Exposure to second-hand smoke and breast cancer risk in non-smoking women: a comprehensive systematic review and meta-analysis.

Through the use of an innovative method to identify original publications, we conducted a meta-analysis of all epidemiological studies evaluating the association between second-hand smoke (SHS) exposure and breast cancer risk among female non-smokers published in English up to October 2022. Pooled relative risks (RR) were obtained through the use of random-effects models. Dose-response relationships were derived using log-linear functions. Out of 73 identified eligible studies, 63 original articles were included in the meta-analysis. The pooled RR for breast cancer for overall exposure to SHS was 1.24 (95% confidence interval, CI, 1.15-1.34, number of articles, n = 52). Regarding the setting of exposure, RRs were 1.17 (95% CI 1.08-1.27, n = 37) for SHS exposure at home, 1.03 (95% CI 0.98-1.08, n = 15) at the workplace, 1.24 (95% CI 1.11-1.37, n = 16) at home or workplace, and 1.45 (95% CI 1.16-1.80, n = 13) for non-specified settings. The risk of breast cancer increased linearly with higher duration (RR 1.29; 95% CI 1.04-1.59 for 40 years of SHS exposure, n = 12), intensity (RR 1.38; 95% CI 1.14-1.67 for 20 cigarettes of SHS exposure per day, n = 6), and pack-years (RR 1.50; 95% CI 0.92-2.45 for 40 SHS pack-years, n = 6) of SHS exposure. This meta-analysis shows a statistically significant excess risk of breast cancer in women exposed to SHS.

Pregnancy rate and time to pregnancy after recurrent implantation failure (RIF)-a prospective cohort follow-up study.

PURPOSE: The goal of this study was to determine ongoing pregnancy rate, time to pregnancy and embryo transfers to pregnancy within a cohort of patients with recurrent implantation failure (RIF). METHODS: IVF patients with RIF were included after referral to the RIF outpatient clinic. They received a questionnaire 1 year after inclusion. If data was missing, medical files were examined to determine pregnancy outcomes and conception methods. The ability of the RIF outpatient clinic to improve pregnancy chance or increase the number of patients who elected to continue treatment was beyond the scope of this study. RESULTS: The cumulative incidence of ongoing pregnancy in IVF patients with RIF (n = 79) after 1 year of follow-up was 40.5% (95% confidence interval = 30.4-51.5%). Median time to pregnancy was 4 months. Pregnancy incidence increased gradually up to 5 embryo transfers (mostly single embryo transfers). The average embryo transfers to pregnancy were 7.3 transfers. CONCLUSION: In IVF patients with RIF, up until the 5th embryo transfer, each transfer represents a good opportunity for ongoing pregnancy. This data can be used to counsel patients that regular treatment continuation seems to be well justified even when IVF patients fulfil the RIF criteria. TRIAL REGISTRATION: CCMO: NL66835.068.18. METC 18-040. OMON: NL-OMON24778.

Counseling pregnant women on calcium: effects on calcium intake.

OBJECTIVES: To evaluate the effect of incorporating calcium advice into early pregnancy counseling on calcium intake during pregnancy in the Netherlands. METHODS: A multicenter prospective before-after cohort study was conducted introducing risk-based care including calculating individual pre-eclampsia risk. Part of the intervention was to incorporate calcium advice into routine counseling. We calculated individual daily calcium intake and adequacy of calcium intake (≥1,000 mg/day) at 16, 24 and 34 weeks of pregnancy. We performed a multiple logistic regression adjusting for covariates to identify any differences in the risk of inadequate calcium intake between RC and CAC. RESULTS: In regular care (RC, 2013-2015, n=2,477) 60% had inadequate calcium intake, compared to 49% during calcium advice care (CAC, 2017-2018, n=774) (aOR 0.75, 95% CI 0.64-0.88). Specific calcium supplements were used by 2% and 29% in RC and CAC, respectively (OR 25.1, 95% CI 17.8-36.0). Determinants of an inadequate calcium intake were lower age (aOR per additional year 0.96, 95% CI: 0.94-0.98), nulliparity (aOR 1.22, 95% CI: 1.03-1.45) and non-Caucasian origin (aOR 1.83, 95% CI 1.09-3.09). In CAC, risk of inadequate intake decreased with increasing predicted pre-eclampsia risk, which was a trend reversal compared to RC. CONCLUSIONS: Incorporating calcium advice into early pregnancy counseling was shown to lead to a decrease in the risk of inadequate calcium intake during pregnancy, but still inadequate intake in half of the women suggesting the need for further study on improving implementation. Awareness of individual increased PE risk had positive effect on calcium intake.

