Supraphysiologic estradiol is an independent predictor of low birth weight in full-term singletons born after fresh embryo transfer

Embryo retention and live birth in frozen embryo transfer cycles: a cohort study

OBJECTIVE

To study the effect of embryo retention in the transfer catheter on pregnancy outcomes in frozen embryo transfer (FET) cycles.

DESIGN

Retrospective cohort study.

SUBJECTS

This retrospective study involved a total of 39,118 women who underwent FET cycles at a tertiary-care academic medical from January 2016 to December 2022.

EXPOSURE

Women were divided into a control group (n = 38,933) and embryo retention group (n = 185). The women in the embryo retention group had been propensity scores matched with those in the control group at a 1:4 ratio.

MAIN OUTCOME MEASURES

The primary outcome was live birth (LB). The secondary outcomes were biochemical pregnancy, clinical pregnancy (CP), miscarriage, and ectopic pregnancy.

RESULTS

The overall incidence of embryo retention in the transfer catheter was 0.47% (185/39,118). The pregnancy outcome in the embryo retention group after propensity score matching (PSM) was comparable to that before PSM, with a reduced likelihood of biochemical pregnancy (odds ratio [OR], 0.83; 95% confidence interval [CI], 0.72-0.95), CP (OR, 0.81; 95% CI, 0.69-0.96), and LB (OR, 0.80; 95% CI, 0.66-0.97). In addition, the birth weight in the embryo retention group was higher compared with the control group. However, no differences were observed in terms of miscarriage, ectopic pregnancy, cesarean delivery, as well as gestational age both before and after PSM.

CONCLUSION

Embryo retention in the transfer catheter decreases the chance of biochemical pregnancy, CP, and LB in FET cycles.

Higher PFOS exposure associated with higher SHBG in third trimester. The Odense Child Cohort

BACKGROUND

Perfluoroalkyl substances (PFAS) are chemicals with endocrine disrupting properties. Experimental studies indicate that PFAS have estrogenic effects by inducing aromatase activity. Sex hormone-binding globulin (SHBG) is a marker of the balance between estrogen and testosterone, as estrogen stimulates and testosterone inhibits SHBG production.

OBJECTIVE

To investigate associations between maternal PFAS concentrations and levels of SHBG and testosterone in pregnancy.

METHODS

In Odense Child Cohort (OCC), concentrations of PFAS: perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured in 1611 eligible women at median gestational week (GW) 12 (25th, 75th percentile: 10, 15). Among these, levels of sex hormone-binding globulin (SHBG), calculated free testosterone (Free-T), free androgen index (FAI), and total testosterone (TT) were assessed in 1048 at median GW 29 (25th, 75th percentile: 28, 30). Associations between PFAS concentrations and levels of SHBG and testosterone were estimated using multiple linear regression models. The effect of combined exposure to PFAS was also assessed via Quantile G-Computation.

RESULTS

A doubling in PFOS concentration was associated with an increment in SHBG concentration by 2.29% (95%CI: 0.04%, 4.59%) in adjusted analyses. PFOS exposure in the third tertile, as compared to the first tertile, significantly increased SHBG concentrations by 4.60% (95%CI: 0.82%, 8.53%). No significant association was demonstrated between PFAS and TT, however, a non-significant inverse association was found between PFAS and Free-T and FAI. Combined PFAS exposure was non-significantly associated with an increase in SHBG, and decrease in Free-T, FAI, and TT.

CONCLUSION

PFOS exposure was associated with an increase in the proportion of estrogen effects to androgen effects, assessed by higher SHBG concentrations, in pregnant women. Estrogenic effects during pregnancy may have implications on offspring neural, metabolic, and endocrine development, hence supporting the necessity of a follow-up of offspring.

Frozen versus fresh embryo transfer in women with low prognosis for in vitro fertilisation treatment: pragmatic, multicentre, randomised controlled trial

OBJECTIVE

To test the hypothesis that a freeze-all strategy would increase the chance of live birth compared with fresh embryo transfer in women with low prognosis for in vitro fertilisation (IVF) treatment.

DESIGN

Pragmatic, multicentre, randomised controlled trial.

SETTING

Nine academic fertility centres in China.

PARTICIPANTS

838 women with a low prognosis for IVF treatment defined by ≤9 oocytes retrieved or poor ovarian reserve (antral follicle count <5 or serum anti-Müllerian hormone level <8.6 pmol/L).

INTERVENTIONS

Eligible participants were randomised (1:1) to undergo either frozen embryo transfer or fresh embryo transfer on the day of oocyte retrieval. Participants in the frozen embryo transfer group had all of their embryos cryopreserved and underwent frozen embryo transfer later. Participants in the fresh embryo transfer group underwent fresh embryo transfer after oocyte retrieval.

MAIN OUTCOME MEASURES

The primary outcome was live birth, defined as the delivery of neonates with a heartbeat and respiration at ≥28 weeks' gestation. Secondary outcomes were clinical pregnancy, singleton or twin pregnancy, pregnancy loss, ectopic pregnancy, birth weight, maternal and neonatal complications, and cumulative live birth after embryo transfers within one year after randomisation.

RESULTS

In an intention-to-treat analysis, the rate of live birth was lower in the frozen embryo transfer group than in the fresh embryo transfer group (32% (132 of 419) v 40% (168 of 419); relative ratio 0.79 (95% confidence interval 0.65 to 0.94); P=0.009). The frozen embryo group had a lower rate of clinical pregnancy than the fresh embryo group (39% (164 of 419) v 47% (197 of 419); 0.83 (0.71 to 0.97)). The cumulative live birth rate was lower in the frozen embryo transfer group compared with the fresh embryo transfer group (44% (185 of 419) v 51% (215 of 419), 0.86 (0.75 to 0.99)). No difference was observed in birth weight, incidence of obstetric complications, or risk of neonatal morbidities.

CONCLUSIONS

Fresh embryo transfer may be a better choice for women with low prognosis in terms of live birth rate compared with a freeze-all strategy. The treatment strategies that prevent fresh embryo transfers, such as accumulating embryos with back-to-back cycles or performing routine preimplantation genetic testing for aneuploidy, warrant further studies in women with a low prognosis.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2100050168.

Fresh vs. frozen: pregnancy outcomes and treatment efficacy between fresh embryo transfer vs. untested freeze-all cycles

Objective

To compare pregnancy outcomes after single blastocyst embryo transfer among patients whose first autologous embryo transfer was either a fresh embryo transfer or a frozen embryo transfer (FET) after a freeze-all, in the absence of preimplantation genetic testing for aneuploidy (PGT-A).

Design

A multicenter retrospective cohort analysis.

Setting

National multicenter fertility practice.

Patients

A total of 8,319 autologous first blastocyst embryo transfers in the absence of PGT-A were analyzed. Of them, 6,755 transfers were fresh embryo transfer (ET) and 1,564 transfers were FET after freeze-all.

Exposure

Patients underwent either a fresh or a frozen initial autologous, single blastocyst transfer in the absence of PGT-A.

Main Outcome Measures

Primary outcome measure was live birth rate. Secondary outcome measures included positive pregnancy test, clinical pregnancy rate, and miscarriage rate.

Results

Live birth rate was comparable between the fresh ET and FET groups in the absence of PGT-A, after performing generalized estimating equation modeling to account for age, body mass index, antral follicle count, basal follicle-stimulating hormone, progesterone on day of trigger/day of final lining check, peak estradiol during in vitro fertilization stimulation cycle, number of oocytes retrieved during ovarian stimulation cycle, and primary diagnosis. Similarly, the secondary outcome variables of positive pregnancy test, clinical pregnancy rate, and miscarriage rates were comparable between the cohorts. These findings were observed in the entire study group, within each age category of <35, 35-37, 38-40, and >40 and among each stratified peak estradiol group.

Conclusions

In the absence of PGT-A, patients and fertility providers can elect to pursue either fresh ET or embryo freeze-all with subsequent FET during the first autologous in vitro fertilization cycle.

Effect of paternal body mass index on maternal and child-health outcomes of singletons after frozen-thawed embryo transfer cycles: a retrospective study

The objective was to analyze the effect of paternal body mass index (BMI) on maternal and child-health outcomes of singletons after frozen-thawed embryo transfer (FET) cycles. A retrospective cohort study was conducted between January 2019 and December 2021. Pregnancy, perinatal complications and neonatal outcomes were compared among different paternal BMI. Multivariate logistic regression was performed to evaluate the relationship between different paternal BMI and pregnancy, obstetric and neonatal outcomes. The paternal normal group was more likely to suffer from gestational hypertension than the paternal obesity group (3.59% vs. 2.42%), and paternal underweight group was more likely to suffer from preeclampsia than the other three groups (11.63% vs. 4.43%, 7.57%, 4.03%). Birthweight among infants in the paternal overweight categories was significantly higher than infants in the paternal normal weight categories. The rate of foetal macrosomia was higher among infants in the paternal overweight (12.36%) category, while lower among infants in the paternal underweight categories (2.33%). The incidence of macrosomia in the paternal overweight categories (aOR 1.527, 95% CI 1.078-2.163) was significantly higher than those normal controls after adjustment for known confounding factors. The rates of LGA babies were higher in the paternal overweight category (aOR 1.260, 95% CI 1.001-1.587) compared with those in the paternal normal weight category, before and after adjustment. The results suggest that parental pre-pregnancy overweight or obesity has an adverse effect on the perinatal complications and neonatal outcomes.

Effect of estrogen exposure on pregnancy outcomes in artificial frozen-thawed embryo transfer cycles

In contemporary times, the employment of vitrification freezing technology has led to the widespread adoption of frozen-thawed embryo transfer (FET) worldwide. Meanwhile, hormone replacement therapy (HRT) is a crucial protocol for priming the endometrium during FET cycles. Estrogen is required in HRT cycles for the induction of progesterone receptors and to promote endometrial thickness. However, there is no universal consensus on the treatment duration, dosage regimen, administration route, and target serum estrogen levels. Therefore, this study aimed to offer a comprehensive review of these topics. A shorter duration of estrogen exposure may elevate the risk of early miscarriage, while prolonged exposure to estrogen does not seem to confer advantages to general population and may be attempted in individuals with thin endometrium. Moreover, excessive estrogen levels on the day of progesterone administration may be associated with higher miscarriage rates and lower live birth rates (LBR). To offer more comprehensive guidance for clinical practice, extensive and prospective studies involving a large sample size are warranted to determine the optimal concentration and duration of estrogen exposure.

