Placental volume and other first-trimester outcomes: are there differences between fresh embryo transfer, frozen-thawed embryo transfer and natural conception?

Perinatal health in a cohort of children conceived after assisted reproduction in the UK: a population-based record-linkage study

OBJECTIVE

To compare the risk of hospitalisation for conditions originating in the perinatal period between children conceived via assisted reproductive technology and those that are naturally conceived, differentiating by treatment type.

STUDY DESIGN, SETTING AND PARTICIPANTS

Population-based record-linkage study of children born after assisted reproduction in the UK between 2002 and 2009 (n=44 618), their naturally conceived siblings (n=8462) and matched naturally conceived population (n=89 072) controls linked to their hospital inpatient records up to 31 March 2016.

PRIMARY AND SECONDARY OUTCOME MEASURES

Robust estimates of the overall and cause-specific risk of hospital admission for adverse perinatal events and the comparison of outcomes by type of treatment.

RESULTS

Over the study period, 17 132 (38.40%) children conceived via assisted reproduction and 30 306 (34.02%) and 1738 (20.54%) naturally conceived population and sibling controls, respectively, were admitted to the hospital for severe perinatal events. Compared with the population controls, singletons (Risk ratio (95% CI 1.30 (1.26, 1.34))) and twins (1.01 (0.99, 1.03)) conceived via assisted reproduction exhibited a higher risk of hospitalisation for any adverse perinatal event. However, no such increase was observed in the within-sibling analysis (0.97 (0.84, 1.12)). Similar patterns were seen for diagnoses related to length of gestation and fetal growth (vs population controls: 1.37 (1.29, 1.46); vs siblings: 1.17 (0.86, 1.60)); birth trauma (vs population controls: 1.23 (1.04, 1.44); vs siblings: 0.78 (0.47, 1.30)); respiratory and cardiovascular disorders (vs population controls: 1.28 (1.20, 1.38); vs siblings: 0.72 (0.53, 0.98)); infections (vs population controls: 1.30 (1.06, 1.59); vs siblings: 0,68 (0.24, 1.90)) and several other conditions. Associations were similar when comparing in vitro fertilisation to intracytoplasmic sperm injection and were higher when comparing fresh to frozen embryo transfers.

CONCLUSION

Children conceived via assisted reproduction showed modest increases in the risk of hospitalisations for severe perinatal events when compared with population controls, although these findings were attenuated in the sibling analyses. The imprecision of within-sibling analyses highlights the need for larger studies to explore potential causal effects.

First-trimester uterine artery pulsatility index and preeclampsia risk in pregnancies after artificial frozen embryo transfer: analysis of over 27,000 pregnancies

BACKGROUND

Accumulating evidence indicates that pregnancies after artificial cycle frozen embryo transfer are associated with an increased risk of preeclampsia. Uterine artery Doppler, along with maternal factors and serum biomarkers, is a crucial biomarker for first-trimester preeclampsia screening, aiding in identifying "high-risk" patients. Guidelines strongly recommend administering aspirin (150 mg/d) in these women, owing to robust evidence demonstrating a 62% reduction in the incidence of preeclampsia. Although previous studies suggested lower uterine artery pulsatility index after frozen embryo transfer, no previous studies explored the impact of the type of endometrial preparation in Uterine Artery Doppler or its influence on estimating first-trimester preeclampsia risk.

OBJECTIVE

The study aims to evaluate the possible impact of endometrial preparation for frozen embryo transfer on the uterine artery pulsatility index during the first-trimester preeclampsia screening.

STUDY DESIGN

This is a retrospective single-center study including 27,289 singleton pregnancies (naturally conceived or after assisted reproductive treatment) who underwent the first-trimester ultrasound screening at our University Hospital between January 2010 and May 2023. Overall, 27,289 pregnancies were included: 23,410 naturally conceived and 3879 following assisted reproductive technologies including 391 after ovulation induction and intrauterine insemination, 888 in vitro fertilization and fresh embryo transfer, and 2600 natural or artificial frozen embryo transfer cycles. An analysis of covariance was conducted to assess if there is an association between the uterine artery pulsatility index value and the mode of conception, adjusting for confounding factors (age, weight, smoking, and oocyte donation).