Nationwide implementation of a decision aid on vaginal birth after cesarean: a before and after cohort study.

OBJECTIVES: Woman with a history of a previous cesarean section (CS) can choose between an elective repeat CS (ERCS) and a trial of labor (TOL), which can end in a vaginal birth after cesarean (VBAC) or an unplanned CS. Guidelines describe women's rights to make an informed decision between an ERCS or a TOL. However, the rates of TOL and vaginal birth after CS varies greatly between and within countries. The objective of this study is to asses nation-wide implementation of counselling with a decision aid (DA) including a prediction model, on intended delivery compared to care as usual. We hypothesize that this may result in a reduction in practice variation without an increase in cesarean rates or complications. METHODS: In a multicenter controlled before and after cohort study we evaluate the effect of nation-wide implementation of a DA. Practice variation was defined as the standard deviation (SD) of TOL percentages. RESULTS: A total of 27 hospitals and 1,364 women were included. A significant decrease was found in practice variation (SD TOL rates: 0.17 control group vs. 0.10 intervention group following decision aid implementation, p=0.011). There was no significant difference in the ERCS rate or overall CS rates. A 21% reduction in the combined maternal and perinatal adverse outcomes was seen. CONCLUSIONS: Nationwide implementation of the DA showed a significant reduction in practice variation without an increase in the rate of cesarean section or complications, suggesting an improvement in equality of care.

External validation of a prediction model on vaginal birth after caesarean in a The Netherlands: a prospective cohort study.

OBJECTIVES: Discussing the individual probability of a successful vaginal birth after caesarean (VBAC) can support decision making. The aim of this study is to externally validate a prediction model for the probability of a VBAC in a Dutch population. METHODS: In this prospective cohort study in 12 Dutch hospitals, 586 women intending VBAC were included. Inclusion criteria were singleton pregnancies with a cephalic foetal presentation, delivery after 37 weeks and one previous caesarean section (CS) and preference for intending VBAC. The studied prediction model included six predictors: pre-pregnancy body mass index, previous vaginal delivery, previous CS because of non-progressive labour, Caucasian ethnicity, induction of current labour, and estimated foetal weight ≥90th percentile. The discriminative and predictive performance of the model was assessed using receiver operating characteristic curve analysis and calibration plots. RESULTS: The area under the curve was 0.73 (CI 0.69-0.78). The average predicted probability of a VBAC according to the prediction model was 70.3% (range 33-92%). The actual VBAC rate was 71.7%. The calibration plot shows some overestimation for low probabilities of VBAC and an underestimation of high probabilities. CONCLUSIONS: The prediction model showed good performance and was externally validated in a Dutch population. Hence it can be implemented as part of counselling for mode of delivery in women choosing between intended VBAC or planned CS after previous CS.

External validation of prognostic models predicting pre-eclampsia: individual participant data meta-analysis.

