Oocyte retrieval in social fertility preservation: challenging traditional beliefs on gonadotropin dosing and follicular size.

OBJECTIVES: To investigate treatment approaches for fertility preservation patients, with a focus on timing of oocyte retrieval, and to determine whether their characteristics differ from those of other IVF patients. Additionally, to evaluate the significance of follicle size on triggering day in the context of fertility preservation. METHODS: This retrospective cohort study was conducted in a tertiary, university-affiliated medical center. It compared 140 matched patients undergoing social fertility preservation to 140 patients undergoing IVF treatment due to male factor infertility. RESULTS: Patients undergoing fertility preservation received a higher initial gonadotropin dose and had more oocytes retrieved than the control group. Within the fertility preservation cohort, a negative correlation was observed between the rate of large follicles and the number of retrieved oocytes. While there was no significant association between rate of large follicles and oocyte maturation rate in the entire group, age-stratified analysis revealed a negative relationship. Analysis revealed that although traditional treatment determinants such as follicular size and gonadotropin dosing were considered, peak estradiol levels were consistently identified as significant predictors of treatment outcomes. CONCLUSIONS: Physicians may modify treatments for fertility preservation, emphasizing a higher gonadotropin dosage to maximize oocyte retrieval. Elevated estradiol levels can serve as a real-time predictive marker for the number of mature oocytes. While treatment strategies can influence outcomes, intrinsic patient factors, particularly baseline ovarian function, remain crucial. These results challenge beliefs regarding the importance of larger follicles and suggest the need for a tailored approach, considering patient age and specific fertility preservation objectives.

Evaluation of women's aging influence on sperm passage inside the fallopian tube using 3D dynamic mechanical modeling.

The fallopian tubes play an important role in human fertility by facilitating the spermatozoa passage to the oocyte as well as later actively facilitating the fertilized oocyte transportation to the uterus cavity. The fallopian tubes undergo changes involving biological, physical, and morphological processes due to women aging, which may impair fertility. Here, we have modelled fallopian tubes of women at different ages and evaluated the chances of normal and pathological sperm cells reaching the fertilization site, the ampulla. By utilizing a unique combination of simulative tools, we implemented dynamic three-dimensional (3D) detailed geometrical models of many normal and pathological sperm cells swimming together in 3D geometrical models of three fallopian tubes associated with different women's age groups. By tracking the sperm cell swim, we found that for all age groups, the number of normal sperm cells in the ampulla is the largest, compared with the pathological sperm cells. On the other hand, the number of normal sperm cells in the fertilization site decreases due to the morphological and mechanical changes that occur in the fallopian tube with age. Moreover, in older ages, the normal sperm cells swim with lower velocities and for shorter distances inside the ampulla toward the ovary. Thus, the changes that the human fallopian tube undergoes due to women's aging have a significant influence on the human sperm cell motility. Our model of sperm cell motility through the fallopian tube in relation to the woman's age morphological changes provides a new scope for the investigation and treatment of diseases and infertility cases associated with aging, as well as a potential personalized medicine tool for evaluating the chances of a natural fertilization per specific features of a man's sperm and a woman's reproductive system.

Machine learning for predicting elective fertility preservation outcomes.

This retrospective study applied machine-learning models to predict treatment outcomes of women undergoing elective fertility preservation. Two-hundred-fifty women who underwent elective fertility preservation at a tertiary center, 2019-2022 were included. Primary outcome was the number of metaphase II oocytes retrieved. Outcome class was based on oocyte count (OC): Low (≤ 8), Medium (9-15) or High (≥ 16). Machine-learning models and statistical regression were used to predict outcome class, first based on pre-treatment parameters, and then using post-treatment data from ovulation-triggering day. OC was 136 Low, 80 Medium, and 34 High. Random Forest Classifier (RFC) was the most accurate model (pre-treatment receiver operating characteristic (ROC) area under the curve (AUC) was 77%, and post-treatment ROC AUC was 87%), followed by XGBoost Classifier (pre-treatment ROC AUC 74%, post-treatment ROC AUC 86%). The most important pre-treatment parameters for RFC were basal FSH (22.6%), basal LH (19.1%), AFC (18.2%), and basal estradiol (15.6%). Post-treatment parameters were estradiol levels on trigger-day (17.7%), basal FSH (11%), basal LH (9%), and AFC (8%). Machine-learning models trained with clinical data appear to predict fertility preservation treatment outcomes with relatively high accuracy.

