Elective single embryo transfer and perinatal outcomes: a systematic review and meta-analysis

Preterm birth in singleton pregnancies conceived by in vitro fertilization or intracytoplasmic sperm injection: an overview of systematic reviews

BACKGROUND

The rate of preterm birth of singletons conceived through in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) is increased, being as high as 15% to 16% across Europe and the United States. However, the underlying etiology, phenotype, and mechanisms initiating preterm birth (PTB) are poorly understood.

OBJECTIVE

To quantify the PTB risk and examine supposed etiology in IVF/ICSI singleton pregnancies compared to naturally conceived.

STUDY DESIGN

Overview of reviews including all available systematic reviews with meta-analysis comparing PTB risk in IVF/ICSI and naturally conceived singletons. A comprehensive search of PubMed/MEDLINE, Embase, Scopus, and Cochrane Library databases was performed up to December 31, 2023. Information available on etiology, phenotype, initiation of PTB, and relevant moderators was retrieved and employed for subgroup analyses. Random-effects meta-analysis models were used for pooling effect measures. Estimates were presented as odds ratios (ORs) with 95% confidence intervals (CIs). The extent of overlap in the original studies was measured using the corrected covered area assessment. The quality of the included reviews was evaluated with the AMSTAR 2 tool. The Grading of Recommendations Assessment, Development and Evaluation approach was applied to rate evidence certainty. The protocol was registered on PROspective Register of Systematic Reviews (CRD42023411418).

RESULTS

Twelve meta-analyses (16,522,917 pregnancies; ˃433,330 IVF/ICSI) were included. IVF/ICSI singletons showed a significantly higher PTB risk compared to natural conception (PTB ˂37 weeks: OR: 1.72, 95% CI: 1.57-1.89; PTB<32 weeks: OR: 2.19, 95% CI: 1.82-2.64). Influential analysis reinforced the strength of this association. Subgroup analyses investigating supposed etiology revealed a comparable risk magnitude for spontaneous PTB (OR: 1.79, 95% CI: 1.56-2.04) and a greater risk for iatrogenic PTB (OR: 2.28, 95% CI: 1.72-3.02). PTB risk was consistent in the subgroup of conventional IVF (OR: 1.95, 95% CI: 1.76-2.15) and higher in the subgroup of fresh only (OR: 1.79, 95% CI: 1.55-2.07) vs frozen-thawed embryo transfers (OR: 1.39, 95% CI: 1.34-1.43). There was minimal study overlap (13%). The certainty of the evidence was graded as low to very low.

CONCLUSION

Singletons conceived through IVF/ICSI have a 2-fold increased risk of PTB compared to natural conception, despite the low certainty of the evidence. There is paucity of available data on PTB etiology, phenotype, or initiation. The greater risk increase is observed in fresh embryo transfers and involves iatrogenic PTB and PTB ˂32 weeks, likely attributable to placental etiology. Future studies should collect data on PTB etiology, phenotype, and initiation. IVF/ICSI pregnancies should undertake specialistic care with early screening for placental disorders, cervical length, and growth abnormalities, allowing appropriate timely follow-up, preventive measures, and therapeutic interventions strategies.

Prevalence of gestational diabetes mellitus risk factors in singleton pregnancies obtained by assisted reproductive technology: An observational, retrospective, real-world study from a pregnancy registry

AIMS

Several studies showed that Assisted Reproductive Technology (ART) could affect gestational diabetes mellitus (GDM) onset. The aim of this study was to estimate the prevalence of GDM risk factors in a cohort of women with singleton pregnancy obtained by ART and complicated by GDM. Maternal and neonatal outcomes were explored.

METHODS

We retrospectively collected data of pregnancies of women with singleton pregnancy obtained by ART and complicated by GDM consecutively cared for at a specialized center for diabetes and pregnancy care. Prevalence and combination of GDM risk factors, their combinations and maternal-fetal outcomes were estimated.

RESULTS

Overall, our cohort included 50 women (mean age of 40.4 ± 4.7 years, mean pre-pregnancy BMI 26.3 ± 6.2 kg/m2). The most frequent GDM traditional risk factors were age ≥ 35 years (94 %), family history of diabetes (44 %), overweight (29 %) and obesity (19 %). Combining risk factors, 5 groups were identified with 1, 2, 3, 4, or 5 risk factors with a prevalence respectively of 28 %, 46 %, 20 %, 4 %, and 2 %. Examining features of the above groups, pre-pregnancy weight (p < 0.0001) and pre-pregnancy BMI (p < 0.0001) statistically significant differed in the 5 groups, increasing with higher numbers of risk factors. Regarding neonatal outcomes only neonatal hypoglycemia (p = 0.03) differed significantly among the groups, with higher percentages in women with higher numbers of combined risk factors.

CONCLUSION

Prevalence of GDM traditional risk factors in singleton ART pregnancies complicated by GDM is considerable. Such pregnancies need appropriate clinical attention because of the risk of adverse outcomes.

The effect of an extended culture period on birth weight among singletons born after single or double vitrified embryo transfer

Aim

To evaluate the effect of an extended culture period on birth weight among singletons born after vitrified-warmed embryo transfer.

Methods

A retrospective cohort study was performed among 12400 women who gave birth to 1015, 1027, 687, and 9671 singletons after single blastocyst transfer, single cleavage-stage embryo transfer, double blastocyst transfer, and double cleavage-stage embryo transfer, respectively.

Results

The unadjusted birth weight of singletons born after vitrified blastocyst transfer were heavier than those born after cleavage-stage transfer (β=30.28, SE=13.17, P=0.022), as were the adjusted birth weights (β=0.09, SE=0.03, P=0.007). In addition, there was a 37% increased odd of having an infant with high birth weight after vitrified blastocyst transfer compared with vitrified cleavage stage transfer (OR=1.37, 95% CI:1.07-1.77).

Conclusion

The unadjusted and adjusted birth weight and odds of having an infant with high birth weight significantly increased after blastocyst transfer compared with cleavage-stage embryo transfer in vitrified-warmed cycles.

Associations of legacy perfluoroalkyl and polyfluoroalkyl substances, alternatives, and isomers with gestational diabetes mellitus and glucose homeostasis among women conceiving through assisted reproduction in Shanghai, China

Prior research has reported that perfluoroalkyl and polyfluoroalkyl substances (PFAS) may be linked to impaired glucose homeostasis in pregnant women. However, few studies have investigated PFAS alternatives and isomers, and even less is known about the association among women conceiving through assisted reproductive technology (ART). The prospective cohort study aimed to explore associations of legacy PFAS, alternatives and isomers with gestational diabetes mellitus (GDM) and glucose homeostasis during pregnancy among 336 women conceiving through ART. Nineteen PFAS, including nine linear legacy PFAS, four short-chain alternatives, four branched isomers, and two emerging PFAS alternatives, were determined in first-trimester maternal serum. Fasting plasma glucose (FPG), 1-h and 2-h glucose concentrations following the oral glucose tolerance test (OGTT), and glycated hemoglobin (HbA1c) were measured during the second trimester. After adjusting for confounding variables, nearly half of individual PFAS (10/19) and PFAS mixtures were correlated with increased GDM risk or elevated 2-h glucose levels. Among PFAS congeners, emerging PFAS alternatives, chlorinated perfluoroalkyl ether sulfonic acids (Cl-PFESAs), showed a notable association with impaired glucose homeostasis. For example, 6:2 Cl-PFESA exhibited a correlation with GDM (OR = 1.31, 95% CI = 1.02, 1.68) and 2-h glucose concentrations (β = 0.22, 95% CI = 0.08, 0.36), and contributed most to the overall association with 2-h glucose concentrations. Compared to those diagnosed with male factor infertility, the associations were more pronounced in infertile women with reproductive endocrine diseases. We provide evidence that exposure to PFAS, especially emerging PFAS alternatives, may impair glucose homeostasis and increase the risk of GDM among women conceiving through ART.

Change of HeART: Cardiovascular Implications of Assisted Reproductive Technology

Cardiovascular (CV) disease is the leading cause of death in women, and it may manifest differently than in men, in part related to sex-specific CV risk factors. In females, assisted reproductive technologies (ARTs) are commonly used to treat infertility, and they utilize controlled ovarian stimulation involving the administration of exogenous sex hormones. ARTs, and especially controlled ovarian stimulation, have been associated with an increased pregnancy and short-term CV risk, although the long-term CV implications of these treatments in individuals treated with ARTs and their offspring remain unclear. This review endeavors to provide a comprehensive examination of what is known about the relationship between ART and CV outcomes for females treated with ARTs, as well as their offspring, and recommendations for future research. Novel insights into female-specific CV risk factors are critical to reduce the disproportionate burden of CV disease in Canadian women. ART has revolutionized reproductive medicine, offering hope to millions of individuals with infertility worldwide, and a further understanding of the CV implications of this important sex-specific CV risk factor is warranted urgently.