BACKGROUND: Pre-eclampsia is a leading cause of maternal and perinatal mortality and morbidity. Early identification of women at risk during pregnancy is required to plan management. Although there are many published prediction models for pre-eclampsia, few have been validated in external data. Our objective was to externally validate published prediction models for pre-eclampsia using individual participant data (IPD) from UK studies, to evaluate whether any of the models can accurately predict the condition when used within the UK healthcare setting. METHODS: IPD from 11 UK cohort studies (217,415 pregnant women) within the International Prediction of Pregnancy Complications (IPPIC) pre-eclampsia network contributed to external validation of published prediction models, identified by systematic review. Cohorts that measured all predictor variables in at least one of the identified models and reported pre-eclampsia as an outcome were included for validation. We reported the model predictive performance as discrimination (C-statistic), calibration (calibration plots, calibration slope, calibration-in-the-large), and net benefit. Performance measures were estimated separately in each available study and then, where possible, combined across studies in a random-effects meta-analysis. RESULTS: Of 131 published models, 67 provided the full model equation and 24 could be validated in 11 UK cohorts. Most of the models showed modest discrimination with summary C-statistics between 0.6 and 0.7. The calibration of the predicted compared to observed risk was generally poor for most models with observed calibration slopes less than 1, indicating that predictions were generally too extreme, although confidence intervals were wide. There was large between-study heterogeneity in each model's calibration-in-the-large, suggesting poor calibration of the predicted overall risk across populations. In a subset of models, the net benefit of using the models to inform clinical decisions appeared small and limited to probability thresholds between 5 and 7%. CONCLUSIONS: The evaluated models had modest predictive performance, with key limitations such as poor calibration (likely due to overfitting in the original development datasets), substantial heterogeneity, and small net benefit across settings. The evidence to support the use of these prediction models for pre-eclampsia in clinical decision-making is limited. Any models that we could not validate should be examined in terms of their predictive performance, net benefit, and heterogeneity across multiple UK settings before consideration for use in practice. TRIAL REGISTRATION: PROSPERO ID: CRD42015029349 .

Impact on perinatal health and cost-effectiveness of risk-based care in obstetrics: a before-after study.

BACKGROUND: Obstetric health care relies on an adequate antepartum risk selection. Most guidelines used for risk stratification, however, do not assess absolute risks. In 2017, a prediction tool was implemented in a Dutch region. This tool combines first trimester prediction models with obstetric care paths tailored to the individual risk profile, enabling risk-based care. OBJECTIVE: To assess impact and cost-effectiveness of risk-based care compared to care-as-usual in a general population. METHODS: A before-after study was conducted using 2 multicenter prospective cohorts. The first cohort (2013-2015) received care-as-usual; the second cohort (2017-2018) received risk-based care. Health outcomes were (1) a composite of adverse perinatal outcomes and (2) maternal quality-adjusted life-years. Costs were estimated using a health care perspective from conception to 6 weeks after the due date. Mean costs per woman, cost differences between the 2 groups, and incremental cost effectiveness ratios were calculated. Sensitivity analyses were performed to evaluate the robustness of the findings. RESULTS: In total 3425 women were included. In nulliparous women there was a significant reduction of perinatal adverse outcomes among the risk-based care group (adjusted odds ratio, 0.56; 95% confidence interval, 0.32-0.94), but not in multiparous women. Mean costs per pregnant woman were significantly lower for risk-based care (mean difference, -€2766; 95% confidence interval, -€3700 to -€1825). No differences in maternal quality of life, adjusted for baseline health, were observed. CONCLUSION: In the Netherlands, risk-based care in nulliparous women was associated with improved perinatal outcomes as compared to care-as-usual. Furthermore, risk-based care was cost-effective compared to care-as-usual and resulted in lower health care costs.

Calcium intake from diet and supplement use during early pregnancy: the Expect study I.

PURPOSE: Adequate calcium intake during pregnancy is of major importance for the health of both mother and fetus. Up to date, evidence on the prevalence of inadequate calcium intake among pregnant women is sparse for Western countries, and it is unknown to what extent inadequate dietary calcium intake is adequately balanced by supplement use. The objective of this study was to estimate calcium intake from diet and supplement use during the early pregnancy in The Netherlands. METHODS: As part of the Expect cohort study, 2477 pregnant women (8-16 weeks of gestation) completed an online questionnaire including questions on baseline characteristics, the use of calcium containing supplements, and a short food-frequency questionnaire (FFQ). Intake data were used to calculate median calcium intakes from diet, from supplements, and combined, and to compare these values with currently accepted requirement levels. RESULTS: Forty-two percent of the pregnant women had a total calcium intake below the estimated average requirement of 800 mg/day. Median (interquartile range) calcium intake was 886 (611-1213) mg/day. Calcium or multivitamin supplements were used by 64.8% of the women at 8 weeks of gestation, with a median calcium content of 120.0 (60.0-200.0) mg/day. Prenatal vitamins were the most often used supplements (60.6%). CONCLUSIONS: Forty-two percent of Dutch pregnant women have an inadequate calcium intake. Supplements are frequently used, but most do not contain sufficient amounts to correct this inadequate intake.