High concentration of estrogen resulted by COH may affect the secretion of pro-angiogenic factors in uNK cells by downregulating the expression of IL-11 in decidual stromal cells

OBJECTIVE

High serum estrogen concentrations after controlled ovarian hyperstimulation (COH) and fresh embryo transfers are associated with the increased risk of pregnancy complications resulting from aberrant placentation. Uterine natural killer (uNK) cells are important for establishment of pregnancy and normal placentation. It has been found that the proliferation and function of uNK cells are compromised by COH. However, the underlying role of high concentration of estrogen following COH in the abnormalities of uNK cells is poorly understood.

METHODS

Expression of cytokines and immunophenotype study of uNK was performed by flow cytometry analysis. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to quantify RNA expression; Western blot was performed to quantify protein levels.

RESULTS

The secretion level of pro-angiogenic factors in uNK cells is significantly reduced by co-culture with decidual stromal cells (DSCs) induced by high estrogen. It was discovered that COH and supraphysiologic levels of estrogen downregulated IL-11 in decidual tissue of mice. Additionally, we found that the downregulation of IL-11 is a major factor contributing to the downregulation of VEGF and PLGF in uNK cells. Moreover, we found that uNK cells may acquire IL-11Rα sequentially during differentiation and that only a portion of uNK cells are IL-11Rα positive. Lastly, we discovered that IL-11 may regulate VEGF and PLGF secretion in uNK cells via the ERK signaling pathway.

CONCLUSION

These results suggested the downregulation of IL-11 expression in DSCs caused by high estrogen levels affects the secretion of pro-angiogenic factors in uNK cells, which provided an explanation for the pregnancy complications caused by COH.

The effects of fresh embryo transfer and frozen-thawed embryo transfer on the perinatal outcomes of single fetuses from mothers with PCOS

PURPOSE

To investigate the effects of fresh embryo transfer and frozen-thawed embryo transfer on perinatal outcomes among patients with PCOS.

METHOD

Patients who underwent in vitro fertilization and embryo transfer at the reproductive medicine center of the Affiliated Hospital of Guangdong Medical University from February 2013 to March 2021 were retrospectively analyzed. Patients were divided into the fresh embryo transfer group and frozen-thawed embryo transfer group according to whether fresh embryo transfer was performed. According to their conditions, patients were further classified into the ET-PCOS group (group A, n = 104), ET-non-PCOS group (group B, n = 212), FET-PCOS group (group C, n = 102), or FET-non-PCOS group (group D, n = 148); the general data, laboratory indicators and pregnancy outcomes of the patients were statistically analyzed, and the perinatal outcomes and related factors between the groups were compared and analyzed.

RESULTS

The level of E2 on the HCG test day in the ET group was lower than that in the FET group. The natural birth rate of group D was lower than that of group A and group B, and the cesarean section rate was higher than that of group A and group B; the clinical pregnancy rate of group A was higher than that of group B and group D, and the difference was statistically significant (P < 0.05). There was no significant difference in the total abortion rate, early abortion rate or late abortion rate between the groups (P > 0.05). There was no significant difference in gestational age, neonatal sex or neonatal weight between the groups (P > 0.05). The incidence of placenta previa in Group B was significantly lower than that in Group D, and the difference was significant (P < 0.05). The incidence of fetal distress in Group B was significantly lower than that in Groups C and D, and the incidence of neonatal jaundice in Group D was significantly higher than that in Groups A and B (P < 0.05). In the multivariate analysis, the number of high-quality embryos was independent factors affecting clinical pregnancy, and the embryo transfer method was an independent factor affecting fetal distress and neonatal jaundice.

CONCLUSION

Young PCOS patients without risk of OHSS have a high clinical pregnancy rate with fresh transplant cycles. PCOS disease itself has no significant effect on the perinatal outcomes of the mother or singleton infant. Frozen-thawed embryo transfer may increase the incidence of low placenta, fetal distress and neonatal jaundice.

Association between serum hormone levels in early pregnancy and risk of hypertensive diseases of pregnancy in women undergoing assisted reproduction

PURPOSE

We examined the association between progesterone (P4), estradiol (E2), and human chorionic gonadotropin (hCG) levels in early pregnancy and the development of hypertensive diseases of pregnancy among women undergoing assisted reproduction.

METHODS

Retrospective study including patients who underwent frozen embryo transfer (FET), ovarian stimulation (OS), or unassisted conception (UC) and had a live singleton birth. The primary outcome was the development of hypertensive diseases of pregnancy (gestational hypertension, preeclampsia, HELLP, or eclampsia). Secondary outcomes were the development of fetal intrauterine growth restriction (IUGR), gestational diabetes mellitus, birth weight, and pre-term birth. Hormone levels and the development of the outcomes were correlated.

RESULTS

A total of 681 patients were included; 189 had FET, 193 had OS, and 299 had UC. Patients undergoing FET or OS were not more likely to develop hypertensive diseases of pregnancy compared with UC patients. While median levels of E2 and P4 were significantly different between P-FET and NC-FET patients (E2: 252 vs 317 pg/mL, P4: 64 vs 29 ng/mL, respectively; both p < 0.01), rates of hypertensive diseases of pregnancy did not significantly differ between those two groups. In the multivariate analyses, P4, E2, and hCG were not associated with the development of hypertensive diseases of pregnancy, but progesterone levels were significantly higher among those with IUGR. This remained consistent when the analysis was limited to FET patients.

CONCLUSION

P4, E2, and hCG levels did not correlate with the development of hypertensive diseases of pregnancy but elevated progesterone levels did correlate with the development of IUGR.

Up-regulated mRNA expression of VEGFA receptors (FLT1 and KDR) in placentas after assisted reproductive technology fertilization

Placental angiogenesis is a pivotal process for feto-maternal circulation and ensures efficient development of the placenta throughout pregnancy. Many factors during in vitro fertilization and embryo transfer procedures may affect placental gene expression and fetus development. The present study aimed to identify differences in angiogenesis-related gene (VEGFA, FGF2, FLT1, and KDR) expression profiles in placentas after assisted reproductive technology fertilization and natural conception in healthy women. In a case-control study, term placentas were collected from Caucasian women after assisted reproductive technology fertilization (N = 20) and after natural conception in women with uncomplicated pregnancy (N = 9). The mRNA expression in placentas was examined for VEGFA, FGF2, FLT1, and KDR genes by real-time quantitative polymerase chain reaction (RT-qPCR). Group stratification was performed for comparison of investigated genes between the type of embryo transferred (fresh/frozen), place of tissue donation (center/margin), and newborns' gender (male/female). In the ART placentas, significant down-regulation of VEGFA gene (p = 0.016) and up-regulation of FLT1 (p = 0.026) and KDR (p < 0.001) gene receptors were observed. Genes encoding VEGFA receptors were up-regulated in both fresh (ET) and frozen (FET) embryo transfer groups compared to controls. For the FLT1 gene, a statistically significant difference was observed between the frozen embryo transfer group and the controls (p = 0.032). Relative expression of KDR was significantly higher for both embryo transfer groups compared to controls (p < 0.001) and between ET and FET (p = 0.002). No statistically significant differences were observed between placental expression in different places of tissue donation and newborns' gender. We observed differences in the placental expression of VEGFA and its receptors FLT1 and KDR in pregnancies after assisted reproductive technology compared to naturally conceived pregnancies. More research is needed to clarify these alterations that may affect placental development and fetal health.

Obstetrical and neonatal outcomes after vitrified-warmed blastocyst transfer in day 1 rescue intracytoplasmic sperm injection cycles: a retrospective cohort study

BACKGROUND

Fertilization failure often occurs in conventional IVF cycles, and day 1 rescue ICSI is frequently recommended. In this study, the effect of rescue ICSI on obstetrical and neonatal outcomes after a single blastocyst transfer in vitrified-warmed cycles is evaluated.

METHODS

This cohort study was a retrospective analysis of 703 vitrified-warmed single blastocyst transfers and 219 singletons in the r-ICSI group compared with 11,611 vitrified-warmed single blastocyst transfers in the IVF/ICSI and 4472 singletons in the IVF/ICSI group, respectively, and patients just undergoing their first IVF treatments were included in this study. Pregnancy rate (PR), live birth rate (LBR), and singleton birthweight were the primary outcome measures. Multiple linear regression analysis and logistic regression analysis were performed to evaluate the possible relationship between obstetrical and neonatal outcomes and fertilization method (including IVF, ICSI, and r-ICSI) after adjusting for other potential confounding factors.

RESULTS

PR and the LBR were lower in the r-ICSI group compared with the IVF/ ICSI group. Singletons from the r-ICSI group had a higher Z-score and the proportion of large for gestational age (LGA) newborns was greater compared with singletons from the IVF/ICSI group.

CONCLUSION

The results of the study indicated that a 31% LBR after r-ICSI is acceptable for vitrified-warmed blastocyst transfer, but the safety of transfer is a concern because of the lower PR and LBR compared with IVF/ICSI. The safety of r-ICSI newborns is also a concern because of the significantly higher birthweight and the proportion of LGA in r-ICSI group newborns compared with the IVF/ICSI group.

Obstetric and Perinatal Outcomes following Ovulation Induction and Unassisted Pregnancies in the Same Mother

OBJECTIVE

We aimed to assess whether ovulation induction treatments affect obstetric and neonatal outcomes.

STUDY DESIGN

This was a historic cohort study of deliveries in a single university-affiliated medical center between November 2008 and January 2020. We included women who had one pregnancy following ovulation induction and one unassisted pregnancy. The obstetric and perinatal outcomes were compared between pregnancies following ovulation induction and unassisted pregnancies, so that each woman served as her own control. The primary outcome measure was birth weight.

RESULTS

A total of 193 deliveries following ovulation induction and 193 deliveries after unassisted conception by the same women were compared. Ovulation induction pregnancies were characterized by a significantly younger maternal age and a higher rate of nulliparity (62.7 vs. 8.3%, p < 0.001). In pregnancies achieved by ovulation induction, we found a higher rate of preterm birth (8.3 vs. 4.1%, p = 0.02) and instrumental deliveries (8.8 vs. 2.1%, p = 0.005), while cesarean delivery rates were higher following unassisted pregnancies. Birth weight was significantly lower in ovulation induction pregnancies (3,167 ± 436 vs. 3,251 ± 460 g, p = 0.009), although the rate of small for gestational age neonates was similar between the groups. On multivariate analysis, birth weight remained significantly associated with ovulation induction after adjustment for confounders, while preterm birth did not.