Does the SARS-CoV-2 mRNA vaccine and its serum IgG levels affect fertility treatments and obstetric outcomes? An observational cohort study.

BACKGROUND: Although there are some data regarding the COVID-19 vaccine and in in vitro fertilization (IVF) treatments, its potential impact in terms of serum immunoglobulin G (IgG) levels has not been evaluated prospectively. This study aimed to assess the effect of COVID-19 vaccine and IgG levels on IVF outcomes. METHODS: This observational, cohort study was conducted at a referral IVF unit. Couples undergoing IVF treatment during the COVID-19 vaccination period were recruited from March-April 2021. The study compared 38 women who had received the Pfizer mRNA COVID-19 vaccination to 10 women who had not and were not infected by the virus. We also compared pre- and post-vaccination IVF treatments for 24 women. The relation between serologic titers and IVF treatment outcomes was also assessed. RESULTS: No significant difference was found between the vaccinated and unvaccinated/uninfected groups regarding the main outcome measures. However, there was a trend toward a higher pregnancy rate for the unvaccinated group (57% vs. 23%, p = 0.078) but no difference in delivery rate (p = 0.236), gestational week (p = 0.537) or birth rate (p = 0.671). CONCLUSION: We cautiously state that the COVID-19 mRNA vaccine does not affect fertility outcomes, including fertilization, pregnancy and delivery rates, obstetric outcomes, and semen parameters, regardless of measured IgG levels.

Obstetric and maternal outcomes of IVF and oocyte donation pregnancies among women ages 40-45-a large cohort study.

PURPOSE: To analyze the perinatal and maternal outcomes of women ranging in age from 40 to 45 years who gave birth after in vitro fertilization or oocyte donation, compared to spontaneous conception. METHODS: This retrospective cohort study used electronic data from a national healthcare service from 2000 through 2019. Three groups were compared: spontaneous pregnancy (SC), in vitro fertilization (IVF) utilizing autologous oocytes, and pregnancies resulting from oocyte donation (OD). The primary study outcomes were preterm labor (PTL) before 37 weeks of gestation, and infants classified as small for gestational age (SGA). RESULTS: The cohort included 26,379 SC, 2237 IVF pregnancies, and 300 OD pregnancies for women ages 40-45 years at delivery. Women with OD or IVF had a higher incidence of PTL < 37 weeks compared to women with SC (19.7% vs. 18% vs. 6.9%, p = 0.001), PTL < 34 (7% vs. 4.5% vs. 1.4%, p = 0.001), PTL < 32 (3.7 vs. 2.1 vs. 0.6, p = 0.001). A multivariable logistic regression for PTL < 37 weeks demonstrated that age (OR = 1.18) and hypertensive diseases (OR = 3.4) were statistically significant factors. The OD group had a lower rate of SGA compared to SC (1% vs. 4.3%, p = 0.001), while the IVF group had a higher rate of SGA compared to SC (9.1% vs. 4.3%, p = 0.001). Hypertensive diseases in pregnancy were significantly higher among the OD group and the IVF group compared to SP pregnancies (3.3% vs. 1%, p = 0.002; 2.3% vs. 1%, p = 0.001, respectively). CONCLUSIONS: Women ages 40-45 undergoing IVF or OD have a greater risk of PTL, possibly due to higher rates of hypertensive disorders of pregnancy.

The Effect of Month-Long Daily Fasting on Semen Parameters: A Retrospective Cohort Study.

