Embryo cryopreservation and preeclampsia risk

Pathologic maternal and neonatal outcomes associated with programmed embryo transfer

PURPOSE

In this first of two companion papers, we critically review the evidence recently published in the primary literature, which addresses adverse maternal and neonatal pregnancy outcomes associated with programmed embryo transfer cycles. We next consider whether these pathological pregnancy outcomes might be attributable to traditional risk factors, unknown parental factors, embryo culture, culture duration, or cryopreservation. Finally, in the second companion article, we explore potential etiologies and suggest strategies for prevention.

METHODS

Comprehensive review of primary literature.

RESULTS

The preponderance of retrospective and prospective observational studies suggests that increased risk for hypertensive disorders of pregnancy (HDP) and preeclampsia in assisted reproduction involving autologous embryo transfer is associated with programmed cycles. For autologous frozen embryo transfer (FET) and singleton live births, the risk of developing HDP and preeclampsia, respectively, was less for true or modified natural and stimulated cycles relative to programmed cycles: OR 0.63 [95% CI (0.57-0.070)] and 0.44 [95% CI (0.40-0.50)]. Though data are limited, the classification of preeclampsia associated with programmed autologous FET was predominantly late-onset or term disease. Other adverse pregnancy outcomes associated with autologous FET, especially programmed cycles, included increased prevalence of large for gestational age infants and macrosomia, as well as higher birth weights. In one large registry study, FET was associated with fetal overgrowth of a symmetrical nature. Postterm birth and placenta accreta not associated with prior cesarean section, uterine surgery, or concurrent placenta previa were also associated with autologous FET, particularly programmed cycles. The heightened risk of these pathologic pregnancy outcomes in programmed autologous FET does not appear to be attributable to traditional risk factors, unknown parental factors, embryo culture, culture duration, or cryopreservation, although the latter may contribute a modest degree of increased risk for fetal overgrowth and perhaps HDP and preeclampsia in FET irrespective of the endometrial preparation.

CONCLUSIONS

Programmed autologous FET is associated with an increased risk of several, seemingly diverse, pathologic pregnancy outcomes including HDP, preeclampsia, fetal overgrowth, postterm birth, and placenta accreta. Though the greater risk for preeclampsia specifically associated with programmed autologous FET appears to be well established, further research is needed to substantiate the limited data currently available suggesting that the classification of preeclampsia involved is predominately late-onset or term. If substantiated, then this knowledge could provide insight into placental pathogenesis, which has been proposed to differ between early- and late-onset or term preeclampsia (see companion paper for a discussion of potential mechanisms). If a higher prevalence of preeclampsia with severe features as suggested by some studies is corroborated in future investigations, then the danger to maternal and fetal/neonatal health is considerably greater with severe disease, thus increasing the urgency to find preventative measures. Presupposing significant overlap of these diverse pathologic pregnancy outcomes within subjects who conceive by programmed embryo transfer, there may be common etiologies.

Pathologic maternal and neonatal outcomes associated with programmed embryo transfer: potential etiologies and strategies for prevention

PURPOSE

In the first of two companion papers, we comprehensively reviewed the recent evidence in the primary literature, which addressed the increased prevalence of hypertensive disorders of pregnancy, late-onset or term preeclampsia, fetal overgrowth, postterm birth, and placenta accreta in women conceiving by in vitro fertilization. The preponderance of evidence implicated frozen embryo transfer cycles and, specifically, those employing programmed endometrial preparations, in the higher risk for these adverse maternal and neonatal pregnancy outcomes. Based upon this critical appraisal of the primary literature, we formulate potential etiologies and suggest strategies for prevention in the second article.

METHODS

Comprehensive review of primary literature.

RESULTS

Presupposing significant overlap of these apparently diverse pathological pregnancy outcomes within subjects who conceive by programmed autologous FET cycles, shared etiologies may be at play. One plausible but clearly provocative explanation is that aberrant decidualization arising from suboptimal endometrial preparation causes greater than normal trophoblast invasion and myometrial spiral artery remodeling. Thus, overly robust placentation produces larger placentas and fetuses that, in turn, lead to overcrowding of villi within the confines of the uterine cavity which encroach upon intervillous spaces precipitating placental ischemia, oxidative and syncytiotrophoblast stress, and, ultimately, late-onset or term preeclampsia. The absence of circulating corpus luteal factors like relaxin in most programmed cycles might further compromise decidualization and exacerbate the maternal endothelial response to deleterious circulating placental products like soluble fms-like tyrosine kinase-1 that mediate disease manifestations. An alternative, but not mutually exclusive, determinant might be a thinner endometrium frequently associated with programmed endometrial preparations, which could conspire with dysregulated decidualization to elicit greater than normal trophoblast invasion and myometrial spiral artery remodeling. In extreme cases, placenta accreta could conceivably arise. Though lower uterine artery resistance and pulsatility indices observed during early pregnancy in programmed embryo transfer cycles are consistent with this initiating event, quantitative analyses of trophoblast invasion and myometrial spiral artery remodeling required to validate the hypothesis have not yet been conducted.

CONCLUSIONS

Endometrial preparation that is not optimal, absent circulating corpus luteal factors, or a combination thereof are attractive etiologies; however, the requisite investigations to prove them have yet to be undertaken. Presuming that in ongoing RCTs, some or all adverse pregnancy outcomes associated with programmed autologous FET are circumvented or mitigated by employing natural or stimulated cycles instead, then for women who can conceive using these regimens, they would be preferable. For the 15% or so of women who require programmed FET, additional research as suggested in this review is needed to elucidate the responsible mechanisms and develop preventative strategies.

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.

Increased Risk of Preeclampsia with Assisted Reproductive Technologies

PURPOSE OF REVIEW

We summarized recent available data to assess the association between assisted reproductive technology (ART) and risk for preeclampsia.

RECENT FINDINGS

The majority of clinical studies supporting the association of preeclampsia and ART are retrospective. Published data from both clinical and pre-clinical studies suggest specific ART procedures may contribute to the increased risk, including in vitro embryo handling and development, hormone stimulation, transfer cycle types, and use of donor oocytes/embryos. Potential mechanisms include epigenetic aberrations leading to abnormal placentation, absence of factors secreted by the corpus luteum, and immunologic responses to allogenic gametes. There is an increased risk of preeclampsia following ART. Treatment plans that favor reduced preeclampsia risk should be considered for ART pregnancies. To make ART pregnancies safer, additional clinical and animal model studies are needed to elucidate the underpinnings of this risk association.

Is artificial endometrial preparation more associated with early-onset or late-onset preeclampsia after frozen embryo transfer?

PURPOSE

To explore whether the risks of early- or late-onset preeclampsia vary among frozen embryo transfer (FET) with different regimens for endometrial preparation and fresh embryo transfer (FreET).

METHODS

We retrospectively included a total of 24129 women who achieved singleton delivery during their first cycles of in vitro fertilization (IVF) between January 2012 and March 2020. The risks of early- and late-onset preeclampsia after FET with endometrial preparation by natural ovulation cycles (FET-NC) or by artificial cycles (FET-AC) were compared to that after FreET.

RESULTS

After adjustment via multivariable logistic regression, the total risk of preeclampsia was higher in the FET-AC group compared to the FreET group [2.2% vs. 0.9%; adjusted odds ratio (aOR): 2.00; 95% confidence interval (CI): 1.45-2.76] and FET-NC group (2.2% vs. 0.9%; aOR: 2.17; 95% CI: 1.59-2.96).When stratified by the gestational age at delivery based on < 34 weeks or ≥ 34 weeks, the risk of late-onset preeclampsia remained higher in the FET-AC group than that in the and FreET group (1.8% vs. 0.6%; aOR: 2.56; 95% CI: 1.83-3.58) and the FET-NC group (1.8% vs. 0.6%; aOR: 2.63; 95% CI: 1.86-3.73). We did not find a statistically significant difference in the risk of early-onset preeclampsia among the three groups.

CONCLUSIONS

An artificial regimen for endometrial preparation was more associated with an increased risk of late-onset preeclampsia after FET. Given that FET-AC is widely used in clinical practice, the potential maternal risk factors for late-onset preeclampsia when using the FET-AC regimen should be further explored, considering the maternal origin of late-onset preeclampsia.

Evidence-Based Pre-Pregnancy Counseling for Oocyte Donation Pregnancies: a Systematic Review and Guide for Physicians

It is well known that oocyte donation (OD) pregnancies are associated with higher complication rates compared to autologous pregnancies. However, evidence-based information for pre-pregnancy counseling designed for health care workers is scarce. Therefore, a systematic literature search was performed to find articles that address pre-pregnancy counseling before OD.A systematic search was conducted in September 2020 in various databases, including PubMed and Embase. Nine (systematic) reviews and meta-analyses were included that reported on pre-pregnancy advice in OD pregnancies.Studies are consistent in documenting a higher risk for hypertensive disorders, cesarean section, preterm birth, postpartum hemorrhage, and low birth weight. Based on these complications, pre-pregnancy advice is mentioned in all included systematic reviews to prevent complications in the next pregnancy. All studies recommend counseling women on the increased risk of complications during OD pregnancy. Other recommendations include the prophylactic use of aspirin in pregnancy and restriction to single embryo transfer. Individualized appropriate surveillance and management strategies should be considered for every patient achieving pregnancy by OD.In conclusion, we provide a summary of the most important outcomes in OD pregnancies, and thereby offer a guide for pre-pregnancy counseling.

Fetal neurosonography and infant neurobehavior following conception by assisted reproductive technology with fresh or frozen embryo transfer

OBJECTIVE

We aimed to explore fetal cortical brain development by neurosonography in fetuses conceived by assisted reproductive technology (ART), including frozen and fresh embryo transfer (ET), compared with those conceived spontaneously (SC), and to investigate its association with infant neurobehavior at 12 months of age.

METHODS

This was a prospective cohort study of 210 singleton pregnancies, including 70 SC pregnancies, 70 conceived by in-vitro fertilization (IVF) following frozen ET and 70 conceived by IVF after fresh ET. Fetal neurosonography was performed at 32 ± 2 gestational weeks to assess cortical development. Sulci depths were measured offline and normalized by biparietal diameter (BPD). Ages and Stages Questionnaires (ASQ) were completed postnatally, at 12 ± 1 months of corrected age. Neurosonographic findings were adjusted by regression analysis for maternal age, ethnicity, parity, fetal sex and fetal-weight centile and gestational age at scan, and ASQ scores were adjusted for maternal age, ethnicity, parity, educational level and employment status, gestational age at birth, breastfeeding, infant sex and infant age at the ASQ evaluation.