CONCLUSION

Pregnancies following ovulation induction treatments are associated with lower birth weight. This may be related to an altered placentation process following uterine exposure to supraphysiological hormonal levels.

KEY POINTS

· Ovulation induction entails lower birthweight.. · This may relate to supraphysiological hormonal levels.. · Monitoring fetal growth is advised in such cases..

High estradiol levels in fresh embryo transfer cycles are not associated with detrimental impact on birth outcomes

PURPOSE

There is an unclear relationship between estradiol levels and fresh embryo transfer (ET) outcomes. We determined the relationship between estradiol on the day of trigger, in fresh ET cycles without premature progesterone elevation, and good birth outcomes (GBO).

METHODS

We identified autologous fresh ET cycles from 2015 to 2021 at multiple clinics in the USA. Patients with recurrent pregnancy loss, uterine factor, and elevated progesterone on the day of trigger (progesterone > 2 ng/mL or 3-day area under the curve > 4.5 ng/mL) were excluded. The primary outcome was GBO (singleton, term, live birth with appropriate weight). Log-binomial generalized estimating equations determined the likelihood of outcomes.

RESULTS

Of 17,608 fresh ET cycles, 5025 (29%) yielded GBO. Cycles with estradiol ≥ 4000 pg/mL had a greater likelihood of GBO compared to cycles < 1000 pg/mL (aRR = 1.32, 95% CI 1.13-1.54). Pairwise comparisons of estradiol between < 1000 pg/mL versus 1000-1999 pg/mL and 1000-1999 pg/mL versus 2000-2999 pg/mL revealed a higher likelihood of GBO with higher estradiol (aRR 0.83, 95% CI 0.73-0.95; aRR 0.91, 95% CI 0.85-0.97, respectively). Comparisons amongst more elevated estradiol levels revealed that the likelihood of GBO remained similar between groups (2000-2999 pg/mL versus 3000-3999 pg/mL, aRR 1.04, 95% CI 0.97-1.11; 3000-3999 pg/mL versus ≥ 4000 pg/mL, aRR 0.96, 95% CI 0.9-1.04).

CONCLUSION

In fresh ET cycles, higher estradiol levels were associated with an increased prevalence of GBO until estradiol 2000-2999 pg/mL, thereafter plateauing. In fresh ET candidates, elevated estradiol levels should not preclude eligibility though premature progesterone rise, and risk of ovarian hyperstimulation syndrome must still be considered.

The POPI-Plus tool: prediction model of outcome of pregnancy in in vitro fertilization from a large retrospective cohort

OBJECTIVE

To create a tool that accurately predicts live birth chances after a positive pregnancy test after elective single embryo transfer (ET).

DESIGN

Retrospective cohort.

SETTING

CHUM hospital and Ovo clinic in Montreal, Canada.

PATIENT(S)

Patients with a positive pregnancy test result who underwent their first single ET after in vitro fertilization (IVF) at the CHUM hospital and Ovo clinic in Montreal, Canada, from 2012 to 2016 were selected. A total of 1,995 patients were included in this study.

INTERVENTION(S)

The data from both centers were combined and divided into training (70%, n = 1,398) and validation (30%, n = 597) sets. The predictive model was developed using backward selection method for the following variables: age of patient at egg retrieval; log β-human chorionic gonadotropin (β-hCG) (β-hCG) 1; log β-hCG 2; and IVF treatment type. Moreover, the classification tree, random forest, and neural network models were generated.

MAIN OUTCOME MEASURE(S)

The measured outcomes were live birth (live fetus ≥24 weeks of gestation) and nonviable pregnancies. The performance of all models was evaluated by area under the receiver operating characteristic curve (AUC).

RESULT(S)

Advancing age was negatively correlated with live birth. The odds ratio (OR) of age of patient at the time of egg retrieval was 0.95 (95% confidence interval [CI], 0.91-0.99). The log β-hCG 1 and log β-hCG 2 were positively correlated with live birth in the univariate analysis (OR, 4.15 [95% CI, 3.19-5.39], and OR, 3.84 [95% CI, 2.99-4.93], respectively). The β-hCG 1 level needed for a successful pregnancy was lower in frozen ET and modified natural IVF than in simulated IVF (OR, 0.55 [95% CI, 0.34-0.91], and OR, 0.49 [95% CI, 0.26-0.95], respectively). The best performance in terms of the AUC was the updated logistic model: POPI-Plus. The AUC values were 0.76 (95% CI, 0.73-0.79) and 0.78 (95% CI, 0.74-0.82) for the training and validation data, respectively. The other models (classification tree, random forest, and neural network) also performed adequately, with an AUC of ≥0.7, but remained below POPI-Plus. An open-access calculator was generated and can be found on the website of the University of Montreal on the following link: https://deptobsgyn.umontreal.ca/departement/divisions/medecine-et-biologie-de-la-reproduction/the-popi-plus-tool/.

CONCLUSION(S)

The POPI-Plus tool offers individualized counseling for patients after an initial positive β-hCG test result. Future studies will assess its impact on patient anxiety while awaiting viability ultrasound and perform prospective validation on new patients.

The impact of serum estradiol and progesterone levels during implantation on obstetrical complications and perinatal outcomes in frozen embryo transfer

BACKGROUND

This study sought to evaluate obstetric complications and perinatal outcomes in frozen embryo transfer (FET) using either a natural cycle (NC-FET) or a hormone therapy cycle (HT-FET). Furthermore, we investigated how serum levels of estradiol (E2) and progesterone (P4) on the day of and 3 days after embryo transfer (ET) correlated with clinical outcomes in the two groups.

METHODS

We conducted a retrospective, single-center study from January 1, 2015, to December 31, 2019. The study included couples who underwent NC-FET or HT-FET resulting in a singleton live birth. Serum levels of E2 and P4 were measured on the day of and 3 days after ET. The primary outcomes assessed were preterm birth rate, low birth weight, macrosomia, hypertensive disorders in pregnancy, gestational diabetes mellitus, postpartum hemorrhage, and placenta-related complications.

RESULTS

A total of 229 singletons were included, with 49 in the NC-FET group and 180 in the HT-FET group. There were no significant differences in obstetric complications and perinatal outcomes between the two groups. The NC-FET group had significantly higher serum levels of P4 (17.2 ng/mL vs 8.85 ng/mL; p < 0.0001) but not E2 (144 pg/mL vs 147 pg/mL; p = 0.69) on the day of ET. Additionally, 3 days after ET, the NC-FET group had significantly higher levels of both E2 (171 pg/mL vs 140.5 pg/mL; p = 0.0037) and P4 (27.3 ng/mL vs 11.7 ng/mL; p < 0.0001) compared with the HT-FET group.

CONCLUSION

Our study revealed that although there were significant differences in E2 and P4 levels around implantation between the two groups, there were no significant differences in obstetric complications and perinatal outcomes. Therefore, the hormonal environment around implantation did not appear to be the primary cause of differences in obstetric and perinatal outcomes between the two EM preparation methods used in FET.

Ultrasound evaluation of the cardiovascular system in offspring conceived through assisted reproductive technology

With the widespread application of assisted reproductive technology, the health issues of offspring conceived through assisted reproductive technology have also received increasing attention. Animal experiments and clinical studies have found subclinical adverse changes in the cardiovascular system of assisted reproductive offspring. Assisted reproductive technology itself may be just one of the many factors contributing to this phenomenon, with epigenetics playing an important role. Ultrasound technology can be used to assess the morphological structure and function of the cardiovascular system in assisted reproductive offspring from the fetal stage, providing the possibility to study the potential cardiovascular damage in this large population. This review aims to explore the effects and mechanisms of assisted reproductive technology on the cardiovascular system of offspring and provide a review of the research progress in ultrasound technology in this area.

Paternal age does not jeopardize the live birth rate and perinatal outcomes after in vitro fertilization: an analysis based on 56,113 frozen embryo transfer cycles

BACKGROUND

The global trend of delaying childbearing has led to an increasing number of couples seeking in vitro fertilization. The adverse effects of advanced maternal age on pregnancy and perinatal outcomes are well documented, regardless of the conception method. In addition, advanced paternal age may contribute to poor reproductive potential because of high levels of sperm DNA fragmentation. However, it remains challenging to guide older men regarding the effect of paternal age on pregnancy and birth outcomes in the field of assisted reproduction.

OBJECTIVE

This study aimed to investigate the association of paternal age with live birth and perinatal outcomes following in vitro fertilization-frozen embryo transfer.

STUDY DESIGN

A retrospective study was performed at a university-affiliated fertility center, involving women who were younger than 36 years and had undergone frozen embryo transfer from January 2011 to June 2021. Subjects were categorized into 6 groups based on paternal age: <25, 25 to 29, 30 to 34, 35 to 39, 40 to 44, and ≥45 years. A generalized estimating equation logistic regression model was used to account for the clustered nature of data and to adjust for confounders. Paternal age between 25 and 29 years served as the reference group in the logistic regression models.

RESULTS

A total of 56,113 cycles who met the inclusion criteria were included in the final analysis. On unadjusted analyses, the reproductive outcome parameters showed a considerable decline with increasing male age. The live birth rate decreased from 47.9% for men aged 25 to 29 years to 40.3% among men aged ≥40 years. Similarly, the clinical pregnancy rate decreased from 54.4% in the reference group to 47.8% in the ≥40 years age group. Conversely, the miscarriage rate increased as male age increased, from 10.2% among men aged 25 to 29 years to 13.5% among men aged ≥45 years. However, the differences in the reproductive outcomes mentioned above were no longer significant in the multivariable models. Compared with the younger controls, advanced paternal age was not associated with a lower chance of live birth (males aged 40-44 years: adjusted odds ratio, 0.94; 95% confidence interval, 0.85-1.04; males aged ≥45 years: adjusted odds ratio, 0.93; 95% confidence interval, 0.79-1.10). In addition, the rates of clinical pregnancy (males aged 40-44 years: adjusted odds ratio, 0.95; 95% confidence interval, 0.85-1.05; males aged ≥45 years: adjusted odds ratio, 0.94; 95% confidence interval, 0.79-1.12) and miscarriage (males aged 40-44 years: adjusted odds ratio, 1.05; 95% confidence interval, 0.85-1.31; males aged ≥45 years: adjusted odds ratio, 1.07; 95% confidence interval, 0.77-1.50) were comparable between the reference and advanced paternal age groups. Furthermore, men in the youngest age group (<25 years) did not have worse pregnancy outcomes than those in the reference group. Regarding perinatal outcomes, there was no difference among the study cohorts in terms of preterm birth, low birthweight, macrosomia, small for gestational age, and large for gestational age, both in the unadjusted and confounder-adjusted models.