OBJECTIVE: The aim of the study was to determine whether Ramadan month-long daily fasting affects semen analysis parameters. METHODS: This retrospective cohort study was conducted in tertiary academic medical center. Medical records of 97 Muslim patients who were admitted to the IVF unit from May 2011 to May 2021 were reviewed. Only men who provided at least one semen sample during Ramadan period (Ramadan month +70 days after) and one sample not during Ramadan were included. Semen characteristics of each patient were independently compared to themselves. RESULTS: The post-gradient semen analysis indicated significantly lower progressive sperm motility (mean 30.01 ± 20.46 vs. 38.12 ± 25.13) (p < 0.001). The decrease in the progressive motility remained significant among patients with non-male factor indications (p < 0.001). In the non-male factor indication group, the difference in the progressive motility of the post-gradient semen analysis between the 2 samples was not statistically significant (p = 0.4). There were no significant differences between semen parameters before centrifuging. The incidence of asthenospermia (progressive sperm motility <32%) as an absolute parameter was higher after centrifuging the semen sample during the Ramadan period (p = 0.04). CONCLUSIONS: Semen samples collected during Ramadan period were associated with lower progressive motility and reduced semen volume compared to semen samples from the same men outside of the Ramadan period. A possible effect of these altered semen parameters on fertility should be investigated further.

Stain-Free Sperm Analysis and Selection for Intracytoplasmic Sperm Injection Complying with WHO Strict Normal Criteria.

This multi-center study evaluated a novel microscope system capable of quantitative phase microscopy (QPM) for label-free sperm-cell selection for intracytoplasmic sperm injection (ICSI). Seventy-three patients were enrolled in four in vitro fertilization (IVF) units, where senior embryologists were asked to select 11 apparently normal and 11 overtly abnormal sperm cells, in accordance with current clinical practice, using a micromanipulator and 60× bright field microscopy. Following sperm selection and imaging via QPM, the individual sperm cell was chemically stained per World Health Organization (WHO) 2021 protocols and imaged via bright field microscopy for subsequent manual measurements by embryologists who were blinded to the QPM measurements. A comparison of the two modalities resulted in mean differences of 0.18 µm (CI -0.442-0.808 µm, 95%, STD-0.32 µm) for head length, -0.26 µm (CI -0.86-0.33 µm, 95%, STD-0.29 µm) for head width, 0.17 (CI -0.12-0.478, 95%, STD-0.15) for length-width ratio and 5.7 for acrosome-head area ratio (CI -12.81-24.33, 95%, STD-9.6). The repeatability of the measurements was significantly higher in the QPM modality. Surprisingly, only 19% of the subjectively pre-selected normal cells were found to be normal according to the WHO2021 criteria. The measurements of cells imaged stain-free through QPM were found to be in good agreement with the measurements performed on the reference method of stained cells imaged through bright field microscopy. QPM is non-toxic and non-invasive and can improve the clinical effectiveness of ICSI by choosing sperm cells that meet the strict criteria of the WHO2021.

General anesthesia with propofol during oocyte retrieval and in vitro fertilization outcomes: retrospective cohort study.

General anesthesia is frequently administered during oocyte retrieval. Its effects on the outcomes of IVF cycles are uncertain. This study investigated whether administration of general anesthesia (specifically propofol) during oocyte retrieval affects IVF outcomes. A total of 245 women undergoing IVF cycles were included in this retrospective cohort study. IVF outcomes of 129 women who underwent oocyte retrieval under propofol anesthesia and 116 without anesthesia were compared. Data were adjusted for age, BMI, estradiol on triggering day and total gonadotropin dose. The primary outcomes were fertilization, pregnancy and live birth rates. A secondary outcome was the efficiency of follicle retrieval associated with the use of anesthesia. Fertilization rate was lower in retrievals under anesthesia compared to without (53.4% ± 34.8 vs. 63.7% ± 33.6, respectively; p = 0.02). There was no significant difference in the ratio of expected to retrieved oocytes between retrievals with and without anesthesia (0.8 ± 0.4 vs. 0.8 ± 0.8, respectively, p = 0.96). The differences in pregnancy and live birth rates between the groups were not statistically significant. General anesthesia administered during oocyte retrieval may have adverse effects on the fertilization potential of oocytes. This impact on the developmental potential of oocytes may lead to negative IVF outcomes and should be investigated further.