RESULTS

Overall, in comparison to the SC fetuses, fetuses conceived by ART showed statistically significant differences in cortical development, with reduced parieto-occipital sulci depth adjusted for BPD (mean ± SD: fresh ET, 12.5 ± 2.5 vs frozen ET, 13.4 ± 2.6 vs SC, 13.4 ± 2.6, P < 0.001), cingulate sulci depth adjusted for BPD (median (interquartile range (IQR)): fresh ET, 5.8 (4.2-7.4) vs frozen ET, 5.8 (4.1-7.5) vs SC, 6.5 (4.8-7.8), P = 0.001) and calcarine sulci depth adjusted for BPD (median (IQR): fresh ET, 13.5 (10.1-16.1) vs frozen ET, 14.5 (12.1-15.8) vs SC, 16.4 (14.3-17.9), P < 0.001), together with lower Sylvian fissure grading score. Changes in cortical development were more pronounced in the fresh ET than in the frozen ET group. ART infants showed lower ASQ scores as compared to SC infants, particularly in the fresh ET group (mean ± SD global ASQ Z-score: fresh ET, -0.3 ± 0.4 vs frozen ET, -0.2 ± 0.4 vs SC, 0 ± 0.4, P < 0.001).

CONCLUSIONS

Fetuses conceived by ART show a distinctive pattern of cortical development and suboptimal infant neurodevelopment, with more pronounced changes in those conceived following fresh ET. These findings support the existence of in-utero brain reorganization associated with ART and warrant follow-up studies to assess its long-term persistence. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Should any use of artificial cycle regimen for frozen-thawed embryo transfer in women capable of ovulation be abandoned: yes, but what's next for FET cycle practice and research?

Over the past decade, the use of frozen-thawed embryo transfer (FET) treatment cycles has increased substantially. The artificial ('programmed') cycle regimen, which suppresses ovulation, is widely used for that purpose, also in ovulatory women or women capable of ovulation, under the assumption of equivalent efficacy in terms of pregnancy achievement as compared to a natural cycle or modified natural cycle. The advantage of the artificial cycle is the easy alignment of the time point of thawing and transferring embryos with organizational necessities of the IVF laboratory, the treating doctors and the patient. However, recent data indicate that pregnancy establishment under absence of a corpus luteum as a consequence of anovulation may cause relevant maternal and fetal risks. Herein, we argue that randomized controlled trials (RCTs) are not needed to aid in the clinical decision for or against routine artificial cycle regimen use in ovulatory women. We also argue that RCTs are unlikely to answer the most burning questions of interest in that context, mostly because of lack of power and precision in detecting rare but decisive adverse outcomes (e.g. pre-eclampsia risk or long-term neonatal health outcomes). We pinpoint that, instead, large-scale observational data are better suited for that purpose. Eventually, we propose that the existing understanding and evidence is sufficient already to discourage the use of artificial cycle regimens for FET in ovulatory women or women capable of ovulation, as these may cause a strong deviation from physiology, thereby putting patient and fetus at avoidable health risk, without any apparent health benefit.

The Maternal-Neonatal Outcomes of Twin Pregnancies with Preeclampsia and Their Association with Assisted Reproductive Technology: A Retrospective Study

Objective: This study aimed to investigate the maternal−neonatal outcomes of twin pregnancies of mothers with preeclampsia and their association with assisted reproductive technology (ART). Methods: A retrospective study on the clinical and maternal−neonatal outcome data of 698 women with twin pregnancies who delivered in our hospital from December 2013 to September 2021 was conducted. Continuous variables were analyzed using a Student’s t-test or Wilcoxon rank-sum test. Categorical variables were analyzed using the Chi-square test. The risk factors of twin pregnancies with preeclampsia were analyzed by logistic regression. Results: The rate of twin pregnancy complicated by preeclampsia was 17.62% (123/698). Logistic regression analysis showed that ART increased the risk of preeclampsia in twin pregnancies (AOR: 1.868, 95% CI: 1.187−2.941). Mothers with preeclampsia carrying twins conceived with ART had a higher rate of delivery at gestational week < 34 (29.9% vs. 12.5%) and asphyxia of the neonate at 5 min after delivery (13.4% vs. 1.8%) than those with preeclampsia conceived without ART (p < 0.05). Conclusions: ART increases the risk of preeclampsia in twin pregnancies and the rate of adverse maternal−neonatal outcomes for twin pregnancies with preeclampsia. The policy of single embryo transfer is a method to reduce the adverse pregnancy outcomes of ART.

Potential role of the corpus luteum in maternal cardiovascular adaptation to pregnancy and preeclampsia risk

Studies in the gravid rat model revealed a key role for the corpus luteal hormone, relaxin, in the maternal circulatory changes of early pregnancy epitomized by profound systemic vasodilation and increased arterial compliance. To determine whether the corpus luteum may play a similar role in human pregnancy, women who conceived by in vitro fertilization were studied. Implementation of artificial (programmed) cycles for embryo transfers, which precluded the formation of a corpus luteum, was associated with notable attenuation of the gestational rise in cardiac output and fall in carotid-femoral pulse wave velocity (reflecting impairment of arterial dilation and increased compliance, respectively) and deficiencies in other cardiovascular changes normally observed during the first trimester. Cardiac output and carotid-femoral pulse wave velocity were restored after the first trimester of pregnancy, consistent with rescue by placental vasodilators, such as placental growth factor. In addition, a potential role of corpus luteal factors in reducing the risk of developing preeclampsia was hypothesized. In most single and multiple center, prospective and retrospective cohort (and registry) studies, the risk of developing preeclampsia and preeclampsia with severe features was increased specifically in women undergoing autologous frozen embryo transfer in artificial cycles without the formation of a corpus luteum relative to natural, modified natural, stimulated, or controlled ovarian stimulation cycles and spontaneous pregnancies-all associated with the formation of at least 1 corpus luteum. Taken together, these observational studies are sufficiently compelling to warrant randomized clinical trials comparing preeclampsia risk in autologous frozen embryo transfer in natural vs artificial cycles. Impaired endometrial function because of suboptimal hormonal administration is an alternative but not mutually exclusive explanation for increased preeclampsia risk in autologous frozen embryo transfer in artificial cycles. Potential mechanisms by which the corpus luteum may reduce the risk of developing preeclampsia and whether autologous frozen embryo transfer in artificial cycles is associated with increased risk of preterm preeclampsia, term preeclampsia, or both are discussed. Last, suggestions for future investigations are noted.

The impact of endometrial preparation for frozen embryo transfer on maternal and neonatal outcomes: a review

The use of frozen embryo transfer in assisted reproductive technology (ART) has steadily increased since development in the early 1980's. While there are many benefits to delayed frozen embryo transfer, certain adverse perinatal outcomes are noted to be more common in these transfers when compared to fresh transfers, specifically hypertensive disorders of pregnancy. Frozen embryo transfers require coordination between the embryo's developmental stage and the endometrial environment and can occur in either ovulatory or programmed cycles. Though there is no consensus on the ideal method of endometrial preparation prior to frozen embryo transfer, emerging data suggests differences in maternal and neonatal outcomes, specifically increased rates of hypertensive disorders of pregnancy in programmed cycles. Other reported differences include an increased risk of cesarean delivery, placenta accreta, postpartum hemorrhage, low birthweight, preterm birth, post term delivery, macrosomia, large for gestational age, and premature rupture of membranes in programmed cycles. The mechanism by which these differences exist could reflect inherent differences in groups selected for each type of endometrial preparation, the role of super physiologic hormone environments in programmed cycles, or the unique contributions of the corpus luteum in ovulatory cycles that are not present in programmed cycles. Given that existing studies are largely retrospective and have several key limitations, further investigation is needed. Confirmation of these findings has implications for current practice patterns and could enhance understanding of the mechanisms behind important adverse perinatal outcomes in those pursuing assisted reproduction.

Obstetric outcomes of young women following in-vitro fertilization: a case-control study

Background

Women undergoing in-vitro fertilization (IVF) treatments are at increased risk for maternal and neonatal complications compared to women who conceive spontaneously. Though spontaneous pregnancies of young women and adolescents have an increased risk for adverse maternal and neonatal outcomes, pregnancy outcomes of this age group, following IVF treatment have been scarcely reported. The aim of this study was to report maternal and neonatal outcomes of young women who conceived following IVF compared to women in the same age group with spontaneous conception.

Methods

We performed a multicenter case–control study. The study group included women aged 17–25 years who conceived by IVF with an ongoing singleton pregnancy. For the purpose of the study, a control group matched (1:2 ratio) for maternal age at delivery and parity was constructed. Demographic, medical history, pregnancy related characteristics and maternal and neonatal outcomes were compared between groups. Finally, factors associated with spontaneous vaginal delivery were assessed for the entire cohort using a univariate and multivariate logistic regression model.

Results

Between 2005 and 2021, we identified 80 women aged 19–25 years who conceived by IVF. A control group of 160 women was matched to the study group by age and parity. The unmatched maternal characteristics and pregnancy associated complications were similar among the groups. However, the IVF group had a significantly higher rate of induction of labor (48.1% vs. 26.6%, p = 0.001), meconium-stained amniotic fluid (27.6% vs. 14.1%, p = 0.025), prolonged second stage of labor (26.0% vs. 7.3%, p = 0.001) and operative vaginal delivery (22.5% vs.12.5%, p = 0.048).

Neonatal outcomes were for the most part comparable; nevertheless, we found a higher rate of neonates with an umbilical artery pH < 7.1 in the IVF group (9.8% vs. 0.0%, respectively; p = 0.022).

A logistic regression analysis for spontaneous vaginal delivery (vs. cesarean or operative vaginal deliveries) found that spontaneous onset of labor (vs. induction of labor) (OR = 2.08; 95% CI = 1.07–4.05, p = 0.03) was positively associated with spontaneous vaginal delivery while prolonged second stage of labor (OR = 0.35; 95% CI = 0.13–0.95, p = 0.04) was negatively associated with this parameter.

Conclusion

Young women who conceive by in-vitro fertilization are expected to reach favorable pregnancy outcomes, comparable to women who conceived spontaneously.

