychological interventions (PIs) may improve pain and QoL, yet studies on the effects of PIs for women with endometriosis are sparse and limited by low-quality study designs. Therefore, this study aimed, in a rigorous three-armed design, to evaluate the effect of PIs on chronic pelvic pain (CPP) and QoL in women with endometriosis. METHODS: This three-armed parallel, multi-center randomized controlled trial included fifty-eight endometriosis patients reporting severe CPP [≥ 5 for pain intensity measured on a 0-10-point numeric rating scale (NRS)]. Patients were randomly assigned to (1) Specific mindfulness- and acceptance-based psychological intervention (MY-ENDO), (2) Carefully matched non-specific psychological intervention (Non-specific), or (3) A wait-list control group (WL). The primary outcome was pelvic pain intensity/unpleasantness measured on NRS. Secondary outcomes included endometriosis-related quality of life, workability, pain acceptance, and endometriosis-related symptoms. Differences in outcomes between groups at post-treatment follow-up were analyzed using mixed linear models. Analyses were performed on an intention-to-treat basis. RESULTS: Compared to WL, psychological intervention (MY-ENDO + Non-specific) did not significantly reduce pain. However, psychological intervention did significantly improve the QoL-subscales 'control and powerlessness', 'emotional well-being', and 'social support' as well as the endometriosis-related symptoms 'dyschezia' and 'constipation'. MY-ENDO was not superior to Non-specific. CONCLUSIONS: Women with endometriosis may have significant and large effects of psychological intervention on QoL despite an ongoing experience of severe CPP. TRIAL REGISTRATION: 12 April 2016, clinicaltrials.gov (NCT02761382), retrospectively registered.

Maternal carriage of H-Y restricting HLA class II alleles is a negative prognostic factor for women with recurrent pregnancy loss after birth of a boy.

Immune system aberrations are suggested to be an important factor in the pathophysiology of unexplained secondary recurrent pregnancy loss (sRPL). The objective was to investigate if the sex ratio of the firstborn child in sRPL patients differs from the background population and whether the sex of the firstborn child has a negative impact on the pregnancy prognosis alone and/or in combination with carriage of male-specific minor histocompatibility (H-Y) restricting HLA class II alleles. From January 2016 to October 2022, 582 patients with unexplained RPL were admitted to the RPL Center of Western Denmark and continuously followed-up. HLA-DRB1 and -DQB1 typing was performed as part of the routine diagnostic work-up. In sRPL patients, a history of a firstborn boy was significantly more frequent than in the Danish background population and was associated with significantly lower odds of a successful reproductive outcome in the first pregnancy after admission compared to a firstborn girl (OR=0.41, 95% CI: 0.20-0.83, p = 0.014). The odds of a successful reproductive outcome were enhanced in patients carrying ≥ 1 H-Y-restricting HLA class II alleles with a first-born girl compared to a firstborn boy (OR=3.33, 95% CI: 1.40-7.88, p = 0.005), while no difference in successful reproductive outcome was seen in sRPL patients not carrying these alleles (OR=1.20, 95% CI: 0.33-4.43, p = 0.781). The sex ratio of children born after RPL was similar to the Danish background population. These findings confirm previous findings and suggests that a harmful immune response triggered by H-Y-antigen exposure during a previous pregnancy in preconditioned women may cause sRPL.

Plasma level of mannose-binding lectin is associated with the risk of recurrent pregnancy loss but not pregnancy outcome after the diagnosis.

STUDY QUESTION: Are low or high plasma mannose-binding lectin (p-MBL) levels associated with recurrent pregnancy loss (RPL) and the reproductive and perinatal outcomes before and after RPL? SUMMARY ANSWER: The prevalence of low p-MBL levels was significantly higher in RPL patients, while high levels were significantly less prevalent. No association was found between p-MBL level and reproductive and perinatal outcomes before and after RPL. WHAT IS KNOWN ALREADY: Mannose-binding lectin (MBL) is an important component in the innate immune system. Low p-MBL levels have been associated with RPL, while the correlation with high levels has been poorly studied. Adverse perinatal outcomes are generally more frequent among RPL patients, but reports concerning the association between maternal p-MBL levels and perinatal outcomes, including birth weight (BW) and gestational age (GA), are conflicting. STUDY DESIGN SIZE DURATION: This study was a combined cross-sectional and cohort study of 267 RPL patients admitted to the RPL Center of Western Denmark between January 2016 and March 2020. RPL patients were followed until birth of a liveborn child or until end of follow-up, March 2021. A sample of 185 healthy female blood donors of reproductive age was used as a MBL reference group. PARTICIPANTS/MATERIALS SETTING METHODS: All RPL patients had ≥3 consecutive pregnancy losses, a regular menstrual cycle and no known significant chromosomal or uterine malformations. At the first consultation, routine blood samples including p-MBL measurement and detailed obstetrical and perinatal information were collected. p-MBL levels in RPL patients were compared to the MBL reference group. A logistic regression analysis adjusted for relevant confounders assessed the association between low p-MBL levels and an unsuccessful reproductive outcome in RPL patients in first pregnancy after admission. Perinatal outcomes before and after RPL were compared between RPL subgroups according to low (≤500 µg/l), intermediate (501-3000 µg/l) and high (>3000 µg/l) p-MBL levels. MAIN RESULTS AND THE ROLE OF CHANCE: Significantly more RPL patients had low p-MBL levels (prevalence proportion ratio (PPR): 1.79, 95% CI: 1.34-2.38) and fewer had high p-MBL levels (PPR: 0.56, 95% CI: 0.40-0.79) compared to the reference group, while the prevalence of intermediate p-MBL level was not different between the groups (PPR: 0.86, 95% CI: 0.69-1.08). In the prospective study, low p-MBL level was not a significant risk factor for a pregnancy loss in the first pregnancy after admission after adjustment for age, BMI and smoking. Neither before nor after the RPL diagnosis were maternal p-MBL levels significantly associated with BW or GA. LIMITATIONS REASONS FOR CAUTION: Only 161 (60.3%) patients had given birth after RPL during the follow-up period, which limited the possibility to detect clear associations between p-MBL levels and perinatal outcomes after RPL. WIDER IMPLICATIONS OF THE FINDINGS: In agreement with several previous studies, low p-MBL levels are strongly associated with RPL, while this study for the first time documents that high levels may play a protective role, which suggests a causal relationship. We suggest that larger prospective studies evaluate the association between p-MBL levels and RPL prognosis. STUDY FUNDING/COMPETING INTERESTS: No external funding was received. We acknowledge the Department of Obstetrics and Gynaecology at Aalborg University Hospital for financial support. U.S.K. has reported personal fees from Merck, consulting fees from IBSA Nordic, and a grant from Gedeon Richter, Merck and IBSA Nordic outside of the submitted work. TRIAL REGISTRATION NUMBER: ID from clinicaltrials.gov is NCT04017754.