GnRH agonist-triggering ovulation in women with advanced age.

This study evaluates the effect of GnRH agonist (GnRHa) trigger for ovulation induction among women with advanced maternal age (AMA). This is a retrospective study performed at a single assisted reproductive technology centre, 2012 to 2020. A total of 306 patients with 515 IVF cycles who were triggered with GnRHa for Ovum Pick Up (OPU), were divided into two groups according to maternal age: age ≥ 40 and age < 40. The groups were compared for demographics, stimulation parameters of IVF treatment and IVF treatment outcomes. The patients in the age < 40 group were approximately 10 years younger than the patients in the age ≥ 40 group (31 ± 5.4 vs. 41.5 ± 1.3 years, p < 0.001). The age ≥ 40 group had significantly higher mean E2/retrieved oocytes ratio, compared to the age < 40 group (310.3 ± 200.6 pg/ml vs. 239 ± 168.2 pg/ml, p = 0.003), and a lower mean MII/retrieved oocyte (35 ± 37.8 vs. 43.4 ± 35.9, p = 0.05, respectively). Multivariable logistic regression analysis for E2/retrieved oocytes demonstrated that age < 40 and total dose of gonadotropins were significant variables. In conclusion, GnRHa for ovulation triggering in high responder patients prior to OPU appears to be a good option for AMA. However, this population is characterized by different parameters of ovarian response that require further evaluation.

High physical activity and ovarian reserve: a prospective study of normo-ovulatory professional athletes.

BACKGROUND: This study investigated whether high physical activity affects ovarian reserve in normo-ovulatory, reproductive-age women. METHODS: This prospective, observational study compared 31 professional female athletes, with 31 women who did not engage in physical activity. It was conducted 2017-2020 in a tertiary medical center. Normo-ovulatory, professional athletes, ages 20-35 years were recruited from The Wingate Institute-the Israeli National Institute for Sport Excellence. They had high International Physical Activity Questionnaire (IPAQ) scores. Non-physically active women, matched by age and body mass index, were recruited from hospital staff. Women were evaluated for ovarian reserve markers on day 2-5 of the menstrual cycle, including follicular stimulating hormone, antral follicle count, anti-Mullerian hormone and Inhibin B. RESULTS: The average age of the high physical activity group was 29.9 ± 4.2 years and the nonactive group 31.6 ± 4.2 years (p = 0.062). Body mass index of both groups were similar (22.5 ± 5.0 vs. 21.4 ± 2.5, respectively; p = 0.1). No differences were observed with respect to follicle stimulating hormone (p = 0.12) and anti-Mullerian hormone (p = 0.16). A trend towards higher total antral follicle count in the high physical activity group vs. the non-active group (34.5 ± 12.9 vs. 28.1 ± 15.2, p = 0.08) and lower Inhibin B (68.1 ± 36.8 vs. 89.4 ± 46.1, p = 0.05). Menarche age correlated with anti-Mullerian hormone (r = 0.387, p = 0.003), as did total antral follicle count (r = 0.368, p = 0.004). IPAQ scores and basal follicle stimulating hormone levels were negatively correlated (r = - 0.292, p = 0.005). CONCLUSIONS: Athletic, normo-ovulatory women have ovarian reserves that are at least as good as those of the general population. As this is the first study examining this issue, it could cautiously reassure women engaged in high physical activity regarding ovarian reserve.

How effective is digital educational content in shaping fertility awareness? An interventional, cross-sectional study.