Study protocol for the randomized controlled EVA (early vascular adjustments) trial: tailored treatment of mild hypertension in pregnancy to prevent severe hypertension and preeclampsia.

BACKGROUND: In contrast to severe gestational hypertension, it is questioned whether antihypertensive medication for mild to moderate gestational hypertension prevents adverse maternal and offspring outcomes. Hypertensive drugs halve the risk of severe hypertension, but do not seem to prevent progression to preeclampsia or reduce the risk of complications in offspring. In fact, beta-blockers, a first line therapy option, are suspected to impair foetal growth. Disappointing effects of antihypertensive medication can be anticipated when the pharmacological mode of action does not match the underlying haemodynamic imbalance. Hypertension may result from 1) high cardiac output, low vascular resistance state, in which beta blockade is expected to be most effective, or 2) low cardiac output, high vascular resistance state where dihydropyridine calcium channel blockers or central-acting alpha agonists might be the best corrective medication. In the latter, beta-blockade might be maternally ineffective and even contribute to impaired foetal growth by keeping cardiac output low. We propose a randomized controlled trial to determine whether correcting the haemodynamic imbalance in women with mild to moderate hypertension reduces the development of severe hypertension and/or preeclampsia more than non-pharmacological treatment does, without alleged negative effects on foetal growth. METHODS: Women diagnosed with mild to moderate hypertension without proteinuria or signs of other organ damage before 37 weeks of pregnancy are invited to participate in this randomized controlled trial. Women randomized to the intervention group will be prescribed tailored antihypertensive medication, using a simple diagnostic and treatment algorithm based on the mean arterial pressure/heart rate ratio, which serves as an easy-to-determine proxy for maternal circulatory state. Women randomized to the control group will receive non-pharmacological standard care according to national and international guidelines. In total, 208 women will be randomized in a 1:1 ratio. The primary outcome is progression to severe hypertension and preeclampsia and the secondary outcomes are adverse maternal and neonatal outcomes. DISCUSSION: This trial will provide evidence of whether tailoring treatment of mild to moderate gestational hypertension to the individual haemodynamic profile prevents maternal disease progression. TRIAL REGISTRATION: NCT02531490 , registered on 24 August 2015.

Low-dose-aspirin usage among women with an increased preeclampsia risk: A prospective cohort study.

INTRODUCTION: Low-dose aspirin (LDA) prophylaxis has been shown to reduce women's preeclampsia risk. Evidence regarding LDA adherence rates of pregnant women is based almost exclusively on clinical trials, giving a potentially biased picture. Moreover, these studies do not report on determinants of adherence. Since 2017, obstetric healthcare professionals in a Dutch region have assessed women's preeclampsia risk by means of a prediction tool and counseled those with an above-population average risk on LDA as a prophylactic measure. MATERIAL AND METHODS: From 2017 to 2018, 865 women were recruited in multiple centers and prospectively followed using web-based surveys (Expect Study II). Rates and determinants of LDA usage among women with an increased preeclampsia risk in daily practice were assessed. Results were compared with findings in a similar cohort from a care-as-usual setting lacking risk-based counseling (Expect Study I, n = 2614). Netherlands Trial Register NTR4143. RESULTS: In total, 306 women had a predicted increased preeclampsia risk. LDA usage was higher for women receiving risk-based care than care-as-usual (29.4% vs 1.5%, odds ratio 19.1, 95% confidence interval 11.2-32.5). Daily LDA usage was positively correlated with both predicted risk and women's concerns regarding preeclampsia. Most reported reasons for non- or incomplete use were unawareness of LDA as a preventive intervention, concerns about potential adverse effects and doubts regarding the benefits. CONCLUSIONS: Risk-based counseling was associated with a higher prevalence of LDA usage, but general usage rates were low. Future research regarding potential factors improving the usage of LDA during pregnancy is necessary.

CCT: continuous care trial - a randomized controlled trial of the provision of continuous care during labor by maternity care assistants in the Netherlands.