Idiopathic early ovarian ageing: risk of miscarriage and chance of delivery following ART in a nationwide cohort study.

STUDY QUESTION: Is idiopathic reduced ovarian reserve in young women, quantified as low response to ovarian stimulation in ART, associated with a concomitant loss of oocyte quality as determined by risk of pregnancy loss and chance of clinical pregnancy and live birth? SUMMARY ANSWER: Young women with idiopathic accelerated loss of follicles exhibit a similar risk of pregnancy loss as young women with normal ovarian reserve. WHAT IS KNOWN ALREADY: Normal ovarian ageing is described as a concomitant decline in oocyte quantity and quality with increasing age. Conflicting results exist with regard to whether a similar decline in oocyte quality also follows an accelerated loss of follicles in young women. STUDY DESIGN, SIZE, DURATION: This national register-based, historical cohort study included treatment cycles from young women (≤37 years) after ART treatment in Danish public or private fertility clinics during the period 1995-2014. The women were divided into two groups dependent on their ovarian reserve status: early ovarian ageing (EOA) group and normal ovarian ageing (NOA) group. There were 2734 eligible cycles in the EOA group and 22 573 in the NOA group. Of those, 1874 (n = 1213 women) and 19 526 (n = 8814 women) cycles with embryo transfer were included for analyses in the EOA and NOA group, respectively. PARTICIPANTS/MATERIALS, SETTING, METHODS: EOA was defined as ≤5 oocytes harvested in both the first and second cycle stimulated with FSH. The NOA group should have had at least two FSH-stimulated cycles with ≥8 oocytes harvested in either the first or the second cycle. Cases with known causes influencing the ovarian reserve (endometriosis, ovarian surgery, polycystic ovary syndrome, chemotherapy, etc.) were excluded. The oocyte quality was evaluated by the primary outcome defined as the overall risk of pregnancy loss (gestational age (GA) ≤22 weeks) following a positive hCG and further stratified into: non-visualized pregnancy loss, early miscarriage (GA ≤ 12 weeks) and late miscarriage (GA > 12 weeks). Secondary outcomes were chance of clinical pregnancy and live birth per embryo transfer. Cox regression models were used to assess the risk of pregnancy loss. Time-to-event was measured from the day of embryo transfer from the second cycle and subsequent cycles. Logistic regression models were used to assess the chance of clinical pregnancy and live birth. MAIN RESULTS AND THE ROLE OF CHANCE: The overall risk of pregnancy loss for the EOA group was comparable with the NOA group (adjusted hazard ratio: 1.04, 95% CI: 0.86; 1.26). Stratifying by pregnancy loss types showed comparable risks in the EOA and NOA group. The odds of achieving a clinical pregnancy or live birth per embryo transfer was lower in the EOA group compared to the NOA group (adjusted odds ratio: 0.77 (0.67; 0.88) and 0.78 (0.67; 0.90), respectively). LIMITATIONS, REASONS FOR CAUTION: Only women with at least two ART cycles were included. We had no information on the total doses of gonadotropin administered in each cycle. WIDER IMPLICATIONS OF THE FINDINGS: The present findings may indicate that mechanism(s) other than aneuploidy may explain the asynchrony between the normal-for-age risk of miscarriage and the reduced chance of implantation found in our patients with EOA. The results of this study could be valuable when counselling young patients with low ovarian reserve. STUDY FUNDING/COMPETING INTERESTS(S): The study was funded by the Health Research Fund of Central Denmark Region. The authors have no conflict of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Health-related quality of life in women with endometriosis: psychometric validation of the Endometriosis Health Profile 30 questionnaire using confirmatory factor analysis.

STUDY QUESTION: Which of the competing models of the Endometriosis Health Profile 30 Questionnaire (EHP-30) factor structure is best supported by confirmatory factor analysis (CFA)? SUMMARY ANSWER: Findings support a five-factor first-order model of the EHP-30, thereby lending support to the model originally suggested by the questionnaire developers. WHAT IS KNOWN ALREADY: Endometriosis has a negative impact on quality of life, and measures specifically developed to address this impact, such as the EHP-30, are vital in research and disease management. Previous studies have found different models of the EHP-30 factor structure, and generated uncertainty regarding how to use the questionnaire. CFA can be applied to compare competing factor models and determine the underlying structure of a questionnaire. STUDY DESIGN SIZE DURATION: This cross-sectional multicenter study included 304 women with endometriosis recruited from three different public health service endometriosis clinics (referral centers for treatment of severe endometriosis) and the Danish Endometriosis Patients Association from 2014 to 2015. PARTICIPANTS/MATERIALS SETTING METHODS: Diagnosis of endometriosis was confirmed in medical records for 84.2% and by histology for 66.8% of participants. Questionnaires (the licensed Danish version of the EHP-30) were sent by post two times with a 6- to 12-week interval. CFA was used to examine construct validity and Bland-Altman plots to examine test-retest reliability and the convergent validity with the Short Form 36 version 2. MAIN RESULTS AND THE ROLE OF CHANCE: Response rate was high (87.6%). CFA supported the original first-order five-factor structure of the EHP-30, and thereby, the use of five separate scale-scores in clinical and research practice. Visual inspection of Bland-Altman plots suggested excellent test-retest reliability of the EHP-30 and supported the use of a disease specific quality of life instrument for women with endometriosis. LIMITATIONS REASONS FOR CAUTION: Diagnosis could not be confirmed through histology data in 33.2% of participants. However, subgroup analyses based on women with confirmed histology only, yielded similar results. Data related to menstrual cycle stage and the use of hormonal and pain medication during questionnaire completion were not collected. A larger study, including data from different countries on different continents, would be better designed to exclude potential population bias. WIDER IMPLICATIONS OF THE FINDINGS: EHP-30, with its original five-factor structure, appears to be a valid, stable, and specific quality of life measure for women with endometriosis. It seems easy to understand, quick to administer, and importantly, scoring might be unaffected by cyclical/menstrual pain symptoms related to endometriosis. The finding of a five-factor model from different studies across several countries supports the crosscultural validity of the EHP-30. STUDY FUNDING/COMPETING INTERESTS: This work was supported by the Danish Endometriosis Association, which is a nongovernmental organization run by women with endometriosis and by a scholarship from the Health Research Fund of Central Denmark Region. The authors have no conflicts of interest. TRIAL REGISTRATION NUMBER: The Danish Data Protection Agency (J.nr: 2013-41-2264).