Comparison of Perinatal Outcomes of Letrozole-Induced Ovulation and Hormone Replacement Therapy Protocols in Patients With Abnormal Ovulation Undergoing Frozen-Thawed Embryo Transfer: A Propensity Score Matching Analysis

BACKGROUND

With the increasing use of frozen embryo transfer (FET), the best endometrial preparation protocol is continuously being discussed. The hormone replacement therapy (HRT) cycle and letrozole-induced ovulation (L-OI) cycle are available protocols for patients with abnormal ovulation. Previous comparisons of the two protocols have focused on pregnancy outcomes, with less attention to perinatal outcomes, and population heterogeneity was large; thus, convincing conclusions about which protocol is more appropriate could not be drawn.

METHODS

We performed a retrospective cohort study using propensity score matching (PSM) analysis for a population of patients undergoing FET cycles in the reproductive center of the Third Affiliated Hospital of Zhengzhou University from January 2016 to September 2020. The main outcome measures were clinical pregnancy rate, live birth rate, very preterm delivery (VPTD), preterm delivery (PTD), low birth weight (LBW), macrosomia, small for gestational age (SGA), large for gestational age (LGA), hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus (GDM), premature rupture of membranes (PROM), placenta previa, and congenital abnormality.

RESULTS

A total of 8010 women were enrolled. Due to the large heterogeneity among the patients, we conducted 1:1 PSM, and 1461 women matched in each group. Compared with the HRT group, the L-OI group had a smaller proportion of thin endometrium (27.38% vs. 41.07%) and thicker endometrium on the day of embryo transfer (9.63 ± 1.82 vs. 8.91 ± 1.38). There were no significant differences in clinical pregnancy rate, early abortion rate or live birth rate between the groups. There was no significant difference in perinatal outcomes of singleton live birth, including VPTD, PTD, postterm delivery, LBW, macrosomia, SGA, LGA, GDM, HDP, placenta previa, and congenital malformation.

CONCLUSION

For women with abnormal ovulation, the pregnancy and perinatal outcomes of HRT and L-OI protocols are reassuring. It seems that both protocols are safe and effective for endometrial preparation in frozen-thawed embryo transfer in the clinic.

Pre-eclampsia in pregnancies resulting from oocyte donation, natural conception or IVF: a systematic review and meta-analysis

STUDY QUESTION

What is the prevalence of pre-eclampsia (PE) in pregnancies after oocyte donation (OD) compared to natural conception (NC) and to IVF with autologous oocytes (AO)?

SUMMARY ANSWER

Overall the prevalence of PE after OD was 4-5 times higher than after NC and 2-3 times higher than after IVF with AO.

WHAT IS KNOWN ALREADY

The indication for OD is expanding to lesbian women requesting shared lesbian motherhood. Previous reviews have shown that the risk of PE is higher in pregnancies after OD than after NC and after IVF with AO. Classification on the severity of PE is lacking as is the relationship with known risk factors such as maternal age and multiple gestations. Furthermore the actual prevalence of PE in pregnancies resulting from OD is not known.

STUDY DESIGN, SIZE, DURATION

A systematic review and meta-analysis was conducted. A literature search was performed using the following databases: PubMed, EMBASE and CINAHL, OpenGrey and Greynet from January 1980 through July 2020.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We included retrospective and prospective cohort studies. The study population consisted of pregnancies after OD and NC or IVF and data had to be available about prevalence of PE. We compared the risk of (severe) PE in OD versus NC and IVF pregnancies, subgrouped by plurality and maternal age. We calculated individual and pooled odds ratios (OR) and prevalence estimates with 95% CI using a random effect model, while heterogeneity was assessed by the I2.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 27 studies comprising of 7089 OD pregnancies, 1 139 540 NC pregnancies and 72 742 IVF pregnancies were available for analysis. The risks of PE and severe PE was increased in OD pregnancies compared to NC pregnancies (pooled OR of all subgroups: 5.09, 95% CI: 4.29-6.04; I2 = 19% and OR: 7.42, 95% CI: 4.64-11.88; I2 = 49%, respectively). This suggests that compared to a PE risk of 2.9% with NC, the risk with OD was between 11.5% and 15.4%. Compared to a severe PE risk of 0.5% with NC, the risk with OD was between 2.3% and 5.6%. The pooled adjusted OR for PE was 3.24 (95% 2.74-3.83) for OD versus NC pregnancies. The risks of PE and severe PE were also increased in OD pregnancies compared to IVF pregnancies (pooled OR of all subgroups: 2.97, 95% CI: 2.49-3.53; I2 = 51% and OR: 2.97, 95% CI: 2.15-4.11; I2 = 0%, respectively). This suggests that compared to a PE risk of 5.9% with IVF, the risk with OD was between 13.5% and 18.0%. Compared to a severe PE risk of 3.3% with IVF, the risk with OD was between 6.8% and 12.2%. The pooled adjusted OR for PE was 2.67 (95% 2.28-3.13) for OD versus IVF. The pooled prevalence of PE in singleton pregnancies after OD was 10.7% (95% CI 6.6-15.5) compared to 2.0% (95% CI 1.0-3.1) after NC and 4.1% (95% CI 2.7-5.6) after IVF. The prevalence in multiple pregnancies was 27.8% (95% CI 23.6-32.2) after OD, 7.5% (95% CI 7.2-7.8) after NC and 9.7% (95% CI 6.2-13.9) after IVF.

LIMITATIONS, REASONS FOR CAUTION

The precise definition of PE is still a matter of debate. The different criteria could have affected the prevalence estimate.

WIDER IMPLICATIONS OF THE FINDINGS

Nearly one in six women will suffer PE after OD. Although it is uncertain whether these risks are consistent for lesbian couples undergoing shared motherhood, we feel that women who can conceive naturally could be advised to reconsider. In women with primary ovarian insufficiency, we feel that factors that may increase risk of PE ever further, such as double embryo transfer, should be avoided whenever possible.

STUDY FUNDING/COMPETING INTEREST(S)

No funding or competing interests.

REGISTRATION NUMBER

CRD42020166899.

Pregnancy Outcomes After Frozen-Thawed Embryo Transfer in the Absence of a Corpus Luteum

Background: Nowadays, frozen-thawed embryo transfer (FET) cycles represent a high proportion of fertility treatments worldwide. Recent studies suggest differences in pregnancy outcomes depending on the FET treatment protocol used. The reason for this is still unclear, but the number of corpora lutea (CL) at conception is discussed as a possible factor. This study aims to investigate whether maternal and neonatal outcomes for pregnancies following FET lacking a CL differ from FET with one or more CL in order to explore a potential link between CL absence and adverse pregnancy outcomes.

Methods: The study was designed as a retrospective, multi-center observational study with two cohorts after singleton live birth [0 CL cohort (FET in a programmed cycle, n = 114) and ≥ 1 CL cohort (FET in a natural or stimulated cycle, n = 68)]. Participants completed a questionnaire on the outcome of pregnancy and birth records were analyzed in a descriptive way. Multivariable logistic and linear regressions were performed in order to explore associations between CL absence and pregnancy outcomes. The strength of the agreement between the information in the survey and the diagnoses extracted from the files was assessed by Cohen's Kappa.

Results: The risk of hypertensive disorders of pregnancy was higher after FET in the absence of a CL compared to FET with CL presence (aOR 5.56, 95% CI 1.12 – 27.72). Birthweights and birthweight percentiles were significantly higher in the 0 CL group. CL absence was a predictor of higher birthweight (adjusted coefficient B 179.74, 95% CI 13.03 – 346.44) and higher birthweight percentiles (adjusted coefficient B 10.23, 95%, 95% CI 2.28 – 18.40) particularly in female newborns of the 0 CL cohort. While the strength of the agreement between the reported information in the survey and the actual diagnoses extracted from the files was good for the majority of outcomes of interest it was fair in terms of hypertension (κ = 0.38).

Conclusion: This study supports observations suggesting a potential link between a lack of CL at conception and adverse maternal and neonatal outcomes. Further investigations on causes and pathophysiological relationships are yet to be conducted.

Natural vs. programmed cycles for frozen embryo transfer: study protocol for an investigator-initiated, randomized, controlled, multicenter clinical trial

Background

Randomized trials of assisted reproductive technology (ART) have been designed for outcomes of clinical pregnancy or live birth and have not been powered for obstetric outcomes such as preeclampsia, critical for maternal and fetal health. ART increasingly involves frozen embryo transfer (FET). Although there are advantages of FET, multiple studies have shown that risk of preeclampsia is increased with FET compared with fresh embryo transfer, and the reason for this difference is not clear. NatPro will compare the proportion of preeclampsia between two commonly used protocols for FET,modified natural and programmed cycle.

Methods

In this two-arm, parallel-group, multi-center randomized trial, NatPro will randomize 788 women to either modified natural or programmed FET and follow them for up to three FET cycles. Primary outcome will be the proportion of preeclampsia in women with a viable pregnancy assigned to a modified natural cycle FET (corpus luteum present) protocol compared to the proportion of preeclampsia in pregnant women assigned to a programmed FET (corpus luteum absent) protocol. Secondary outcomes will compare the proportion of live births and the proportion of preeclampsia with severe features between the protocols.

Conclusion

This study has a potential significant impact on millions of women who pursue ART to build their families. NatPro is designed to provide clinically relevant guidance to inform patients and clinicians regarding maternal risk with programmed and modified natural cycle FET protocols. This study will also provide accurate point estimates regarding the likelihood of live birth with programmed and modified natural cycle FET.

Trial registration

ClinicalTrials.govNCT04551807. Registered on September 16, 2020

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05637-3.

Embryo biopsy and maternal and neonatal outcomes following cryopreserved-thawed single embryo transfer

BACKGROUND

Contemporary embryo biopsy in the United States involves the removal of several cells from a blastocyst that would become the placenta for preimplantation genetic testing. Embryos are then cryopreserved while patients await biopsy results, with transfers occurring in a subsequent cycle as a single frozen-thawed embryo transfer, if euploid.

OBJECTIVE

We sought to determine if removal of these cells for preimplantation genetic testing was associated with adverse obstetrical or neonatal outcomes after frozen-thawed single embryo transfer.