RESULTS

Overall, pregnancies after artificial frozen embryo transfer demonstrated significantly lower first-trimester uterine artery pulsatility index as compared with all other modes of conception in a multivariable regression analysis adjusted for age, weight, smoking, and oocyte donation. The percent difference was 22.6 [confidence interval, CI 95%: 20.6; 24.5] compared to naturally conceived pregnancy, 24.5 [CI 95%: 20.7; 28.1] to ovulation induction or intrauterine insemination, 24.8 [CI 95%: 22.9; 27.6] to fresh embryo transfer and 21.7 [CI 95%: 17.6; 25.5] compared to natural cycle frozen embryo transfer. When calculating the risk for initiating preventive aspirin administration, the number of patients with increased risk (>1/100) who initiated prophylactic aspirin was significantly lower in the artificial cycle frozen embryo transfer group (7.8% vs 16.0% in natural cycle P<.001 vs 11.0% in Fresh embryo transfer P=.01 vs 10.5% in ovulation induction or intrauterine insemination P=.14 vs 9.3% in naturally conceived pregnancy P=.03). Surprisingly although significantly fewer patients were considered at high risk for preeclampsia in the artificial cycle frozen embryo transfer group, analysis of the actual incidence of preeclampsia demonstrated 3 times higher preeclampsia incidence in artificial cycle group 5.3% (122/2284) as compared with naturally conceived 1.4% (321/23,410), ovulation induction and intrauterine insemination 1.3% (5/391) or natural cycle pregnancies 1.6% (5/316) and more than 2 times higher when compared to fresh embryo transfer pregnancies 2.3% (20/888), P<.001.

CONCLUSION

Pregnancies following frozen embryo transfer in artificial cycle are associated with significantly lower uterine artery pulsatility index during first-trimester preeclampsia screening. This results in a significantly lower number of patients being classified as high-risk for developing preeclampsia, despite accumulating evidence that artificial cycles are linked to an increased risk of preeclampsia. Therefore, the first-trimester preeclampsia risk algorithm should be adjusted to accurately assess risk for those patients undergoing artificial cycle frozen embryo transfer, to prevent the undertreatment of patients who are at very high risk of developing preeclampsia and may benefit from prophylactic aspirin.

Impact of different progesterone timings on live birth rates for blastocyst frozen embryo transfer cycles

RESEARCH QUESTION

Do different timings of progesterone administration for day 5 and day 6 blastocysts affect the live birth rate (LBR) of artificial frozen embryo transfer (FET) cycles?

DESIGN

This retrospective cohort study included 1362 patients who underwent artificial FET cycles. The effects of 6 and 7 days of progesterone administration prior to blastocyst transfer on clinical outcomes were compared in day 5 and day 6 blastocysts. Univariable and multivariable regression analyses were undertaken.

RESULTS

In all patients, LBR was comparable between the two groups (51.8% versus 47.9%, P = 0.165). For day 6 blastocysts, after adjusting for confounders, the 7-day progesterone regimen resulted in a significantly higher LBR (44.8% versus 36.4%, P = 0.039, adjusted OR = 1.494, 95% CI 1.060-2.106) and lower pregnancy loss rate (15.4% versus 25.2%, P = 0.031, adjusted OR = 0.472, 95% CI 0.260-0.856) compared with the 6-day progesterone regimen. For day 5 blastocysts, there were no significant differences in pregnancy outcomes between the two regimens, but the rate of low birthweight was higher with the 7-day progesterone regimen than with the 6-day progesterone regimen (13.9% versus 6.7%, P = 0.032).

CONCLUSIONS

In all blastocyst analyses, no difference in LBR was found between the 6- and 7-day progesterone regimens in artificial FET cycles. For day 6 blastocysts, LBR was significantly higher with the 7-day progesterone regimen than with the 6-day progesterone regimen, whereas for day 5 blastocysts, pregnancy outcomes were comparable between the two regimens.

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.

Major postpartum haemorrhage after frozen embryo transfer: A population-based study

OBJECTIVE

To investigate the effect on major postpartum haemorrhage (PPH) of mode of conception, differentiating between naturally conceived pregnancies, fresh embryo in vitro fertilisation (fresh-IVF) and frozen embryo transfer (frozen-IVF).

DESIGN

Retrospective cohort study.

SETTING

The French Burgundy Perinatal Network database, including all deliveries from 2006 to 2020, was linked to the regional blood centre database.

POPULATION OR SAMPLE

In all, 244 336 women were included, of whom 240 259 (98.3%) were singleton pregnancies.

METHODS

The main analyses were conducted in singleton pregnancies, including 237 608 naturally conceived, 1773 fresh-IVF and 878 frozen-IVF pregnancies. Multivariate logistic regression models adjusted on maternal age, body mass index, smoking, parity, induction of labour, hypertensive disorders, diabetes, placenta praevia and/or accreta, history of caesarean section, mode of delivery, birthweight, birth place and year of delivery, were used.

MAIN OUTCOME MEASURES

Major PPH was defined as PPH requiring blood transfusion and/or emergency surgery and/or interventional radiology.