Factors and outcomes for placental anomalies: An umbrella review of systematic reviews and meta-analyses

Background

Placental anomalies, including placenta previa (PP), placenta accreta spectrum disorders (PAS), and vase previa (VP), are associated with several adverse foetal-neonatal and maternal complications. However, there is still a lack of robust evidence on the pathogenesis and adverse outcomes of the diseases. Through this umbrella review, we aimed to systematically review existing meta-analyses exploring the factors and outcomes for pregnancy women with placental anomalies.

Methods

We searched PubMed, Embase, Web of Science, and the Cochrane Library from inception to February 2023. We used AMSTAR 2 to assess the quality of the reviews and estimated the pooled risk and 95% confidence intervals (CIs) for each meta-analysis.

Results

We included 34 meta-analyses and extracted 55 factors (27 for PP, 22 for PAS, and 6 for VP) and 16 outcomes (12 for PP, and 4 for VP) to assess their credibility. Seven factors (maternal cocaine use (for PP), uterine leiomyoma (for PP), prior abortion (spontaneous) (PP), threatened miscarriage (PP), maternal obesity (PP), maternal smoking (PAS), male foetus (PAS)) had high epidemiological evidence. Twelve factors and six outcomes had moderate epidemiological evidence. Twenty-two factors and eight outcomes showed significant association, but with weak credibility.

Conclusions

We found varying levels of evidence for placental anomalies of different factors and outcomes in this umbrella review.

Registration

PROSPERO: CRD42022300160.

Risk factors for preterm birth: an umbrella review of meta-analyses of observational studies

BACKGROUND

Preterm birth defined as delivery before 37 gestational weeks is a leading cause of neonatal and infant morbidity and mortality. The aim of this study is to summarize the evidence from meta-analyses of observational studies on risk factors associated with PTB, evaluate whether there are indications of biases in this literature, and identify which of the previously reported associations are supported by robust evidence.

METHODS

We searched PubMed and Scopus until February 2021, in order to identify meta-analyses examining associations between risk factors and PTB. For each meta-analysis, we estimated the summary effect size, the 95% confidence interval, the 95% prediction interval, the between-study heterogeneity, evidence of small-study effects, and evidence of excess-significance bias. Evidence was graded as robust, highly suggestive, suggestive, and weak.

RESULTS

Eighty-five eligible meta-analyses were identified, which included 1480 primary studies providing data on 166 associations, covering a wide range of comorbid diseases, obstetric and medical history, drugs, exposure to environmental agents, infections, and vaccines. Ninety-nine (59.3%) associations were significant at P < 0.05, while 41 (24.7%) were significant at P < 10-6. Ninety-one (54.8%) associations had large or very large heterogeneity. Evidence for small-study effects and excess significance bias was found in 37 (22.3%) and 12 (7.2%) associations, respectively. We evaluated all associations according to prespecified criteria. Seven risk factors provided robust evidence: amphetamine exposure, isolated single umbilical artery, maternal personality disorder, sleep-disordered breathing (SDB), prior induced termination of pregnancy with vacuum aspiration (I-TOP with VA), low gestational weight gain (GWG), and interpregnancy interval (IPI) following miscarriage < 6 months.

CONCLUSIONS

The results from the synthesis of observational studies suggest that seven risk factors for PTB are supported by robust evidence. Routine screening for sleep quality and mental health is currently lacking from prenatal visits and should be introduced. This assessment can promote the development and training of prediction models using robust risk factors that could improve risk stratification and guide cost-effective preventive strategies.

TRIAL REGISTRATION

PROSPERO 2021 CRD42021227296.

Nomogram for predicting the risk of preterm delivery after IVF/ICSI treatment: an analysis of 11513 singleton births

Background

There is a higher risk of preterm delivery (PTD) in singleton live births conceived after in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) compared with spontaneously conceived pregnancies. The objective of our study was to build a predictive nomogram model to suggest the possibility of PTD in singleton pregnancies after IVF/ICSI treatment.

Method

11513 IVF/ICSI cycles with singleton live births were enrolled retrospectively. These cycles were randomly allocated into a training group (80%) and a validation group (20%). We used the multivariate logistics regression analysis to determine prognostic factors for PTD in the training group. A nomogram based on the above factors was further established for predicting PTD. Receiver operating characteristic curves (ROC), areas under the ROC curves (AUC), concordance index (C-index), and calibration plots were analyzed for assessing the performance of this nomogram in the training and validation group.

Results

There were fourteen risk factors significantly related to PTD in IVF/ICSI singleton live births, including maternal body mass index (BMI) > 24 kg/m2, smoking, uterine factors, cervical factors, ovulatory factors, double embryo transferred (DET), blastocyst transfer, FET, vanishing twin syndrome (VTS), obstetric complications (placenta previa, placenta abruption, hypertensive of pregnancies, and premature rupture of membrane), and a male fetus. These factors were further incorporated to construct a nomogram prediction model. The AUC, C-index, and calibration curves indicated that this nomogram exhibited fair performance and good calibration.

Conclusions

We found that the occurrence of PTD increased when women with obesity, smoking, uterine factors, cervical factors, ovulatory factors, DET, VTS, and obstetric complications, and a male fetus. Furthermore, a nomogram was constructed based on the above factors and it might have great value for clinic use.

Expression of Toll-Like Receptors in the Lung Tissue of Mouse Fetuses Generated by in vitro Embryo Culture and Embryo Transfer

Mouse fetuses generated by in vitro embryo culture and embryo transfer exhibit impaired lung development, altered composition of pulmonary epithelial cells associated with downregulation of several genes involved in lung development and toll-like receptor (TLR) signaling pathway. The aims of the present study were to determine the expression of all TLRs and to examine if the expression of TLRs, along with genes involved in TLR signaling pathway, is altered in the lung tissue of mouse fetuses generated through embryo culture and embryo transfer. Two experimental (EGs) and one control (CG) group were included in the study. Embryos cultured at 5% CO2-95% air for 95 h or less than 24 h were transferred to pseudo-pregnant females to obtain fetuses comprising EGin vitro (n = 18) and EGin vivo (n = 18), respectively. Fetuses obtained from naturally ovulating females on day 18 of pregnancy served as the CG (n = 18). Western blot and immunohistochemistry were used to determine the expression of TLR proteins. The expression of transcripts encoding TLRs, and the genes involved in TLR signaling pathway (Lbp, Pik3r1, Pik3cb, Nfkbia, and Fos), was determined using qRT-PCR. While all TLRs were expressed by cells lining the bronchial/bronchiolar epithelium of lung tissues in all groups, some of the TLRs were expressed in a specific pattern. When compared to CG, the expression of transcripts encoding TLR-2, -3, -4, -5, -7, -8, -9, -12, -13, Lbp, Pik3r1, Pik3cb, Nfkbia, and Fos was significantly downregulated in both EGs. It appears that stress imposed on embryos at preimplantation stages of development is associated with downregulation of TLRs, along with some of the genes involved in TLR signaling pathway, in the lung tissue during the perinatal period. It remains to be determined if downregulation of TLRs, along with the genes involved in TLR signaling pathway, has any functional consequences in the adult lung tissue.

Risk factors for preterm labor: An Umbrella Review of meta-analyses of observational studies

Preterm birth defined as delivery before 37 gestational weeks, is a leading cause of neonatal and infant morbidity and mortality. Understanding its multifactorial nature may improve prediction, prevention and the clinical management. We performed an umbrella review to summarize the evidence from meta-analyses of observational studies on risks factors associated with PTB, evaluate whether there are indications of biases in this literature and identify which of the previously reported associations are supported by robust evidence. We included 1511 primary studies providing data on 170 associations, covering a wide range of comorbid diseases, obstetric and medical history, drugs, exposure to environmental agents, infections and vaccines. Only seven risk factors provided robust evidence. The results from synthesis of observational studies suggests that sleep quality and mental health, risk factors with robust evidence should be routinely screened in clinical practice, should be tested in large randomized trial. Identification of risk factors with robust evidence will promote the development and training of prediction models that could improve public health, in a way that offers new perspectives in health professionals.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Assisted reproductive technology, risk of gestational diabetes, and perinatal outcomes in singleton pregnancies

AIMS

To evaluate the impact of assisted reproductive technology (ART) on the risk of gestational diabetes mellitus (GDM) in single pregnancies.

MATERIALS AND METHODS

We retrospectively collected clinical and anthropometric data of 219ART- and 256 age- and body mass index (BMI)-matched women with spontaneous conception screened for GDM. The primary outcome was to evaluate GDM prevalence in ART women.