STUDY DESIGN

We linked assisted reproductive technology surveillance data from the Society for Assisted Reproductive Technology Clinic Outcome Reporting System to birth certificates and maternal and neonatal hospitalization discharge diagnoses in Massachusetts from 2014 to 2017, considering only singleton births after frozen-thawed single embryo transfers. We compared outcomes of cycles having embryo biopsy (n=585) to those having no biopsy (n=2191) using chi-square for categorical and binary variables and logistic regression for adjusted odds ratios and 95% confidence intervals, adjusting for mother's age, race, education, parity, body mass index, birth year, insurance, and all infertility diagnoses.

RESULTS

Considering no biopsy as the reference, there was no difference between groups with respect to preeclampsia (adjusted odds ratio, 0.82; 95% confidence interval, 0.42-1.61; P=.5685); pregnancy-induced hypertension (adjusted odds ratio, 0.85; 95% confidence interval, 0.46-1.59; P=.6146); placental disorders, including placental abruption, placenta previa, placenta accreta, placenta increta, and placenta percreta (adjusted odds ratio, 1.16; 95% confidence interval, 0.60-2.24; P=.6675); preterm birth (adjusted odds ratio, 1.22; 95% confidence interval 0.73-2.03; P=.4418); low birthweight (adjusted odds ratio, 1.12; 95% confidence interval, 0.58-2.15; P=.7355); cesarean delivery (adjusted odds ratio, 1.04; 95% confidence interval, 0.79-1.38; P=.7762); or gestational diabetes mellitus (adjusted odds ratio, 0.83; 95% confidence interval, 0.50-1.38; P=.4734). In addition, there was no difference between the groups for prolonged hospital stay for mothers (adjusted odds ratio, 1.23; 95% confidence interval, 0.83-1.80; P=.3014) or for infants (95% confidence interval, 1.29; 95% confidence interval, 0.72-2.29; P=.3923).

CONCLUSION

Embryo biopsy for preimplantation genetic testing does not increase the odds for diagnoses related to placentation (preeclampsia, pregnancy-related hypertension, placental disorders, preterm delivery, or low birthweight), maternal conditions (gestational diabetes mellitus), or maternal or infant length of stay after delivery.

Secretory products of the corpus luteum and preeclampsia

BACKGROUND

Despite significant advances in our understanding of the pathophysiology of preeclampsia (PE), there are still many unknowns and controversies in the field. Women undergoing frozen-thawed embryo transfer (FET) to a hormonally prepared endometrium have been found to have an unexpected increased risk of PE compared to women who receive embryos in a natural FET cycle. The differences in risk have been hypothesized to be related to the absence or presence of a functioning corpus luteum (CL).

OBJECTIVE AND RATIONALE

To evaluate the literature on secretory products of the CL that could be essential for a healthy pregnancy and could reduce the risk of PE in the setting of FET.

SEARCH METHODS

For this review, pertinent studies were searched in PubMed/Medline (updated June 2020) using common keywords applied in the field of assisted reproductive technologies, CL physiology and preeclampsia. We also screened the complete list of references in recent publications in English (both animal and human studies) on the topics investigated. Given the design of this work as a narrative review, no formal criteria for study selection or appraisal were utilized.

OUTCOMES

The CL is a major source of multiple factors regulating reproduction. Progesterone, estradiol, relaxin and vasoactive and angiogenic substances produced by the CL have important roles in regulating its functional lifespan and are also secreted into the circulation to act remotely during early stages of pregnancy. Beyond the known actions of progesterone and estradiol on the uterus in early pregnancy, their metabolites have angiogenic properties that may optimize implantation and placentation. Serum levels of relaxin are almost undetectable in pregnant women without a CL, which precludes some maternal cardiovascular and renal adaptations to early pregnancy. We suggest that an imbalance in steroid hormones and their metabolites and polypeptides influencing early physiologic processes such as decidualization, implantation, angiogenesis and maternal haemodynamics could contribute to the increased PE risk among women undergoing programmed FET cycles.

WIDER IMPLICATIONS

A better understanding of the critical roles of the secretory products of the CL during early pregnancy holds the promise of improving the efficacy and safety of ART based on programmed FET cycles.

Frozen embryo transfer and preeclampsia: where is the link?

PURPOSE OF REVIEW

Preeclampsia is the leading cause of maternal death and has a higher incidence in patients undergoing assisted reproduction treatments. New studies about the mechanisms by which it is more frequent in this population have emerged. The purpose of this review is to gather current information about the available results on this correlation and its possible physiopathology.

RECENT FINDINGS

Recent publications on the physiopathology of preeclampsia indicate that the corpus luteum is the main source of hormonal production until placental formation and that apart from the secretion of estrogen and progesterone, corpus luteum also produces important substances involved in maternal circulatory adaptation, such as relaxin.With the recent increasing number of frozen embryos transfer in natural cycles or under hormonal replacement, this adaptive circulatory process may be unbalanced and predispose this population to preeclampsia.

SUMMARY

This article provides a review of frozen embryo transfer and available protocols, the highest incidence of gestational hypertensive disorders presented by the infertile population and an overview of the possible impact of the absence of corpus luteum on the genesis of this disease.

When Should We Freeze Embryos? Current Data for Fresh and Frozen Embryo Replacement IVF Cycles

Recent years have seen a dramatic rise in the number of frozen-thawed embryo replacement (FER) cycles. Along with the advances in embryo cryopreservation techniques, the optimization of endometrial receptivity has resulted in outcomes for FER that are similar to fresh embryo transfer. However, the question of whether the Freeze all strategy is for all is nowadays a hot topic. This review addresses this issue and describes current evidence based on randomized controlled trials and observational studies. To date, it is reasonable to perform FER in cases with a clear indication for the benefits of such strategy including impending ovarian hyperstimulation syndrome (OHSS) or preimplantation genetic testing for aneuploidy (PGT-A); however, this strategy does not fit for all. This review analyses the pros and cons of the freeze all strategy highlighting the need to follow a personalized plan in embryo transfer, avoiding a freeze all methodology for all patients in an unselected manner.

A Review of Research Progress of Pregnancy with Twins with Preeclampsia

Preeclampsia has a significant long-term effect on the health of both mothers and babies. Preeclampsia-related pregnancy complications increase the morbidity and mortality of pregnant women and their fetuses by 5-8%. The recent advancement of assisted reproductive technology, combined with a rise in the number of elderly pregnant women, has resulted in pregnancy incidence with twins. Twins pregnant women have a 2-3 times greater risk of developing preeclampsia than singleton pregnant women, and it happens sooner and progresses faster. It is more severe and may appear in an atypical way. End-organ damage, such as renal failure, stroke, cardiac arrest, pulmonary edema, placental abruption, and cesarean section, are related maternal complications. Fetal growth retardation, stillbirth, and premature delivery with obstetric signs are all fetal complications. According to studies, all multiple pregnancies can take low-dose aspirin (60-150 mg) to minimize the risk of preeclampsia. To improve pregnancy outcomes and reduce the inherent risk of pregnancy with twins, twins should be handled as a high-risk pregnancy and treated differently than singletons. The literature on twin pregnancy with preeclampsia is the subject of this review. It will examine the current state of research on preeclampsia in pregnancy with twins, including the occurrence, diagnosis, and pathophysiological process. Moreover, the effect of pregnancy with twins on the perinatal outcome and pregnancy management of pregnancy with twins, including blood pressure management and preeclampsia prevention and treatment, is examined in this literature review. The goal is to figure out what kind of diagnosis and care you may need.

Frozen Embryo Transfer and Preeclampsia Risk

Worldwide, the use of Assisted Reproductive Technology (ART) has been steadily rising over recent years. With the continuous improvements in cryopreservation techniques and the growing practice of single embryo transfer, the proportion of frozen embryo transfer (FET) cycles has been increasing, therefore raising concern about the safety of this ART technique to both mothers and infants. This review aims to summarize the current evidence regarding the risk of preeclampsia in singleton pregnancies achieved by autologous FET compared to fresh embryo transfer, and to discuss the influence of different protocols used for endometrium preparation in frozen cycles on the risk of this obstetric complication. Several studies have reported a higher risk of hypertensive disorders, including preeclampsia, in pregnancies following FET compared with fresh embryo transfer. Recently, artificial FET cycles, which preclude the development of a corpus luteum, were shown to be associated with an increased preeclampsia risk in comparison with natural and stimulated cycles. Importantly, no difference was found between FET in a modified natural cycle and spontaneous conception. It has been proposed that the absence of the corpus luteum in artificial cycles may, at least partly, contribute to the observed increased risk of preeclampsia. Indeed, the corpus luteum secretes vasoactive hormones, such as relaxin, which are not replaced in artificial cycles, thereby compromising maternal cardiovascular adaptations to pregnancy, resulting in an increased risk of preeclampsia. If these findings are confirmed by a randomized controlled trial, natural, modified natural or stimulated cycles might be preferred over artificial cycles in eligible patients.

Comparison of the Method of Endometrial Preparation Prior to Frozen-Thawed Embryo Transfer: a Retrospective Cohort Study from 9733 Cycles

Our objective was to compare the effectiveness of natural cycles (NC), modified natural cycle (mNC), and artificial cycles (AC) in women undergoing frozen-thawed embryo transfer (FET) after in vitro fertilization (IVF). This is a retrospective cohort study analyzing 9733 women undergoing the first cycle of FET over a 3-year period (June 2014-December 2017) at Northwest Women's and Children's Hospital after IVF-ICSI cycles. The type of endometrial preparation was determined by the treating physician's preference, based on patients' characteristics. Women with regular ovulation were allocated to natural cycles (n = 1480) or modified natural cycles (n = 196) when the leading follicle was triggered with hCG, while patients who were reluctant to frequently monitoring or living far from the hospital were allocated to artificial cycles (n = 8057). A logistic regression model was used to assess the association between endometrial preparation and clinical outcomes while adjusting for potential confounders. Live birth rate was primary outcome while miscarriage rate, clinical pregnancy rate, preterm birth rate, and ectopic pregnancy rate were secondary outcomes. In the adjusted model, type of endometrial preparation did not affect live birth (OR, 0.89; 95% CI, 0.74-0.96), clinical pregnancy (OR, 0.93; 95% CI, 0.81-1.06), preterm birth (OR, 1.03; 95% CI, 0.84-1.26), and ectopic pregnancy (OR, 0.73; 95% CI, 0.33-1.59), while AC significantly increased the miscarriage rate (OR, 1.49; 95% CI, 1.17-1.89, P=0.001). In conclusions, in women undergoing FET, natural cycles and artificial cycles resulted in comparable live birth rate while miscarriage rate was higher in artificial cycles.