Fertility treatment with clomiphene citrate and childhood epilepsy: a nationwide cohort study.

STUDY QUESTION: Is fertility treatment with clomiphene citrate associated with an increased risk of childhood epilepsy, including specific subtypes of epilepsy? SUMMARY ANSWER: Fertility treatment with clomiphene citrate may be associated with a small increased risk of idiopathic generalized epilepsy and focal epilepsy in childhood. WHAT IS KNOWN ALREADY: Clomiphene citrate is among the most commonly prescribed drugs for fertility treatment. However, concerns have been raised as to whether the treatment may harm the developing fetus. STUDY DESIGN, SIZE, DURATION: This nationwide cohort study included all pregnancies in Denmark from 1 July 1995 resulting in a live-born singleton child before 31 December 2013. The children were followed until 31 December 2016. PARTICIPANTS/MATERIALS, SETTING, METHODS: Children conceived after fertility treatment with clomiphene citrate were identified from the Danish National Prescription Registry. The primary outcomes were childhood epilepsy, idiopathic generalized epilepsy, and focal epilepsy identified from the Danish National Patient Register and from antiepileptic drug prescriptions in the Danish National Prescription Registry. All analyses were conducted using Cox proportional hazards regression. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 1 081 291 pregnancies were included; 12 644 children (1.2%) developed epilepsy. Fertility treatment with clomiphene citrate was associated with a small increased risk of childhood epilepsy (hazard ratio [HR]: 1.10; 95% CI: 1.00-1.22), idiopathic generalized epilepsy (HR: 1.41; 95% CI: 1.16-1.72), and focal epilepsy (HR: 1.26; 95% CI: 1.04-1.53). LIMITATIONS, REASONS FOR CAUTION: The increased risk of idiopathic generalized epilepsy may be due to confounding from time stable parental characteristics related to treatment with clomiphene citrate, since the association was strongest with the lowest administered dosage of clomiphene citrate prior to conception, and the association disappeared in a sibling analysis. WIDER IMPLICATIONS OF THE FINDINGS: The increased risk of focal epilepsy may be related to the hormonal treatment, since the association tended to increase with increasing cumulative dosage of clomiphene citrate prior to conception, and the association persisted in a sibling analysis. This finding may be of clinical importance, since alternative hormones are available for fertility treatment. STUDY FUNDING/COMPETING INTEREST(S): Financial support from Aarhus University and the Aase and Ejnar Danielsen Foundation. U.S.K. received personal teaching fees from Merck, outside the submitted work. TRIAL REGISTRATION NUMBER: N/A.

Developmental stage and morphology of the competent blastocyst are associated with sex of the child but not with other obstetric outcomes: a multicenter cohort study.

STUDY QUESTION: Are transfer day, developmental stage and morphology of the competent blastocyst in pregnancies leading to live birth associated with preterm birth, birthweight, length at birth and sex of the child? SUMMARY ANSWER: A high score in blastocyst developmental stage and in trophectoderm (TE) showed a significant association with the sex of the child, while no other associations with obstetric outcomes were observed. WHAT IS KNOWN ALREADY: The association between blastocyst assessment scores and obstetric outcomes have been reported in small single-center studies and the results are conflicting. STUDY DESIGN, SIZE, DURATION: Multicenter historical cohort study based on exposure data (transfer day (blastocyst developmental stage reached by Day 5 or Day 6)) blastocyst developmental stage (1-6) and morphology (TE and inner cell mass (ICM): A, B, C)) and outcome data (preterm birth, birthweight, length at birth, and sex of the child) from women undergoing single blastocyst transfer resulting in a singleton pregnancy and live birth. PARTICIPANTS/MATERIALS, SETTING, METHODS: Data from 16 private and university-based facilities for clinical services and research were used. A total of 7246 women, who in 2014-2018 underwent fresh-embryo transfer with a single blastocyst or frozen-thawed embryo transfer (FET) with a single blastocyst resulting in a singleton pregnancy were identified. Linking to the Danish Medical Birth Registry resulted in a total of 4842 women with a live birth being included. Cycles with pre-implantation genetic testing and donated gametes were excluded. The analyses were adjusted for female age (n = 4842), female BMI (n = 4302), female smoking (n = 4290), parity (n = 4365), infertility diagnosis (n = 4765), type of treatment (n = 4842) and center (n = 4842); some analyses additionally included gestational age (n = 4368) and sex of the child (n = 4833). MAIN RESULTS AND THE ROLE OF CHANCE: No statistically significant associations between blastocyst assessment scores (transfer day, developmental stage, TE, ICM) and preterm birth (8.3%) or birthweight (mean 3461.7 g) were found. The adjusted association between blastocysts with a TE score of C and a TE score of A and length at birth (mean 51.6 cm) were statistically significant (adjusted mean difference 0.4 cm (95% CI: 0.02; 0.77)). Blastocysts transferred with developmental stage score 5 compared to blastocysts transferred with score 3 had a 34% increased probability of being a boy (odds ratio (OR) 1.34 (95% CI: 1.09; 1.64). Further, TE score B blastocysts compared to TE score A blastocysts had a 31% reduced probability of being a boy (OR 0.69 (95% CI: 0.60; 0.80)). LIMITATIONS, REASONS FOR CAUTION: It is possible that some residual confounding remains. WIDER IMPLICATIONS OF THE FINDINGS: Blastocyst selection during ART does not appear to introduce any negative effects on obstetric outcome. Therefore, clinicians and patients can be reassured that the assessment scores of the selected blastocyst will not in themselves pose a risk of preterm birth or affect birthweight and the length at birth. STUDY FUNDING/COMPETING INTEREST(S): Unrestricted grant from Gedeon Richter Nordics AB, Sweden. None of the authors have any competing interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Early ovarian ageing: is a low number of oocytes harvested in young women associated with an earlier and increased risk of age-related diseases?