RESULTS

The prevalence of major PPH was 0.74% (n = 1749) in naturally conceived pregnancies, 1.92% (n = 34) in fresh-IVF pregnancies, and 3.30% (n = 29) in frozen-IVF pregnancies. The risk of major PPH was higher in frozen-IVF pregnancies than in both naturally conceived pregnancies (adjusted odds ratio [aOR] 2.63, 95% CI 1.68-4.10) and fresh-IVF pregnancies (aOR 2.78, 95% CI 1.44-5.35).

CONCLUSIONS

We found that frozen-IVF pregnancies have a higher risk of major PPH and they should be subject to increased vigilance in the delivery room.

Polygenic embryo screening: are there potential maternal and fetal harms?

Polygenic embryo screening (PES) and its derivate the Embryo Health Score (EHS) have generated interest in both infertile and fertile populations due to their potential ability to select embryos with a reduced risk of disease and improved long-term health outcomes. Concerns have been raised regarding the potential harms of IVF itself, including possible epigenetic changes that may affect the health of the offspring in late adulthood, which are not fully captured in the EHS calculation. Knowledge of the potential impacts of the trophectoderm biopsy, which is a key component of the PES procedure, on the offsprings' health is limited by the heterogeneity of the population characteristics used in the published studies. Nonetheless, the literature suggests a possible increased risk of preterm delivery, birth defects and pre-eclampsia after trophectoderm biopsy. Overall, the risks of PES for prenatal and postnatal health remain uncertain, and further research is needed. Counselling patients regarding these risks before considering PES is important, to provide an understanding of the risks and benefits. This review aims to highlight some of these issues, the need for continued investigation in this area, and the importance of informed decision-making in the context of PES.

Fetal Growth Velocity according to the Mode of Assisted Conception

INTRODUCTION

Pregnancies conceived through assisted reproductive techniques (ARTs) are on the rise worldwide and have been associated with a higher risk of placental-related disease in the third trimester.

METHODS

A cohort was created of singleton pregnancies after assisted reproduction, admitted at our institution for delivery, between January 2020 and August 2022. Fetal growth velocity from the second trimester to delivery was compared against a gestational-age-matched group of pregnancies spontaneously conceived according to the origin of the selected oocyte (i.e., autologous vs. donated).

RESULTS

125 singleton pregnancies conceived through ART were compared to 315 singleton spontaneous conceptions. Overall, after adjusting for possible confounders, multivariate analysis demonstrated that ART pregnancies had a significantly lower estimated fetal weight (EFW) z-velocity from the second trimester to delivery (adjusted mean difference = -0.002; p = 0.035) and a higher frequency of EFW z-velocity in the lowest decile (adjusted OR = 2.32 [95% CI, 1.15-4.68]). Also, when ART pregnancies were compared according to the type of oocyte, those conceived with donated oocytes showed a significantly lower EFW z-velocity from the second trimester to delivery (adjusted mean difference = -0.008; p = 0.001) and a higher frequency of EFW z-velocity in the lowest decile (adjusted OR = 5.33 [95% CI, 1.34-21.5]).

CONCLUSIONS

Pregnancies achieved through ART exhibit a pattern of lower growth velocity across the third trimester, especially those conceived with donated oocytes. The former represents a sub-group at the highest risk of placental dysfunction that may warrant closer follow-up.

The impact of blastocyst freezing and biopsy on the association of blastocyst morphological parameters with live birth and singleton birthweight

OBJECTIVE

To explore whether the associations of 3 blastocyst morphological parameters, namely, degree of blastocyst expansion (expansion), appearance of trophectoderm (TE) and inner cell mass, with live birth and singleton birth weight are influenced by blastocyst freezing and biopsy.

DESIGN

A retrospective study.

SETTING

An assisted reproductive technology center.

PATIENT(S)

28,515 single blastocyst transfer cycles between January 2014 and August 2019.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Live birth and singleton birth weight.

RESULT(S)

Blastocyst transfer cycles were divided into 4 groups: biopsied blastocyst cycles (biopsied-blast), thawed blastocyst cycles (thawed-blast), blastocyst from thawed cleavage embryo cycles (blast-thawed-D3), and fresh blastocyst cycles (fresh-blast). Subgroup analyses by blastocyst stage (day 5 and day 6) were performed in thawed-blast and blast-thawed-D3. Because almost all blastocysts were biopsied on day 6 and fresh blastocysts were transferred on day 5, the biopsied-blast and fresh-blast were not divided into subgroups. First, the associations between blastocyst morphological parameters and live birth were analyzed. To explore the effect of freezing, we compared day-5 frozen cycles (thawed-blast) vs. day-5 fresh cycles (including fresh-blast and blast-thawed-D3) and day 6 frozen cycles (thawed-blast) vs. day-6 fresh cycles (blast-thawed-D3). Inner cell mass and TE were associated with live birth for day 5 embryos, and only TE affected live birth for day-6 embryos. The associations were the same in frozen cycles and fresh cycles. To explore the effect of biopsy, we compared day-6 biopsied cycles (biopsied-blast) vs. day-6 nonbiopsied cycles (including thawed-blast and blast-thawed-D3). All the 3 parameters were associated with live birth in biopsied-blast, whereas only TE was associated with live birth in nonbiopsied cycles. In addition, the associations between blastocyst morphological parameters and singleton birthweight were analyzed. In the 6 subgroups, expansion stage of day-6 embryos in biopsied-blast and TE grade of day-6 embryos in thawed-blast were associated with birth weight, and there are no associations in other subgroups.