Should we still offer elective freezing of all embryos in all IVF cycles?

Elective 'freeze all', also called 'freeze only', refers to an IVF cycle where all embryos are frozen for later embryo transfer in a non-stimulated cycle, with the promise of increased success rates and prevention of ovarian hyperstimulation syndrome (OHSS) in most patients. However, 'freeze all' is associated with significantly higher perinatal complications including eclampsia, preeclampsia, chronic hypertension and large-for-gestational-age infants, without the demonstrated advantages of providing better results, except for a decrease in the incidence of OHSS, which should matter to women with polycystic ovary syndrome (PCOS) and high responders to ovarian stimulation but not to all patients. 'Freeze all' is also suggested for all simulated IVF cycles, due to the alleged 'faulty endometrium' caused by ovarian stimulation. However, there is no direct evidence that asynchronous endometrium exists, and only if preovulatory progesterone level increase, can 'freeze all' confer an advantage. We conclude that an alleged diagnosis of 'faulty endometrium' should not be used as an indication for 'freeze all'. To offset the risk of OHSS more simply, less costly and less risky solutions such as mild ovarian stimulation, to dampen the number of oocytes and to aim for transfer of a single blastocyst, should be the preferred solution to treat women with PCOS and high responders for oocyte retrieval.

Endometrial Receptivity Analysis (ERA) test: an unproven technology

This article addresses the limitations of the endometrial receptivity array (ERA) methodology to increase implantation. Such limitations vary from the assumed inconsistency of the endometrial biopsy, the variable number of genes found to be dysregulated in endometrium samples without the embryonal-induced effect, the failure to account for the simultaneous serum progesterone level, and the expected low percentage of patients who may need this add-on procedure, to the difficulties in synchronising the endometrium with hormone replacements in successive cycles and the inherent perinatal risks associated with routine cryopreservation of embryos. Without a gold standard to compare, the claim that the window of implantation (WOI) might be off by ±12 h only requires a good argument for the advantage it provides to human procreation, knowing that embryos can linger for days before actual embedding starts and that the window is actually a few days. The intra-patient variations in the test need to be addressed. In summary, like all other add-ons, it is doubtful whether the ERA test use can significantly enhance implantation success rates.

Influence of Placental Abnormalities and Pregnancy-Induced Hypertension in Prematurity Associated with Various Assisted Reproductive Technology Techniques

OBJECTIVE

Assisted reproductive technology (ART)-treated women exhibit increased risk of premature delivery compared to fertile women. We evaluated whether ART treatment modalities increase prematurity and whether placental abnormalities and pregnancy-induced hypertensive (PIH) disorders mediate these risks.

METHOD(S)

This retrospective study of ART-treated and fertile deliveries (2004-2017) used an ART-cycle database linked to Massachusetts birth certificates and hospital discharges. Outcomes of late preterm birth (LPTB: 34-36 weeks gestation) and early preterm birth (EPTB: <34 weeks gestation) were compared with term deliveries (≥37 weeks gestation) in ART-treated (linked to the ART database) and fertile (no indicators of infertility or ART) deliveries. ART treatments with autologous oocyte, donor oocyte, fresh or frozen embryo transfer (FET), intracytoplasmic sperm injection (ICSI) and no-ICSI were separately compared to the fertile group. Adjusted odds ratios (AOR) were calculated with multivariable logistic regression: placental abnormalities or PIH were quantified in the pathway as mediators.

RESULTS

There were 218,320 deliveries: 204,438 fertile and 13,882 ART-treated. All treatment types increased prematurity (AOR 1.31-1.58, LPTB; AOR 1.34-1.48, EPTB). Placental abnormalities mediated in approximately 22% and 38% of the association with LPTB and EPTB, respectively. PIH mediated 25% and 33% of the association with LPTB and EPTB in FET and donor oocyte cycles, more than other treatments (<10% LPTB and <13% EPTB).

CONCLUSIONS

ART-treatment and all ART modalities increased LPTB and EPTB when compared with fertile deliveries. Placental abnormalities modestly mediated associations approximately equally, while PIH was a stronger mediator in FET and donor oocyte cycles. Reasons for differences require exploration.

A case of hypertensive disorders of pregnancy that developed at 9 weeks of gestation

Preeclampsia and superimposed preeclampsia usually develop after 20 weeks of gestation. We report a case of a 35-year-old Japanese woman who developed hypertensive disorders of pregnancy (HDP) before 20 weeks of gestation. She presented with hypertension and proteinuria at 9 and 11 weeks of gestation, respectively, and developed nephrotic syndrome at 17 weeks of gestation. She did not have definite hypertension or urinary abnormalities before pregnancy. The patient was serologically positive for the antinuclear antibody. However, the complement levels were normal and anti-phospholipid antibody was not detected. A renal biopsy performed at 18 weeks of gestation showed diffuse endotheliosis and tip lesions of secondary focal segmental glomerulosclerosis but no hypertensive changes of the arterioles. Although electron microscopic examination showed electron-dense deposits in the subendothelial lesions, they were considered nonspecific plasma exudation by mass spectrometry. An abortion was performed at 20 weeks gestation because the patient's congestive symptoms due to nephrotic syndrome had worsened and marked fetal growth restriction was observed. After delivery, the patient's symptoms resolved immediately without any additional treatment; however, continuous antihypertensive medication was required. Finally, the patient was diagnosed with HDP based on the renal biopsy findings and her clinical course after delivery. Compared to previous reports, this case describes the earliest onset of HDP. Thus, HDP should be considered as a differential diagnosis in pregnant women with hypertension or proteinuria presenting with symptoms before 20 weeks of gestation.

Health of 2-year-old children born after vitrified oocyte donation in comparison with peers born after fresh oocyte donation

STUDY QUESTION

Does oocyte vitrification adversely affect the health of 2-year-old children compared with peers born after use of fresh oocytes in a donation programme?

SUMMARY ANSWER

The growth and health of 2-year-old children born after oocyte vitrification are similar to those of peers born after use of fresh oocytes.

WHAT IS KNOWN ALREADY

Although oocyte vitrification is a well-established procedure in ART, the evidence on its safety for offspring is limited. Currently, no disadvantageous effects of oocyte vitrification have been shown in terms of obstetric and neonatal outcome. However, no data beyond the neonatal period are available to date.

STUDY DESIGN, SIZE, DURATION

A combined retrospective and prospective observational study was performed in a tertiary reproductive centre. The retrospective data were available in our extensive database of children born after ART. Donor cycles with an oocyte retrieval between January 2010 and March 2017 and a fresh embryo transfer resulting in the livebirth of a singleton were selected from the established oocyte donation programme. Fresh or vitrified oocytes were used in the donor cycles and all pregnancies in oocyte recipients were achieved after ICSI. Only children residing in Belgium were eligible for follow-up.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Biometric and health parameters of 72 children born after oocyte vitrification were compared with those of 41 children born after use of a fresh oocyte. Data were collected by means of questionnaires and physical examinations at the age of 21–30 months. The primary outcome measures were anthropometry and health at 2 years of age.

MAIN RESULTS AND THE ROLE OF CHANCE

Length, weight, BMI, head circumference, left arm circumference and waist circumference at the age of 2 years were comparable between the vitrification and fresh group, also after adjustment for treatment, and maternal and neonatal characteristics (all P > 0.05). Health of the children in terms of hospital admission and surgical intervention rates were comparable between the vitrification and fresh group (both P > 0.05).

LIMITATIONS, REASONS FOR CAUTION

Although the current study is the largest series describing health parameters beyond the neonatal period, the small numbers still preclude definite conclusions.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides the first evidence indicating that oocyte vitrification does not adversely affect the growth and health of offspring beyond the neonatal period.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by Methusalem grants and by grants from Wetenschappelijk Fonds Willy Gepts, all issued by the Vrije Universiteit Brussel. All co-authors declared no conflict of interest in relation to this work. Both the Centre for Reproductive Medicine and the Centre for Medical Genetics from the UZ Brussel have received several educational grants from IBSA, Ferring, MSD and Merck for either research on oocyte vitrification or for establishing the database for follow-up research and organizing the data collection.

Does contemporary ART lead to pre-eclampsia? A cohort study and meta-analysis

PURPOSE

Recent publications suggested that the risk for pre-eclampsia (PE) is higher with frozen-thawed embryo transfers (FETs) compared to fresh transfers (IVF-ETs). These studies were based on old data that reflects outdated practices. In this paper, we wanted to assess the incidence of PE in current assisted reproductive technology (ART) practice.

METHODS

In this cohort study, we present the incidence of PE in all births in the province of Ontario, Canada, for the years 2013-2017 for FET, IVF-ET, and natural conceptions (NC). We also compare our findings to previous studies in a meta-analysis that includes over 4 million births.

RESULTS

The results of our study show that contemporary practice of ART results in comparable risk for PE between FET and IVF-ET; however, the risk is higher than NC.

CONCLUSION

Current ART practice is associated with a lower risk for PE in frozen embryo transfer; this RR can be further attenuated by using ovulatory endometrial preparation for FETs.

Adverse obstetric and perinatal outcomes in 1,136 singleton pregnancies conceived after programmed frozen embryo transfer (FET) compared with natural cycle FET

OBJECTIVE

To investigate whether obstetric and perinatal outcomes in pregnancies differ after different frozen embryo transfer (FET) protocols.

DESIGN

Register-based cohort study.

SETTING

Not applicable.

PATIENT(S)

All singleton deliveries after assisted reproductive technology in Denmark from 2006 to 2014. Data consisted of 1,136 deliveries after frozen in vitro fertilization. Frozen embryo transfer cycles were grouped by type of FET protocol: programmed FET (n = 357); modified natural cycle FET (n = 611); and true natural cycle FET (n = 168).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Obstetric outcomes (hypertensive disorders in pregnancy, preterm prelabor rupture of membranes, placenta previa, placental abruption, induction of labor, postpartum hemorrhage, and cesarean section) and perinatal outcomes (post-term birth, preterm birth, birth weight, small for gestational age, large for gestational age).

RESULT(S)

The risk of hypertensive disorders in pregnancy, postpartum hemorrhage, and cesarean section was significantly higher after programmed FET compared with natural cycle FET (modified natural cycle FET and true natural cycle FET). A higher risk of birth weight > 4,500 g was observed in the programmed FET group compared with natural cycle FET.