CONCLUSION

This study did not demonstrate a significant association between paternal age and live birth and perinatal outcomes after in vitro fertilization-frozen embryo transfer when the female partners were younger than 36 years. With the global trend toward delaying childbirth, our findings provide useful information for counseling patients that increasing paternal age may not adversely affect pregnancy and perinatal outcomes in assisted reproduction.

Long-term health risk of offspring born from assisted reproductive technologies

Since the world's first in vitro fertilization baby was born in 1978, there have been more than 8 million children conceived through assisted reproductive technologies (ART) worldwide, and a significant proportion of them have reached puberty or young adulthood. Many studies have found that ART increases the risk of adverse perinatal outcomes, including preterm birth, low birth weight, small size for gestational age, perinatal mortality, and congenital anomalies. However, data regarding the long-term outcomes of ART offspring are limited. According to the developmental origins of health and disease theory, adverse environments during early life stages may induce adaptive changes and subsequently result in an increased risk of diseases in later life. Increasing evidence also suggests that ART offspring are predisposed to an increased risk of non-communicable diseases, such as malignancies, asthma, obesity, metabolic syndrome, diabetes, cardiovascular diseases, and neurodevelopmental and psychiatric disorders. In this review, we summarize the risks for long-term health in ART offspring, discuss the underlying mechanisms, including underlying parental infertility, epigenetic alterations, non-physiological hormone levels, and placental dysfunction, and propose potential strategies to optimize the management of ART and health care of parents and children to eliminate the associated risks. Further ongoing follow-up and research are warranted to determine the effects of ART on the long-term health of ART offspring in later life.

High estrogen during ovarian stimulation induced loss of maternal imprinted methylation that is essential for placental development via overexpression of TET2 in mouse oocytes

BACKGROUND

Ovarian stimulation (OS) during assisted reproductive technology (ART) appears to be an independent factor influencing the risk of low birth weight (LBW). Previous studies identified the association between LBW and placenta deterioration, potentially resulting from disturbed genomic DNA methylation in oocytes caused by OS. However, the mechanisms by which OS leads to aberrant DNA methylation patterns in oocytes remains unclear.

METHODS

Mouse oocytes and mouse parthenogenetic embryonic stem cells (pESCs) were used to investigate the roles of OS in oocyte DNA methylation. Global 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) levels were evaluated using immunofluorescence or colorimetry. Genome-wide DNA methylation was quantified using an Agilent SureSelectXT mouse Methyl-Seq. The DNA methylation status of mesoderm-specific transcript homologue (Mest) promoter region was analyzed using bisulfite sequencing polymerase chain reaction (BSP). The regulatory network between estrogen receptor alpha (ERα, ESR1) and DNA methylation status of Mest promoter region was further detected following the knockdown of ERα or ten-eleven translocation 2 (Tet2).

RESULTS

OS resulted in a significant decrease in global 5mC levels and an increase in global 5hmC levels in oocytes. Further investigation revealed that supraphysiological β-estradiol (E2) during OS induced a notable decrease in DNA 5mC and an increase in 5hmC in both oocytes and pESCs of mice, whereas inhibition of estrogen signaling abolished such induction. Moreover, Tet2 may be a direct transcriptional target gene of ERα, and through the ERα-TET2 axis, supraphysiological E2 resulted in the reduced global levels of DNA 5mC. Furthermore, we identified that MEST, a maternal imprinted gene essential for placental development, lost its imprinted methylation in parthenogenetic placentas originating from OS, and ERα and TET2 combined together to form a protein complex that may promote Mest demethylation.

CONCLUSIONS

In this study, a possible mechanism of loss of DNA methylation in oocyte caused by OS was revealed, which may help increase safety and reduce epigenetic abnormalities in ART procedures.

State of the Science and Ethical Considerations for Preimplantation Genetic Testing for Monogenic Cystic Kidney Diseases and Ciliopathies

There is a broad phenotypic spectrum of monogenic polycystic kidney diseases (PKDs). These disorders often involve cilia-related genes and lead to the development of fluid-filled cysts and eventual kidney function decline and failure. Preimplantation genetic testing for monogenic (PGT-M) disorders has moved into the clinical realm. It allows prospective parents to avoid passing on heritable diseases to their children, including monogenic PKD. The PGT-M process involves embryo generation through in vitro fertilization, with subsequent testing of embryos and selective transfer of those that do not harbor the specific disease-causing variant(s). There is a growing body of literature supporting the success of PGT-M for autosomal-dominant and autosomal-recessive PKD, although with important technical limitations in some cases. This technology can be applied to many other types of monogenic PKD and ciliopathies despite the lack of existing reports in the literature. PGT-M for monogenic PKD, like other forms of assisted reproductive technology, raises important ethical questions. When considering PGT-M for kidney diseases, as well as the potential to avoid disease in future generations, there are regulatory and ethical considerations. These include limited government regulation and unstandardized consent processes, potential technical errors, high cost and equity concerns, risks associated with pregnancy for mothers with kidney disease, and the impact on all involved in the process, including the children who were made possible with this technology.

Effect of development speed and quality of blastocyst on singleton birthweight in single frozen-thawed blastocyst transfer cycles

Background

Assisted reproductive technology (ART) has revolutionized infertility treatment, leading to a surge in ART-conceived children. Despite its success, ART-born offspring face higher risks of preterm birth (PTB), low birth weight (LBW), and small for gestational age (SGA). The mechanisms behind these outcomes remain unclear, partly attributed to multiple embryo transfers. Recent advancements advocate single blastocyst transfers for improved outcomes. However, the influence of blastocyst quality and development speed on neonatal outcomes is underexplored.

Objective

This study investigated whether blastocyst development speed and quality affect singleton birthweight when the blastocyst is selected for single frozen-thawed blastocyst transfer (FBT).

Methods

Data from patients who performed an FBT cycle at our center from July 2011 to June 2021 were collected and analyzed. Based on the inclusion and exclusion criteria, 420 single FBT cycles were assessed. The women were divided into four groups, Group A (day 5, good-quality blastocysts), Group B (day 5, non-good-quality blastocysts), Group C (day 6, good-quality blastocysts), and Group D (day 6, non-good-quality blastocysts) according to the developmental speed and quality of the transferred blastocyst.

Results

The birthweight was relatively the highest in Group A, which developed rapidly and transferred good quality blastocysts. However, no significant difference existed among the groups (P>0.05). The prevalence of premature birth (PTB), low birth weight (LBW), very low birth weight (VLBW), or high birth weight (HBW) was similar among the four groups (P > 0.05). No correlation existed between birth weight and blastocyst development speed or quality after adjusting for possible confounders (P > 0.05 respectively). However, the difference in the proportion of males born among the four groups was significant, especially in Group D, which was significantly lower than that in Group A (adjusted odds ratio = 0.461, 95% confidence interval: 0.230-0.921, P < 0.05).

Conclusions

This retrospective cohort study suggests that the combined effect of blastocyst development speed and quality on neonatal birthweight is insignificant. The transfer of slow-growing, non-good-quality blastocysts increases the chance of a female baby being born.

Comparison of the duration of estradiol administration and the effect on pregnancy outcome of day 3 vitrified-warmed embryo transfer cycle: a randomized controlled trial

Based on the fact that the follicular phase in the menstrual cycle has length variation, it has been assumed that the duration of oestrogen (E2) administration could also be variable; therefore, for the first time, this randomized clinical trial study was conducted to investigate and compare the duration of estradiol administration and the effect on pregnancy outcomes in the cleavage-stage frozen embryo transfer (FET) cycle. We included women aged 20-40 with a normal uterus on hysteroscopy between September and December 2022 and who were divided randomly into three groups: group A [n = 79; 8-11 days of oestrogen before progesterone (P4) supplementation], group B (n = 78; 12-14 days of oestrogen before P4 supplementation), and group C (n = 76; 15-18 days of estrogen before P4 supplementation). Serum levels for E2 on the initial progesterone day and P4 on the transfer day were measured. The effect of the duration of E2 administration on clinical pregnancy and pregnancy loss was investigated. We found no significant differences between the three groups in the clinical pregnancy rate (P = 0.696) and clinical abortion rate (P = 0.925) according to the duration of the E2. There was no significant difference in the E2, P4 levels, and endometrial thickness in pregnant vs. non-pregnant women. The mean of the E2 and P4 levels was 300.03 ± 22.21 and 25.36 ± 5.78, respectively. Our findings suggest that variation in the length of E2 administration (8-18 days) before progesterone initiation in day 3 FET cycles does not affect pregnancy outcome and transfer time can be flexibly arranged.

Young women were associated with higher risk of hypertensive disorders of pregnancy and cesarean section from hormone replaced cycles in frozen-thawed embryo transfer: a retrospective study of 5316 singleton deliveries

Background

The utilization of frozen-thawed embryo transfer (FET) cycles has been linked to heightened risks of adverse perinatal outcomes. However, the potential association between adverse perinatal outcomes and distinct endometrial preparation regimens remains unclear. Therefore, we aim to investigate the maternal and neonatal outcomes after hormone replacement treatment (HRT) cycles, natural cycles (NC) and HRT cycles with pretreatment using GnRHa (HRT + GnRHa) for ovulatory women undergoing FET cycles.

Methods

A large sample retrospective cohort study was carried out from 2016 to 2020. The data included a total of 5316 women who had singleton deliveries undergoing FET cycles and which were divided into three groups based on different endometrial preparation protocols: 4399 patients in HRT groups, 621 in GnRHa+HRT groups, 296 in NC groups. The outcomes consisted of maternal outcomes (cesarean section, hypertensive disorders of pregnancy (HDP), placenta previa, gestational diabetes mellitus (GDM));and neonatal outcomes (preterm birth, newborn birthweight, low birthweight, small for gestational age (SGA), macrosomia, large for gestational age (LGA), fetal malformation).