RESULTS

There were no differences in age, BMI, and family history of diabetes in the two groups of women. ART-women were more frequently primiparous, whereas the prevalence of previous GDM was higher in SC-women. The prevalence of GDM in the whole cohort was 36.1% and was higher in ART-women (52.3% vs. 23.4%; p < 0.0001). In the whole cohort, on multivariate analysis, family history of diabetes (OR 1.67; 95% CI: 1.03-2.69), previous GDM (OR 7.05; 95% CI: 2.92-17.04), pre-pregnancy obesity (OR 2.72; 95% CI 1.21-6.13), and ART (OR 4.14; 95% CI 2.65-6.48) were independent risk factors for GDM. Among ART-women, age over 40 years was associated with GDM. Preterm delivery was more common in ART-women; gestational week at delivery, birth weight, ponderal index, and Apgar score were lower in ART-women than in SC-women, both in the whole cohort and in GDM women.

CONCLUSIONS

Among women undergoing ART treatment, at least one in two develops GDM. ART appears to be an independent risk factor for GDM in single pregnancies, particularly above the age of 40. ART treatment seems to be associated with an increased rate of preterm delivery and lower neonatal birth weight and Apgar score, especially in GDM women.

CLINICAL TRIAL REGISTRATION

The study was not registered as it is an observational retrospective evaluation.

The cost of preterm birth and cesarean section as a result of infertility and its treatment: A review

Infertility, irrespective of receipt of fertility treatment, is associated with an increased risk of adverse pregnancy outcomes, including cesarean section (CS) and preterm birth (PTB). These complications are associated with significant physical, mental, emotional, social, and financial costs to individuals, healthcare systems, and society at large. Although multiple pregnancy is one of the most significant contributors to the elevated CS and PTB rates in women receiving fertility treatment, singleton pregnancy is also at an increased risk of these outcomes. Single embryo transfer policies through publicly funded in vitro fertilization programs have demonstrated beneficial health outcomes and cost savings. Low-dose aspirin prophylaxis may be considered for PTB reduction in patients with infertility. Finally, upstream prevention strategies such as lifestyle modification and social policies to address the underlying needs for fertility treatment may also beneficially impact both CS and PTB rates.

Maternal stress during pregnancy and gestational duration: A cohort study from the Danish National Birth Cohort

BACKGROUND

Preterm birth is one of the most important contributors to neonatal mortality and morbidity. Experiencing stress during pregnancy may increase the risk of adverse birth outcomes, including preterm birth. This association has been observed in previous studies, but differences in measures used limit comparability.

OBJECTIVE

The objective of the study was to investigate the association between two measures of maternal stress during pregnancy, life stress and emotional distress, and gestation duration.

METHODS

Women recruited in the Danish National Birth Cohort from 1996 to 2002, who provided information on their stress level during pregnancy and expecting a singleton baby, were included in the study. We assessed the associations between the level of life stress and emotional distress in quartiles, both collected at 31 weeks of pregnancy on average, and the rate of giving birth using Cox regression within intervals of the gestational period.

RESULTS

A total of 80,991 pregnancies were included. Women reporting moderate or high levels of life stress vs no stress had a higher rate of giving birth earlier within all intervals of gestational age (e.g. high level: 27-33 weeks: hazard ratio (HR) 1.38, 95% confidence interval (CI) 1.04, 1.84; 34-36 weeks: 1.10, 95% CI 0.97, 1.25; 37-38 weeks: 1.21, 95% CI 1.15, 1.28). These associations between life stress and preterm birth were mainly driven by pregnancy worries. For emotional distress, a high level of distress was associated with shorter length of gestation in the preterm (27-33 weeks: 1.38, 95% CI 1.02, 1.86; 34-36 weeks: 1.05, 95% CI 0.91, 1.19) and early term (1.11, 95% CI 1.04, 1.17) intervals.

CONCLUSIONS

Emotional distress and life stress were shown to be associated with gestational age at birth, with pregnancy-related stress being the single stressor driving the association. This suggests that reverse causality may, at least in parts, explain the earlier findings of stress as a risk factor for preterm birth.

Pregnancy outcomes following in vitro fertilization treatment in women with previous recurrent ectopic pregnancy

Objectives

The aim of this study was to investigate the impact of a history of recurrent ectopic pregnancy (EP) on pregnancy outcomes of subsequent in vitro fertilization (IVF) treatment.

Methods

A retrospective cohort study involving 457 women with a history of recurrent EP (REP group), 912 women with a history of single EP (SEP group), and 1169 women with a history of intrauterine pregnancy (IUP group) as the control group, was conducted. IVF outcomes were compared for each cohort.

Results

The incidence of EP in the REP group after IVF treatment was significantly lower than those in the SEP group (2.4% vs. 6.8%, P = 0.011), and similar to those in the IUP group (2.4% vs. 2.1%, P = 0.830). No significant differences were observed in the clinical pregnancy rate, miscarriage rate, and live birth rate among the three groups. There was no statistically significant difference in the recurrent EP rate between the salpingectomy and salpingostomy treatments. Adjusting for maternal and treatment factors did not influence live birth rates for women with previous REP compared with women with previous SEP and those with IUP. The odds of EP were 82.2% lower (OR 0.178, 95% CI 0.042–0.762; P = 0.020) in women who had blastocyst transfer compared with cleavage embryo transfer in the SEP group. The odds of EP were over six times (OR 6.260, 95% CI 1.255–31.220; P = 0.025) in women who underwent double embryo transfer as opposed to single embryo transfer in the IUP group.

Conclusion

Our results indicate that women with previous recurrent EP have a lower risk of EP after IVF in comparison with women with previous single EP. Previous EP has no significant adverse effect on the main IVF outcomes. The salpingostomy and salpingectomy treatments of EP do not significantly affect the incidence of recurrent EP after IVF.

The influence of regulation of medically assisted reproduction on the risk of hospitalization in the first 2 years of life

STUDY QUESTION

Do publicly funded fertility treatment and single embryo transfer (SET) result in lower hospitalization rates of children of parents with infertility?

SUMMARY ANSWER

Following the 2010 Quebec law introducing free fertility treatment and SET, neonatal intensive care unit (NICU) admissions decreased among all children born to parents with infertility, but not among singletons, whose risk remained slightly higher than that of children of parents without infertility, even accounting for treatment and maternal age.

WHAT IS KNOWN ALREADY

Previous studies reported lower NICU admission rates among children conceived with ART after the 2010 law; however, children conceived without ART by parents with infertility were not considered.

STUDY DESIGN, SIZE, DURATION

Cohort study of children born in 1997-2017 to patients evaluated for infertility ('exposed') at an academic fertility center in Montreal (Canada) in 1996-2015. A random sample of births to Montreal residents served as comparison. Outcomes were identified from Quebec administrative databases.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We compared children's healthcare utilization before and after the 2010 law in 6273 exposed and 12 583 randomly sampled births (6846 and 12 775 children, respectively). We repeated the analysis among children conceived in the 63 months before and after the law ('restricted period'), and examined whether differences in twinning, fertility treatment, and maternal age explained the higher risk of NICU admission among children of parents with infertility.

MAIN RESULTS AND THE ROLE OF CHANCE

In the exposed cohort, the proportion of twin births and of several adverse outcomes declined after the law. NICU admission and duration of NICU stay decreased overall, but not in singletons. Both measures remained higher in exposed children. Except for NICU admission, hospitalization rates were similar in exposed and random sample children. After accounting for fertility treatment and maternal age, exposed singletons were 17% more likely to be admitted to the NICU than children of parents with no medical history of infertility.

LIMITATIONS, REASONS FOR CAUTION

Sample size was relatively small; infertile patients were from a single center and the random sample from one city. Despite some limitations, administrative databases are likely to accurately reflect healthcare utilization.

WIDER IMPLICATIONS OF THE FINDINGS

Universal access to treatment and, particularly, SET results in an overall reduction of adverse outcomes among children conceived with treatment; however, children of parents with infertility are at a slightly higher risk, regardless of treatment.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Canadian Institutes for Health Research (CIHR, grant no. 123362). No competing interests.

TRIAL REGISTRATION NUMBER

N/A.

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.

Neurological development in 36‐month‐old children conceived via assisted reproductive technology: The Japan Environment and Children's Study

Purpose

This study aimed to investigate neurodevelopment in children conceived via in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) with several types of embryo transfers.

Methods

We analyzed data for 77 928 children and their mothers included in a Japanese birth cohort study. Among the included children, 4071 were conceived via IVF, while 1542 were conceived via ICSI. Neurodevelopmental delay at the age of 3 years was assessed using the Japanese version of the Ages and Stages Questionnaires, 3rd edition.

Results

In the crude model, the odds ratios for developmental delay in 1–4 domains were higher among children conceived via IVF, ICSI, and non‐ART (ovulatory induction or intrauterine insemination) than in spontaneously conceived children. After adjusting for parental background factors and the child's sex, there were no differences in the risk of developmental delay when comparing singletons conceived by IVF, ICSI, or non‐ART and those conceived spontaneously. Higher odds ratios for developmental delay in one domain were observed in singleton girls conceived via IVF when compared with those who were spontaneously conceived.

Conclusion

Most cases of developmental delay may be associated with multiple pregnancies and factors related to infertility, such as parental age, irrespective of the use of ART.