CONCLUSION(S)

The association of blastocyst morphological parameters with live birth may be affected by blastocyst biopsy and/or genetic testing, and its association with birth weight may be affected by blastocyst freezing and biopsy and/or genetic testing.

Placental Volume and Uterine Artery Doppler in Pregnancy Following In Vitro Fertilization: A Comprehensive Literature Review

The number of pregnancies achieved using in vitro fertilization (IVF) is rapidly increasing around the world. The chance of obtaining a successful pregnancy is also significantly improved due to technological advances and improvement in infertility treatment. Despite this success, there is evidence that pregnancy conceived by IVF has an increased risk of adverse maternal and perinatal outcome mainly represented by the development of hypertensive diseases, pre-eclampsia, and fetal growth restriction. Although different cofactors may play a role in the genesis of these diseases, the development of the placenta has a pivotal function in determining pregnancy outcomes. Advances in ultrasound technology already allows for evaluation in the first trimester, the impedance to flow in the uterine artery, and the placental volume using Doppler and three-dimensional techniques. This review article aims to describe the modification occurring in placental volume and hemodynamics after IVF and to summarize the differences present according to the type of IVF (fresh vs. frozen-thawed embryos).

Supraphysiological hCG day estradiol levels can predict pregnancy-associated plasma protein A levels in maternal serum in the first trimester

OBJECTIVE

To investigate the effect of hCG day estradiol (hCG-E2) used in Down Syndrome screening on maternal serum levels of PAPP-A in fresh in vitro fertilization (IVF) cycles.

METHODS

This study was a retrospective analysis of a cohort that resulted in a single pregnancy after a total of 92 fresh IVF cycles. The primary outcome of this study was to determine the effect of fresh IVF cycle parameters on the PAPP-A level and the cutoff value for hCG-E2 predicting a low PAPP-A level, while the secondary outcome was to determine whether the effect of IVF parameters on the PAPP-A level was significant.

RESULTS

There was a negative correlation between PAPP-A levels and the number of hCG-E2 and grade 1 embryos (respectively, p = .049; .047), while a positive correlation was observed between baby weight at birth and the PAPP-A (p < .05). At a PAPP-A value of 0.82, the difference between the two groups, in terms of hCG-E2, the number of grade 1 embryos, and pregnancy-related complications was significant (p = .050; .029; .033, respectively). The threshold value of hCG-E2 affecting PAPP-A levels was statistically significant (AUC = 0.618; p = .050; hCG-E2 = 4869.5 pg/ml). In the model, an increase in the number of grade 1 embryos resulted in higher PAPP-A levels (OR = 2.26; p = .044).

CONCLUSION

The fact that the hCG-E2 cutoff value, which lowers PAPP-A, reflects excessive ovarian stimulation argues for the correction of the dual screening test in a subset of patients with high response to the first-trimester screening test.

The association between assisted reproductive technology and cardiac remodeling in fetuses and early infants: a prospective cohort study

BACKGROUND

Limited data exist regarding the potential impact of assisted reproductive technology (ART) on cardiac remodeling. In particular, whether different ART techniques are related to different cardiac alterations remains unclear. We aimed to evaluate cardiac changes in fetuses and infants arising from ART and fetal cardiac alterations in fetuses conceived by specific ART procedures.

METHODS

This prospective and observational cohort study recruited 111 fetuses conceived by ART and 106 spontaneously conceived controls between December 2017 and April 2019. Echocardiography was performed between 28⁺⁰ and 32⁺⁶ weeks-of-gestation and at 0-2 and 6 months after birth.

RESULTS

A total of 88 ART fetuses and 85 controls were included in the final analysis. Compared to controls, ART fetuses demonstrated a globular enlarged left ventricle (LV) (LV sphericity index of mid-section, 2.29 ± 0.34 vs. 2.45 ± 0.39, P = 0.006; LV area, 262.33 ± 45.96 mm² vs. 244.25 ± 47.13 mm², P = 0.002), a larger right ventricle (RV) (RV area, 236.10 ± 38.63 mm² vs. 221.14 ± 42.60 mm², P = 0.003) and reduced LV systolic deformation (LV global longitudinal strain (GLS), -19.56% ± 1.90% vs. -20.65% ± 1.88%, P = 0.013; LV GLS rate S, -3.32 ± 0.36 s^-1 vs. -3.58 ± 0.39 s^-1, P = 0.023). There were no significant differences between the ART and control groups at postnatal follow-ups. Furthermore, we found fetal cardiac morphometry and function were comparable between different ART procedures. Compared to controls, the fetuses derived from various ART procedures all exhibited impairments in the LV GLS and the LV GLS rate S.