BACKGROUND: In 2009, the Steering Committee for Pregnancy and Childbirth in the Netherlands recommended the implementation of continuous care during labor in order to improve perinatal outcomes. However, in current care, routine maternity caregivers are unable to provide this type of care, resulting in an implementation rate of less than 30%. Maternity care assistants (MCAs), who already play a nursing role in low risk births in the second stage of labor and in homecare during the postnatal period, might be able to fill this gap. In this study, we aim to explore the (cost) effectiveness of adding MCAs to routine first- and second-line maternity care, with the idea that these MCAs would offer continuous care to women during labor. METHODS: A randomized controlled trial (RCT) will be performed comparing continuous care (CC) with care-as-usual (CAU). All women intending to have a vaginal birth, who have an understanding of the Dutch language and are > 18 years of age, will be eligible for inclusion. The intervention consists of the provision of continuous care by a trained MCA from the moment the supervising maternity caregiver establishes that labor has started. The primary outcome will be use of epidural analgesia (EA). Our secondary outcomes will be referrals from primary care to secondary care, caesarean delivery, instrumental delivery, adverse outcomes associated with epidural (fever, augmentation of labor, prolonged labor, postpartum hemorrhage, duration of postpartum stay in hospital for mother and/or newborn), women's satisfaction with the birth experience, cost-effectiveness, and a budget impact analysis. Cost effectiveness will be calculated by QALY per prevented EA based on the utility index from the EQ-5D and the usage of healthcare services. A standardized sensitivity analysis will be carried out to quantify the outcome in addition to a budget impact analysis. In order to show a reduction from 25 to 17% in the primary outcome (alpha 0.05 and bèta 0.20), taking into account an extra 10% sample size for multi-level analysis and an attrition rate of 10%, 2 × 496 women will be needed (n = 992). DISCUSSION: We expect that adding MCAs to the routine maternity care team will result in a decrease in the use of epidural analgesia and subsequent costs without a reduction in patient satisfaction. It will therefore be a cost-effective intervention. TRIAL REGISTRATION: Trial Registration: Netherlands Trial Register, NL8065 . Registered 3 October 2019 - Retrospectively registered.

External validation and clinical utility of prognostic prediction models for gestational diabetes mellitus: A prospective cohort study.

INTRODUCTION: We performed an independent validation study of all published first trimester prediction models, containing non-invasive predictors, for the risk of gestational diabetes mellitus. Furthermore, the clinical potential of the best performing models was evaluated. MATERIAL AND METHODS: Systemically selected prediction models from the literature were validated in a Dutch prospective cohort using data from Expect Study I and PRIDE Study. The predictive performance of the models was evaluated by discrimination and calibration. Clinical utility was assessed using decision curve analysis. Screening performance measures were calculated at different risk thresholds for the best model and compared with current selective screening strategies. RESULTS: The validation cohort included 5260 women. Gestational diabetes mellitus was diagnosed in 127 women (2.4%). The discriminative performance of the 12 included models ranged from 68% to 75%. Nearly all models overestimated the risk. After recalibration, agreement between the observed outcomes and predicted probabilities improved for most models. CONCLUSIONS: The best performing prediction models showed acceptable performance measures and may enable more personalized medicine-based antenatal care for women at risk of developing gestational diabetes mellitus compared with current applied strategies.

Gestational Weight Gain by Maternal Pre-pregnancy BMI and Childhood Problem Behaviours in School-Age Years: A Pooled Analysis of Two European Birth Cohorts.

OBJECTIVES: Maternal pre-pregnancy weight is known to affect foetal development. However, it has not yet been clarified if gestational weight gain is associated with childhood behavioural development. METHODS: We performed a pooled analysis of two prospective birth cohorts to investigate the association between gestational weight gain and childhood problem behaviours, and the effect modification of maternal pre-pregnancy BMI. In total, 378 mother-child pairs from the Maastricht Essential Fatty Acids Birth cohort (MEFAB) and 414 pairs from the Rhea Mother-Child cohort were followed up from early pregnancy to 6-7 years post-partum. At follow up, parents assessed their children's behaviour, measured as total problems, internalizing and externalizing behaviours, with the Child Behaviour Checklist. We computed cohort- and subject-specific gestational weight gain trajectories using mixed-effect linear regression models. Fractional polynomial regressions, stratified by maternal pre-pregnancy BMI status, were then used to examine the association between gestational weight gain and childhood problem behaviours. RESULTS: In the pre-pregnancy overweight/obese group, greater gestational weight gain was associated with higher problem behaviours. On average, children of women with overweight/obesity who gained 0.5 kg/week scored 25 points higher (on a 0-100 scale) in total problems and internalizing behaviours, and about 18 points higher in externalizing behaviours than children whose mothers gained 0.2 kg/week. Inconsistent results were found in the pre-pregnancy normal weight group. CONCLUSIONS FOR PRACTICE: Excessive gestational weight gain in women with pre-pregnancy overweight/obesity might increase problem behaviours in school-age children. Particular attention should be granted to avoid excessive weight gain in women with a pre-pregnancy overweight or obesity.

