Frozen Embryo Transfer and Preeclampsia Risk

Adverse maternal and neonatal outcomes of preimplantation genetic testing with trophectoderm biopsy: a retrospective cohort study of 3373 intracytoplasmic sperm injection single frozen-thawed blastocyst transfer cycles

PURPOSE

To investigate whether trophectoderm biopsy increases the risk of adverse maternal and neonatal outcomes in intracytoplasmic sperm injection (ICSI) single frozen-thawed blastocyst transfer cycles.

METHODS

This respective cohort study enrolled 3373 ICSI single frozen-thawed blastocyst transfer cycles with and without trophectoderm biopsy. Statistical methods including univariate logistic regression analysis, multivariate logistic regression analysis, and stratified analyses were performed to explore the impact of trophectoderm biopsy on adverse maternal and neonatal outcomes.

RESULTS

The rates of adverse maternal and neonatal outcomes were comparable between the two groups. Univariate analysis showed that the live birth rate (45.15% vs. 40.75%; P = 0.010) in the biopsied group was statistically higher than that in the unbiopsied group, and the rates of miscarriage (15.40% vs. 20.00%; P = 0.011) and birth defects (0.58% vs. 2.16%; P = 0.007) were statistically lower in the biopsied group. After adjusting for confounding factors, the rates of miscarriage (aOR = 0.74; 95% CI = 0.57-0.96; P = 0.022) and birth defects (aOR = 0.24, 95% CI = 0.08-0.70, P = 0.009) in the biopsied group were significantly lower than those in the unbiopsied group. Stratified analyses showed that the birth defects rate after biopsy was significantly reduced in the subgroups of age < 35 years old, BMI ≥ 24 kg/m2, artificial cycle with downregulation, poor-quality blastocysts, and Day 5 poor-quality blastocysts.

CONCLUSION

Preimplantation genetic testing (PGT) with trophectoderm biopsy does not increase the risk of adverse maternal and neonatal outcomes in ICSI single frozen-thawed blastocyst transfer cycles, and PGT can effectively reduce the rates of miscarriage and birth defects.

What is the optimal means of preparing the endometrium in frozen-thawed embryo transfer cycles among anovulatory women? A retrospective cohort study

OBJECTIVE

Different endometrial preparation protocols are used prior to frozen-thawed embryo transfer (FET). It is not clear whether letrozole-stimulated cycles are beneficial for anovulatory women compared to artificial cycles (AC) in anovulatory women. Our objective was to investigate whether clinical outcomes following frozen-thawed embryo transfer in letrozole-stimulated cycles differ from artificial cycles in anovulatory women.

STUDY DESIGN

This is a retrospective cohort study conducted in a public fertility center in China comparing letrozole-stimulated and artificial cycles during FET. A total of 5,322 anovulatory women undergoing the first cycle of FET between January 2020 and December 2021. The primary outcome was the live birth rate. The secondary outcomes included biochemical pregnancy, clinical pregnancy, ongoing pregnancy, miscarriage, and ectopic pregnancy.

RESULTS

The live birth rates were significantly higher in the letrozole compared with AC (49.57 % vs. 45.22 %) both in the crude (odds ratio [OR] 1.19, 95 % confidence interval [CI] 1.01-1.40) and adjusted analysis (aOR 1.27, 95 %CI 1.08-1.50). After controlling for potential covariates, the adjusted probability of biochemical pregnancy (65.71 % vs. 63.25 %, aOR 1.20, 95 %CI: 1.01-1.43), clinical pregnancy (61.53 % vs. 58.79 %, aOR 1.20, 95 %CI: 1.02-1.43), and ongoing pregnancy (50.14 % vs. 45.66 %, aOR 1.28, 95 %CI: 1.08-1.51) were higher among those using letrozole-stimulated cycles than among those undergoing artificial cycles. The miscarriage rate was lower following letrozole compared with artificial cycles (aOR 0.59, 95 %CI: 0.43-0.80). The ectopic pregnancy in the letrozole group was similar to that in the artificial cycles.

CONCLUSIONS

Letrozole-stimulated FET was significantly associated with higher rates of biochemical pregnancy, clinical pregnancy, ongoing pregnancy and live birth, and with a lower rate of miscarriage, compared with artificial cycles.