CONCLUSION(S)

This study shows that obstetric and perinatal outcomes are adversely affected in programmed FET cycles. Hence, when possible, an endometrial preparation with the creation of a corpus luteum should be considered. Properly sized randomized controlled trials of FET in programmed cycle versus natural cycle including perinatal outcomes are warranted in the future.

CLINICAL TRIAL REGISTRATION NUMBER

ISRCTN11780826.

Vanishing Twins Conceived Through Fresh In Vitro Fertilization: Obstetric Outcomes and Placental Pathology

OBJECTIVE

To characterize the obstetric outcomes and placental pathology in live births arising from vanishing twin pregnancies compared with nonreduced in vitro fertilization (IVF) pregnancies.

METHODS

This is a retrospective cohort study of live births resulting from fresh embryo transfers after IVF cycles with autologous oocytes from 2004 through 2017 at a large academic fertility center. Clinical information and pathology reports were reviewed. Placental diagnoses were coded using established nosology by expert placental pathologists. Analysis of variance, Kruskal-Wallis, Pearson's χ, and Fisher exact tests were used, as appropriate, to compare pathology categories between pregnancy outcomes. Mixed effects logistic regression models were generated to reveal the association between pregnancy outcome and placenta pathology, controlling for pregnancies arising in the same woman and various suspected confounders.

RESULTS

Of 905 fresh autologous IVF cycles with placental pathology available for review, we identified 73 vanishing twin pregnancies (8.1%), 556 singleton pregnancies (61.4%), and 276 twin pregnancies (30.5%). Vanishing twin syndrome was not associated with preterm delivery, route of delivery, growth restriction or other obstetric outcomes as compared with IVF singleton pregnancies. However, vanishing twin syndrome pregnancies showed distinctive placental pathologies including an increased rate of small placentas (less than the 10th percentile by weight), with more anatomical abnormalities than IVF singleton pregnancies (odds ratio 1.73, 95% CI 0.94-3.19; adjusted odds ratio 2.15, 95% CI 1.08-4.28). The frequency of placental vascular and inflammatory pathologies associated with IVF vanishing twin syndrome pregnancies were similar to that of IVF singleton pregnancies. Loss of a twin after 8 weeks of gestation was not associated with greater risks of placental pathologies.

CONCLUSION

In vitro fertilization pregnancies affected by vanishing twin syndrome did not have significant differences in obstetric or perinatal outcomes as compared with twin or singleton gestations. However, early twin loss was potentially associated with differences in placental development associated with a higher rate of small placentas and other anatomic pathologies.

Activin A increases human trophoblast invasion by upregulating integrin β1 through ALK4

Activin A promotes human trophoblast invasion during the first trimester of pregnancy and is associated with preeclampsia and pregnancy-induced hypertension (PE/PIH) in naturally conceived pregnancies. However, whether integrin β1 mediates activin A-increased trophoblast invasion remains unknown and the evidence is limited regarding the predictive value of activin A for PE/PIH in women receiving in vitro fertilization (IVF) treatment. Here, we studied the role and underlying molecular mechanisms of integrin β1 in activin A-promoted invasion in immortalized (HTR8/SVneo) and primary human extravillous trophoblast (EVT) cells. A nest case-control study was designed to investigate the predictive/diagnostic value of activin A in IVF pregnancies. Results showed that integrin β1 expression increased after activin A treatment and knockdown of integrin β1 significantly decreased both basal and activin A-increased HTR8/SVneo cell invasion. SB431542 (TGF-β type I receptors inhibitor) abolished activin A-induced SMAD2/SMAD3 phosphorylation and integrin β1 overexpression. Activin A-upregulated integrin β1 expression was attenuated after the depletion of ALK4 or SMAD4 in both HTR8/SVneo and primary EVT cells. Furthermore, we found similar first-trimester activin A levels in IVF patients with or without subsequent PE/PIH. These results reveal that integrin β1 mediates activin A-promoted trophoblast invasion through ALK4-activated SMAD2/3-SMAD4 pathway, and the predictive/diagnostic value of first-trimester maternal serum activin A for hypertensive disorders of pregnancy might be different in IVF population.

Evidence for Corpus Luteal and Endometrial Origins of Adverse Pregnancy Outcomes in Women Conceiving with or Without Assisted Reproduction

Preeclampsia may arise from impaired decidualization in some women. Transcriptomics of mid-secretory biopsy endometrial stromal cells decidualized in vitro and of early gestation choriodecidua from women who experienced preeclampsia with severe features overlapped significantly with the classical endometrial disorders giving rise to the concept of "endometrium spectrum disorders". That is, recurrent implantation failure and miscarriage, endometriosis, normotensive intrauterine growth restriction, preeclampsia and preterm birth may all lie on a continuum of decidual dysregulation, in which phenotypic expression is determined by the specific molecular pathway(s) disrupted and severity of disruption. Women conceiving by programmed IVF protocols showed widespread dysregulation of cardiovascular function and increased rates of adverse pregnancy outcomes including preeclampsia. Programmed cycles preclude development of a corpus luteum (CL), a major regulator of endometrial function. Lack of circulating CL product(s) that are not replaced in programmed cycles (eg, relaxin) could adversely impact the maternal cardiovascular system directly and/or compromise decidualization, thereby increasing preeclampsia risk.

Number of embryos transferred and diagnosis of preeclampsia

BACKGROUND

Multiple births and first pregnancy are associated with higher preeclampsia risk. It is unknown if the transfer of multiple embryos or first embryo transfer with assisted reproductive technology (ART) is also associated with greater preeclampsia risk.

METHODS

We performed a retrospective cohort study of IVF clinics and hospitals in Massachusetts. We used linked ART surveillance, birth certificate, and maternal hospitalization discharge data for 21,188 births, considering resident singleton (12,810) and twin (8378) live-births from autologous or donor eggs from 2005 to 2012. We used log binomial and Poisson regression to calculate adjusted relative risks (aRRs) and 95% confidence intervals (CI) for the association between preeclampsia and predictors of preeclampsia. Outcomes were stratified by singleton and twin birth, donor versus autologous cycles, and use of fresh versus cryopreserved embryos.

RESULTS

Considering all singleton births, the transfer of multiple embryos increased the risk of preeclampsia [aRR = 1.10 (95% CI: 1.01-1.19)]. Relative risks were greatest for fresh non-donor cycles [aRR = 1.14 (95% CI: 1.03-1.26)]. Vanishing twin and number of prior ART cycles was not associated with preeclampsia among singleton births [aRR = 1.18 (95% CI: 0.91-1.53)], and aRR = 1.01 (95% CI: 0.96-1.05)], respectively. Considering all twin births, the transfer of > 2 embryos increased the risk of preeclampsia [aRR = 1.09 (95% CI: 1.001-1.19)]. Vanishing triplet and number of prior ART cycles were not associated with preeclampsia among twin births [aRR = 0.93 (95% CI: 0.69-1264), and aRR = 0.98 (CI: 0.95-1.02)], respectively.

CONCLUSIONS

Among ART births, the transfer of more than 1 embryo for singleton gestations and more than 2 embryos for twin gestations increased the risk for preeclampsia diagnosis.

Impact of elective frozen vs. fresh embryo transfer strategies on cumulative live birth: Do deleterious effects still exist in normal & hyper responders?

Background

Is freeze-all strategy effective in terms of cumulative live birth rates (CLBRs) in all patients?

Methods

This retrospective single-center study analyzed the CLBRs of 2523 patients undergoing fresh or electively frozen blastocyst transfer cycles. In 1047, cycles, the fresh embryo transfer (ET) strategy was applied for the 1^st ET, whereas electively frozen ET (e-FET) was performed in 1476 cycles. Female age ≤ 37 and blastocysts frozen via vitrification were included. The patients in each arm were further stratified into four subgroups according to the number of oocytes retrieved as follows: Group A: 1–5, group B: 6–10, group C: 11–15 and group D: 16–25 oocytes retrieved. The primary endpoint was the CLBR. The secondary endpoints were the ovarian hyperstimulation syndrome (OHSS) rate and the live birth rates (LBRs) following fresh ETs and e-FETs for the first transfers.

Result(s)

The CLBR was similar between the fresh ET and e-FET arms in group A (35/76 (46.1%) vs 29/67 (43.3%), p = 0.74) and group B (165/275 (60%) vs 216/324 (66.7%), p = 0.091), whereas significantly higher rates were detected in favor of the e-FET arm within group C (328/460 (71.3%) vs 201/348 (57.8%), p<0.001) and group D (227/348 (65.2%), vs 446/625 (71.5%), p<0.001). The OHSS rate was also found to be higher in the fresh ET arm among group C (12/348 (3.4%) vs 0/460 (0%), p<0.001) and group D (38/348 (10.9%) vs 3/625 (0.5%), p<0.001) patients than e-FET arm. Perinatal and obstetrical outcomes were nonsignificantly different between fresh and e-FET arms. However, the birth weights were significantly lower for fresh ET, 3064 versus 3201 g for singletons (p<0.001)

Conclusion

Compared with a fresh-transfer strategy, the e-FET strategy resulted in a higher CLBR among patients with >10 oocytes retrieved during stimulated cycles.

Pre-Pregnancy Obesity, Excessive Gestational Weight Gain, and the Risk of Pregnancy-Induced Hypertension and Gestational Diabetes Mellitus

Excessive pre-pregnancy weight is a known risk factor of pregnancy complications. The purpose of this analysis was to assess the relationship between several categories of maternal weight and the risk of developing hypertension and diabetes in pregnancy, and the relationship of these complications with the results of the newborn. It was carried out in a common cohort of pregnant women and taking into account the influence of disturbing factors. Our analysis was conducted in a prospective cohort of 912 Polish pregnant women, recruited during 2015-2016. We evaluated the women who subsequently developed diabetes with dietary modification (GDM-1) (n = 125) and with insulin therapy (GDM-2) (n = 21), as well as the women who developed gestational hypertension (GH) (n = 113) and preeclampsia (PE) (n = 24), compared to the healthy controls. Odds ratios of the complications (and confidence intervals (95%)) were calculated in the multivariate logistic regression. In the cohort, 10.8% of the women had pre-pregnancy obesity (body mass index (BMI) ≥ 30 kg/m²), and 36.8% had gestational weight gain (GWG) above the range of the Institute of Medicine recommendation. After correction for excessive GWG and other confounders, pre-pregnancy obesity (vs. normal BMI) was associated with a higher odds ratio of GH (AOR = 4.94; p < 0.001), PE (AOR = 8.61; p < 0.001), GDM-1 (AOR = 2.99; p < 0.001), and GDM-2 (AOR = 11.88; p <0.001). The threshold risk of development of GDM-2 occurred at lower BMI values (26.9 kg/m²), compared to GDM-1 (29.1 kg/m²). The threshold point for GH was 24.3 kg/m², and for PE 23.1 kg/m². For GWG above the range (vs. GWG in the range), the adjusted odds ratios of GH, PE, GDM-1, and GDM-2 were AOR = 1.71 (p = 0.045), AOR = 1.14 (p = 0.803), AOR = 0.74 (p = 0.245), and AOR = 0.76 (p = 0.672), respectively. The effect of maternal edema on all the results was negligible. In our cohort, hypertension and diabetes were associated with incorrect birth weight and gestational age at delivery. Conclusions: This study highlights the importance and influence of excessive pre-pregnancy maternal weight on the risk of pregnancy complications such as diabetes and hypertension which can impact fetal outcomes.