Development and internal validation of prediction models for colorectal cancer survivors to estimate the 1-year risk of low health-related quality of life in multiple domains.

BACKGROUND: Many colorectal cancer (CRC) survivors experience persisting health problems post-treatment that compromise their health-related quality of life (HRQoL). Prediction models are useful tools for identifying survivors at risk of low HRQoL in the future and for taking preventive action. Therefore, we developed prediction models for CRC survivors to estimate the 1-year risk of low HRQoL in multiple domains. METHODS: In 1458 CRC survivors, seven HRQoL domains (EORTC QLQ-C30: global QoL; cognitive, emotional, physical, role, social functioning; fatigue) were measured prospectively at study baseline and 1 year later. For each HRQoL domain, scores at 1-year follow-up were dichotomized into low versus normal/high. Separate multivariable logistic prediction models including biopsychosocial predictors measured at baseline were developed for the seven HRQoL domains, and internally validated using bootstrapping. RESULTS: Average time since diagnosis was 5 years at study baseline. Prediction models included both non-modifiable predictors (age, sex, socio-economic status, time since diagnosis, tumor stage, chemotherapy, radiotherapy, stoma, micturition, chemotherapy-related, stoma-related and gastrointestinal complaints, comorbidities, social inhibition/negative affectivity, and working status) and modifiable predictors (body mass index, physical activity, smoking, meat consumption, anxiety/depression, pain, and baseline fatigue and HRQoL scores). Internally validated models showed good calibration and discrimination (AUCs: 0.83-0.93). CONCLUSIONS: The prediction models performed well for estimating 1-year risk of low HRQoL in seven domains. External validation is needed before models can be applied in practice.

Intakes of Vitamin B-12 from Dairy Food, Meat, and Fish and Shellfish Are Independently and Positively Associated with Vitamin B-12 Biomarker Status in Pregnant Dutch Women.

Background: The effect of vitamin B-12 from different animal foods on vitamin B-12 biomarker status has not previously been evaluated in pregnant women. Objective: We examined the association of vitamin B-12 intake from dairy, meat, fish (including shellfish), and eggs with circulating concentrations of vitamin B-12 biomarkers and with the presence of vitamin B-12 deficiency in 1266 pregnant women participating in the KOALA Birth Cohort Study. Methods: Blood samples were collected in weeks 34-36 of pregnancy, and vitamin B-12 intake from foods and supplements was estimated with a semiquantitative food-frequency questionnaire (FFQ). Total vitamin B-12, holotranscobalamin (holoTC), and methylmalonic acid (MMA) were determined in plasma. Vitamin B-12 deficiency was defined as holoTC <35 pmol/L and MMA >0.45 µmol/L. Associations were evaluated with linear and logistic regression analyses, adjusting for potential confounders. Results: Significant dose-response relations were observed between vitamin B-12 intake from dairy, meat, and fish and plasma vitamin B-12, holoTC, and MMA [P-trend for (shell)fish with MMA = 0.002; P-trend for dairy, meat, and fish with all other markers < 0.001]. The OR (95% CI) of vitamin B-12 deficiency in the third compared with the first tertile of dairy-derived vitamin B-12 was 0.13 (0.04, 0.49), and the ORs for vitamin B-12 from meat and fish were 0.33 (0.11, 0.97) and 0.25 (0.08, 0.82), respectively. Egg-derived vitamin B-12 was only associated with holoTC. Additional analyses showed that self-defined vegetarians and FFQ-defined lacto-ovo-vegetarians had lower median total dietary vitamin B-12 intake and considerably worse vitamin B-12 biomarker status than omnivores and pescatarians. Conclusions: In pregnant Dutch women, higher intakes of vitamin B-12 from dairy, meat, and fish were positively associated with vitamin B-12 status, suggesting that dairy, meat, and fish are good sources of bioactive vitamin B-12 in pregnancy. Nevertheless, for (lacto-)vegetarians, vitamin B-12 supplementation is recommended.