STUDY QUESTION: Do young women with early ovarian ageing (EOA), defined as unexplained, and repeatedly few oocytes harvested in ART have an increased risk of age-related events? SUMMARY ANSWER: At follow-up, women with idiopathic EOA had an increased risk of age-related events compared to women with normal ovarian ageing (NOA). WHAT IS KNOWN ALREADY: Early and premature menopause is associated with an increased risk of cardiovascular diseases (CVDs), osteoporosis and death. In young women, repeated harvest of few oocytes in well-stimulated ART cycles is a likely predictor of advanced menopausal age and may thus serve as an early marker of accelerated general ageing. STUDY DESIGN, SIZE, DURATION: A register-based national, historical cohort study. Young women (≤37 years) having their first ART treatment in a public or private fertility clinic during the period 1995-2014 were divided into two groups depending on ovarian reserve status: EOA (n = 1222) and NOA (n = 16 385). Several national registers were applied to assess morbidity and mortality. PARTICIPANTS/MATERIALS, SETTING, METHODS: EOA was defined as ≤5 oocytes harvested in a minimum of two FSH-stimulated cycles and NOA as ≥8 oocytes in at least one cycle. Cases with known causes influencing the ovarian reserve (endometriosis, ovarian surgery, polycystic ovary syndrome, chemotherapy etc.) were excluded. To investigate for early signs of ageing, primary outcome was an overall risk of ageing-related events, defined as a diagnosis of either CVD, osteoporosis, type 2 diabetes, cancer, cataract, Alzheimer's or Parkinson's disease, by death of any-cause as well as a Charlson comorbidity index score of ≥1 or by registration of early retirement benefit. Cox regression models were used to assess the risk of these events. Exposure status was defined 1 year after the first ART cycle to assure reliable classification, and time-to-event was measured from that time point. MAIN RESULTS AND THE ROLE OF CHANCE: Median follow-up time from baseline to first event was 4.9 years (10/90 percentile 0.7/11.8) and 6.4 years (1.1/13.3) in the EOA and NOA group, respectively. Women with EOA had an increased risk of ageing-related events when compared to women with a normal oocyte yield (adjusted hazard ratio 1.24, 95% CI 1.08 to 1.43). Stratifying on categories, the EOA group had a significantly increased risk for CVD (1.44, 1.19 to 1.75) and osteoporosis (2.45, 1.59 to 3.90). Charlson comorbidity index (1.15, 0.93 to 1.41) and early retirement benefit (1.21, 0.80 to 1.83) was also increased, although not reaching statistical significance. LIMITATIONS, REASONS FOR CAUTION: Cycles never reaching oocyte aspiration were left out of account in the inclusion process and we may therefore have missed women with the most severe forms of EOA. We had no information on the total doses of gonadotrophin administered in each cycle. WIDER IMPLICATIONS OF THE FINDINGS: These findings indicate that oocyte yield may serve as marker of later accelerated ageing when, unexpectedly, repeatedly few oocytes are harvested in young women. Counselling on life-style factors as a prophylactic effort against cardiovascular and other age-related diseases may be essential for this group of women. STUDY FUNDING/COMPETING INTEREST(S): No external funding was received for this study. All authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Low-to-moderate alcohol consumption and success in fertility treatment: a Danish cohort study.

STUDY QUESTION: Does female weekly alcohol intake and binge drinking impact the chance of a successful fertility treatment? SUMMARY ANSWER: Low-to-moderate weekly alcohol drinking and binge drinking were not associated with the chance of achieving a clinical pregnancy or a live birth among women and couples undergoing medically assisted reproduction (MAR) treatments. WHAT IS KNOWN ALREADY: Alcohol consumption is common among women of reproductive age, even though health authorities advise women trying to conceive to abstain from drinking. A growing number of couples struggle with infertility, but it is unknown whether low-to-moderate levels of alcohol consumption and alcohol binge drinking impair success in fertility treatment. STUDY DESIGN, SIZE, DURATION: Cohort study with prospectively collected exposure information including 1708 women and potential partners undergoing fertility treatment at the public fertility clinic, Aarhus University Hospital, 1 January 2010 to 31 August 2015. In total, data on 1511 intrauterine insemination (IUI) cycles, 2870 in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles and 1355 frozen embryo transfer cycles. PARTTICIPANTS/MATERIALS, SETTING, METHODS: Exposure to weekly average alcohol intake was assessed from questionnaires completed by participants before the start of treatment. Outcome measures are the achievement of a clinical pregnancy and live birth in consecutive treatment cycles in the Danish national health registries, enabling complete follow-up. A modified Poisson regression with robust standard errors was used to evaluate associations between a weekly average alcohol intake and MAR outcomes, adjusting for female age, body mass index, cigarette smoking, coffee consumption, chronic diseases, level of education, and cycle number. When evaluating the association between binge drinking in the month prior to baseline and MAR outcomes the analyses were further adjusted for average weekly alcohol consumption. MAIN RESULTS AND THE ROLE OF CHANCE: Low-to-moderate average weekly alcohol intake was not statistically significantly associated with the chance of achieving a clinical pregnancy or a live birth following IUI or IVF/ICSI treatment cycles. Compared to women abstaining from alcohol, the adjusted relative risks for achieving a live birth among those reporting 1-2, 3-7, and >7 drinks per week were 1.00 (95% CI 0.66; 1.53), 1.20 (0.76; 1.91), and 1.48 (0.56; 3.93), respectively, among women initiating IUI treatments. Among those initiating IVF/ICSI treatments, the chance for achieving a live birth among those reporting 1-2, 3-7, and >7 drinks per week were 1.00 (0.83; 1.21), 0.95 (0.75; 1.20), and 0.89 (0.53; 1.51), respectively. The chance of achieving a live birth in the first IUI or IVF/ICSI treatment cycle was unrelated to the number of binge drinking episodes in the month preceding baseline. LIMITATIONS, REASONS FOR CAUTION: The risk of non-differential exposure misclassification, confounding, or chance cannot be ruled out. In addition, due to the low number of women reporting an intake of >7 drinks/week, the potential effect of high alcohol consumption should be interpreted with caution. WIDER IMPLICATIONS OF THE FINDINGS: Although it remains unsettled if and how alcohol affects female reproduction, our results indicate that is not necessary to abstain from alcohol when striving for a successful outcome following fertility treatment. STUDY FUNDING/COMPETING INTEREST(S): J.L. is supported by a fully financed Ph.D. scholarship from Aarhus University and has received funds from the A.P. Møller foundation. The funding sources had no involvement in the conduct of the article. Dr Kesmodel reports personal fees from MSD and Ferring Pharmaceuticals outside the submitted work. All other authors have no conflicts of interest to declare and all have completed the ICMJE disclosure form. TRIAL REGISTRATION NUMBER: Not relevant.