The ART of frozen embryo transfer: back to nature!

The implementation of cryopreservation-techniques in the IVF laboratory and the improved survival rates of oocytes, cleavage and blastocyst stage embryos have led to a significant increase in the number of frozen-thawed embryo transfer cycles (FET). FETs can be planned either in a 'pure' natural cycle, a modified natural cycle, a stimulated cycle or a hormonal replacement therapy cycle and the optimal means to prepare the endometrium for frozen embryo transfer is a topic of ongoing controversy. Recent findings report an increased risk of hypertensive disorders if pregnancy is achieved in a frozen embryo transfer cycle without an existing corpus luteum. Therefore, the question of how to prepare the endometrium has gained even more importance and taken on a new dimension as it should not simply be reduced to the basic question of 'which approach will result in superior pregnancy rates?' but instead 'which approach will result in the best pregnancy rates and the safest outcome for mother and baby?'. The aim of this review is to summarize and critically appraise the existing data on the different approaches of endometrial preparation for frozen embryo transfer with a special focus on the 'pure' natural cycle.

In vitro fertilization and risk for hypertensive disorders of pregnancy: associations with treatment parameters

BACKGROUND

Although in vitro fertilization has been associated with an increased risk for hypertensive disorders of pregnancy, the association of risk with in vitro fertilization treatment parameters is unclear.

OBJECTIVE

To evaluate risk for hypertensive disorders of pregnancy by maternal fertility status and in vitro fertilization treatment parameters.

MATERIALS AND METHODS

Women in 8 states who underwent in vitro fertilization resulting in a live birth during 2004-2013 were linked to their infant's birth certificates. A 10:1 sample of births from non-in vitro fertilization deliveries were selected for comparison. Those with an indication of infertility treatment on the birth certificate were categorized as subfertile and omitted from the study population; all others were categorized as fertile. The in vitro fertilization pregnancies were additionally categorized by oocyte source (autologous versus donor) and embryo state (fresh versus thawed). Both the fertile and in vitro fertilization births were limited to singletons only, and the in vitro fertilization pregnancies were limited to those using partner sperm. Hypertensive disorders of pregnancy (including gestational hypertension and preeclampsia) were identified from the birth certificate, modeled using logistic regression, and reported as adjusted odds ratios and 95% confidence intervals. For analyses of in vitro fertilization pregnancies from autologous oocytes-fresh embryos, the reference group was fertile women (subgroup analysis 1). For analyses within the in vitro fertilization group, the reference group was autologous oocytes-fresh embryos (subgroup analysis 2).

RESULTS

The study population included 1,465,893 pregnancies (1,382,311 births to fertile women and 83,582 births to in vitro fertilization-treated women). Compared to fertile women, in vitro fertilization-treated women with autologous-fresh cycles were not at increased risk for hypertensive disorders of pregnancy (adjusted odds ratio, 1.04; 95% confidence interval, 0.99, 1.08). Among in vitro fertilization births (subgroup analysis 2), the risk for hypertensive disorders of pregnancy was increased for the autologous-thawed (adjusted odds ratio, 1.30; 95% confidence interval, 1.20, 1.40); donor-fresh (adjusted oddds ratio, 1.92; 95% confidence interval, 1.71, 2.15); and donor-thawed (adjusted odds ratio, 1.70; 95% confidence interval, 1.47, 1.96) groups. Excluding women with pregestational diabetes or chronic hypertension as well as adjusting for body mass index and infertility diagnoses did not substantially change the results. When stratified by <34 weeks (early-onset hypertensive disorders of pregnancy) versus ≥34 weeks (late-onset hypertensive disorders of pregnancy), only the donor-fresh group had an increased risk of early-onset hypertensive disorders of pregnancy, but the risks for all other oocyte source-embryo state groups compared to autologous-fresh were increased for late-onset hypertensive disorders of pregnancy.

CONCLUSION

The risk for hypertensive disorders of pregnancy is increased for in vitro fertilization-treated women in pregnancies conceived via frozen embryo transfer (with both autologous or donor oocyte) and fresh donor oocyte embryo transfer. No increase in risk was seen with autologous oocyte-fresh embryo transfers in vitro fertilization cycles. Excluding women with pregestational diabetes or chronic hypertension as well as adjusting for body mass index and infertility diagnoses did not substantially change the results.

Placental pathology in live births conceived with in vitro fertilization after fresh and frozen embryo transfer

BACKGROUND

The availability and use of frozen embryos after ovarian hyperstimulation for assisted reproduction has increased with improvement in vitrification techniques and the rise of preimplantation genetic testing. However, there are conflicting data regarding whether obstetric outcomes differ between fresh and frozen embryo transfer cycles.

OBJECTIVE

To compare placental pathology from live births arising from fresh and frozen embryo transfer cycles.

MATERIALS AND METHODS

A cohort of 1140 live births with placental pathology arising from autologous in vitro fertilization cycles with fresh or frozen programmed transfer performed at MGH Fertility Center between 2004 and 2017 was retrospectively reviewed. An experienced placental pathologist categorized the reported placental pathology as anatomic, infectious, inflammatory, or vascular/thrombotic. Our primary outcomes were differences in these placental pathologies between the 2 groups. Patient demographic, cycle, and birth outcomes were compared with the use of χ² tests, Student t test, or nonparametric tests, as appropriate. Multivariate logistic regression models were used to compare placental pathology between the fresh and frozen transfer groups.

RESULTS

Of the 1140 cycles included in our analysis, 929 arose from fresh embryo transfers (81.3%) and 211 arose from programmed frozen embryo transfers (18.5%). For both transfer types, the average age of the women at time of treatment was 35 years; mean body mass indices were within the normal range (23.6 kg/m² for fresh transfers and 23.2 kg/m² for frozen transfers, P = .26), and mean day 3 follicle-stimulating hormone values were 7.1 and 7.0 IU/L (P = .44), respectively. Deliveries occurred on average at 37.5 and 38.0 weeks' gestational age (P = .04) in the fresh versus frozen transfer group, with similar rates of obstetric complications. However, frozen transfers were more likely to be associated with marginal cord insertion (adjusted odds ratio, 1.87; confidence interval, 1.21, 2.91; P = .01), accessory lobe formation (adjusted odds ratio, 2.96; confidence interval, 1.12, 7.79; P = 0.03), subchorionic thrombi (adjusted odds ratio, 3.72; confidence interval, 1.80, 7.71; P < .001), and fetal vascular malperfusion characteristics with cord anomalies (adjusted odds ratio, 2.34; confidence interval, 1.22, 4.46; P = .01). These trends persisted when we analyzed day 5 transfers alone, and single frozen embryo transfers remained associated with increased rates of subchorionic thrombi compared to single fresh embryo transfers.

CONCLUSION

Pregnancies arising from frozen embryo transfers demonstrated more anatomic and vascular placental pathology than those from fresh transfers in our cohort of patients, despite similar maternal outcomes. More research is needed to explore how these differences in pathology may influence obstetric and perinatal outcomes.

Maternal Vascular Health in Pregnancy and Postpartum After Assisted Reproduction

Although most pregnancies after assisted reproduction are associated with a favorable outcome for the mother and infant, reports of abnormal vascular adaptation in early pregnancy and emerging maternal and perinatal pathology warrant further investigations. Herein we extended our previous work and further examined whether perturbations of blood pressure and endothelial function during the first trimester in conceptions with nonphysiological corpus luteum (CL) numbers would persist through the third trimester of pregnancy and into the postpartum period. We investigated both maternal and perinatal outcomes. Participants were grouped according to CL number and method of conception: 0 CL (programmed autologous frozen-thawed embryo transfer, N=10-18); 1 CL (spontaneous conception [N=16] and natural cycle frozen-thawed embryo transfer [N=12]); or >3 CL associated with autologous fresh embryo transfer [N=8-12]. Augmentation index was higher during the third trimester in the absence of a CL compared to 1 CL (P=0.03) and in frozen-thawed embryo transfer in a programmed compared to a natural cycle (P=0.02). Moreover, baseline pulse-wave amplitude was higher in >3 CL conceptions at all time points (all P<0.05). The incidence of preeclampsia and preeclampsia with severe features was significantly higher in the absence of a CL compared to the presence of one or >3 CL (P=0.045 and P=0.03). Infants from conceptions with >3 CL had lower birth weights (P=0.02) and a higher rate of low birth weight offspring (P=0.008). Deficient vascular adaptation during early gestation in conceptions with nonphysiological CL numbers might predispose women to adverse pregnancy outcomes, for example, preeclampsia.

Frozen-thawed embryo transfer: the potential importance of the corpus luteum in preventing obstetrical complications

The use of frozen-thawed embryo transfer (FET) has increased over the past decade with improvements in technology and increasing live birth rates. FET facilitates elective single-embryo transfer, reduces ovarian hyperstimulation syndrome, optimizes endometrial receptivity, allows time for preimplantation genetics testing, and facilitates fertility preservation. FET cycles have been associated, however, with an increased risk of hypertensive disorders of pregnancy for reasons that are not clear. Recent evidence suggests that absence of the corpus luteum (CL) could be at least partly responsible for this increased risk. In a recent prospective cohort study, programmed FET cycles (no CL) were associated with higher rates of preeclampsia and preeclampsia with severe features compared with modified natural FET cycles. FET cycles are commonly performed in the context of a programmed cycle in which the endometrium is prepared with the use of exogenous E2 and P. In these cycles, ovulation is suppressed and therefore the CL is absent. The CL produces not only E2 and P, but also vasoactive products, such as relaxin and vascular endothelial growth factor, which are not replaced in a programmed FET cycle and which are hypothesized to be important for initial placentation. Emerging evidence has also revealed other adverse obstetrical and perinatal outcomes, including postpartum hemorrhage, macrosomia, and post-term birth specifically in programmed FET cycles compared with natural FET cycles. Despite the widespread use of FET, the optimal protocol with respect to live birth rate, maternal health, and perinatal outcomes has yet to be determined. Future practice regarding FET should be based on high-quality evidence, including rigorous controlled trials.