Prognostic Gene Predictors of Gestational Diabetes in Endometrium and Follicular Fluid of Women after Infertility

Background and objectives. Gestational diabetes mellitus is an increasingly diagnosed metabolic disorder during pregnancy with unknown pathological pathways. Taking into account the growing numbers of women who are conceiving after assisted reproductive technologies, they comprise an engaging target group for gestational diabetes mellitus etiopathogenesis research. In terms of metabolism and genetics, as the evidence shows, both unexplained infertility and gestational diabetes mellitus pose challenges for their interpretation due to the complex bodily processes. Materials and Methods. Our study examined the expression of genes (IGF2, GRB10, CRTC2, HMGA2, ESR1, DLK1, SLC6A15, GPT2, PLAGL1) associated with glucose metabolism in unexplained infertility patients who conceived after in vitro fertilization procedure, were diagnosed with GDM and their findings were compared with control population. Results. There were no significant differences in gene expression of endometrium stromal cells between healthy pregnant women and women with gestational diabetes, although the significant downregulation of CRTC2 was observed in the follicular fluid of women with gestational diabetes mellitus. Moreover, expression of HMGA2 and ESR1 was significantly reduced in FF cells when compared to endometrial cells. Conclusions. These findings may indicate about the importance of follicular fluid as an indicator for gestational diabetes and should be explored more by further research.

Comparing maternal outcomes in spontaneous singleton pregnancies versus in vitro fertilization conception: Single-center 10-year cohort study

OBJECTIVE

A successful assisted reproductive technique (ART) cycle is not flawless, and several studies have reported high incidences of maternal complications, but the association is inconclusive. In addition, the racial and ethnic effects of the Asian population undergoing ART on maternal outcomes is not well studied. This study attempts to compare various maternal outcome parameters ART and spontaneously conceived singleton pregnancies from a single high volume tertiary care centre.

METHODS

A retrospective cohort study from a single tertiary infertility center was conducted from January 2011 to September 2020. The study included 1125 IVF conceived singletons (AP group) and 7193 spontaneous conceived singletons (SP group). The groups were compared using the Pearson Chi-square test and the adjusted odds ratio calculated using multivariate analysis.

RESULTS

Maternal outcomes like gestational hypertension, pre-eclampsia, gestational diabetes (GDM), oligohydramnios, chorioamnionitis, operative, and instrumental delivery were significantly different in the two groups (p<0.05). The AP group had a significantly increased risk of GDM (aOR 1.093; 95% CI 1.076-1.110) and pregnancy-induced hypertension (PIH) (aOR 1.577; 95% CI 1.288-1.930) as compared to the SP group. IVF significantly increases the risk of abruption by 2 times (p=0.028), and independently increases the risk of caesarean section by 3.1-fold (p<0.001). But overall the IVF is the protective factor for oligohydramnios (p=0.024).

CONCLUSIONS

ART increases the likelihood of pregnancy-related maternal complications, such as PIH, GDM, abruption, chorioamnionitis, and an increased rate of caesarean delivery. Thus, all patients undergoing ART procedures should receive pre-conceptional counselling regarding the associated obstetric risks and consider ART pregnancy as a high-risk pregnancy.

Prognosis of Congenital Anomalies in Conceptions Following In Vitro Fertilization: A Multicenter Retrospective Cohort Study in China

BACKGROUND

Conceptions following in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) have an increased risk of congenital anomalies. Few studies have explored the prognosis of fetuses with congenital anomalies. This study aimed to investigate the prevalence and prognosis of congenital anomalies in IVF/ICSI pregnancies, and to analyze the influencing factors contributing to poor prognosis.

METHODS

In this multicenter retrospective cohort study, we followed 405,473 embryo transfer cycles at 15 reproductive centers between January 2010 and December 2019 and enrolled 2,006 intrauterine pregnancies with congenital anomalies. The relatively positive prognosis group with one or more live births and neonatal survival for more than 7 days was compared with the poor prognosis group with poorer outcomes.

RESULTS

Among the 168,270 ongoing intrauterine pregnancy cycles, the prevalence of congenital anomalies was 1.19%, wherein the malformation rates of cycles with late abortion and delivery were 2.37% (716/30,202) and 0.93% (1,290/138,068), respectively. Among all IVF/ICSI cycles with congenital anomalies, the relatively positive prognosis rate was 61.39%. Moreover, the fertilization failure rate (2 pro-nuclei rate < 25%) in the poor prognosis group was significantly higher than that in the relatively positive prognosis group (10.89% vs. 5.09%, p < 0.001). Multivariate logistic regression analysis revealed no significant differences in the relatively positive prognosis rate among the various IVF/ICSI protocols. The relatively positive prognosis rate of fertilization failure cycles was 0.180 times that of normal fertilization cycles.

CONCLUSION

Poor fertilization rates during IVF/ICSI treatments are more likely to have poor prognosis in fetuses or neonates with congenital anomalies, and obstetric management should be strengthened in pregnant women, with which pregnant women should be recommended to strengthen obstetric management.

Placental Abnormalities and Placenta-Related Complications Following In-Vitro Fertilization: Based on National Hospitalized Data in China

INTRODUCTION

Emerging evidence has shown that in-vitro fertilization (IVF) is associated with higher risks of certain placental abnormalities or complications, such as placental abruption, preeclampsia, and preterm birth. However, there is a lack of large population-based analysis focusing on placental abnormalities or complications following IVF treatment. This study aimed to estimate the absolute risk of placental abnormalities or complications during IVF-conceived pregnancy.

METHODS

We conducted a retrospective cohort study of 16 535 852 singleton pregnancies with delivery outcomes in China between 2013 and 2018, based on the Hospital Quality Monitoring System databases. Main outcomes included placental abnormalities (placenta previa, placental abruption, placenta accrete, and abnormal morphology of placenta) and placenta-related complications (gestational hypertension, preeclampsia, eclampsia, preterm birth, fetal distress, and fetal growth restriction (FGR)). Poisson regression modeling with restricted cubic splines of exact maternal age was used to estimate the absolute risk in both the IVF and non-IVF groups.

RESULTS

The IVF group (n = 183 059) was more likely than the non-IVF group (n = 16 352 793) to present placenta previa (aRR: 1.87 [1.83-1.91]), placental abruption (aRR: 1.16 [1.11-1.21]), placenta accrete (aRR: 2.00 [1.96-2.04]), abnormal morphology of placenta (aRR: 2.12 [2.07 to 2.16]), gestational hypertension (aRR: 1.55 [1.51-1.59]), preeclampsia (aRR: 1.54 [1.51-1.57]), preterm birth (aRR: 1.48 [1.46-1.51]), fetal distress (aRR: 1.39 [1.37-1.42]), and FGR (aRR: 1.36 [1.30-1.42]), but no significant difference in eclampsia (aRR: 0.91 [0.80-1.04]) was found. The absolute risk of each outcome with increasing maternal age in both the IVF and non-IVF group presented two patterns: an upward curve showing in placenta previa, placenta accreta, abnormal morphology of placenta, and gestational hypertension; and a J-shape curve showing in placental abruption, preeclampsia, eclampsia, preterm birth, fetal distress, and FGR.

CONCLUSION

IVF is an independent risk factor for placental abnormalities and placental-related complications, and the risk is associated with maternal age. Further research is needed to evaluate the long-term placenta-related chronic diseases of IVF patients and their offspring.

The Kind of Conception Affects the Kind of Cesarean Delivery in Primiparous Women

BACKGROUND

So far, multiple factors have been found to be related to the IVF procedure, the most prevalent being extremes of maternal age, infections, previous gynecological history, infertility and others. Although women achieve the coveted pregnancy with the development of IVF technology, the rapid increase contributes to the increase of primary cesarean sections rates.

OBJECTIVE

The aim of the study was to identify if the kind of conception affects the kind of cesarean delivery among primiparous women in Greece.

METHODS

This cross-sectional observational study took place from September 2019 to February 2020 at the University Hospital of Larisa in Greece. One hundred and sixty-two primiparous women who underwent a cesarean section (c-section) after IVF (n=27) and natural conception (n=135) participated in the study.

RESULTS

The mean age of the IVF and natural conception groups were 36.22 and 31.08 years, respectively. Nineteen (70.4%) women of the IVF group had a previous medical or gynecological history in contrast to 48 (35.6%) women of the natural conception group. Only 55.6% of the IVF group had a full-term pregnancy unlike 88.1% of women in the natural conception group. An elective c-section was performed in 18 (66.7%) of the women who conceived after IVF, as opposed to 45 (33.3%) of the women who conceived naturally.

CONCLUSION

This cross-sectional study showed that IVF conception was associated with high rates of elective cesarean section as opposed to women with natural conception. The causes of c-sections must be evidence based because the primary cesarean delivery is a major factor contributing to increased c-section rates.