Childhood growth of singletons conceived following in vitro fertilisation or intracytoplasmic sperm injection: a systematic review and meta-analysis.

BACKGROUND: Assisted reproductive techniques are associated with an increased risk of adverse pregnancy outcomes, including low birthweight and intrauterine growth restriction. Yet, the long-term follow-up on the growth of these children is limited. OBJECTIVE: To systematically review the literature on post-neonatal height and weight among children conceived following in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment, compared with that of children born after spontaneous conception. SEARCH STRATEGY: A systematic computerised literature search using the online databases PubMed, Embase, and Scopus. SELECTION CRITERIA: Cohort or case-control studies with an exposed group of singletons conceived following IVF or ICSI along with a control group of spontaneously conceived singletons. DATA COLLECTION AND ANALYSIS: Studies were reviewed by at least two authors. Meta-analyses were conducted using Cochrane Review Manager. The quality of the studies was assessed with the Newcastle-Ottawa Scale. MAIN RESULTS: Twenty studies were included, with 13 of these eligible for meta-analyses. The meta-analyses compared 3972 children born after IVF/ICSI with 11 012 spontaneously conceived children and revealed no statistically significant difference in child weight [mean difference (MD) in weight of -160 g; 95% confidence interval (95% CI) -360, 3]. When stratifying by age of child at follow-up, we found a significant lower weight in children aged 0-4 years conceived following IVF/ICSI treatment (MD -180 g; 95% CI -320, -4), but this was no longer significant in children from 5 years of age (MD -160 g; 95% CI -580, 260). The pooled analysis revealed no statistically significant difference in childhood height. CONCLUSIONS: In vitro fertilisation/ICSI was not associated with long-term weight and height. TWEETABLE ABSTRACT: Children born following IVF/ICSI do not have impaired long-term weight or height compared with spontaneously conceived children.

Risk of stillbirth in low-risk singleton term pregnancies following fertility treatment: a national cohort study.

OBJECTIVE: To assess the risk of stillbirth in low-risk in vitro fertilisation (IVF) pregnancies. DESIGN: Register-based national cohort study. SETTING: Denmark 2003-2013. POPULATION: Cohort of 425 732 singleton pregnancies including 10 235 conceived following IVF/intracytoplasmic sperm injection (ICSI), 4521 conceived following intrauterine insemination (IUI), and 410 976 spontaneously conceived. METHODS: Information on pregnancy, obstetrical risk factors, stillbirth, and fertility treatment was obtained from the Danish national health registers for all pregnancies after gestational week 21+6 . We estimated the overall and gestational age-specific risk of stillbirth in low-risk term pregnancies following IVF, ICSI, and IUI. Further, we estimated the association between stillbirth and IVF and ICSI respectively as well as fresh or frozen-thawed embryo transfer. MAIN OUTCOME MEASURES: Risk of stillbirth. RESULTS: The number of stillbirths in spontaneously conceived and IVF/ICSI low-risk term pregnancies was 525 (0.1%) and 35 (0.3%), respectively. In multivariate analysis, the risk of stillbirth in pregnancies following IVF/ICSI was increased (odds ratio 2.1, 95% CI 1.4-3.1). The risk of stillbirth was correspondingly increased in time-to-event analyses taking risk time for each fetus into account from gestational week 37 and onwards (hazard ratio 2.4, 95% CI 1.6-3.6). In sub-analyses, the risk of stillbirth was increased for pregnancies following ICSI (odds ratio 2.2, 95% CI 1.2-3.1), but not IVF (odds ratio 1.7, 95% CI 0.9-3.1). CONCLUSION: We found a systematically increased risk of stillbirth in low-risk term pregnancies following IVF/ICSI. Whether the risk was related to the treatment or to underlying subfertility is uncertain. The results may indicate a need for obstetrical surveillance for these pregnancies when reaching term. TWEETABLE ABSTRACT: Increased risk of stillbirth in low-risk term pregnancies following fresh cycle IVF/ICSI.

The impact of luteal serum progesterone levels on live birth rates-a prospective study of 602 IVF/ICSI cycles.