Intrauterine insemination: simultaneous with or 36 h after HCG? A randomized clinical trial.

RESEARCH QUESTION: Does intrauterine insemination (IUI) carried out simultaneously with HCG triggering ('simultaneous IUI') increase the ongoing pregnancy rate compared with IUI 32-36 h after HCG triggering ('regular IUI')? STUDY DESIGN: An open-label randomized clinical trial was conducted in seven Dutch fertility clinics. One hundred and sixty-six couples were randomized to receive simultaneous IUI and 208 couples to receive regular IUI. Treatment was allocated using a computer-based randomization algorithm using sealed opaque envelopes. Data were analysed according to the intention-to-treat principle. Couples with unexplained or mild-to-moderate male factor subfertility were eligible. Exclusion criteria were female age 42 years or older, female body mass index 35 kg/m2 or over, double-sided tubal pathology or severe male factor subfertility. Mild ovarian stimulation was carried out by subcutaneous FSH self-administration. 'Simultaneous IUI' was carried out at the point of HCG triggering for ovulation. 'Regular IUI' was carried out 32-36 h after HCG triggering. RESULTS: The cumulative ongoing pregnancy rate after a maximum of four cycles was 26.2% for simultaneous IUI (43 ongoing pregnancies) and 33.7% for regular IUI (70 ongoing pregnancies) (RR 0.78 95% CI 0.57 to 1.07). Ongoing pregnancy rates per cycle in the simultaneous IUI group were 6.8%, 10.5%, 9.5% and 7.4% for the first, second, third and fourth IUI cycle. In the regular IUI group, ongoing pregnancy rates were 8.3%, 16.4%, 13.5% and 9.0% for the first, second, third and fourth IUI cycle. CONCLUSIONS: This multicentre randomized controlled trial did not demonstrate that IUI carried out at the point of HCG triggering increases pregnancy rates compared with IUI carried out around the time of ovulation.

External Validation and Clinical Usefulness of First Trimester Prediction Models for the Risk of Preeclampsia: A Prospective Cohort Study.

INTRODUCTION: This study assessed the external validity of all published first trimester prediction models for the risk of preeclampsia (PE) based on routinely collected maternal predictors. Moreover, the potential utility of the best-performing models in clinical practice was evaluated. MATERIAL AND METHODS: Ten prediction models were systematically selected from the literature. We performed a multicenter prospective cohort study in the Netherlands between July 1, 2013, and December 31, 2015. Eligible pregnant women completed a web-based questionnaire before 16 weeks' gestation. The outcome PE was established using postpartum questionnaires and medical records. Predictive performance of each model was assessed by means of discrimination (c-statistic) and a calibration plot. Clinical usefulness was evaluated by means of decision curve analysis and by calculating the potential impact at different risk thresholds. RESULTS: The validation cohort contained 2,614 women of whom 76 developed PE (2.9%). Five models showed moderate discriminative performance with c-statistics ranging from 0.73 to 0.77. Adequate calibration was obtained after refitting. The best models were clinically useful over a small range of predicted probabilities. DISCUSSION: Five of the ten included first trimester prediction models for PE showed moderate predictive performance. The best models may provide more benefit compared to risk selection as used in current guidelines.

Ovarian stimulation for IVF and risk of primary breast cancer in BRCA1/2 mutation carriers.