CONCLUSIONS

Our analysis demonstrated that subclinical cardiac remodeling and dysfunction were evident in ART fetuses, although these alterations did not persist in early infancy. In addition, various ART procedures may cause the same unfavorable changes in the fetal heart.

TRIAL REGISTRATION

This trial was registered at the Chinese Clinical Trial Registry ( www.chictr.org.cn ) ( ChiCTR1900021672 ) on March 4, 2019, retrospectively registered.

The expression of pregnancy-associated plasma protein-A (PAPP-A) in human blastocoel fluid-conditioned media: a proof of concept study

Purpose

The aim of this study was to determine if pregnancy-associated plasma protein-A (PAPP-A), typically measured in maternal serum and a potential predictor of adverse maternal and fetal outcomes such as spontaneous miscarriage, pre-eclampsia, and stillbirth, is expressed in blastocoel fluid–conditioned media (BFCM) at the embryonic blastocyst stage.

Design

This is an in vitro study.

Methods

BFCM samples from trophectoderm-tested euploid blastocysts (n = 80) from in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) patients were analyzed for PAPP-A mRNA. BFCM was obtained from blastocyst stage embryos in 20 uL drops. Blastocysts underwent trophectoderm biopsy for preimplantation genetic testing for aneuploidy prior to blastocyst vitrification and BFCM collection for snap freezing. cfDNA was synthesized using BFCM collected from 80 individual euploid blastocysts. Next, real-time qPCR was performed to detect expression of PAPP-A with GAPDH for normalization of expression in each sample.

Results

PAPP-A mRNA was detected in 45 of 80 BFCM samples (56.3%), with varying levels of expression across samples.

Conclusion

Our study demonstrates the expression of PAPP-A in BFCM. To our knowledge, this is the first study to report detection of PAPP-A mRNA in BFCM. Further studies are required and underway to investigate a greater number of BFCM samples as well as the possible correlation of PAPP-A expression with pregnancy outcomes of transferred euploid blastocysts. If found to predict IVF and obstetric outcomes, PAPP-A may provide additional information along with embryonic euploidy for the selection of the optimal blastocyst for embryo transfer.

Advanced trophectoderm quality increases the risk of a large for gestational age baby in single frozen-thawed blastocyst transfer cycles

STUDY QUESTION

Does trophectoderm (TE) quality affect birthweight after single frozen-thawed blastocyst transfer?

SUMMARY ANSWER

Transfer of single blastocyst with advanced TE quality was associated with higher birthweight and increased risk of a large for gestational age (LGA) baby.

WHAT IS KNOWN ALREADY

Transfer of blastocysts with advanced TE quality results in higher ongoing pregnancy rates and a lower miscarriage risk. However, data on the relationship between TE quality and birthweight are still lacking.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort study at a tertiary-care academic medical center included 1548 singleton babies born from single frozen-thawed blastocyst transfer from January 2011 to June 2019.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Babies were grouped into four groups according to embryo expansion (Stages 3, 4, 5 and 6), three groups according to inner cell mass (ICM) quality (A, B and C), and three groups according to TE quality (A, B and C). Main outcomes included absolute birthweight, Z-scores adjusted for gestational age and gender, and adverse neonatal outcomes. Multivariable linear and logistic regression analyses were performed to investigate the association of neonatal outcomes with expansion stage, ICM quality and TE quality.

MAIN RESULTS AND THE ROLE OF CHANCE

As TE quality decreased, birthweight (3468.10 ± 471.52, 3357.69 ± 522.06, and 3288.79 ± 501.90 for A, B and C, respectively, P = 0.002), Z-scores (0.59 ± 1.07, 0.42 ± 1.04, and 0.27 ± 1.06 for A, B and C, respectively, P = 0.002) and incidence of LGA (28.9%, 19.7% and 17.4% for A, B and C, respectively, P = 0.027) decreased correspondingly. After adjusting for confounders, compared with the Grade A group, blastocysts with TE Grade B (standardized coefficients (β): -127.97 g, 95% CI: -234.46 to -21.47, P = 0.019) and blastocysts with TE grade C (β: -200.27 g, 95% CI: -320.69 to -79.86, P = 0.001) resulted in offspring with lower birthweight. Blastocysts with TE grade C brought babies with lower Z-scores than TE Grade A (β: -0.35, 95% CI: -0.59 to -0.10, P = 0.005). Also, embryos with TE Grade B (adjusted odds ratio (aOR):0.91, 95% CI: 0.84 to 0.99, P = 0.033) and embryos with TE Grade C (aOR : 0.89, 95% CI: 0.81 to 0.98, P = 0.016) had lower chance of leading to a LGA baby than those with TE Grade A. No association between neonatal outcomes with embryo expansion stage and ICM was observed (all P > 0.05).