Results

After adjusting for a series of confounding variables, we found an increased risk of HDP (aOR=3.362; 95%CI, 1.059-10.675) and cesarean section (aOR=1.838; 95%CI, 1.333-2.535) in HRT cycles compared with NC, especially for ovulatory women under 35 years old. However, in all three groups, newborn birth weight was not significantly different. Meanwhile, perinatal outcomes did not differ significantly in terms of perinatal outcomes in HRT +GnRHa cycles compared with HRT cycles solely.

Conclusion

During FET cycles, singletons from HRT were related to higher risks of HDP and cesarean section, particularly for young women. GnRHa pretreatment didn't bring any benefit to perinatal outcomes compared with HRT cycles alone. Therefore, the natural cycle may be a more appropriate and safer option for young ovulatory women.

Obstetric and perinatal outcomes after embryos cultured in one-step versus sequential culture media systems in vitrified-warmed single blastocyst transfer cycles

RESEARCH QUESTION

Does type of culture medium used influence obstetric and perinatal outcomes after vitrified-warmed single blastocyst transfers?

DESIGN

Retrospective cohort study involving singletons after vitrified-warmed single blastocyst embryo transfers, using embryos cultured in either Irvine Continuous Single Culture medium (CSC) or Vitrolife G5TM PLUS medium culture system between 2013 and 2020.

RESULTS

A total of 2475 women who had singleton deliveries were included for final analysis: 1478 had embryos cultured in CSC and 997 had embryos cultured in G5TM PLUS medium. Birth outcomes, including preterm birth, mean birth weight, gestational age- and sex-adjusted birth weight (Z-scores), rates of large-for-gestational-age, small-for-gestational-age, low birth weight and macrosomia, and the distribution of newborn gender did not differ significantly between groups in crude and adjusted analyses. Women whose embryos were cultured in G5TM PLUS frequently suffered from pregnancy-induced hypertensive disorders compared with those who had embryos cultured in CSC (4.7% versus 3.0%; P = 0.031). This difference was no longer significant after adjusting for several key confounders (adjusted odds ratio 1.49, 95% CI 0.94 to 2.38, P = 0.087). Other obstetric complications, including gestational diabetes mellitus, preterm premature rupture of membranes, abnormal placentation, postpartum haemorrhage and the mode of delivery were all similar between the two groups.

CONCLUSIONS

The present study adds new information to the current evidence by suggesting that the embryo culture medium does not affect birth outcomes and obstetric complications when comparison is limited to Irvine CSC and Vitrolife G5TM PLUS in vitrified-warmed single blastocyst transfer cycles.

Progesterone levels during ovarian stimulation in segmented ART cycles inversely correlate with normalized birthweight of neonates conceived through subsequent frozen-thawed embryo transfer

PURPOSE

To evaluate the association between serum progesterone (P) at the day of ovulation trigger and neonatal birthweight in singletons born after frozen-thawed embryo transfer in segmented ART cycles.

METHODS

A retrospective multicenter cohort study involving data from patients who achieved uncomplicated pregnancy and term delivery of ART-conceived singleton babies following a segmented GnRH antagonist cycle. The main outcome was birthweight's z-score of the neonate. Univariate and multivariate linear logistic regression analyses were made to investigate the relation of z-score with variables inherent to the patient and to the ovarian stimulation. The variable P per oocyte was created by dividing the value of progesterone at ovulation trigger by the number of oocytes retrieved at oocyte retrieval.

RESULTS

A total of 368 patients were included in the analysis. At univariate linear regression, the birthweight z-score of the neonate appeared to be inversely related to both P levels at the ovulation trigger (- 0.101, p = 0.015) and P levels per oocyte at trigger (- 1.417, p = 0.001), while it was directly related to the height of the mother (0.026, p = 0.002) and to the number of previous live births (0.291, p = 0.016). In multivariate analysis, both serum P (- 0.1; p = 0.015) and P per oocyte (- 1.347, p = 0.002) maintained the significant inverse association with birthweight z-score after adjusting for height and parity.

CONCLUSIONS

Serum progesterone level on the day of ovulation trigger inversely correlates with normalized birthweight of neonates in segmented GnRH antagonist ART cycles.

The duration of estrogen treatment before progesterone application does not affect neonatal and perinatal outcomes in frozen embryo transfer cycles

Objective

To explore whether the duration of estrogen treatment before progesterone application affects neonatal and perinatal outcomes in artificial frozen embryo transfer (FET) cycles.

Methods

This was a retrospective cohort study. Patients who underwent FET via artificial cycles and delivered a singleton live birth between January 2015 and August 2019 were included in the analysis. According to the duration of estrogen treatment before progesterone application, we divided the cycles into four groups: ①≤12 days, ②13-15 days, ③16-19 days, and ④≥20 days. The '≤12 days group' was considered the reference group. The main outcome measures were preterm birth (PTB), small-for-gestational age (SGA), low birth weight (LBW), macrosomia, large-for-gestational age (LGA), gestational diabetes mellitus (GDM), gestational hypertension, premature rupture and placenta previa.

Results

Overall, 2010 FET cycles with singleton live births were included for analysis. Cycles were allocated to four groups according to the duration of estrogen treatment before progesterone application: ①≤12 days (n=372), ②13-15 days (n=745), ③16-19 days (n=654), ④≥20 days (n=239). The neonatal outcomes, including PTB, SGA, LBW, macrosomia and LGA, were comparable among the groups (P=0.328, P=0.390, P=0.551, P=0.565, P=0.358). The rates of gestational hypertension, premature rupture and placenta previa (P=0.676, P=0.662, P=0.211) were similar among the groups. The rates of GDM among the four groups were 4.0% (15/372), 6.7% (50/745), 6.4% (42/654), and 11.3% (27/239), with statistical significance (P=0.006). After multiple logistic regression analysis, the duration of estrogen treatment did not affect the rate of GDM or other outcomes.

Conclusion

The estrogen treatment duration before progesterone application does not affect neonatal and perinatal outcomes in single frozen blastocyst transfer cycles.

The effect of peak serum estradiol level during ovarian stimulation on cumulative live birth and obstetric outcomes in freeze-all cycles

Objective

To determine whether the peak serum estradiol (E2) level during ovarian stimulation affects the cumulative live birth rate (CLBR) and obstetric outcomes in freeze-all cycles.

Methods

This retrospective cohort study involved patients who underwent their first cycle of in vitro fertilization followed by a freeze-all strategy and frozen embryo transfer cycles between January 2014 and June 2019 at a tertiary care center. Patients were categorized into four groups according to quartiles of peak serum E2 levels during ovarian stimulation (Q1-Q4). The primary outcome was CLBR. Secondary outcomes included obstetric and neonatal outcomes of singleton and twin pregnancies. Poisson or logistic regression was applied to control for potential confounders for outcome measures, as appropriate. Generalized estimating equations were used to account for multiple cycles from the same patient for the outcome of CLBR.

Results

A total of 11237 patients were included in the analysis. Cumulatively, live births occurred in 8410 women (74.8%). The live birth rate (LBR) and CLBR improved as quartiles of peak E2 levels increased (49.7%, 52.1%, 54.9%, and 56.4% for LBR; 65.1%, 74.3%, 78.4%, and 81.6% for CLBR, from the lowest to the highest quartile of estradiol levels, respectively, P<0.001). Such association remained significant for CLBR after accounting for potential confounders in multivariable regression models, whereas the relationship between LBR and peak E2 levels did not reach statistical significance. In addition, no significant differences were noticed in adverse obstetric and neonatal outcomes (gestational diabetes mellitus, pregnancy-induced hypertension, preeclampsia, placental disorders, preterm birth, low birthweight, and small for gestational age) amongst E2 quartiles for either singleton or twin live births, both before and after adjustment.

Conclusion

In freeze-all cycles, higher peak serum E2 levels during ovarian stimulation were associated with increased CLBR, without increasing the risks of adverse obstetric and neonatal outcomes.

Influence of maternal age on the birthweight of infants delivered from frozen-thawed blastocyst transfer cycles

The aim of this study was to investigate whether maternal age had an effect on the birthweight of singletons delivered from frozen-thawed blastocyst transfer (FBT) cycles. A total of 1203 FBT cycles occurring between July 2011 and June 2021 at a single centre were retrospectively analysed. Based on the maternal age at FBT, the patients were divided into four groups: <30, 30-34, 35-37, and ≥38 years of age. Main outcomes measured included singleton birthweights, preterm births, large-for-gestational-age (LGA) and small-for-gestational-age (SGA) live births among the groups. There was no significant difference in birth weight among the four groups, while the highest birth weight was found in the <30 years group. The incidence of very preterm births and very low birth weights demonstrated an increasing trend with age; on the contrary, the incidence of preterm births, low birth weight (LBW), high birth weight and LGA and SGA live births gradually decreased with increasing age, but these differences were not statistically significant among groups (P>0.05, respectively). Although the proportion of females was lower than that of males, the difference was not statistically significant among the groups. After adjusting for possible confounders, maternal age was found to have no effect on adverse neonatal outcomes in the regression analyses (P>0.05). Birthweight in singleton births from FBT was not affected by maternal age.

Pregnancy Outcomes Associated with Ovarian Hyperstimulation Syndrome: A Retrospective Cohort Study of Infertile Women

Objective

To assess the relationship between ovarian hyperstimulation syndrome (OHSS) and adverse outcomes using population-based data in the United States. The hypothesis is that patients with OHSS were more likely to deliver preterm and more likely to have hypertensive disorders.

Methods

This retrospective cohort study identified 94 patients with OHSS and 183 matched referents in eight counties in Minnesota. Data were collected regarding pregnancy history, infertility treatment, and pregnancy outcomes. Using the Rochester Epidemiology Project, study subjects were identified from female patients, aged 18 to 49 years, who were diagnosed with infertility from January 2, 1995 to December 1, 2017, and had a pregnancy greater than 20 weeks' gestation. The primary outcome was preterm delivery or hypertensive disorder of pregnancy incidence in the OHSS group when compared with control patients. Chi-squared test, t test, and multivariate logistic models were used where appropriate.