BACKGROUND: The effect of in vitro fertilisation (IVF) on breast cancer risk for BRCA1/2 mutation carriers is rarely examined. As carriers may increasingly undergo IVF as part of preimplantation genetic diagnosis (PGD), we examined the impact of ovarian stimulation for IVF on breast cancer risk in BRCA1/2 mutation carriers. METHODS: The study population consisted of 1550 BRCA1 and 964 BRCA2 mutation carriers, derived from the nationwide HEBON study and the nationwide PGD registry. Questionnaires, clinical records and linkages with the Netherlands Cancer Registry were used to collect data on IVF exposure, risk-reducing surgeries and cancer diagnosis, respectively. Time-dependent Cox regression analyses were conducted, stratified for birth cohort and adjusted for subfertility. RESULTS: Of the 2514 BRCA1/2 mutation carriers, 3% (n = 76) were exposed to ovarian stimulation for IVF. In total, 938 BRCA1/2 mutation carriers (37.3%) were diagnosed with breast cancer. IVF exposure was not associated with risk of breast cancer (HR: 0.79, 95% CI: 0.46-1.36). Similar results were found for the subgroups of subfertile women (n = 232; HR: 0.73, 95% CI: 0.39-1.37) and BRCA1 mutation carriers (HR: 1.12, 95% CI: 0.60-2.09). In addition, age at and recency of first IVF treatment were not associated with breast cancer risk. CONCLUSION: No evidence was found for an association between ovarian stimulation for IVF and breast cancer risk in BRCA1/2 mutation carriers.

Prediction models for the risk of spontaneous preterm birth based on maternal characteristics: a systematic review and independent external validation.

INTRODUCTION: Prediction models may contribute to personalized risk-based management of women at high risk of spontaneous preterm delivery. Although prediction models are published frequently, often with promising results, external validation generally is lacking. We performed a systematic review of prediction models for the risk of spontaneous preterm birth based on routine clinical parameters. Additionally, we externally validated and evaluated the clinical potential of the models. MATERIAL AND METHODS: Prediction models based on routinely collected maternal parameters obtainable during first 16 weeks of gestation were eligible for selection. Risk of bias was assessed according to the CHARMS guidelines. We validated the selected models in a Dutch multicenter prospective cohort study comprising 2614 unselected pregnant women. Information on predictors was obtained by a web-based questionnaire. Predictive performance of the models was quantified by the area under the receiver operating characteristic curve (AUC) and calibration plots for the outcomes spontaneous preterm birth <37 weeks and <34 weeks of gestation. Clinical value was evaluated by means of decision curve analysis and calculating classification accuracy for different risk thresholds. RESULTS: Four studies describing five prediction models fulfilled the eligibility criteria. Risk of bias assessment revealed a moderate to high risk of bias in three studies. The AUC of the models ranged from 0.54 to 0.67 and from 0.56 to 0.70 for the outcomes spontaneous preterm birth <37 weeks and <34 weeks of gestation, respectively. A subanalysis showed that the models discriminated poorly (AUC 0.51-0.56) for nulliparous women. Although we recalibrated the models, two models retained evidence of overfitting. The decision curve analysis showed low clinical benefit for the best performing models. CONCLUSIONS: This review revealed several reporting and methodological shortcomings of published prediction models for spontaneous preterm birth. Our external validation study indicated that none of the models had the ability to predict spontaneous preterm birth adequately in our population. Further improvement of prediction models, using recent knowledge about both model development and potential risk factors, is necessary to provide an added value in personalized risk assessment of spontaneous preterm birth.

The Association of Intrapair Birth-Weight Differences With Internalizing and Externalizing Behavior Problems.

Problem behaviors are of increasing public health concern. Twin studies have revealed substantial genetic and environmental influences on children's behavior, and examining birth-weight difference could allow the identification of the specific contribution of multiple non-shared prenatal environmental factors. The Twins and Multiple Births Association Heritability Study, a UK, volunteer-based study, recruited mothers of twins aged 18 months to 5 years; 960 twins (480 pairs) were included in the analysis. Twins' mothers answered questions relative to their pregnancy and their twins' characteristics, and completed the Child Behavior Checklist (CBCL) 1½-5. The association between the absolute birth-weight difference and each CBCL scale's score difference was analyzed by means of multiple linear regressions. Expected mean CBCL score differences were calculated. In monozygotic (MZ) twins, statistically and clinically significant associations were found between intrapair birth-weight difference and difference in total problems, internalizing problems, and emotional reactiveness. No significant results were observed neither in dizygotic (DZ) twins when analyzed as a separate group nor in MZ and DZ twins combined. The results of the present study suggest that with increasing the absolute birth-weight difference, the intrapair difference in total problems, internalizing behaviors and emotionality increases, with smaller twins being at major risk for later behavior problems. Moreover, these results suggest a causal association between birth weight and behavior development.