PURPOSE: To determine whether exposure to digital educational content affects fertility awareness and attitudes towards fertility preservation treatments? METHODS: A total of 957 women ages 20 to 45 years participated in this internet-based, interventional, cross-sectional study. A questionnaire assessing knowledge of the reproductive span and attitudes towards fertility preservation treatment was completed by these women before and after exposure to online educational content on ovarian reserve and fertility preservation treatments. Responses before and after exposure to the educational content were compared. RESULTS: Knowledge about female age-related fertility decline improved significantly after exposure to educational content (51.6% vs. 79.6%, p < 0.001). Increased willingness to pursue fertility preservation treatments (38.6% vs. 42.9%, p < 0.001) and to recommend fertility preservation treatments to friends (55% vs. 65.2%, p < 0.001) was observed. Participants who desired to conceive were more positively influenced by the exposure to educational content in their attitudes towards fertility treatments compared to those who do not desire to conceive. CONCLUSIONS: Online educational content has the potential to improve fertility awareness and shape a more positive attitude towards fertility preservation treatments for the public.

Physiological and psychological stress responses to labor and delivery during COVID-19 pandemic: a cohort study.

OBJECTIVE: To evaluate objective (saliva cortisol) and subjective (questionnaire) stress levels during the Coronavirus disease (COVID-19) pandemic compared to before the pandemic and their effects on obstetric and neonatal outcomes. METHODS: This cohort study included 36 women with low-risk, singleton, term deliveries at a tertiary academic center during the COVID-19 pandemic and 49 who delivered before. Physiological stress was evaluated with salivary cortisol measurements, and emotional stress with stress scale questionnaires (0-10) during active and full dilation stages of labor, and 2-min postpartum. Cord blood cortisol and pH were obtained. Delivery mode, complications, and neonatal outcomes were evaluated. RESULTS: Psychological stress was higher for the COVID-19 group compared to controls during full dilation (6.2 ± 3.4 vs. 4.2 ± 3, p = .009). The COVID-19 group had significantly lower cord cortisol levels (7.3 vs. 13.6 mcg/dl, p = .001). No differences were found regarding salivary cortisol level assessments at active, full dilation and 2-min post-delivery (p = .584, p = .254, p = .829, respectively). No differences were found regarding pH < 7.1 (p = .487), 1- and 5-min Apgar scores < 7 (p = .179) and neonatal weight (p = .958). CONCLUSIONS: Women who delivered during COVID-19 pandemic had higher stress levels at full dilation and lower cord cortisol levels, as may be expected after exposure to a chronic stressor.

Does fresh single embryo transfer outcome predict the result of a subsequent vitrified-warmed blastocyst of the same cohort?

Reflecting the current trends, the utilization of frozen-thawed transfer cycles has been steadily increasing worldwide; outcome predictors of these cycles are therefore a major research goal. Our aim was to investigate whether the outcome of a fresh single blastocyst transfer (SBT) can serve as a prognostic factor for the subsequent vitrified-warmed SBT originating from the same cohort. A retrospective cohort study was performed at a single unit. Non-donor fresh cycles were analyzed as predictors of the following vitrified-warmed cycle. Only SBTs were included. Cycles designated to a freeze-all policy and cycles involving pre-implantation genetic analysis were excluded. A total of 1127 vitrified-warmed single blastocyst cycles were included. The indications for artificial reproductive technologies were comparable across the study groups. Vitrified-warmed cycles following a live birth outcome in the fresh cycle were more likely to result in a clinical pregnancy than those following a fresh cycle, which failed to reach a live birth. The same trend was observed for live birth rate following vitrified-warmed transfer in the fresh cycle. After correcting for possible confounders, age and embryo quality were significantly correlated with the chance for a live birth, but the previous fresh cycle did not affect the results. We therefore conclude that after adjustment for age, embryo quality and number of previous oocyte retrieval cycles, the fresh cycle outcome was not a significant influential factor for the following vitrified-warmed cycle.

Gonadotropin releasing hormone agonist triggering for in vitro maturation cycles.