The predictive value of uterine artery Doppler in the success rate of pregnancy from the first frozen embryo transfer during the implantation window

BACKGROUND

Worldwide, frozen embryo transfer (FET) has become a new strategy for the treatment of infertility. The success of FET is closely related to endometrial receptivity. Does uterine artery Doppler during the implantation window predict pregnancy outcome from the first FET?

METHODS

A total of 115 retrospectively collected cycles were included in the study, with 64 cycles of clinical pregnancy and 51 cycles of nonclinical pregnancy; There were 99 nonabsent end-diastolic flow (NAEDF) cycles and 16 absent end-diastolic flow (AEDF) cycles. The differences in uterine artery Doppler findings between different pregnancy outcomes were investigated. The clinical pregnancy rate and spontaneous abortion rate in the NAEDF and AEDF groups were compared. The predictive value of uterine artery Doppler during the implantation window in the success rate of pregnancy from the first FET was also investigated.

RESULTS

Between the clinical pregnancy group and the nonclinical pregnancy group, there were no significant differences in the mean resistance index (mRI) (Z = -1.065, p = 0.287), mean pulsatility index (mPI) (Z = -0.340, p = 0.734), and mean peak systolic/end-diastolic velocity(mS/D) (Z = -0.953, p = 0.341); there were significant differences in the mean peak systolic velocity (mPSV) (Z = -1.982, p = 0.048) and mean end-diastolic velocity (mEDV) (Z = -2.767, p = 0.006). Between the NAEDF and AEDF groups, there was no significant difference in the clinical pregnancy rate (χ2 = 0.003, p = 0.959), and there was a significant difference in the spontaneous abortion rate (χ2 = 3.465, p = 0.019). Compared with uterine artery Doppler alone, its combination with artificial abortion history, waist-to-hip ratio, LH (Luteinizing hormone) of P (Progesterone) administration day, mPSV and mEDV had a higher predictive value regarding clinical pregnancy from the first FET [ROC-AUC 0.782, 95% CI (0.680-0.883) vs. 0.692, 95% CI (0.587-0.797)].

CONCLUSIONS

Uterine artery Doppler, particularly mPSV and mEDV during the implantation window, was useful for predicting clinical pregnancy, and AEDF was related to spontaneous abortion in the first trimester. Uterine artery Doppler combined with artificial abortion history, waist-to-hip ratio, LH of P administration day, mPSV and mEDV have a higher predictive value than uterine artery Doppler alone regarding the pregnancy from the first FET.

Natural Cycle Frozen Embryo Transfer: Evaluating Optimal Protocols for Preparation and Timing

Background

While natural cycle frozen embryo transfer (NC-FET) is becoming increasingly common, significant practice variation exists in the use of ovulation induction medications, administration of ovulation trigger, and timing of embryo transfer without consensus as to the optimal protocol.

Aims

The objective of this study is to evaluate the association of key aspects of the NC-FET protocol with implantation, pregnancy and live birth.

Settings and Design

This was a retrospective cohort study of blastocyst stage NC-FET cycles from October 2019 to July 2021 at a single academic fertility centre.

Materials and Methods

Protocols varied between cycles across three key parameters which were evaluated as primary predictors of cycle outcomes: (1) use of letrozole for mild ovarian stimulation/ovulation induction, (2) administration of exogenous ovulation trigger versus spontaneous luteinising hormone surge and (3) transfer timing based on ovulation trigger versus sequential progesterone monitoring. Primary outcomes included implantation rate, clinical pregnancy and ongoing pregnancy.

Statistical Analysis Used

Generalised estimating equations were fitted to obtain adjusted odds ratios or rate ratios as appropriate with 95% confidence intervals for each outcome across the three primary predictors.

Results

A total of 183 cycles from 170 unique patients were eligible for inclusion. The average implantation rate was 0.58, resulting in an overall clinical pregnancy and ongoing pregnancy rate of 59.0% and 51.4%, respectively. After adjusting for age at embryo freeze and history of a failed embryo transfer, there were no significant associations between any predictor and implantation rate, clinical pregnancy, ongoing pregnancy, or live birth.

Conclusion

In NC-FET, a variety of preparation and timing protocols may lead to comparable cycle outcomes, potentially allowing for flexibility on the basis of patient and physician preference. These findings warrant validation in a larger, randomised trial.