Pregnancy potential and perinatal outcomes of embryos cryopreserved twice: a case-control study

RESEARCH QUESTION

What are the pregnancy and perinatal outcomes of twice-cryopreserved embryos compared with embryos cryopreserved once?

DESIGN

Retrospective register-based case-control study. The case group consisted of transfers of twice-cryopreserved embryos (n = 89), and the control group of transfers of embryos cryopreserved once (n = 304). Matching criteria were embryonic age at transfer and female age category of less than 35 years or 35 and greater.

RESULTS

The survival rate of twice-cryopreserved embryos was 92.2%, and 93.7% of the planned frozen embryo transfers (FET) could be completed. FET was performed with cleavage-stage embryos in 17 cases and 68 controls and with blastocysts in 72 cases and 238 controls. The rates of live birth (27.0% versus 31.9%, adjusted odds ratio [OR] 0.70, 95% CI 0.40-1.22, P = 0.21), clinical pregnancy (31.5% versus 36.8%, adjusted OR 0.71, 95% CI 0.42-1.21, P = 0.21) and miscarriage (4.5% versus 3.9%, adjusted OR 1.10, 95% CI 0.33-3.60, P = 0.88) in the case and the control groups were comparable. No difference was seen in the preterm delivery rate (cases 4.2% versus controls 10.3%, P = 0.69). Twenty-five children were born in the case group and 100 in the control group. No difference in birthweight was detected between the groups and there were no large for gestational age fetuses or congenital malformations in the case group.

CONCLUSIONS

Uncompromised live birth rates and neonatal outcomes may be expected after the transfer of twice-cryopreserved embryos. To avoid embryo wastage and transfer of multiple embryos, good quality surplus embryos from FET cycles may be cryopreserved again by vitrification.

The influence of oxygen concentration during embryo culture on obstetric and neonatal outcomes: a secondary analysis of a randomized controlled trial

STUDY QUESTION

Does oxygen concentration during 3-day embryo culture affect obstetric and neonatal outcomes?

SUMMARY ANSWER

Oxygen concentration during 3-day embryo culture does not seem to affect the obstetric and neonatal outcomes measured.

WHAT IS KNOWN ALREADY

Atmospheric oxygen appears to be harmful during extended embryo culture. Embryo culture conditions might therefore be a potential risk factor for subsequent fetal development and the health of future children. No data are available concerning the obstetrics and neonatal outcomes after Day 3 transfer of embryos cultured under reduced and atmospheric oxygen tensions.

STUDY DESIGN, SIZE, DURATION

A secondary analysis of a previous randomized controlled trial assessing clinical pregnancy outcomes was carried out. This analysis included 1125 consecutive oocyte donation cycles utilizing ICSI or IVF and Day 3 embryo transfers between November 2009 and April 2012. The whole cohort of donated oocytes from patients who agreed to participate in the study were randomly allocated (1:1 ratio) to a reduced O2 tension group (6% O2) or an air-exposed group (20% O2) based on a computer-generated randomization list. Fresh and vitrified oocytes were used for oocyte donation. Only those pregnancies with a live birth at or beyond 24 weeks of gestation were included.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Day 3 embryos were cultured in an atmosphere of 5.5% CO2, 6% O2, 88.5% N2 versus a dual gas system in air.

MAIN RESULTS AND THE ROLE OF CHANCE

From the eligible 1125 cycles, 564 were allocated to the 6% O2 group and 561 cycles to the 20% O2 group. However, 50 and 62 cycles did not reach embryo transfer in the 6% and 20% O2 groups, respectively. No differences were found between 6% O2 and atmospheric O2 tension in the number of livebirths per embryo transfer (mean ± SD, 0.5 ± 0.7 versus 0.5 ± 0.7), pregnancy complications or neonatal outcomes. Both groups (6% and atmospheric O2) had similar single and twin delivery rates (40.8% versus 38.1% and 10.7% versus 12.3%, respectively). Preterm delivery rates and very preterm delivery rates (10.80% versus 13.24% and 1.25% versus 2.94%, respectively), birthweight (3229 ± 561 g versus 3154 ± 731 g), low birthweight (2.92% versus 2.45%), birth height (50.18 ± 2.41 cm versus 49.7 ± 3.59 cm), head circumference (34.16 ± 1.87 cm versus 33.09 ± 1.85 cm) and 1 min Apgar scores (8.96 ± 0.87 versus 8.89 ± 0.96) were also similar between 6% and atmospheric O2 groups, respectively.

LIMITATIONS, REASONS FOR CAUTION

The number of liveborns finally analyzed is still small and not all obstetric and neonatal variables could be evaluated. Furthermore, a small proportion of the obstetric and neonatal data was obtained through a questionnaire filled out by the patients themselves. One reason for the lack of effect of oxygen concentration on pregnancy outcome could be the absence of trophectoderm cells at cleavage stage, which may make Day 3 embryos less susceptible to hypoxic conditions.

WIDER IMPLICATIONS OF THE FINDINGS

Nowadays many IVF laboratories use a more physiological oxygen concentration for embryo culture. However, the benefits of using low oxygen concentration on both laboratory and clinical outcomes during embryo culture are still under debate. Furthermore, long-term studies investigating the effect of using atmospheric O2 are also needed. Gathering these type of clinical data is indeed, quite relevant from the safety perspective. The present data show that, at least in egg donation cycles undergoing Day 3 embryo transfers, culturing embryos under atmospheric oxygen concentration seems not to affect perinatal outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

The present project was supported by the R + D program of the Regional Valencian Government, Spain (IMPIVA IMDTF/2011/214). The authors declare that they have no conflict of interest with respect to the content of this manuscript.

TRIAL REGISTRATION NUMBER

NCT01532193.

The effect of endometrial thickness on live birth outcomes in women undergoing hormone-replaced frozen embryo transfer

Objective

To determine the impact of endometrial thickness on live birth outcomes and obstetric complication rate after hormone-replaced frozen embryo transfer.

Design

Retrospective cohort study.

Setting

Large, urban, academic fertility center.

Patients

All patients with a singleton live birth after single euploid embryo transfer (by array comparative genomic hybridization or next-generation sequencing) in a hormone-replaced frozen embryo transfer cycle between January 2017 and December 2018 were reviewed.

Interventions

None.

Main Outcome measures

The primary outcomes were birth weight and obstetric complication rate.

Results

A total of 492 patients were included. The median endometrial thickness was 8.60 mm (range, 6.0-20.0). The median gestational age at live birth was 39.4 weeks with a median birth weight of 3,345.2 g. Endometrial thickness was significantly correlated with birth weight. When patients were dichotomized into groups (those with an endometrial thickness of <7 mm and those with an endometrial thickness of >7 mm), neonates born from endometria with a thickness of <7 mm were born earlier (37.3 vs. 39.4 weeks and born with lower birth weights (2,749.9 vs. 3,345.2 g). It should be noted that only seven patients had an endometrium measuring <7 mm. Moreover, 7.1% (n = 35) of patients had an obstetric complication. Endometrial thickness was not significantly associated with obstetric complications, even with adjustments for age and medical history.

Conclusions

Endometrial thickness may be a valuable predictor of placental health and birth weight. Further study is required to examine the relationship with individual obstetric complications, as our study may not have been powered to observe differences in obstetric complication rate, as well as the relationship between endometrial thickness and outcomes in natural frozen embryo transfer cycles.

Are ovarian reserve tests reliable in predicting ovarian response? Results from a prospective, cross-sectional, single-center analysis

OBJETIVE

Several biomarkers of ovarian reserve have been proposed as possible predictors of the response to controlled ovarian stimulation (COS). We aimed to evaluate age, FSH, AMH, antral follicle count (AFC), and ovarian response prediction index (ORPI), as potential predictors of response to COS.

METHODS

Cross-sectional study enrolling of 188 infertile women who underwent the first cycle of IVF/ICSI. AFC was evaluated; serum FSH and AMH levels were measured by ELISA. ORPI was calculated as AMH x AFC/patient´s age.

RESULTS

As expected, hypo-responder group had less retrieved oocytes, MII, and embryos compared to the good responders. The hyper-response patients were younger, with lower FSH, increased AMH, AFC, and ORPI values. Regarding the assessment of the predictive capacity of ovarian reserve tests, none of them individually or combined showed a good predictive capacity for hypo-response. With respect to the hyper-responder group, individually AMH was the best predictor, while in the multivariable model, ORPI demonstrated the best predictive capacity. Furthermore, patients with serum AMH < 2.09 ng/mL (p25) had fewer AFC than patients with higher AMH values.

CONCLUSIONS

Our findings suggest that none of the ovarian reserve tests showed a good predictive capacity for hypo-response, while the ORPI was the strongest predictor of hyper-response in normovulatory infertile women.

Is guided, targeted information about the risks of twin pregnancy able to increase the acceptance of single embryo transfer among IVF couples? A prospective study

OBJECTIVE

To assess whether receiving information about twin pregnancy in the form of oral presentation given by a physician could affect the acceptance of single embryo transfer (SET) by couples undergoing IVF.