Results

Patients with OHSS were more likely to deliver preterm (odds ratio, 2.14; 95% confidence interval, 1.26-3.65; P < 0.01), and their neonates were more likely to be small for gestational age (odds ratio, 4.78; 95% confidence interval, 1.61-14.19; P < 0.01). No significant differences between the groups were observed in any other outcome. Patients with OHSS are more likely to deliver preterm if they undergo fresh transfer compared with a freeze all and subsequent frozen transfer (odds ratio, 3.03, 95% confidence interval, 1.20-7.66, P = 0.02).

Conclusion

OHSS may lead to preterm birth and small-for-gestational-age neonates, which changes patient counseling and leads to arranging specialized obstetrical care for these patients with OHSS.

IVF/ICSI Outcomes After a Freeze-All Strategy: an Observational Cohort Study

In order to inform patients undergoing ART regarding their chances for motherhood, it seems useful to describe "freeze all" outcomes according to the different potential indications. The goal of this study was to examine the impact of a "freeze-all approach" on the cumulative live birth rate (cLBR) according to the indication. It is a cohort study including women who had undergone ovarian stimulation (OS) using an antagonist protocol with GnRH agonist triggering between 09.2016 and 09.2018 followed by a freeze-all cycle of blastocyst embryos. The ART outcomes were compared between the two main indications of the freeze-all strategy which were in our cohort: risk of ovarian hyperstimulation syndrome (OHSS) and endometriosis. The ART outcomes were also described for the others indications (inadequate endometrium and/or premature progesterone elevation at trigger day, two or more previous ART failures, and autoimmune disease and/or a high risk of thromboembolic disease (AI and/or TE risk)). In total, 658 women were included. The cLBR in the total population was 37.7% (248/658). The cLBR was significantly higher in the "OHSS risk" group (133/281, 47.3%) than in the "endometriosis" group (69/190, 36.3%) (p = 0.017). No significant differences were noted regarding perinatal outcomes, except a significantly higher risk of placenta praevia (PP) observed in the "endometriosis" group (10.1%) (p = 0.002). The "freeze-all approach" yielded good results in terms of the cLBR and especially in case of OHSS risk. These data should be taken into account when informing patients about the ART strategy and their chances of motherhood.

Number of oocytes and IVF outcomes: Real-world evidence

Randomized controlled trials (RCTs) are gold standard to study the effect of an intervention and establish causation between the treatment and outcomes. However, RCTs have the disadvantage of being expensive, entailing high resource investments and involving only selected patient populations under experimental settings. Real-world evidence (RWE) from real-world data (RWD) involves a heterogenous patient population in real-world settings. RWE is less expensive and quicker than RCTs; it can provide complimentary evidence if methodological challenges, such as residual confounding and susceptibility to bias, are considered when interpreting the findings. This review examines RWE regarding the association between the number of oocytes following ovarian stimulation and IVF outcomes into shaping current IVF practices.

Effect of serum progesterone on human chorionic gonadotropin trigger day / metaphase II oocyte ratio on pregnancy and neonatal outcomes in women undergoing ICSI cycle

BACKGROUND

The serum progesterone on human chorionic gonadotropin trigger day / metaphase II oocyte (P/MII) ratio might be a more predictable indicator of pregnancy and neonatal outcomes as compare to P/estradiol (E2) or P alone. Hence, we conducted a larger population study to compare the pregnancy and neonatal outcomes in the low and high P/MII ratio.

METHODS

A retrospective, single-center, larger population cohort study between January 2015 and August 2021. Calculate the threshold effect of P/MII ratio on clinical pregnancy rate according to the construct smooth curve fitting. Divide data into two groups by threshold for comparison.

RESULTS

3566 fresh ICSI-ET cycles were included, in which 929 singleton delivery and 676 twin deliveries. Compare to P/MII ≤ 0.367 group, it indicated that the P/MII > 0.367 group had a lower clinical pregnancy rate and live birth rate, furthermore, a significantly higher rate of LBW and SGA were observed in the singleton and twin deliveries. No deleterious impact of high P/MII ratio on embryo quality and undesirable pregnancy outcomes was shown.

CONCLUSIONS

When P/MII is higher than 0.367, may have adverse impacts on pregnancy and neonatal outcomes for ICSI cycle.

The effect of the day 3 embryo cell number on the neonatal outcomes of day 5 single blastocyst transfer in frozen embryo transfer cycles

OBJECTIVE

To evaluate the influence of the day 3 embryo cell number on the neonatal outcomes of day 5 single blastocyst transfer in frozen embryo transfer (FET) cycles.

METHODS

This retrospective study analysed a total of 2315 delivery cycles of day 5 single blastocyst transfer in FET cycles, including 489, 761 and 1103 live-born infants segregated according to a day 3 embryo cell number of <8, 8 and >8 cells, respectively. The neonatal outcomes of the three groups were compared.

RESULTS

The day 3 embryo cell number did not significantly affect the incidence of monozygotic twins. The sex ratio increased as the day 3 embryo cell number increased, but the difference was not statistically significant. There were no significant differences in the rates of preterm birth or low birth weight among the three groups. The rates of stillbirths and neonatal deaths were also not significantly different among the three groups. Moreover, the day 3 embryo cell number did not increase the risk of birth defects in newborns.

CONCLUSIONS

The day 3 embryo cell number did not significantly affect neonatal outcomes.

Does endometrial thickness affect birth weight and serum levels of pregnancy-associated plasma protein-A in frozen cycles?

OBJECTIVE

To investigate whether endometrial thickness (EMT) affects birth weight and maternal serum pregnancy-associated plasma protein-A (PAPP-A) level in singleton pregnancies following frozen-thawed blastocyst transfer (FET).

METHODS

This retrospective study included women who underwent first-trimester combined screening for aneuploidy after FET, and subsequently delivered a singleton live birth after 24 weeks of gestation at a private in-vitro fertilization centre. The subjects were stratified into three groups based on EMT percentiles: <7.7 mm (<10th percentile), 7.7-12 mm (10-90th percentile), and > 12 mm (>90th percentile). Multi-variable linear regression analysis was undertaken to identify the association between birth weight and EMT after adjusting for variables with p < 0.1 on univariate analysis.

RESULTS

In total, 560 women met the inclusion criteria. Mean (±standard deviation) birth weight was 3127 ± 783 g in those with EMT < 7.7 mm, 3225 ± 644 g in those with EMT 7.7-12 mm, and 3256 ± 599 g in those with EMT > 12 mm (p = 0.577). Mean PAPP-A and PAPP-A < 0.5 rates were similar in the three groups. On multi-variate analysis, maternal serum PAPP-A was found to be a significant predictor of birth weight (p = 0.013), but EMT was not found to be predictive of birth weight on univariate or multi-variate analysis.

CONCLUSION

This study provided a new angle to evaluate the association between EMT and neonatal birth weight by analysing this association along with maternal serum PAPP-A as a marker for placental function, suggesting that EMT is not an independent factor for neonatal birth weight.

The gestational age-specific difference in birthweight between singletons born after fresh and frozen embryo transfer: A cohort study

INTRODUCTION

Accumulating studies have suggested singletons born after frozen embryo transfer (FET) were higher than those born after fresh embryo transfer (Fre-ET). However, fewer studies had investigated the gestational age-specific between-group difference in birthweight. This study aimed to investigate the gestational week-specific difference in singleton birthweight after FET vs Fre-ET and explore potential factors that impact the difference.

MATERIAL AND METHODS

In this retrospective cohort study, a total of 25 863 singletons were included. Multivariable linear regression and logistic regression were used to evaluate the between-group differences in mean birthweight and the incidences of large for gestational age (LGA) and small for gestational age (SGA), respectively.

RESULTS

Multivariable regression analyses showed a statistically significant interaction between types of embryo transfer (ie FET vs Fre-ET) and the gestational week on mean birthweight (P < 0.001) and on the risks of large for gestational age (P = 0.001) and small for gestational age (P < 0.001). When stratified by gestational week, the differences in mean birthweight and the risks of LGA and SGA were only observed in singletons born at 37 gestational weeks or later. After adjusting for confounders, full-term but not preterm singletons born after FET had a higher birthweight (3497.58 ± 439.73 g vs 3445.67 ± 450.24 g; adjusted mean difference 58.35 g; 95% confidence interval [CI] 38.72-77.98 g), a higher risk of LGA (24.3% vs 21.1%; adjusted odds ratio [OR] 1.28, 95% CI 1.15-1.42) and a lower risk of SGA (3.1% vs 4.8%; adjusted OR 0.61, 95% CI 0.53-0.70) compared with those born after Fre-ET.

CONCLUSIONS

The differences in birthweight between FET and Fre-ET were observed in full-term singletons but not preterm singletons.

The impact of maternal ABO blood type on obstetric and perinatal outcomes after frozen embryo transfer

RESEARCH QUESTION

Does the maternal ABO blood type affect obstetric and perinatal outcomes following frozen embryo transfer (FET)?

DESIGN

A retrospective study was performed at a university-affiliated fertility centre, involving women with singleton and twin deliveries conceived by FET. Subjects were divided into four groups based on ABO blood type. The primary end-points were obstetric and perinatal outcomes.

RESULTS

A total of 20,981 women were involved, with 15,830 having singletons and 5151 delivering twins. In singleton pregnancies, women with blood group B had a slight but significantly increased risk of gestational diabetes mellitus compared to women with blood group O (adjusted odds ratio [aOR] 1.16; 95% confidence interval [CI] 1.01-1.34). Furthermore, singletons born to women with the B antigen (blood type B or AB) were more likely to be large for gestational age (LGA) and with macrosomia. In twin pregnancies, blood type AB was related to a decreased risk of hypertensive diseases of pregnancy (aOR 0.58; 95% CI 0.37-0.92), while blood type A was associated with a higher risk of placenta praevia (aOR 2.04; 95% CI 1.15-3.60). When compared with the O blood group, twins from the AB blood group had a lower risk of low birthweight (aOR 0.83; 95% CI 0.71-0.98) but a higher risk of LGA (aOR 1.26; 95% CI 1.05-1.52).

CONCLUSIONS

This study demonstrates that the ABO blood group may influence the obstetric and perinatal outcomes for both singletons and twins. These findings emphasize that patient characteristics could be, at least partly, responsible for adverse maternal and birth outcomes following IVF.

The effect of oestrogen dose and duration in programmed frozen cycles on obstetric outcomes and placental findings

RESEARCH QUESTION

Does programmed frozen embryo transfer (FET) with high-dose oestrogen affect obstetric outcomes and placental findings?