The objective was to evaluate the outcomes of in vitro maturation (IVM) cycles using gonadotropin releasing hormone agonist (GnRH-ag) triggering. A retrospective cohort of IVM cycles from January 2015 to December 2019 in a single university-affiliated centre was examined. Main outcome measures were: (i) IVM maturation rate; and (ii) IVM maturation result. Secondary outcome measures were: (i) metaphase II (MII) rate on the day of egg retrieval; (ii) final MII maturation rate; and (iii) pregnancy rates. A total of 98 IVM cycles were performed during the study period: 50 (51%) were triggered with GnRH-ag (17 received FSH priming and 33 did not) and 48 cycles (49%) were triggered by hCG (37 with FSH priming and 11 without). A significant (p = 0.01) difference was noticed in maturation rate on egg retrieval day, in favour of the GnRH-ag group, although not in the final maturation rate achieved. Pregnancy rates were comparable between treatment sub-groups. GnRH-ag triggering in IVM cycles is an optional triggering mode and can be considered an acceptable option, especially when fertility preservation is a concern. GnRH agonists resulted in higher maturation rate on day of oocyte retrieval, but no difference in the total maturation rate.

Can Social Support on Facebook Influence Fertility Outcomes?

Social support is known to reduce stress and increase quality of life among patients undergoing IVF. Increasing social media use introduces a social support mechanism, yet data regarding the effect of this support on IVF outcomes are scarce. This observational, retrospective cohort study included women undergoing their first IVF cycle at an academic tertiary medical center. Fertility outcomes were compared between 82 women who were active users of social media (posting on Facebook at least 3 times a week) and 83 women who did not use Facebook or any other social media platform (the control group). For the social media group, we coded all Facebook Feed activities (Posts, Comments, Likes) for each participant up to 8 weeks prior to beta hCG test. Social support was measured by average Likes and Comments per post, on fertility outcomes. The social media group included more single women than the control group (17% vs. 5%, respectively, p = 0.012) and had a shorter infertility duration (1.6 ± 0.9 years vs. 2.3 ± 1.4, respectively, p = 0.001(. We found a trend in fertilization rates between groups (social media group 58% vs. controls 50%, p = 0.07). No difference was found regarding pregnancy rate between groups (p = 0.587). The social media group had a lower miscarriage rate compared to the controls (6% vs. 25%, p = 0.042). These results were also validated in the multivariant regression analysis. Social support (via Facebook) may have a positive effect on IVF outcomes, especially regarding miscarriages rate, with minor effect regrading fertilization rate and no effect regarding pregnancy rate. Therefore, encouraging women to be active on Facebook during treatment, including OPU day, may impact treatment results.

Thawing day 3 embryos and culturing to day 5 may be a better method for frozen embryo transfer.

PURPOSE: Does thawing cleavage embryos and culturing them for transfer as blastocysts improve pregnancy and perinatal outcomes compared to transferring thawed blastocysts? METHODS: Retrospective, observational cohort study performed at two assisted reproductive technology centers, 2014 to 2020. A total of 450 patients with 463 thawed embryo transfer cycles were divided into 2 groups according to the embryonic developmental stage at cryopreservation and transfer: 231 thawed blastocysts (day 5 group) and 232 thawed cleavage embryos that were cultured for 2 days and transferred as blastocysts (day 3-5 group). The two groups were compared for demographics, routine parameters of IVF treatment, pregnancy rates, and perinatal outcomes. RESULTS: Multivariable logistic regression analysis for ongoing pregnancy and delivery demonstrated that the day 3-5 group had a greater likelihood of achieving ongoing pregnancy and delivery compared to the day 5 group (OR 1.58, 95%CI 1.062-2.361, p = 0.024). Perinatal outcomes were comparable between the three groups. CONCLUSION: Our results support culturing post-thaw cleavage embryos for 2 days and transferring them as blastocysts to increase chances of ongoing pregnancy and delivery.