STUDY QUESTION: Is the chance of a live birth following IVF treatment and fresh embryo transfer affected by early and mid-luteal serum progesterone (P4) levels? SUMMARY ANSWER: Low as well as high serum P4 levels in the early and mid-luteal phase reduce the chance of a live birth following IVF treatment with fresh embryo transfer. WHAT IS KNOWN ALREADY: Data from non-human studies and studies of frozen-thawed embryo transfer cycles indicate that low as well as high P4 levels during the mid-luteal phase decrease the chance of pregnancy. The altered P4 pattern may disrupt the endometrial maturation leading to asynchrony between embryonic development and endometrial receptivity, thereby, compromising implantation and early development of pregnancy. STUDY DESIGN, SIZE, DURATION: Prospective multicenter cohort study of 602 women undergoing IVF treatment. Patients were recruited from four Danish public Fertility Centers from May 2014 to June 2017. The study population was unselected, thus, representing a normal everyday patient cohort. Patients were treated in a long GnRH-agonist protocol or a GnRH-antagonist protocol and triggered for final oocyte maturation with either hCG or a GnRH-agonist. The same vaginal luteal support regimen was applied in all patients. PARTICIPANTS/MATERIALS, SETTING, METHODS: Serum P4 levels from the early or mid-luteal phase were correlated to positive hCG and live birth rates (delivery > gestational week 20). Patients were divided into four P4 groups based on raw data of P4 serum levels and reproductive outcomes during early luteal phase (P4<60 nmol/l, P4 60-100 nmol/l, P4 101-400 nmol/l and P4>400 nmol/l) and during mid-luteal phase (P4<150 nmol/l, P4 150-250 nmol/l, P4 251-400 nmol/l and P4>400 nmol/l). MAIN RESULTS AND THE ROLE OF CHANCE: The optimal chance of pregnancy was achieved with serum P4 levels of 60-100 nmol/l in the early luteal phase whereas the optimal P4 level during the mid-luteal phase was 150-250 nmol/l. Below, but most distinctly above these levels, the chance of pregnancy was consistently reduced. With an early luteal P4 level of 60-100 nmol/l, the chance of a positive hCG-test was 73%, 95% CI: [59, 84] following cleavage stage embryo transfer. In contrast, with P4 levels >400 nmol/l, the chance of a positive hCG-test was significantly reduced to 35%, 95% CI: [17, 57], thus, an absolute risk difference of -38%, P = 0.01. A similar negative association between early luteal P4 and live birth rate was found, although it did not reach statistical significance. During the mid-luteal phase, a P4 level of 150-250 nmol/l resulted in an optimal chance of live birth: 54%, 95% CI: [37, 70] compared to 38%, 95% CI: [20, 60] with a P4 level >400 nmol/l, thus, an absolute risk difference of -16%, P = 0.14. All estimates were adjusted for maternal age, maternal BMI, study site, final follicle count and late follicular P4 levels. LIMITATIONS, REASONS FOR CAUTION: This study is the first to explore the possible upper and lower thresholds for luteal P4 following IVF treatment and fresh embryo transfer, and the optimal P4 ranges found in this study should be corroborated in future clinical trials. Furthermore, the P4 thresholds in this study only apply to fresh IVF cycles, using vaginal luteal phase support, as the optimal P4 level in cycles using intramuscular P4 may be different. WIDER IMPLICATIONS OF THE FINDINGS: Future studies are necessary to explore whether additional exogenous luteal P4 supplementation in the low P4 group could increase the chance of a live birth following fresh embryo transfer, and whether patients with luteal P4 levels >400 nmol/l would benefit from segmentation followed by subsequent transfer in frozen/thawed cycles. TRIAL REGISTRATION NUMBER: NCT02129998 (Clinicaltrials.gov). STUDY FUNDING/COMPETING INTEREST(S): L.H.T. received an unrestricted grant from Ferring Pharmaceuticals, Denmark, to support this study. P.H. received unrestricted research grants from MSD, Merck, Gedeon Richter and Ferring Pharmaceuticals outside of this work as well as honoraria for lectures from MSD, Merck and Gedeon Richter outside of this work. U.K. received honoraria for lectures from MSD and Ferring Pharmaceuticals outside of this work. C.A. received unrestricted research grants from MSD, IBSA, and Ferring Pharmaceuticals outside of this work as well as honoraria for lectures from MSD and IBSA. H.O.E. and B.B.P. received an unrestricted research grant from Gedeon Richter outside of this work. K.E., L.B., D.P. and B.H. have no conflict of interest. Furthermore, grants from 'The Health Research Fund of Central Denmark Region', 'The Research Foundation of the Hospital of Central Jutland', 'The Research Foundation of A.P. Møller', 'The Research Foundation of Aase & Ejnar Danielsen', 'The Research Foundation of Dagmar Marshall', 'The Research Foundation of Dir. Jacob Madsen & Hustru Olga Madsen', 'The Research Foundation of Fam. Hede Nielsen' and 'The Danish Medical Research Grant' supported conducting this study. The providers of funding were neither involved in the conduction of the study nor in the writing of the scientific report.

Bowel Endometriosis Syndrome: a new scoring system for pelvic organ dysfunction and quality of life.

STUDY QUESTION: Is it possible to develop a validated score that can identify women with Bowel Endometriosis Syndrome (BENS) and be used to monitor the effect of medical and surgical treatment? SUMMARY ANSWER: The BENS score can be used to identify women with BENS and to monitor the effect of medical and surgical treatment of women suffering from bowel endometriosis. WHAT IS KNOWN ALREADY: Endometriosis is a heterogeneous disease with extensive variation in anatomical and clinical presentation, and symptoms do not always correspond to the disease burden. Current endometriosis scoring systems are mainly based on anatomical and surgical findings. STUDY DESIGN, SIZE, DURATION: The score was developed and validated from a cohort of 525 women with medically or surgically treated bowel endometriosis from Aarhus and Copenhagen University Hospitals, Denmark. PARTICIPANTS/MATERIALS, SETTING AND METHODS: Patients filled in questionnaires on pelvic pain, quality of life (QoL) and urinary, sexual and bowel function. Items were selected for the final score using clinical and statistical criteria. The chosen variables were included in a multivariate analysis. Individual score values were designated items to form the BENS score, which was divided into 'no BENS', 'minor BENS' and 'major BENS.' Internal and external validations were performed. MAIN RESULTS AND THE ROLE OF CHANCE: The six most important items were 'pelvic pain', 'use of analgesics', 'dyschezia', 'straining to urinate', 'fecal urgency' and 'satisfaction with sexual life'. The range of the BENS score (0-28) was divided into 0-8 (no BENS), 9-16 (minor BENS) and 17-28 (major BENS). External validation showed a significant association between BENS score and QoL (P = 0.0001). LIMITATIONS, REASONS FOR CAUTION: The BENS scoring system is limited by the fact that it was developed from a single endometriosis unit in Denmark, making it susceptible to social, cultural and demographic bias. WIDER IMPLICATIONS OF THE FINDINGS: It is the first endometriosis classification system to be based directly on the symptomatology of the patient. Validation in other languages will promote comparison of treatments and results across borders. STUDY FUNDING/COMPETING INTEREST(S): No external funding was either sought or obtained for this study. A.F. is an investigator for Bayer, outside this work.