DESIGN

A retrospective cohort of live singleton deliveries at a single institution between 2009 and 2017, including deliveries attained by IVF with programmed FET; oocyte recipients were excluded. High-dose oestrogen was defined as a daily dose >6 mg throughout treatment. All placentas were evaluated regardless of complication status and the Amsterdam classification was used to analyse findings.

RESULTS

A total of 57 deliveries in the high-dose oestrogen group were compared with 274 controls. The high-dose oestrogen group displayed significantly longer duration of oestrogen treatment (18.8 ± 4.9 versus 13.3 ± 2.7 days, P < 0.001), total cumulative oestrogen dose (149.7 ± 46.1 versus 80.3 ± 16.8 mg, P < 0.001) and lower endometrial thickness (8.5 ± 1.4 versus 9.8 ± 1.7 mm, P < 0.001). After adjustment for confounders, higher dose oestrogen was found to be associated with a lower average birthweight (coefficient -252.4 g, 95% confidence interval [CI] -483.5 to -21.2), a higher rate of low-birthweight neonates (adjusted odds ratio [aOR] 4.88, 95% CI 1.05 to 22.57), bilobated placentas (aOR 3.36, 95% CI 1.04 to 10.89), accessory lobes (aOR 8.74, 95% CI 1.24 to 61.5), accelerated villous maturation (aOR 2.06, 95% CI 1.09 to 3.87), retroplacental haematoma (aOR 5.39, 95% CI 1.11 to 26.13) and maternal malperfusion lesions (aOR 1.46, 95% CI 1.04 to 2.05).

CONCLUSION

A higher daily oestrogen dose in programmed FET is associated with low birthweight and placental changes, although this may relate to altered endometrial properties and not to the treatment itself.

E2 level > 2950 pg/ml on hCG trigger day is an independent predictor for birthweight loss of full-term singletons born after fresh embryo transfers in non-PCOS patients

BACKGROUND

Previous studies have demonstrated that the supraphysiological E2 level is negatively correlated with birthweight. However, the cut-off value of E2 level that significantly affects birthweight is unknown, and there is no definite conclusion regarding this level. Our study aimed to explore the threshold of the effect of E2 levels on birthweight.

DESIGN

A retrospective cohort study of 1846 samples was performed. All patients ≤42-years-old underwent autologous IVF cycles between August 1st, 2016 and April 30th, 2020. We categorized our data into four groups according to the E2 level: Group 1: ≤2000 pg/mL; Group 2: 2001-3000 pg/mL; Group 3: 3001-4000 pg/mL; and Group 4: > 4000 pg/mL.

RESULTS

The results of the multivariate regression analyses showed that when the E2 level was 3001-4000 pg/mL (adjusted β: - 89.64, 95% [CI]: - 180.29 to - 6.01; P = 0.0336) and greater than 4000 pg/mL (adjusted β: - 138.10, 95% [CI]: - 272.87 to - 10.33; P = 0.0181), weight loss was significant. Furthermore, the odds of full-term SGA were 1.40 times higher with E2 levels of 3001-4000 pg/mL (adjusted OR: 1.40, 95% [CI]: 1.090 to 3.18; P = 0.0256) and 2.55 times higher with E2 > 4000 pg/mL (adjusted OR: 2.55, 95% [CI]: 1.84 to 3.86; P = 0.0063) compared to the reference group. It can also be seen from the adjusted curves and the threshold effects that when the E2 level > 2950 pg/mL and > 3121 pg/mL, the incidence of SGA increased and the birthweight decreased, respectively.

CONCLUSIONS

Our data suggest that E2 levels > 2950 pg/mL is an independent predictor for greater odds of full-term SGA singletons born after fresh embryo transfer.

Obstetric outcomes following ovarian hyperstimulation syndrome in IVF - a comparison with uncomplicated fresh and frozen transfer cycles

Background

We aimed to assess the correlation between ovarian hyperstimulation syndrome (OHSS) in the early course of in vitro fertilization (IVF) pregnancies and obstetric outcomes.

Methods

We identified records of patients admitted due to OHSS following IVF treatment at our institution between 2008 and 2020. Cases were included if pregnancy resulted in a live singleton delivery (OHSS group). OHSS cases were matched at a 1:5:5 ratio with live singleton deliveries following IVF with fresh embryo transfer (fresh transfer group) and frozen embryo transfer (FET group), according to maternal age and parity. Computerized files were reviewed, and maternal, obstetric and neonatal outcomes compared.

Results

Overall, 44 OHSS cases were matched with 220 fresh transfer and 220 FET pregnancies. Patient demographics were similar between the groups, including body mass index, smoking and comorbidities. Gestational age at delivery, the rate of preterm births, preeclampsia and cesarean delivery were similar between the groups. Placental abruption occurred in 6.8% of OHSS pregnancies, 1.4% of fresh transfer pregnancies and 0.9% of FET pregnancies (p=0.02). On post-hoc analysis, the rate of placental abruption was significantly higher in OHSS pregnancies, compared with the two other groups, and this maintained significance after adjustment for confounders. Birthweights were 3017 ± 483, 3057 ± 545 and 3213 ± 542 grams in the OHSS, fresh transfer and FET groups, respectively (p=0.004), although the rate of small for gestational age neonates was similar between the groups.

Conclusions

OHSS in the early course of IVF pregnancies is associated with an increased risk of placental abruption.

Gonadotropin Stimulation Reduces the Implantation and Live Birth Rate but Not the Miscarriage Rate of Embryos Transferred When Compared to Unstimulated In Vitro Fertilization

Research suggests that gonadotropin stimulation in in vitro fertilization (IVF) treatment affects embryo quality and the endometrium that might influence embryo implantation, placentation and establishment of a viable pregnancy. We assessed the impact of gonadotropin stimulation on implantation, live birth and miscarriage rates per transferred embryo by comparing stimulated and unstimulated IVF treatment. In a cohort of 728 couples, 1310 IVF cycles with successful embryo transfer were analysed; 857 cycles were stimulated with gonadotropins > 75 IU/day (333 poor responder < 4 oocytes; 524 normal responders), and 453 were unstimulated. In total, 1913 fresh cleavage-stage embryos were transferred. Zygote but no embryo selection was performed, and supernumerous zygotes were vitrified. The implantation rate was defined as number of sonographically detected amniotic sacs; live birth rate as number of children born per transferred embryo. Modified mixed effect Poisson regression was used to account for the dependency of cycles and embryos within the same women and the same transfer cycle. Adjustments were made for maternal age, parity, primary or secondary infertility and indication for IVF. Per transferred embryo, implantation rates (rate ratio (RR) 1.37; 95% CI 1.04-1.81; p = 0.028; aRR 1.42; 95% CI 1.10-1.84; p = 0.008) and live birth rates (RR 1.33; 95% CI 0.95-1.86; p = 0.093; aRR 1.38; 95% CI 1.01-1.88; p = 0.044) were higher in NC-IVF compared to cIVF normal responders. Miscarriage did not differ (RR 0.99; 95% CI 0.59-1.65; p = 0.965; aRR 0.90; 95% CI 0.52-1.53 p = 0.698). Similar results were obtained in poor responders. The study suggests an impact of gonadotropin stimulation on the implantation potential of embryos.

Maternal and obstetric outcomes are influenced by developmental stage and cryopreservation of transferred embryos after clomiphene citrate-based minimal stimulation IVF

STUDY QUESTION

Is the embryo transfer (ET) method associated with maternal and perinatal outcomes after minimal stimulation IVF using clomiphene citrate (CC)?

SUMMARY ANSWER

The incidence of pregnancy complications and adverse perinatal outcomes was influenced by the developmental stage (cleavage versus blastocyst stages) and cryopreservation (fresh versus vitrified) of the transferred embryos.

WHAT IS KNOWN ALREADY

Pregnancies resulting from IVF are associated with higher risks of adverse perinatal outcomes compared to natural conceptions; therefore, the next focus in reproductive medicine should be to assess whether these increased risks are attributable to IVF. Pregnancy complications and perinatal outcomes should be considered in addition to pregnancy outcomes when selecting the ET method, however, studies that describe the influence of transfer methods on perinatal and maternal outcomes are limited.

STUDY DESIGN, SIZE, DURATION

This study retrospectively analysed a large single-centre cohort. The clinical records of 36 827 women who underwent oocyte retrieval (during a CC-based minimal stimulation cycle) followed by their first ET at the fertility treatment centre between January 2008 and December 2017 were retrospectively analysed. The patients underwent a single fresh cleavage-stage ET (SFCT), single vitrified-warmed cleavage-stage ET (SVCT) or single vitrified-warmed blastocyst transfer (SVBT). This study only included one cycle per patient.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Oocyte retrieval was performed following CC-based minimal ovarian stimulation. The embryos were transferred 2–3 days after retrieval or vitrified at the cleavage or blastocyst stage. The vitrified embryos were then warmed and transferred within the natural cycles. Pregnancy complications and perinatal outcomes were stratified according to the transfer methods used. Multivariate logistic regression analysis was performed to evaluate the effect of ET methods on the prevalence of pregnancy complications and congenital anomalies.

MAIN RESULTS AND THE ROLE OF CHANCE

The rates of clinical pregnancy and delivery were significantly different among the groups. We analysed pregnancy complications in 7502 singleton births (SFCT, 3395 cycles; SVCT, 586 cycles; and SVBT, 3521 cycles). Multivariate logistic regression analysis revealed that the adjusted odds ratio (AOR) for hypertensive disorders in pregnancy was significantly lower in the SVBT group than in the SFCT group [AOR, 0.72; 95% CI, 0.56–0.92]. The AOR for low-lying placenta was lower in the SVBT group than in the SFCT group (AOR, 0.34; 95% CI, 0.19–0.60). The AOR for placenta previa was lower in the SVCT and SVBT groups than in the SFCT group (AOR, 0.21; 95% CI, 0.07–0.58 versus AOR, 0.53; 95% CI, 0.38–0.75, respectively). A total of 7460 follow-up data on neonatal outcomes was analysed. The AOR for preterm delivery was lower in the SVBT group than in the SFCT group (AOR, 0.78; 95% CI, 0.64–0.94). The AOR for low birthweight was significantly lower after SVCT and SVBT than after SFCT (AOR, 0.68; 95% CI, 0.46–0.98 versus AOR, 0.57; 95% CI, 0.48–0.66, respectively). The AOR for small for gestational age was lower in the SVCT and SVBT groups than in the SFCT group (AOR, 0.68; 95% CI, 0.46–0.98 versus AOR, 0.44; 95% CI, 0.36–0.55, respectively). The AOR for large for gestational age babies was higher in the SVBT group than in the SFCT group (AOR, 1.88; 95% CI, 1.62–2.18). The incidence of each congenital anomaly was similar among the groups.