A prospective study of C-reactive protein in patients with obesity during IVF.

This prospective cohort pilot study investigated the physiology of C-reactive protein (CRP) during in vitro fertilization (IVF) cycles and its effect on outcomes in women with and without obesity. The study was conducted from April to August 2014, in the IVF Unit of a university-affiliated hospital. Women aged 18-42 years were enrolled. Those with chronic inflammatory diseases or acute illness were excluded. A total of 31 patients were included: 17 with BMI < 30 kg/m2 and 14 with BMI ≥ 30 kg/m2. Serum CRP levels were measured: (i) before starting ovarian stimulation; (ii) on the day of ß-HCG administration; and (iii) on day of ovum pick-up (OPU), in both serum and follicular fluid. Serum CRP levels were significantly higher in women with obesity at all time points. For the entire cohort, a positive correlation was found between basal oestradiol (E2) and basal CRP (r = 0.71, p < 0.05). A specific pattern of CRP levels was not detected during the IVF cycle. High serum CRP levels on OPU day had a negative effect on embryo quality (p = 0.056). CRP ≥ 0.5 mg/dL was associated with lower quality embryos (2.6 ± 0.3 vs. 3.3 ± 0.3; p = 0.04). High serum CRP level on OPU day negatively affects embryo quality.

Conception after early IVF pregnancy loss: should we wait?

RESEARCH QUESTION: Is the interval length between an early pregnancy loss and the following treatment cycle a predictor for achieving clinical pregnancy among IVF patients? DESIGN: This retrospective cohort study of 257 women who reinitiated treatment after first-trimester IVF pregnancy loss was conducted at a tertiary, university-affiliated medical centre between 1 January 2014 to 1 January 2018. Women aged 18-40 years, with normal uterine cavity, who experienced first-trimester pregnancy loss at less than 14 weeks after IVF, were included. Miscarriages were classified as spontaneous, biochemical, medical or surgical. RESULTS: Among 257 women, interval to subsequent IVF treatment was not associated with achieving pregnancy. Patients after biochemical pregnancy (72.7 ± 56.4, median 60 days) or spontaneous miscarriage (97.7 ± 93.1, median 66 days) had shorter intervals to next cycle, compared with medical (111.9 ± 103.2, median 65 days) or surgical (123.4 ± 111.1, median 84 days) (Kaplan-Meier, P = 0.03) miscarriages. Logistic regression analysis showed that the chance of subsequent pregnancy was affected by the number of embryos transferred (P = 0.009) and the type of miscarriage. Medical (P = 0.005) and surgical (P = 0.017) miscarriages were related to lower likelihood of pregnancy compared with biochemical pregnancy (reference group). When pregnancy was achieved in the first post-miscarriage cycle, the chance of live birth increased with shorter intervals (median 57.5 days), whereas second miscarriage was related to longer intervals (median 82.5 days) between miscarriage and subsequent IVF cycle (P = 0.03). CONCLUSION: On the basis of this cohort, IVF should not be postponed after pregnancy loss, as shorter intervals were associated with greater likelihood of live birth.

The effect of maternal body mass index (BMI) and telomere function on in vitro fertilization (IVF) outcome: a preliminary cohort study.

Telomeres are a specific base sequence of DNA, responsible for chromosome stability and DNA protection. We aimed to investigate the association between telomere systems and IVF outcomes according to patients' BMI. For all telomere characteristics, there was a distinct trend towards shorter telomeres and activation of telomere shortening compensatory mechanisms in the BMI group >25 kg/m2, reaching statistical significance for senescence only (r = 0.7, p value <0.01). There was a trend towards a relationship between telomere length and number of oocytes between telomere length and fertilization rate, but these did not reach a statistical significance. For pregnancy outcome, all telomere characteristics were better for the patients who achieved a pregnancy. While there is paucity of data in the literature concerning the association between telomere characteristics and infertility, telomeres might contribute to the association between obesity and sub-optimal IVF results.