LIMITATIONS, REASONS FOR CAUTION

The retrospective design, lack of controlling for several unknown confounders, and inter-observer variation limited this study.

WIDER IMPLICATIONS OF THE FINDINGS

The study extends our knowledge of the down-stream effect of TE quality on newborn birthweight and the risk of LGA.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by National Key R&D Program of China (2018YFC1003000), National Natural Science Foundation of China (81771533 to Y.P.K. and 31200825 to L.S.) and Innovative Research Team of High-level Local Universities in Shanghai (SSMU-ZLCX20180401), Shanghai Sailing Program(21YF1423200) and the Fundamental research program funding of Ninth People's Hospital affiliated to Shanghai Jiao Tong university School of Medicine (JYZZ117). The authors declare no conflict of interest in this present study.

TRIAL REGISTRATION NUMBER

N/A.

The influence of frozen-thawed and fresh embryo transfer on utero-placental (vascular) development: the Rotterdam Periconception cohort

STUDY QUESTION

Does frozen-thawed or fresh embryo transfer (ET) influence utero-placental (vascular) development, when studied using three-dimensional (3D) ultrasound and virtual reality imaging techniques?

SUMMARY ANSWER

In the first trimester, placental developmental parameters, that is, placental volume (PV) and utero-placental vascular volume (uPVV), were comparable between pregnancies resulting from frozen-thawed ET, fresh ET and natural conception; and in the second and the third trimester, uterine artery Doppler indices were lower in pregnancies after frozen-thawed ET compared to pregnancies after fresh ET and natural conception.

WHAT IS KNOWN ALREADY

Pregnancies after frozen-thawed ET are at risk of developing placenta-related pregnancy complications. There is strong evidence that impaired first-trimester spiral artery remodelling is involved in the pathophysiology of these complications. Studies on longitudinal placental development in pregnancies with different modes of conception, that is, after frozen-thawed ET, fresh ET or natural conception, are lacking.

STUDY, DESIGN, SIZE, DURATION

Women with singleton pregnancies were included before 10 weeks of gestation, between January 2017 and July 2018, as a subcohort of the ongoing Rotterdam Periconception cohort. Results were partially validated in 722 women from the total cohort, which was conducted from November 2010 onwards.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 214 women, of whom 32 conceived after frozen-thawed ET, 56 conceived after fresh ET and 126 conceived naturally, were selected. PV and uPVV measurements were obtained at 7, 9 and 11 weeks of gestation by transvaginal 3D (power Doppler) ultrasound. The uterine artery pulsatility index (UtA-PI) and resistance index (UtA-RI) were measured transvaginally at 7, 9, 11 and 13 weeks and abdominally at 22 and 32 weeks of gestation by pulsed wave Doppler ultrasound. In the validation cohort, the PV was measured in 722 women. Associations between mode of conception and placental development were studied using linear mixed models.

MAIN RESULTS AND THE ROLE OF CHANCE

First-trimester parameters of placental development, that is, PV, uPVV, UtA-PI and UtA-RI, were comparable between pregnancies after frozen-thawed and fresh ET and naturally conceived pregnancies. In our validation cohort, comparable results were found for PV. However, the second- and third-trimester UtA-PI and UtA-RI in pregnancies after frozen-thawed ET were significantly lower than in pregnancies after fresh ET (βUtA-PI -0.158 (95% CI: -0.268, -0.048), P = 0.005; βUtA-RI -0.052 (95% CI: -0.089, -0.015), P = 0.006). The second- and third-trimester uterine artery indices in pregnancies after fresh ET were comparable to those in pregnancies after natural conception.

LIMITATIONS, REASONS FOR CAUTION

The main limitation of this study is the lack of power to optimally detect differences in placental development and placenta-related pregnancy outcomes between pregnancies after different modes of conception. Moreover, our population was selected from a tertiary hospital and included a relatively limited number of pregnancies. Therefore, external validity of the results should be confirmed in a larger sample size.