STUDY DESIGN

Prospective interventional study.

SETTING

University hospital IVF unit.

PATIENTS

One hundred and forty patients (70 couples) undergoing IVF.

INTERVENTIONS

A questionnaire to measure patients' emotions about twin pregnancy was administered to IVF patients just before and immediately after attending a slide presentation in which the risks of twin pregnancy were explained. Patients scored (1 to 6) ten adjectives linked either to positive or negative emotions; scores before and after presentation were compared. The patients' preference between double embryo transfer (DET) and SET was also registered before and after the presentation.

RESULTS

The presentation about twin pregnancy caused a significant (p < 0.001) shift of the score distribution toward lower values for positive adjectives referred to twin pregnancy and higher values for negative adjectives. Information impacted similarly on women and men. Despite the relevant change in the emotional attitude, after presentation, 45.7% of women and 48.6% of men were still favorable to DET, whereas 24.3% of women and 37.1% of men preferred SET.

CONCLUSIONS

Oral information on the risks of twin pregnancy can affect the emotional attitude of patients toward twin pregnancy, but the wish of getting pregnant after fresh embryo transfer overcomes all rational consideration, and the majority of patients still prefer DET.

Suboptimal endometrial-embryonal synchronization is a risk factor for ectopic pregnancy in assisted reproduction techniques

RESEARCH QUESTION

What are the main risk factors associated with ectopic pregnancy and what is the true incidence of ectopic pregnancies in an IVF programme?

DESIGN

Retrospective single-centre study of 12,429 blastocyst transfers (8182 fresh and 4247 frozen embryo transfers) conducted between January 2010 and December 2017. IVF outcome was analysed, and ectopic pregnancy risk evaluated according to patient's characteristics and assisted reproductive technology treatment factors.

RESULTS

Of 5061 patients reporting a positive pregnancy test, 43 were diagnosed with ectopic pregnancy (0.85%). Neither female age (36.7 versus 35.8 years), body mass index, quality of transfer nor stimulation protocol affected the ectopic pregnancy rate, but history of previous ectopic pregnancy (OR 3.26; P = 0.0080), tubal surgery, or both (OR 6.20; P < 0.0001) did. The incidence of ectopic pregnancy was increased in women with uterine malformations (OR 3.85; P = 0.0052), uterine pathologies (OR 5.35; P = 0.0001), uterine surgeries (OR 2.29; P = 0.0154) or sub-optimal endometrial build-up (OR 4.46 to 5.31; P < 0.0001). Transfer of slow-developing blastocysts (expressed by expansion) significantly increased the risk of ectopic pregnancy (OR 2.59; P = 0.0102).

CONCLUSIONS

Unfavourable uterine environment, including uterine pathologies, uterine or tubal surgery and suboptimal endometrial build-up were related to ectopic pregnancy. Low expansion grade of blastocysts was identified as an additional putative risk factor for ectopic pregnancy, indicating the importance of proper embryonal-maternal synchronization. The overall ectopic pregnancy rate after blastocyst transfer was low, comparable with reported ectopic pregnancy rates in spontaneous conceptions. Proper evaluation of tubal and uterine pathologies, optimizing endometrial preparation and the transfer of expanded blastocysts in a frozen embryo transfer cycle, might be beneficial.

Assisted reproductive technology and the risk of gestational diabetes mellitus: a systematic review and meta-analysis

Background

The use of assisted reproductive technology (ART) is increasing worldwide, and observational studies have indicated that women who conceived by ART have an increased risk of pregnancy complications including gestational diabetes mellitus (GDM). We aimed to determine the risk of GDM among women who conceived with ART by systematic review and meta-analysis.

Main text

A systematic literature search was conducted in ISI Web of Knowledge, MEDLINE, Scopus, and Embase through May 2017 for English-language articles using a list of keywords. All studies comparing GDM in women conceived by ART and those who conceived spontaneously were included. Data extraction was performed by two authors independently and discrepancies were resolved by discussion. In total, 48 studies with 91,487 pregnancies conceived through ART and 2,525,234 spontaneously conceived met the inclusion criteria. There was evidence of substantial heterogeneity among these studies (P < 0.001, I2 = 98.6%). Random effects meta-analysis showed a significant increase in GDM among those who conceived by ART compared with those who conceived spontaneously (pooled relative risk = 1.51, 95% confidence interval = 1.18–1.93). Visual inspection of the funnel plot did not reveal any publication bias, which was supported by Egger’s test and Begg’s test.

Conclusion

The findings of this systematic review indicate that the use of ART treatment is associated with a 1.51-fold increase in GDM. Women need to be counselled carefully before undergoing ART treatment about the possibility and risk of GDM.

Clinical outcomes following frozen-thawed blastocyst transfers with blastocysts derived from different cell numbers on day 3: a retrospective cohort study

PURPOSE

To evaluate clinical outcomes after frozen-thawed blastocyst transfer (TBT) with blastocysts which were derived from different cell numbers on day 3.

METHODS

The study included 1444 patients undergoing single autologous frozen-thawed blastocyst transfer cycles, which were allocated to five groups according to the cell numbers on day 3 of the transferred blastocysts: ≤ 6-cell (n = 109), 7-cell (n = 169), 8-cell (n = 811), 9-cell (n = 136), and ≥ 10-cell (n = 219).

RESULTS

The LBR of the ≤ 6-cell group was found to be statistically lower than that of the 8-cell group in single TBT cycles which had been transferred with fair quality blastocysts (defined as 4BB according to Gardner's grading scale) (41.28% vs 55.73%, P = 0.004), while the miscarriage rate was significantly higher for the ≤ 6-cell group compared with the 8-cell group (25.00% vs 13.74%, P = 0.02). No differences were found between the two groups in terms of cPR (P = 0.06). However, for blastocysts categorized as high quality according to Gardner's classification (defined as 4AA/4AB/4BA), cPR, LBR, and early miscarriage rates did not differ between the two groups (P = 0.76, P = 0.44, P = 0.40, respectively).

CONCLUSIONS

When transferring blastocysts, an evaluation of the cleavage stage should be performed along with blastocyst morphology to shorten the time of conceiving.

Placental Implantation Disorders

Primary disorders of placental implantation have immediate consequences for the outcome of a pregnancy. These disorders have been known to clinical science for more than a century, but have been relatively rare. Recent epidemiologic obstetric data have indicated that the rise in their incidence over the last 2 decades has been iatrogenic in origin. In particular, the rising numbers of pregnancies resulting from in vitro fertilization (IVF) and the increased use of caesarean section for delivery have been associated with higher frequencies of previa implantation, accreta placentation, abnormal placental shapes, and velamentous cord insertion. These disorders often occur together.

Birthweight difference of singletons conceived through in vitro fertilization with frozen versus fresh embryo transfer: An analysis of 5406 embryo transfers in a retrospective study 2013-2018

INTRODUCTION

Perinatal risks after frozen embro transfer (FET) have been reassuring but some authors suggest that birthweights are higher after FET than after fresh embryo transfer (ET). The primary objective of this retrospective study, conducted in Clinique de la Sagesse, Rennes (France) from December 2013 to March 2017, was to determine whether a difference in birthweight exists between children conceived through in vitro fertilization (IVF) with frozen versus fresh ET. The secondary objective was to compare live birth rates after frozen versus fresh cycles.

MATERIAL AND METHODS

All couples undergoing IVF were included. Cycles with gamete donation and twin pregnancies were excluded. Hormone therapy was used in all embryo transfers. The main outcome measures were the child's birthweight, mode of delivery, gestation length and sex, maternal characteristics, and IVF characteristics. The primary endpoint was birthweight.

RESULTS

We studied 5406 embryo transfers and the 708 resulting singleton live births on which birthweight data were available. Mean birthweight was 3357g after frozen embryo transfer versus 3183g after fresh embryo transfer (p<0.001). After adjusting for confounding factors, the children born after frozen embryo transfer were 165.2g heavier (95%CI [92.96-237.51]). No difference was found in gestation length. Live birth was obtained after the 1.6th IVF attempt. Live birth rate was higher for fresh cycles (19% versus 12%, p<0.001), and the caesarean rate lower (16% versus 21%).

DISCUSSION

Birthweight was higher after frozen embryo transfer for a similar gestational age. Further research is needed to elucidate the mechanisms responsible for this difference.

Risk of gestational diabetes mellitus following assisted reproductive technology: systematic review and meta-analysis of 59 cohort studies

OBJECTIVE

The use of assisted reproductive technology (ART) has been associated with an increased risk of gestational diabetes mellitus (GDM) in previous studies, but its risk has not been consistent. Therefore, we aimed to estimate the risk of GDM in women who conceived with ART via a systematic review and meta-analysis of cohort studies.