Progesterone Intramuscularly or Vaginally Administration May Not Change Live Birth Rate or Neonatal Outcomes in Artificial Frozen-Thawed Embryo Transfer Cycles

BACKGROUNDS

Previous studies suggested that singletons from frozen-thawed embryo transfer (FET) were associated with higher risk of large, post-date babies and adverse obstetrical outcomes compared to fresh transfer and natural pregnancy. No data available revealed whether the adverse perinatal outcomes were associated with aberrantly high progesterone level from different endometrium preparations in HRT-FET cycle. This study aimed to compare the impact of progesterone intramuscularly and vaginally regimens on neonatal outcomes in HRT-FET cycles.

METHODS

A total of 856 HRT-FET cycles from a fertility center from 2015 to 2018 were retrospectively analyzed. All patients had their first FET with two cleavage-staged embryos transferred. Endometrial preparation was performed with sequential administration of estrogen followed by progesterone intramuscularly 60 mg per day or vaginal gel Crinone 90 mg per day. Pregnancy outcomes including live birth rate, singleton birthweight, large for gestational age (LGA) rate, small for gestational age (SGA) rate, and preterm delivery rate were analyzed. Student's t test, Mann-Whitney U-test, Chi square analysis, and multivariable logistic regression were used where appropriate. Differences were considered significant if p < 0.05.

RESULTS

No significant difference of live birth rate was found between different progesterone regimens (Adjusted OR 1.128, 95% CI 0.842, 1.511, p = 0.420). Neonatal outcomes like singleton birthweight (p = 0.744), preterm delivery rate (Adjusted OR 1.920, 95% CI 0.603, 6.11, p = 0.269), SGA (Adjusted OR 0.227, 95% CI 0.027, 1.934, p = 0.175), and LGA rate (Adjusted OR 0.862, 95% CI 0.425, 1.749, p=0.681) were not different between two progesterone regimens. Serum P level >41.82 pmol/L at 14 day post-FET was associated with higher live birth rate than serum P level ≤41.82 pmol/L in HRT-FET cycles when progesterone was intramuscularly delivered (Adjusted OR 1.690, 95% CI 1.002, 2.849, p = 0.049). But singleton birthweight, preterm delivery rate, SGA and LGA rate were not different between these two groups.

CONCLUSIONS

Relatively higher serum progesterone level induced by intramuscular regimen did not change live birth rate or neonatal outcomes compared to vaginal regimen. Monitoring serum progesterone level and optimizing progesterone dose of intramuscular progesterone as needed in HRT-FET cycles has a role in improving live birth rate without impact on neonatal outcomes.

Increased Preeclampsia Risk and Reduced Aortic Compliance With In Vitro Fertilization Cycles in the Absence of a Corpus Luteum

In vitro fertilization involving frozen embryo transfer and donor oocytes increases preeclampsia risk. These in vitro fertilization protocols typically yield pregnancies without a corpus luteum (CL), which secretes vasoactive hormones. We investigated whether in vitro fertilization pregnancies without a CL disrupt maternal circulatory adaptations and increase preeclampsia risk. Women with 0 (n=26), 1 (n=23), or >1 (n=22) CL were serially evaluated before, during, and after pregnancy. Because increasing arterial compliance is a major physiological adaptation in pregnancy, we assessed carotid-femoral pulse wave velocity and transit time. In a parallel prospective cohort study, obstetric outcomes for singleton livebirths achieved with autologous oocytes were compared between groups by CL number (n=683). The expected decline in carotid-femoral pulse wave velocity and rise in carotid-femoral transit time during the first trimester were attenuated in the 0-CL compared with combined single/multiple-CL cohorts, which were similar (group-time interaction: P=0.06 and 0.03, respectively). The blunted changes of carotid-femoral pulse wave velocity and carotid-femoral transit time from prepregnancy in the 0-CL cohort were most striking at 10 to 12 weeks of gestation ( P=0.01 and 0.006, respectively, versus 1 and >1 CL). Zero CL was predictive of preeclampsia (adjusted odds ratio, 2.73; 95% CI, 1.14-6.49) and preeclampsia with severe features (6.45; 95% CI, 1.94-25.09) compared with 1 CL. Programmed frozen embryo transfer cycles (0 CL) were associated with higher rates of preeclampsia (12.8% versus 3.9%; P=0.02) and preeclampsia with severe features (9.6% versus 0.8%; P=0.002) compared with modified natural frozen embryo transfer cycles (1 CL). In common in vitro fertilization protocols, absence of the CL perturbed the maternal circulation in early pregnancy and increased the incidence of preeclampsia.

Vascular Health of Children Conceived via In Vitro Fertilization

OBJECTIVE

To evaluate whether in vitro fertilization (IVF) has an effect on the cardiovascular health of offspring.

STUDY DESIGN

This was a cross-sectional pilot study. We performed vascular health assessment for 17 children aged 10-14 years who were conceived via IVF with autologous oocytes at Stanford University. Carotid artery ultrasound evaluated intima-media thickness and stiffness, carotid-femoral pulse wave velocity determined segmental arterial stiffness, and endothelial pulse amplitude testing assessed endothelial function. We compared IVF offspring with control adolescents assessed in the same laboratory, with all comparisons adjusted for age, sex, and race/ethnicity.

RESULTS

All participants had normal body mass index and blood pressure. Compared with controls, IVF children had thicker common carotid artery intima-media thickness (0.44 ± 0.03 mm vs 0.38 ± 0.03 mm; P < .01), higher elastic modulus (395.29 ± 185.33 mm Hg vs 242.79 ± 37.69 mm Hg; P = .01), higher βstiffness (2.65 ± 0.38 vs 2.28 ± 0.23; P < .01), and higher peak velocity (142.29 ± 31.62 cm/s vs 117.71 ± 32.69 cm/s; P = .04). The mean endothelial pulse amplitude testing reactive hyperemia index was not significantly different between IVF and controls. The mean pulse wave velocity was 4.69 ± 0.51 m/s compared with the controls 4.60 ± 0.57 m/s (P = .11), with 8 (47%) having abnormal values.

CONCLUSION

In an assessment of endothelial function and arterial properties of children conceived via IVF, we found that children conceived via IVF seem to have evidence of abnormal vascular health. Further studies with larger sample size and long-term follow-up are warranted.

In vitro fertilization is associated with the onset and progression of preeclampsia

OBJECTIVE

We aimed to estimate the risk of preeclampsia (PE) associated with in vitro fertilization (IVF) and potential predisposing factors responsible for the observed association.

METHODS

This retrospective cohort study included 114485 pregnant women who delivered at the Nanjing Maternity and Child Health Care Hospital between 2013 and 2018. Of the 114485 women, 4601 (4%) conceived through IVF (IVF group) and 109884 (96%) conceived spontaneously (SC group). We performed logistic regression analysis to evaluate the risk of PE following IVF compared to spontaneous conception (SC). Then, we used propensity score matching analysis to compare the clinical characteristics and pregnancy outcomes between IVF patients with and without PE.

RESULT

There were 1339 PE cases in the total study population, with a significantly higher incidence of PE in IVF relative to spontaneous pregnancies (6.1% vs. 1.0%, p < 0.01). Severe PE was more prevalent in singleton IVF-PE group than in singleton SC-PE group (40% vs. 24.1%, p = 0.025). Placenta accreta was more common in singleton preeclamptic patients with IVF than without IVF (12.5vs.2.6%, p = 0.003). Placental hypoxia was more prevalent in twin IVF pregnancies with PE than without PE (6% vs. 12.2%, p = 0.045). Moreover, the IVF-PE group showed more frequent first-trimester bleeding (31.6% vs. 10.5%, p = 0.024) compared to the control group.

CONCLUSION

IVF is associated with the onset and progression of PE. Defective placentation and placental insufficiency may predispose IVF patients to PE and may manifest as first-trimester bleeding.

Risk of adverse perinatal outcomes after oocyte donation: a systematic review and meta-analysis

RESEARCH QUESTION

In women with singleton pregnancies conceived after assisted reproductive technologies, does the in vitro fertilization with oocyte donation (IVF-OD) affect the perinatal and maternal outcomes compared to autologous in vitro fertilization (IVF-AO)?

DESIGN

Systematic review and meta-analysis of studies comparing perinatal and maternal outcomes in singleton pregnancies resulting from IVF-OD versus IVF-AO. An electronic literature search in Pubmed, MEDLINE, and Cochrane database was performed. The main outcome measures were hypertensive disorders in pregnancy, preeclampsia, severe preeclampsia, pregnancy-induced hypertension, preterm birth, early preterm birth, low birth weight, and very low birth weight.

RESULTS

Twenty-three studies were included. IVF-OD is associated with a higher risk of hypertensive disorders in pregnancy (OR 2.63, 2.17-3.18), preeclampsia (OR 2.64; 2.29-3.04), severe preeclampsia (OR 3.22; 2.30-4.49), pregnancy-induced hypertension (OR 2.16; 1.79-2.62), preterm birth (OR 1.57; 1.33-1.86), early preterm birth (OR 1.80; 1.51-2.15), low birth weight (OR 1.25, 1.20-1.30), very low birth weight (OR 1.37, 1.22-1.54), gestational diabetes (OR 1.27; 1.03-1.56), and cesarean section (OR 2.28; 2.14-2.42). There was no significant difference in the risk of preterm birth or low birth weight when adjusted for preeclampsia.

CONCLUSIONS

IVF-OD patients should be considered an independent risk factor for some adverse perinatal outcomes, mainly hypertensive disorders in pregnancy, preeclampsia, and severe preeclampsia. Immunological and hormonal aspects may be involved in these results, and further research focusing in the etiopathogenesis of these pathologies are needed.