LIMITATIONS, REASONS FOR CAUTION

The study data were collected through self-reported parental questionnaires on maternal and neonatal outcomes. Our findings were not compared with the incidence of pregnancy complications and congenital anomalies in natural pregnancies. Furthermore, this study was retrospective in nature; therefore, further studies are required to ascertain the generalizability of these findings to other clinics with different protocols and/or different patient demographics.

WIDER IMPLICATIONS OF THE FINDINGS

This study demonstrated reassuring outcomes for SVBT (in terms of a lower incidence of pregnancy complications) compared to SFCT. Our findings provide valuable knowledge that will help improve perinatal and maternal outcomes in CC-based stimulation and inform couples of the possible benefits and risks of each type of ET method.

STUDY FUNDING/COMPETING INTEREST(S)

This research did not receive any specific grants from funding agencies in the public, commercial, or not-for-profit sectors. The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Temporary Increased LDL-C in Offspring with Extreme Elevation of Maternal Preconception Estradiol: A Retrospective Cohort Study

Objective

To investigate the effect of maternal estradiol (E₂) elevation on long-term metabolic manifestations in the offspring.

Study Design and Setting

This was a retrospective cohort study. Overall, 3690 children conceived by in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) between July 2014 and December 2017 were recruited and divided into four groups categorized by maternal E₂ quartiles (Q1, <2420; Q2, 2420–3839; Q3, 3839–5599; and Q4, ≥5599 pg/mL). The metabolic profiles were measured during childhood. Linear mixed models were used to evaluate the association between maternal E₂ elevation and metabolic phenotypes of the offspring.

Results

Lipoprotein cholesterol (LDL-C) was significantly higher in the highest quartile group than in the lowest quartile group during infancy (adjusted mean difference [95% confidence interval, CI]): 0.11 [0.02, 0.20], P = 0.005), but the difference disappeared in the later childhood phase. In children born after fresh embryo transfer, LDL-C showed an increasing trend with the increase in maternal E₂ level (adjusted mean difference [95% CI]: Q2 vs Q1, −0.01 [−0.11, 0.08], Q3 vs Q1, 0.06 [−0.04, 0.15], Q4 vs Q1, 0.10 [0, 0.20]). Other metabolic variables were comparable across increasing quartiles of maternal E₂ levels.

Conclusion

This study demonstrates a temporary increase in LDL-C levels in infants with higher levels of maternal preconception E₂ levels. However, the long-term safety of hyperestrogens after ovarian stimulation in the next generation is favorable. The mechanism underlying the transiently increased metabolic dysfunction risk in infants conceived by IVF/ICSI requires investigation in future studies.

The relationship between serum oestrogen levels and clinical outcomes of hormone replacement therapy-frozen embryo transfer: a retrospective clinical study

BACKGROUND

This study aimed to explore the relationship between serum oestrogen (E2) levels before endometrial transformation and pregnancy outcomes of hormone replacement therapy-frozen embryo transfer (HRT-FET) cycles, which has been investigated for years without any consensus.

METHODS

A retrospective cohort study of 10,209 cycles HRT-FET cycles was conducted at the Reproductive Medicine Center of Nanjing Drum Tower Hospital from March 2017 to December 2020. A smooth fitting curve was constructed to identify the relationship between serum E2 levels before endometrial transformation and the clinical pregnancy rate. Then, threshold and saturation effect analysis was employed to explore the cut-off value of serum E2 levels. In addition, patients were divided into 2 groups based on their levels of serum E2 measured before progesterone-induced endometrial transformation: Group 1, < 300 pg/mL (n = 6251) and Group 2, ≥ 300 pg/mL (n = 3958). The clinical pregnancy and miscarriage rates of all groups were compared. Further smooth fitting curve analysis was employed by different subgroups segmented according to different endometrial thicknesses.

RESULTS

When the serum E2 level was greater than 300 pg/mL, the clinical pregnancy rate decreased significantly (62.9% vs. 59.8%, p < 0.01), but the miscarriage rates were similar (13.5% vs. 15.6%, p = 0.14). While serum E2 level reached or exceeded 1400 pg/mL, there was no significant correlation between the clinical pregnancy rate and E2 level. The clinical pregnancy rate reached its higher level at lower E2 levels, regardless of the different endometrail thicknesses.

CONCLUSIONS

Patients with a lower pretransformation serum E2 level (less than 300 pg/mL) have a higher clinical pregnancy rate and there was no correlation between the clinical pregnancy rate and a higher serum E2 level (greater than 1400 pg/mL) in HRT-FET cycles.

Impact of Maternal Age on Singleton Birthweight in Frozen Embryo Transfer Cycles

Background

Previous studies have investigated the effect of maternal age on assisted reproductive technology success rates. However, little is known about the relationship between maternal age and neonatal birthweight in frozen embryo transfer (FET) cycles. Whether maternal age influences singleton birthweight in FET cycles remains to be elucidated.

Methods

This study was conducted at a tertiary care center, involving singleton live births born to women undergoing frozen-thawed embryo transfer during the period from January 2010 to December 2017. A total of 12,565 women who fulfilled the inclusion criteria were enrolled and grouped into four groups according to the maternal age: <30, 30-34, 35-39, and ≥40 years old. A multivariable linear regression analysis was conducted to reveal the relationship between maternal age and neonatal birthweight with controlling for a number of potential confounders.

Results

The highest proportions of low birthweight (LBW, 4.1%), high birthweight (1.2%), preterm birth (PTB, 5.9%), and very PTB (0.9%) were found in the group over 40 years old, but no significant difference was observed among the four groups. Additionally, the 35-39-year-old group had the highest rate of very LBW (0.6%), whereas the 30-34-year-old group had the lowest rate of small for gestational age (SGA, 2.7%). However, multivariate analyses revealed that neonatal outcomes including PTB, LBW, and SGA were similar between the different maternal age groups.

Conclusion

Grouping with different maternal age was not associated with mean birthweight and Z-scores of singletons resulting from FET.

The sex-specific difference in singleton birth weight after frozen embryo transfer compared with fresh embryo transfer: a secondary analysis of 3 randomized trials

OBJECTIVE

To assess whether the between-group difference in singleton birth weight following frozen vs. fresh embryo transfer varied with infant sex.

DESIGN

A post hoc exploratory secondary analysis of data from three multicenter randomized trials compared the live birth rates between freeze-only vs. fresh embryo transfer.

SETTING

Academic fertility centers.

PATIENT(S)

A total of 1,886 women who achieved singleton live birth after a frozen or fresh embryo transfer during these trials were included.

INTERVENTION(S)

Women underwent either a frozen or fresh embryo transfer.

MAIN OUTCOME MEASURE(S)

Mean birth weight, large for gestational age (LGA), and small for gestational age (SGA).

RESULT(S)

There was an interaction between the types of embryo transfer and infant sex on the birth weight and on the incidences of LGA and SGA. Among male infants, compared with singletons following fresh embryo transfer, singletons following frozen embryo transfer had higher mean birth weights (3,520.6 ± 526.1 vs. 3,345.1 ± 524.9 g), a higher risk of being LGA (25.2% vs. 15.7%), and a lower risk of being SGA (3.3% vs. 6.1%). However, among the female infants, no statistically significant difference was found in the mean birth weight (3,336.5 ± 514.8 vs. 3,299.5 ± 485.0 g) or the risks of being LGA (18.8% vs. 15.7%) or SGA (5.2% vs. 6.0%) between frozen and fresh embryo transfer.

CONCLUSION(S)

Male singletons born after frozen embryo transfer were more likely to have a higher birth weight than those born after fresh embryo transfer.

Optimizing estradiol level for gonadotrophin-releasing hormone antagonist initiation among patients with simple tubal factor infertility

OBJECTIVE

The aim of this study is to investigate the optimal estradiol (E₂) level on the day of gonadotropin-releasing hormone antagonist (GnRH-ant) initiation to maximize the clinical pregnancy rate (CPR) after fresh embryo transfer among patients with simple tubal factor infertility.

METHODS

A retrospective cohort study was conducted in the Reproductive Medicine Center, the Second Hospital of Hebei Medical University. A total of 1,493 IVF-ET cycles of patients diagnosed with single tubal factor infertility from August 2016 to August 2021 were included and equally allocated into five distinct groups according to the quintile serum E₂ levels on the day of GnRH-ant initiation. The five groups had similar baseline data except for antral follicle count.

RESULTS

The serum E ₂ level on GnRH-ant initiation day was determined as an independent predictor of clinical pregnancy after adjusting for confounding factors such as age, infertility duration, body mass index, cycle number, antral follicle count, and the number of transferred embryos. Through smooth curve fitting, we found that, with the increase of serum E₂ levels on the day of GnRH-ant initiation, CPR showed a trend of slight increase and then slight decrease. The maximal CPR was achieved when the serum E₂ level on GnRH-ant initiation day was 498 pg/ml. When E₂ was less than 498 pg/ml, the odds ratio (OR) of clinical pregnancy was 1.05 (95% CI: 1.00, 1.11, P = 0.0583). When E₂ was greater than 498 pg/ml, the OR of clinical pregnancy was 0.97 (95% CI: 0.95, 0.98, P = 0.0003). Furthermore, CPR remained high when E₂ was 436.8-658.6 pg/ml but declined significantly by more than 40% when E₂ was ≥ 894.4 pg/ml (P < 0.05).

CONCLUSIONS

The serum E₂ level should be considered as an adjuvant parameter for GnRH-ant initiation. The best E₂ value was 498 pg/ml, and GnRH-ant administration could be recommended to initiate when serum E₂ was 436.8-658.6 pg/ml. If GnRH-ant was initiated when serum E₂ was above 894.4 pg/ml, then the CPR after fresh embryo transfer may decline dramatically, and thus, cancellation of fresh embryo transfer and earlier initiation of GnRH-ant in future cycles should be considered.