METHODS

ISI Web of Knowledge, Medline/PubMed, Scopus, and Embase databases were searched to identify studies that evaluated the risk of GDM through May 2017 using the relevant keywords. Two reviewers independently performed the screening, data extraction, and quality assessment. Meta-analysis was performed with a random effects model.

RESULTS

The search yielded 957 records relating to GDM and use of ART, from which 59 eligible cohorts were selected for meta-analysis (n = 96,785). There was evidence of substantial heterogeneity among these studies (χ₍₅₈₎² = 3072.34, p < .001; I²=98.1%). The pooled estimate of GDM risk using the random effects model was 9.00% (95% CI: 7.90-10.20). Visual inspection of the funnel plot indicated the presence of low publication bias, but Egger's test did not reveal publication bias.

CONCLUSIONS

The findings revealed that the risk of GDM was very high among women who conceived with ART treatment. GDM screening, management, and improved care are vital in ART pregnancy.

Maternal and environmental risk factors for neonatal AKI and its long-term consequences

Acute kidney injury (AKI) is a common and life-threatening complication in critically ill neonates. Gestational risk factors for AKI include premature birth, intrauterine growth restriction and low birthweight, which are associated with poor nephron development and are often the consequence of pre-gestational and gestational factors, such as poor nutritional status. Our understanding of how to best optimize renal development and prevent AKI is in its infancy; however, the identification of pre-gestational and gestational factors that increase the risk of adverse neonatal outcomes and the implementation of interventions, such as improving nutritional status early in pregnancy, have the potential to optimize fetal growth and reduce the risk of preterm birth, thereby improving kidney health. The overall risk of AKI among critically ill and premature neonates is exacerbated postnatally as these infants are often exposed to dehydration, septic shock and potentially nephrotoxic medications. Strategies to improve outcomes - for example, through careful evaluation of nephrotoxic drugs - may reduce the incidence of AKI and its consequences among this population. Management strategies and updated technology that will support neonates with AKI are greatly needed. Extremely premature infants and those who survive an episode of AKI should be screened for chronic kidney disease until early adulthood. Here, we provide an overview of our current understanding of neonatal AKI, focusing on its relationship to preterm birth and growth restriction. We describe factors that prevent optimal nephrogenesis during pregnancy and provide a framework for future explorations designed to maximize outcomes in this vulnerable population.

Vitamin D and assisted reproductive treatment outcome: a prospective cohort study

Background

Vitamin D deficiency has been associated with an increased risk of abnormal pregnancy implantation leading to obstetric complications such as pre-eclampsia and fetal growth restriction. However, the effect of vitamin D on reproductive treatment outcomes in couples undergoing assisted reproductive treatment is poorly understood. This study investigates the association between vitamin D and reproductive treatment outcomes in women undergoing assisted reproductive treatments?

Methods

A prospective cohort study conducted at a large tertiary teaching hospital, United Kingdom. Five hundred women undergoing assisted reproductive treatment were recruited between September 2013 and September 2015. All participants had their serum vitamin D measured and their reproductive treatment outcomes collated. Women were categorised in to three groups: vitamin D replete (> 75 nmol/L), insufficient (50-75 nmol/L) and deficient (< 50 nmol/L) according to Endocrine Society guidance. The primary outcome was live birth. Secondary outcomes included biochemical pregnancy, clinical pregnancy and pregnancy loss rates.

Results

Vitamin D deficiency was found in 53.2% (266/500) of participants and vitamin D insufficiency was found in 30.8% (154/500) of participants. Only 16% (80/500) of women were vitamin D replete. The live birth rates for vitamin D deficient, insufficient and replete women were 23.2% (57/246), 27.0% (38/141) and 37.7% (29/77) respectively (p = 0.04). The respective live birth rates for vitamin D deficient, insufficient and replete women were 24.3, 27.1, 34.4% after adjustment for key prognostic factors (p = 0.25).

Conclusions

Vitamin D deficiency and insufficiency are common in women undergoing assisted reproductive treatments. The crude live birth rate achieved in women undergoing assisted reproductive treatments are associated with serum vitamin D, although statistical significance is lost when adjusting for important prognostic variables. Vitamin D deficiency could be an important condition to treat in women considering fertility treatment. A research trial to investigate the benefits of vitamin D deficiency treatment would test this hypothesis.

Trial registration

Clinicaltrials.gov - NCT02187146.

Electronic supplementary material

The online version of this article (10.1186/s12978-019-0769-7) contains supplementary material, which is available to authorized users.

Comparative study on the pregnancy outcomes of in vitro fertilization-embryo transfer between patients with different ovarian responses (a STROBE-compliant article)

There have been few studies on large-sample data of cleavage-stage embryo and blastocyst transfers. We compared the pregnancy outcomes of patients with different ovarian responses after the transfer of different numbers of embryos in different developmental stages.Patients were divided into 3 groups including low response group, medium response group, and high response group according to different ovarian responses. Patients in each group were further divided into 4 subgroups including group A: transfer of 1 D3 embryo, group B: transfer of 2 D3 embryos; group C: transfer of 1 D5 blastocyst; and group D: transfer of 2 D5 blastocysts.In low ovarian responders, the implantation rate, clinical pregnancy rate and live birth rate were significantly lower in the group A than in the groups B and C. In medium ovarian responders, the implantation rate was significantly higher, but the multiple pregnancy rate was significantly lower in the group C than in the group B. The multiple pregnancy rate was significantly higher in the group D than in the group C. In high ovarian responders, the implantation rate was significantly lower, but the multiple pregnancy rate was significantly higher in the group B than in group C.Based on the above results, the single blastocyst transfer is preferable for the patients with different ovarian responses.

Ovarian response to stimulation and suboptimal endometrial development are associated with adverse perinatal outcomes in intracytoplasmic sperm injection cycles

Objective:

To study which factors affect perinatal outcomes in intracytoplasmic sperm injection (ICSI) cycles.

Methods:

Data was obtained from 402 live births born to 307 patients undergoing ICSI cycles in a private university-affiliated IVF center between Jan/2014 and Dec/2015. The influences of the cycles' characteristics on the number of gestational weeks to livebirth (GW), baby birth weight (BW), and baby birth length (BL) were evaluated by linear regression models, adjusted for maternal age and body mass index, number of transferred embryos, number of gestational sacs, and number of born infants. In a subsequent analysis, GW, BW and baby sex were utilized for cycle classification into the groups Appropriate for gestational age (AGA n=256) and Small for gestational age (SGA n=146), which were compared by general linear models adjusted for the same confounder variables.

Results:

The number of follicles (β=-0.069 p=0.018) and retrieved oocytes (β=-0.087 p=0.049) were negatively correlated with BL. The endometrial thickness was positively correlated with GW (β=0.198 p=0.003) and BW (β=28.351 p=0.044). When each baby was classified into AGA and SGA groups, it was observed that SGA babies were derived from cycles with higher estradiol levels at hCG day (SGA: 3897.01±550.35 vs. AGA: 2324.78±101.86 p=0.006) and higher number of retrieved oocytes (SGA: 16.70±1.78 vs. AGA: 12.92±0.42 p=0.042). The endometrial thickness was significantly lower in the SGA group (SGA: 10.2±0.23 vs. AGA: 11.68±0.17 vs. p=0.029).

Conclusion:

Higher ovarian response to stimulation and suboptimal endometrial development are associated with adverse perinatal outcomes in ICSI cycles.

[Comparison of birth weights of children born after slow frozen embryo replacement versus fresh embryo transfer]

OBJECTIVE

It is already known that children born after slow frozen embryo replacement have a significantly higher birth weight compared to children born after fresh embryo transfer. Similar data have been reported related to frozen embryo transfer using an open vitrification system. However, few data relative to birth weight using a complete embryo closed vitrification system has been reported. The purpose of this study was to know if frozen embryo in closed vitrification system is associated with a higher birth weight compared to fresh embryo replacement.

DESIGN

This was a monocentric retrospective cohort study, 371 children were issued from fresh embryo replacement and 127 from vitrified embryo transfer.

MATERIALS AND METHODS

All singletons born after fresh or vitrified embryo transfer between January 2011 and April 2015 were included. Births from the vitrified or fresh transfers of egg or sperm donation, and preimplantation genetic diagnosis were excluded. In addition, pregnancies with more than one gestational sac at the first ultrasound were excluded. An analysis of covariance (ANCOVA) was used for multivariate analysis.

RESULTS

Mean birth weight was 205g higher in the frozen embryo compared with fresh embryos transfer groups (3368g vs. 3163g respectively, P<0.001). This difference remained after multivariate analysis adjusted on confounding factors such as gestational age, maternal age, maternal body mass index (BMI), tobacco exposure, number of embryo transferred and birth order (P<0.001)..

CONCLUSIONS

Embryo frozen in closed vitrification system is associated with a higher birth weight compared to fresh embryo replacement. Our findings are consistent with the previous studies related to slow freezing and open vitrification systems data. The effects of controlled ovarian stimulation (COS), ex vivo culture conditions and cryopreservation systems on birth weight of children born should be further explored.