WIDER IMPLICATIONS OF THE FINDINGS

These findings indicate no significant impact of conception mode on early placental development and a beneficial impact for frozen-thawed ET on the second- and third-trimester Doppler indices. This suggests that frozen-thawed ET may not be as detrimental for placental perfusion as previous research has demonstrated. As the number of clinics applying the 'freeze-all strategy' increases, future research should focus on establishing the optimal uterine environment, with regards to hormonal preparation, prior to ET to reduce placental-related pregnancy complications after frozen-thawed ET.

STUDY FUNDING/COMPETING INTEREST(S)

This research was funded by the Erasmus MC Medical Research Advisor Committee's 'Health Care Efficiency Research' program and the department of Obstetrics and Gynaecology of the Erasmus MC, University Medical Center, Rotterdam, The Netherlands. JSEL reports grants and personal fees from Ferring, personal fees from Titus Healthcare, grants and personal fees from Ansh Labs, grants from NIH, grants from Dutch Heart Association and grants from ZonMW outside the submitted work. None of the other authors have a conflict of interest.

TRIAL REGISTRATION NUMBER

Registered at the Dutch Trial Register (NTR6684).

Fertility outcomes in women after controlled ovarian stimulation with gonadotropin releasing hormone agonist long protocol: fresh versus frozen embryo transfer

Background

Along with progress in embryo cryopreservation, especially the vitrification, freeze all strategy has become more acceptable than ever. Some studies have found comparable or higher live birth rate with frozen embryo transfer (FET) than with fresh embryo transfer(ET)in gonadotropin releasing hormone antagonist (GnRH-ant) protocol. However from our literature research, there have been no reports about live birth rate comparison between fresh ET and FET with gonadotropin releasing hormone agonist (GnRH-a) long protocol. The aim of this study is to retrospectively investigate whether patients benefit from freeze all strategy in GnRH-a protocol using real-world data.

Methods

This is a retrospective cohort study, in which women undergoing fresh ET or FET with GnRH-a long protocol at Chongqing Reproductive and Genetics Institute from January 2016 to December 2018 were evaluated. The primary outcome was live birth rate. The secondary outcomes were implantation rate, clinical pregnancy rate, pregnancy loss and ectopic pregnancy rate.

Results

A total of 7,814 patients met inclusion criteria, implementing 5,216 fresh ET cycles and 2,598 FET cycles, respectively. The demographic characteristics of the patients were significantly different between fresh ET and FET groups, except BMI. After controlling for a broad range of potential confounders including age, infertility duration, BMI, AMH, number of oocytes retrieved and of available embryos, multivariate logistic regression analysis demonstrated that there was no significant difference in clinical pregnancy rate, ectopic pregnancy rate and pregnancy loss rate between two groups (all P > 0.05). However, the implantation rate and live birth rate in fresh ET group were significantly higher than FET group (P < 0.001 and P = 0.012, respectively).

Conclusions

Under GnRH-a long protocol, compared to FET, fresh ET was associated with higher implantation rate and live birth rate in infertile patients that underwent in vitro fertilization (IVF). The freeze all strategy should be individualized and made with caution especially with GnRH-a long protocol.

Lower risk of adverse perinatal outcomes in natural versus artificial frozen-thawed embryo transfer cycles: a systematic review and meta-analysis

This systematic review of literature and meta-analysis of observational studies reports on perinatal outcomes after frozen embryo transfer (FET). The aim was to determine whether natural cycle frozen embryo transfer (NC-FET) in singleton pregnancies conceived after IVF decreased the risk of adverse perinatal outcomes compared with artificial cycle frozen embryo transfer (AC-FET). Thirteen cohort studies, including 93,201 cycles, met the inclusion criteria. NC-FET was associated with a lower risk of hypertensive disorders in pregnancy (HDP) (RR 0.61, 95% CI 0.50 to 0.73), preeclampsia (RR 0.47, 95% CI 0.42 to 0.53), large for gestational age (LGA) (RR 0.93, 95% CI 0.90 to 0.96) and macrosomia (RR 0.82, 95% CI 0.69 to 0.97) compared with AC-FET. No significant difference was found in the risk of gestational hypertension and small for gestational age. Secondary outcomes assessed were the risk of preterm birth (RR 0.83, 95% CI 0.79 to 0.88); post-term birth (RR 0.48, 95% CI 0.29 to 0.80); low birth weight (RR 0.84, 95% CI 0.80 to 0.89); caesarean section (RR 0.84, 95% CI 0.77 to 0.91); postpartum haemorrhage (RR 0.39, 95% CI 0.35 to 0.45); placental abruption (RR 0.61, 95% CI 0.38 to 0.98); and placenta accreta (RR 0.18, 95% CI 0.10 to 0.33). All were significantly lower with NC-FET compared with AC-FET. In assessing safety, NC-FET significantly decreased the risk of HDP, preeclampsia, LGA, macrosomia, preterm birth, post-term birth, low birth weight, caesarean section, postpartum haemorrhage, placental abruption and placenta accreta. Further randomized controlled trials addressing the effect of NC-FET and AC-FET on maternal and perinatal outcomes are warranted. Clinicians should carefully monitor pregnancies achieved by FET in artificial cycles prenatally, during labour and postnatally.