Pelvic organ function before and after laparoscopic bowel resection for rectosigmoid endometriosis: a prospective, observational study.

OBJECTIVE: To assess urinary, sexual, and bowel function before and after laparoscopic bowel resection for rectosigmoid endometriosis. DESIGN: Prospectively collected data regarding the function of the pelvic organs. SETTING: Tertiary endometriosis referral unit, Aarhus University Hospital. SAMPLE: A cohort of 128 patients who underwent laparoscopic bowel resection for endometriosis. METHODS: The International Consultation on Incontinence Questionnaire (ICIQ), Sexual Function-Vaginal Changes Questionnaire (SVQ), and the Low Anterior Resection Syndrome (LARS) questionnaire were answered before and after surgery. Non-invasive urodynamic testing was performed. MAIN OUTCOME MEASURES: Pre- and postoperative function of the pelvic organs was compared, and risk factors for improved/impaired function were identified. RESULTS: A total of 96.1% of the women completed the 1-year follow-up. A significant decrease (P = 0.002) in bladder filling problems (F-score) was observed 1 year after surgery, primarily caused by a significant decrease in bladder pain (P = 0.0001). No change for urodynamic parameters was observed. A significant increase in overall sexual satisfaction (P = 0.0001) and decrease in worries about sexual life (P = 0.001) was seen 1 year after surgery. Frequency of defecation was significantly increased 1 year after surgery (P = 0.0001), but the overall bowel function measured by LARS score was unchanged. Patients with anastomotic leakage had a significantly higher risk (odds ratio, OR 5.40; P = 0.002) of increased incontinence problems (I-score) 1 year after surgery. CONCLUSION: A significant and clinically relevant improvement in urinary and sexual function 1 year after laparoscopic bowel resection for endometriosis was found. Except for anastomotic leakage, this could be observed independent of any patient- or treatment-related factor. Apprehension about impairment of urinary and sexual function should not be a contraindication for bowel resection in endometriosis patients. TWEETABLE ABSTRACT: Rectal resection for endometriosis does not impair urinary and sexual function 1 year after surgery.

Maternal stress before and during pregnancy and subsequent infertility in daughters: a nationwide population-based cohort study.

STUDY QUESTION: Is maternal stress following the death of a close relative before or during pregnancy associated with the risk of infertility in daughters? SUMMARY ANSWER: Compared with unexposed women, women whose mothers had experienced bereavement stress during, or in the year before, pregnancy had a similar risk of infertility overall, but those exposed to maternal bereavement during the first trimester had a higher risk of infertility. WHAT IS KNOWN ALREADY: Animal studies have shown that prenatal maternal stress results in reduced offspring fertility. In humans, there is evidence that girls who have been prenatally exposed to stress have a more masculine behaviour and a slight delay in having their first child. STUDY DESIGN, SIZE AND DURATION: This population-based cohort study, included 660 099 females born in Denmark between 1 January 1973 and 31 December 1993 to mothers of Danish origin and with at least one living relative in the exposure window, and followed the women through 31 December 2011. PARTICIPANTS/MATERIALS, SETTING, METHODS: Overall, 13 334 women (2.0%) were considered prenatally exposed to stress because their mother had lost a spouse/partner, a child, a parent, or a sibling during pregnancy or in the year before conception. Infertility was defined as any record of infertility treatment or diagnosis of female infertility. We considered the date of onset as the date of the first appearance of any such record. The association between exposure and outcome was examined using hazard ratios (HR) with 95% confidence intervals (CI). MAIN RESULTS AND THE ROLE OF CHANCE: Based on our definition, 40 052 (6.5%) women were infertile in the follow-up period (median age at the end of follow-up: 26.7 years, maximum age: 39 years). Overall, prenatal exposure to maternal stress was not associated with risk of infertility (adjusted HR = 1.04 [CI: 0.95-1.14]). However, women prenatally exposed during the first trimester had a higher estimated risk (adjusted HR = 1.40 [CI: 1.05-1.86]). These findings were consistent in subgroups defined by the relationship of the mother to the deceased and in several sensitivity analyses, including a sibling-matched analysis, and in analyses restricted to women who were married or cohabitating with a man, or to women born at term. LIMITATIONS, REASONS FOR CAUTION: We did not have a direct measure of stress, but bereavement due to death of a close relative is likely to be very stressful. We based the timing of exposure on the date of the death of the family member, although the stress may well have started earlier. Infertility was also defined indirectly, and many women in the cohort were too young at the end of the follow-up to have been diagnosed. However, misclassification of the outcome was most likely non-differential, and the similar results from all sensitivity analyses suggest that it is unlikely that the effect observed in first trimester exposure would be due to chance. WIDER IMPLICATIONS OF THE FINDINGS: Prenatal exposure to maternal stress in the first trimester may affect the later fecundity of daughters. STUDY FUNDING/COMPETING INTERESTS: This study was supported by a grant from the European Research Council (ERC-2010-StG-260242-PROGEURO) to the ProgEuro project (http://progeuro.au.dk). O.P.-R. is partly supported by a fellowship from Aarhus University and a travel grant from Oticon Fonden. The authors report no conflict of interests.

The association of pre-pregnancy alcohol drinking with child neuropsychological functioning.