Frozen blastocyst transfer reduces incidence of ectopic pregnancy compared with fresh blastocyst transfer: a meta-analysis

BACKGROUND

Ectopic pregnancy (EP) is the main cause of maternal death during early pregnancy. Blastocyst transfer (BT) reduces EP rates compared with cleavage stage embryo transfer (ET), and frozen ET reduces EP rates compared with fresh ET. However, data comparing the EP rate of fresh BT and frozen BT are limited. The objective of this meta-analysis was to determine whether frozen BT decreases the EP rate compared with fresh BT.

MATERIALS AND METHODS

PUBMED, EMBASE, and Cochrane Library databases were searched for papers with no limitation on language and publication year. A systemic literature search identified 14 studies which met the inclusion criteria for further analysis. EP rate is our only outcome measure. All statistical analyses were carried out using RevMan software [version 5.3]. Random effects models were chosen to calculate the odds ratio (OR).

RESULTS

Fourteen retrospective studies (n = 251,762 cycles) were finally analyzed, including 154,214 and 97,548 cycles undergoing fresh and frozen BT, respectively. Compared with fresh BT, the frozen BT was associated with an decrease in EP rate [OR = 1.79; 95% confidence interval (CI) = 1.37-2.34, heterogeneity was 71%], the EP rate was 1.74% (2683/154,214 pregnancies) for fresh BT and 0.97% (949/97,548 pregnancies) for frozen BT. The number of embryos transferred in subgroup analysis found that the incidence of EP in frozen BT is lower than fresh BT (OR = 1.62; 95% CI = 1.38-1.91), the EP rate was 1.2% (206/16,610 pregnancies) for one fresh BT and 0.8% (153/19,569 pregnancies) for one frozen BT, also the EP rate was 1.9% (78/4043 pregnancies) for two fresh BT and 1.1% (19/1790 pregnancies) for two frozen BT.

CONCLUSIONS

Our meta-analysis found that frozen BT was associated with an decrease in EP rate compared with fresh BT in IVF/ICSI patients. We also found that a single frozen BT is the better choice as a method to reduce the incidence of EP.

High implantation and clinical pregnancy rates with single vitrified-warmed blastocyst transfer and optional aneuploidy testing for all patients

This study reports the results of a 2-year long IVF programme ('One by One') in which all patients (median age 40 years; range 27-45 years) were offered preimplantation genetic testing for aneuploidy (PGT-A) and had all blastocysts vitrified (freeze-only), followed later by single vitrified-warmed blastocyst transfer (vSET) in managed cycles. Between January 2016 and December 2017, a total of 155 patients started 222 treatment cycles and 99 (45%) cycles resulted in one or more vitrified blastocysts (untested or with normal copy number for all chromosomes) available for transfer. Seventeen patients (11%) aged ≤35 years opted out of PGT-A. Over this period, 85 vSETs in 74 patients resulted in an implantation rate of 80% (68/85) and a singleton clinical pregnancy rate of 66% (56/85). Cumulative live birth rates will not be known for 1-2 years. Nevertheless, these high success rates with vSET confirm larger studies using selected patients and are likely to deliver similar, if not higher, live birth rates per cycle started than rates typically reported in national registries with conventional IVF and transfer of one or more fresh and/or frozen embryos.

Superovulation alters the expression of endometrial genes critical to tissue remodeling and placentation

PURPOSE

Epidemiologic data suggest that in vitro fertilization (IVF) is associated with an increased risk of disorders of placentation including preeclampsia and fetal growth restriction. Specifically, studies have demonstrated that singleton pregnancies conceived following a fresh embryo transfer are at an increased risk of delivering an infant with low birth weight compared to those conceived following a frozen embryo transfer. The mechanism responsible for this association remains unclear. Procedures utilized in IVF have also been linked with epigenetic changes and gene expression changes in both fetal and maternal tissues. Data suggest that modifications in the maternal endometrium can lead to disordered trophoblast invasion and placentation. This study examines the effect of ovarian stimulation on endometrial gene expression and DNA methylation during the window of implantation to examine potential pathways playing a role in the adverse outcomes associated with IVF.

METHODS

Endometrial biopsies were obtained from oocyte donors and age-matched naturally cycling women 11 days following oocyte retrieval in donors or 12 days following luteinizing hormone (LH) surge in naturally cycling women. Global gene expression was analyzed via Affymetrix Human Gene 1.1 ST array and confirmed with RT-qPCR. DNA methylation was assessed with the Infinium DNA methylation 450 K BeadChip.

RESULTS

Analysis of endometrial gene expression from 23 women (11 oocyte donors and 12 controls) demonstrated 165 genes with a greater than twofold change in expression between donors and controls. While there were 785 genes with significant differential methylation in the endometrium of donors when compared with control subjects, none of the genes with altered expression showed significant changes in DNA methylation. Analysis of the differentially expressed genes showed enrichment for genes involved in endometrial remodeling including PLAT, HSPE2, MMP2, and TIMP1. Validation studies using RT-qPCR found a 73% reduction in expression of heparanase 2 (HSPE2) an enzyme associated with both angiogenesis and cell invasion, a greater than twofold increase in tissue-type plasminogen activator (PLAT), a serine protease participating in matrix degradation, and a 70% increase in MMP2, a gelatinase involved in collagen and fibronectin breakdown.

CONCLUSIONS

Superovulation alters expression of genes critical to endometrial remodeling during early implantation. Such changes could lead to altered trophoblast migration and impaired endovascular invasion. These findings offer a potential mechanism for the adverse perinatal outcomes observed following embryo transfer during fresh IVF cycles.

Effect of morphokinetics and morphological dynamics of cleavage stage on embryo developmental potential: A time-lapse study

OBJECTIVE

Using a non-invasive method to select the most competent embryo is essential in in vitro fertilization (IVF). Since the beginning of clinical application of time-lapse technology, several studies have proposed models using the time-lapse imaging system for predicting the IVF outcome. This study used both morphokinetic and morphological dynamic parameters to select embryos with the highest developmental potential.

MATERIALS AND METHODS

A total of 23 intracytoplasmic sperm injection treatment cycles with 138 fertilized oocytes were included in this study. All embryos were cultured to the blastocyst stage, and embryo development was recorded every 10 min by using a time-lapse imaging system. Morphokinetic parameters and eight major abnormal division behaviors were studied to determine their effects on blastocyst formation. The most influential variables were used in hierarchical classification for blastocyst formation prediction.

RESULTS

Several parameters were significantly related to the developmental potential. Embryos with the timing of pronuclear fading (tPNF) of >26.4 h post insemination (hpi), the timing of division to two cells (t2) of >29.1 hpi, and the timing of division to four cells (t4) of >41.3 hpi showed the lowest blastocyst formation rate. The abnormal division behaviors of fragmentation >50%, direct cleavage, reverse cleavage, and delayed division or developmental arrest were found to be detrimental to blastocyst formation. On the basis of these results, we propose a hierarchical model classification, in which embryos are classified into groups A-D according to their developmental potential. The blastocyst formation rates of groups A, B, C, and D were 80.0%, 77.8%, 53.7%, and 22.2% (p < 0.001). The good blastocyst rates of groups A, B, C, and D were 60.0%, 44.4%, 14.6%, and 11.1% (p = 0.007).

CONCLUSION

We propose a hierarchical classification system for blastocyst formation prediction, which provides information for embryo selection by using a time-lapse imaging system.

Endometrial thickness of less than 7.5 mm is associated with obstetric complications in fresh IVF cycles: a retrospective cohort study

RESEARCH QUESTION

Does endometrial thickness affect the occurrence of obstetric complications in fresh IVF cycles?

DESIGN

We conducted a retrospective cohort study that included all singleton deliveries resulting from fresh embryo transfers in a single centre between 2008 and 2014. Obstetric complications, i.e. preeclampsia, placental abruption, placenta previa, small for gestational age and preterm delivery, in singleton live births were compared among patients with an endometrial thickness of less than 7.5 mm and 7.5 mm or over on day of HCG triggering. We adjusted for confounders, including maternal age, body mass index, smoking, peak oestradiol, parity, chronic hypertension, pre-gestational diabetes, gestational diabetes, vanishing twin, inherited or acquired thrombophilia, and past pregnancy complications.

RESULTS

A total of 5546 fresh embryo transfer cycles were carried out during the study period, of which 864 singleton deliveries met inclusion criteria. After adjusting for potential confounders, an endometrial thickness of less than 7.5 mm was found to be associated with increased risk for adverse obstetric outcome (adjusted OR 1.53; 95% CI 1.03 to 2.42; P = 0.04) even after excluding patients with prior pregnancy complications (adjusted OR 2.2; 95% CI 1.05 to 4.59; P = 0.035).

CONCLUSIONS

Our results demonstrated that a thin endometrial lining was associated with obstetric complications that might be related to poor placentation. These findings should be validated in large prospective cohort studies.