Analysis of ultrasonographic and hystopathologic features of placental invasiveness in Vitro Fertilization (IVF) pregnancies: a prospective study

PURPOSE

In Vitro Fertilization (IVF) techniques make up 1.5-5% of all births in developed countries. These pregnancies are characterized by implantation and functional alterations of the placenta, higher incidence of multiple pregnancies, higher incidence of hypertensive syndromes and pre and post partum hemorrhage (PPH).

METHODS

Since January 2017 to May 2018 all single IVF pregnancies coming to San Camillo Hospital were considered prospectively for routine pregnancy checks until delivery and compared with a control group of spontaneous pregnancies. Each patient underwent to an obstetrical ultrasound of the third trimester at our clinic, with particular attention on the study of the placenta. Birth modalities, type and timing of third stage of labor, peri and post-partum complications were recorded.

RESULTS

We had a higher incidence of cesarean sections in the IVF group (85% versus 25%) and peri and post-partum complications (38% versus 5%). We recorded a statistically significant difference of reduction in IVF pregnancies of VI (p = .0039) and VFI (p = .0043), while the FI index was not statistically significant in the two study groups (p = .4351).

CONCLUSION

Despite the small sample size of our study, our data follow the trend of scientific literature, with an effective increase in placental anomalies in IVF pregnancies compared to healthy controls.

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.

Frozen-warmed blastocyst transfer after 6 or 7 days of progesterone administration: impact on live birth rate in hormone replacement therapy cycles

OBJECTIVE

To study the difference in live birth rate (LBR) between frozen-warmed blastocyst transfer (FET) on the 6th or the 7th day of progesterone administration in artificially prepared cycles.

DESIGN

Retrospective cohort study.

SETTING

Tertiary university-based referral hospital.

PATIENT(S)

Patients who underwent FET between December 2015 and December 2017 in a hormone replacement therapy cycle (HRT).

INTERVENTION(S)

Group A included all eligible patients who underwent transfer of a vitrified-warmed blastocyst on the 6th day of progesterone administration; group B included patients who underwent blastocyst transfer on the 7th day of progesterone. The artificial HRT protocol in this study consisted of estrogen administration at a dose of 2 mg twice daily for 7 days followed by 2 mg three times daily for 6 days and micronized vaginal progesterone 200 mg three times daily from an adequately considered endometrial thickness onward.

MAIN OUTCOME MEASURE(S)

Live birth rate.

RESULTS

The study included 619 patients, 346 in group A and 273 in group B. The LBRs were comparable between both groups (36.6% for group A and group B), even after adjustment for confounding factors (adjusted odds ratio 1.073, 95% confidence interval 0.740-1.556). Subgroup analysis revealed significantly higher miscarriage rates for day 6 blastocysts transferred on the 6th day of progesterone supplementation compared with transfer on the 7th day of progesterone supplementation (50.0% versus 21.4%, respectively). Additionally, there was a tendency toward a higher LBR when the 7-day progesterone supplementation protocol was used for transfer of a day 6 blastocyst (21.5% and 35.5% for group A and group B, respectively).

CONCLUSION

Warmed blastocyst transfer on the 6th compared with the 7th day of progesterone administration in an HRT cycle results in similar LBR. Subgroup analysis of day 6 blastocysts showed significantly higher miscarriage rates when FET was performed on the 6th day of progesterone administration.

Assisted reproductive technologies induce temporally specific placental defects and the preeclampsia risk marker sFLT1 in mouse

Although widely used, assisted reproductive technologies (ARTs) are associated with adverse perinatal outcomes. To elucidate their underlying causes, we have conducted a longitudinal analysis of placental development and fetal growth using a mouse model to investigate the effects of individual ART procedures: hormone stimulation, in vitro fertilization (IVF), embryo culture and embryo transfer. We demonstrate that transfer of blastocysts naturally conceived without hormone stimulation and developed in vivo prior to transfer can impair early placentation and fetal growth, but this effect normalizes by term. In contrast, embryos cultured in vitro before transfer do not exhibit this compensation but rather display placental overgrowth, reduced fetal weight, reduced placental DNA methylation and increased levels of sFLT1, an anti-angiogenic protein implicated in causing the maternal symptoms of preeclampsia in humans. Increases in sFLT1 observed in this study suggest that IVF procedures could increase the risk for preeclampsia. Moreover, our results indicate that embryo culture is the major factor contributing to most placental abnormalities and should therefore be targeted for optimization.