OBJECTIVE: To examine the effects of pre-pregnancy alcohol drinking on child neuropsychological functioning. DESIGN: Prospective follow-up study. SETTING AND POPULATION: 154 women and their children sampled from the Danish National Birth Cohort. METHODS: Participants were sampled based on maternal alcohol consumption before pregnancy. At 5 years of age, the children were tested with the Wechsler Preschool and Primary Scale of Intelligence-Revised, the Test of Everyday Attention for Children at Five (TEACh-5), and the Movement Assessment Battery for Children (MABC). The Behaviour Rating Inventory of Executive Function (BRIEF) was completed by the mothers and a preschool teacher. Parental education, maternal IQ, prenatal maternal smoking, child's age at testing, child's sex, and maternal alcohol intake during pregnancy were considered potential confounders. MAIN OUTCOME MEASURES: Performance on the Wechsler Preschool and Primary Scale of Intelligence-Revised, the TEACh-5, the MABC, and the BRIEF. RESULTS: Intake of 15-21 drinks/week on average prior to pregnancy was not associated with any of the outcomes, but intake of ≥22 drinks/week on average was associated with a significantly lower adjusted mean full scale IQ and lower adjusted means in overall attention and sustained attention score, but not in selective attention score or any of the BRIEF index scores or MABC scores. CONCLUSIONS: Intake of ≥22 drinks/week before pregnancy was associated with lower mean full scale IQ, overall attention and sustained attention. Assessment of pre-pregnancy drinking provides additional information regarding potential prenatal alcohol exposure and its implications for child neurodevelopment.

Fertility treatment and child intelligence, attention, and executive functions in 5-year-old singletons: a cohort study.

OBJECTIVE: To assess the association of fertility treatment and subfertility with offspring intelligence, attention, and executive functions in 5-year-old singletons. DESIGN: Follow-up study. SETTING: Denmark 2003-2008. POPULATION: A cohort of 1782 children sampled from the Danish National Birth Cohort. METHODS: The children were tested with a neuropsychological battery at age five. In addition to tests of intelligence, attention and executive functions, the follow up included extensive information on important covariates. The analyses were conducted using multiple linear regression and adjusted for parental educational level, maternal intelligence, age, parity, body mass index, smoking in pregnancy, alcohol consumption in pregnancy and child gender, child age, and examiner. MAIN OUTCOME MEASURES: Wechsler Preschool and Primary Scale of Intelligence-Revised, the Test of Everyday Attention for Children at Five, and the Behavior Rating Inventory of Executive Functions scores. RESULTS: A consistent pattern of nonsignificantly lower scores were only observed for intelligence and executive functions in children born after fertility treatment or by subfertile parents when the results were unadjusted for maternal intelligence and parental educational level. When adjusted for these and other covariates, there were no significant mean differences in intelligence (mean difference -2.8, 95% CI -7.8, 2.2), overall attention (-0.1, 95% CI -0.6, 0.3), or parent-rated executive functions (-0.1, 95% CI -3.0, 2.9) between children born after spontaneous conception and children born to parents conceiving after fertility treatment. Similarly, there were no significant mean differences in intelligence (mean difference 0.6, 95% CI -2.2, 3.4), overall attention (0.1, 95% CI -0.2, 0.4), or parent-rated executive functions (1.0, 95% CI -1.8, 3.7) between children born after spontaneous conception and children born to subfertile parents waiting more than 12 months before conceiving naturally. CONCLUSIONS: This study suggests that parental subfertility and fertility treatment are unrelated to offspring intelligence, attention and executive functions.

Increased venous thrombosis incidence in pregnancies after in vitro fertilization.

STUDY QUESTION: Is venous thrombosis risk increased in pregnancies after in vitro fertilization? SUMMARY ANSWER: The venous thrombosis incidence was significantly increased in pregnancies after in vitro fertilization; especially in the first trimester and in the first 6 weeks post-partum. WHAT IS KNOWN ALREADY: In vitro fertilization without pregnancy is not associated with increased venous thrombosis incidence. STUDY DESIGN, SIZE, DURATION: This national register-based cohort study covered the period from 1995 to 2005. PARTICIPANTS/MATERIALS, SETTING, METHODS: All Danish pregnancies conceived by in vitro fertilization (n = 18 787) were included. Venous thrombosis incidence rates in pregnancies after in vitro fertilization were compared with venous thrombosis incidence rates in reference pregnancies, by calculating incidence rate ratios. MAIN RESULTS AND THE ROLE OF CHANCE: In total, 48 cases were identified. In pregnancies after in vitro fertilization, the overall venous thrombosis incidence rate was 28.6 per 10 000 pregnancy-years (95% confidence interval (CI) 20.6-39.6) in comparison to 10.7 per 10 000 woman-years in reference pregnancies. Post-partum, the venous thrombosis incidence rate was 27.9 per 10 000 woman-years (95% CI 15.8-49.1) after in vitro fertilization in comparison to 17.5 per 10 000 woman-years in reference pregnancies. The overall venous thrombosis incidence rate ratio during in vitro fertilization (IVF) pregnancies compared with reference pregnancies was 3.0 (95% CI 2.1-4.3). The venous thrombosis incidence rate ratios during pregnancy were 2.8 (95% CI 1.9-4.1) in singleton IVF pregnancies and 4.4 (95% CI 2.4-8.3) in multiple IVF pregnancies, compared with reference pregnancies. The venous thrombosis incidence rate ratio post-partum was 1.2 (95% CI 0.6-2.8) for singleton IVF pregnancies and 3.9 (95% CI 1.7-8.8) for multiple IVF pregnancies compared with reference pregnancies. The post-partum venous thrombosis risk was higher in multiple IVF pregnancies compared with singleton IVF pregnancies. Maternal age, smoking and parity did not significantly affect the venous thrombosis risk. Ovarian hyperstimulation syndrome and polycystic ovarian syndrome did increase the risk of venous thrombosis during pregnancy. Caesarean section also increased the post-partum venous thromboembolism risk, but the increase was not significant. LIMITATIONS, REASONS FOR CAUTION: Other known confounders in our reference population could have contributed to the results. Access to such data may have helped to explain the observations, but would not have changed the conclusion that IVF pregnancies have an increased risk of venous thrombosis compared with other pregnancies. WIDER IMPLICATIONS OF THE FINDINGS: Our study adds new insights by demonstrating an excess venous thrombosis incidence post-partum after in vitro fertilization. The high venous thrombosis incidence in first trimester after in vitro fertilization supports previous studies. Our findings are generalizable to other Western Countries. STUDY FUNDING/COMPETING INTERESTS: Expenses for the acquirement of data were covered by a grant from The Secretary of Doctors further education, Central Denmark Region. None of the authors have any competing interests to declare. TRIAL REGISTRATIONS NUMBER: Not applicable.