Obstetric and neonatal outcomes after natural versus artificial cycle frozen embryo transfer and the role of luteal phase support: a systematic review and meta-analysis

BACKGROUND

The number of frozen embryo transfers (FET) has increased dramatically over the past decade. Based on current evidence, there is no difference in pregnancy rates when natural cycle FET (NC-FET) is compared to artificial cycle FET (AC-FET) in subfertile women. However, NC-FET seems to be associated with lower risk of adverse obstetric and neonatal outcomes compared with AC-FET cycles. Currently, there is no consensus about whether NC-FET needs to be combined with luteal phase support (LPS) or not. The question of how to prepare the endometrium for FET has now gained even more importance and taken the dimension of safety into account as it should not simply be reduced to the basic question of effectiveness.

OBJECTIVE AND RATIONALE

The objective of this project was to determine whether NC-FET, with or without LPS, decreases the risk of adverse obstetric and neonatal outcomes compared with AC-FET.

SEARCH METHODS

A systematic review and meta-analysis was carried out. A literature search was performed using the following databases: CINAHL, EMBASE, and MEDLINE from inception to 10 October 2022. Observational studies, including cohort studies, and registries comparing obstetric and neonatal outcomes between singleton pregnancies after NC-FET and those after AC-FET were sought. Risk of bias was assessed using the ROBINS-I tool. The quality of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation approach. We calculated pooled odds ratios (ORs), pooled risk differences (RDs), pooled adjusted ORs, and prevalence estimates with 95% CI using a random effect model, while heterogeneity was assessed by the I2.

OUTCOMES

The conducted search identified 2436 studies, 890 duplicates were removed and 1546 studies were screened. Thirty studies (NC-FET n = 56 445; AC-FET n = 57 231) were included, 19 of which used LPS in NC-FET. Birthweight was lower following NC-FET versus AC-FET (mean difference 26.35 g; 95% CI 11.61-41.08, I2 = 63%). Furthermore NC-FET compared to AC-FET resulted in a lower risk of large for gestational age (OR 0.88, 95% 0.83-0.94, I2 = 54%), macrosomia (OR 0.81; 95% CI 0.71-0.93, I2 = 68%), low birthweight (OR 0.81, 95% CI 0.77-0.85, I2 = 41%), early pregnancy loss (OR 0.73; 95% CI 0.61-0.86, I2 = 70%), preterm birth (OR 0.80; 95% CI 0.75-0.85, I2 = 20%), very preterm birth (OR 0.66, 95% CI 0.53-0.84, I2 = 0%), hypertensive disorders of pregnancy (OR 0.60, 95% CI 0.50-0.65, I2 = 61%), pre-eclampsia (OR 0.50; 95% CI 0.42-0.60, I2 = 44%), placenta previa (OR 0.84, 95% CI 0.73-0.97, I2 = 0%), and postpartum hemorrhage (OR 0.43; 95% CI 0.38-0.48, I2 = 53%). Stratified analyses on LPS use in NC-FET suggested that, compared to AC-FET, NC-FET with LPS decreased preterm birth risk, while NC-FET without LPS did not (OR 0.75, 95% CI 0.70-0.81). LPS use did not modify the other outcomes. Heterogeneity varied from low to high, while quality of the evidence was very low to moderate.

WIDER IMPLICATIONS

This study confirms that NC-FET decreases the risk of adverse obstetric and neonatal outcomes compared with AC-FET. We estimate that for each adverse outcome, use of NC-FET may prevent 4 to 22 cases per 1000 women. Consequently, NC-FET should be the preferred treatment in women with ovulatory cycles undergoing FET. Based on very low quality of evidence, the risk of preterm birth be decreased when LPS is used in NC-FET compared to AC-FET. However, because of many uncertainties-the major being the debate about efficacy of the use of LPS-future research is needed on efficacy and safety of LPS and no recommendation can be made about the use of LPS.

Pregnancy outcomes and disease phenotype of hypertensive disorders of pregnancy in singleton pregnancies after in vitro fertilization: a retrospective analysis of 1130 cases

BACKGROUND

Although in vitro fertilization (IVF) can increase the incidence of hypertensive disorders of pregnancy (HDP), the pregnancy outcomes and disease phenotype of HDP in singleton pregnancies conceived via IVF remain unclear.

METHODS

This retrospective cohort study enrolled 1130 singleton pregnancies with HDP from 2016 to 2020. According to the mode of conception, they were allocated into IVF (n = 102) and natural conception (NC) groups (n = 1028). All IVF pregnancies were subdivided into frozen embryo transfer (FET) group (n = 42) and fresh embryo transfer (ET) group (n = 60). Demographic data, pregnancy outcomes and disease phenotypes of HDP among the groups were compared. The risk factors for severe preeclampsia (PE) and early-onset PE were analyzed.

RESULTS

The incidences of early-onset PE (P<0.001), severe PE (P = 0.016), cesarean section (P<0.001) and preterm births (P = 0.003) in the IVF-HDP group were significantly higher than those in the NC-HDP group, and gestational age at diagnosis of HDP (P = 0.027) and gestational age at delivery (P = 0.004) were earlier and birthweight of the neonates (P = 0.033) were lower in the IVF group. In singleton pregnancies with HDP, IVF was associated with increased risks for both severe PE and early-onset PE (aOR 1.945, 95% CI 1.256, 3.014; and aOR 2.373, 95% CI 1.537, 3.663, respectively), as well as FET, family history of preeclampsia, intrahepatic cholestasis of pregnancy, gestational hypothyroidism and multiparity were associated with increased risks of severe PE and early-onset PE.

CONCLUSIONS

In singleton pregnancies with HDP, IVF was associated with an increased incidence of the disease phenotype (severe or early-onset PE), as well as an increased incidence of pregnancy outcomes related to severe PE and early-onset PE.

Impact of maternal body mass index on outcomes of singleton pregnancies after assisted reproductive technology: a 14-year analysis of the US Nationwide Inpatient Sample

BACKGROUND

Obesity is increasing globally, which affects multiple human functions, including reproductive health. Many women with overweight and obesity of child-bearing years are treated with assisted reproductive technology (ART). However, the clinical impact of body mass index (BMI) on pregnancy outcomes after ART remains to be determined. Therefore, this population-based retrospective cohort study aimed to assess whether and how higher BMI affects singleton pregnancy outcomes.

METHODS

This study used the large nationally representative database of the US National Inpatient Sample (NIS), extracting data of women with singleton pregnancies who had received ART from 2005 to 2018. Diagnostic codes of the International Classification of Diseases, Ninth and Tenth edition (ICD-9 and ICD-10) were used to identify females admitted to US hospitals with delivery-related discharge diagnoses or procedures and secondary diagnostic codes for ART, including in vitro fertilization. The included women were further categorized into three groups based on BMI values < 30, 30-39, and ≥ 40 kg/m². Univariate and multivariable regression analysis were conducted to assess the associations between study variables and maternal and fetal outcomes.

RESULTS

Data of totally 17,048 women were included in the analysis, which represented a population of 84,851 women in the US. Number of women in the three BMI groups were 15, 878 (BMI < 30 kg/m²), 653 (BMI 30-39 kg/m²), and 517 (BMI ≥ 40 kg/m²), respectively. The multivariable regression analysis revealed that, compared to BMI < 30 kg/m², BMI 30-39 kg/m² was significantly associated with increased odds for pre-eclampsia and eclampsia (adjusted OR = 1.76, 95% CI = 1.35, 2.29), gestational diabetes (adjusted OR = 2.25, 95% CI = 1.70, 2.98), and Cesarean delivery (adjusted OR = 1.36, 95% CI = 1.15, 1.60). Further, BMI ≥ 40 kg/m² was associated with greater odds for pre-eclampsia and eclampsia (adjusted OR = 2.25, 95% CI = 1.73, 2.94), gestational diabetes (adjusted OR = 3.64, 95% CI = 2.80, 4.72), disseminated intravascular coagulation (DIC) (adjusted OR = 3.79, 95% CI = 1.47, 9.78), Cesarean delivery (adjusted OR = 1.85, 95% CI = 1.54, 2.23), and hospital stay ≥ 6 days (adjusted OR = 1.60, 95% CI = 1.19, 2.14). However, higher BMI was not significantly associated with greater risk of the fetal outcomes assessed.

CONCLUSIONS

Among US pregnant women who received ART, having a higher BMI level independently increases the risk for adverse maternal outcomes such as pre-eclampsia and eclampsia, gestational diabetes, DIC, longer hospital stays, and higher rates of Cesarean delivery, while risk is not increased for fetal outcomes.