Comparison of outcomes of monochorionic twin pregnancies conceived by assisted reproductive technology vs. spontaneous conceptions: A systematic review and meta-analysis

Is There a Cumulative Effect for Congenital Heart Defects in Monochorionic Twins after Assisted Reproduction? - A Retrospective Analysis at a Tertiary Referral Center

Introduction

The aim of our study was to compare maternal, chorionicity and neonatal complications in monochorionic (MC) twins between spontaneously conceived (SC) and assisted reproductive technologies (ART) pregnancies.

Material and Methods

This was a retrospective cohort study between January 2010 to December 2019 at a tertiary referral University center. All consecutive pregnancies with MC twins that delivered at our University hospital were included. Maternal, chorionicity and neonatal complications were recorded and compared between SC and ART pregnancies.

Results

393 MC pregnancies were included for final analysis, including 353 (89.8%) SC and 40 (10.2%) pregnancies conceived after ART. Hypothyroidism was the only maternal condition seen significantly more often in ART pregnancies (35.0% vs 12.5%, p = 0.001). There were no significant differences in chorionicity complications, such as twin-twin transfusion syndrome, selective fetal growth restriction and twin anemia-polycythemia sequence (40.0% in ART pregnancies vs 31.6% in SC pregnancies, p = 0.291). At least one congenital anomaly in one twin was seen significantly more often in ART pregnancies (18.8% vs 8.1%, p = 0.004), especially congenital heart defects (16.3% vs 6.2%, p = 0.005). There were no other significant differences in neonatal outcomes between both groups, however, there were non-significant trends in gestational age at delivery (34 weeks in ART pregnancies vs 35 weeks, p = 0.078) and birthweight (1951 g ± 747 in ART pregnancies vs 2143 g ± 579, p = 0.066).

Conclusion

This is the largest cohort study to date comparing maternal, chorionicity and neonatal complications between MC twin pregnancies after ART and after SC. Hypothyroidism was the only maternal condition occurring more frequently in pregnancies conceived after ART. There were no significant differences in chorionicity complications, in contrast to previously reported studies. While MC twins and ART pregnancies per se are known to be at risk for congenital heart defects, there seems to be a cumulative effect in MC pregnancies conceived after ART.

Maternal and neonatal outcomes of dichorionic twin pregnancies achieved with assisted reproductive technology: meta-analysis of contemporary data

PURPOSE

Assisted reproductive technology (ART) is commonly used to achieve pregnancy and often results in dichorionic diamniotic (DCDA) twin pregnancies. However, the potential risks of ART on maternal and neonatal outcomes in these pregnancies are not well understood. The objective is to compare the maternal and neonatal outcomes in DCDA twin pregnancies between those achieved through ART and those spontaneously conceived (SC).

METHODS

We carried out a systematic comprehensive search of electronic databases; namely, PubMed, Embase, Scopus, and the Cochrane Library, from inception to March 2023 with a study period of recruitment between 2003 and 2023. We included all studies comparing the maternal and neonatal outcomes of DCDA twin pregnancies between those achieved by ART and those SC.

RESULTS

We analyzed data from 18 cohort studies involving 10,485 women with DCDA twin pregnancies. The meta-analysis showed that ART-conceived pregnancies had a significantly higher risk of preeclampsia or gestational hypertension (GH), gestational diabetes mellitus (GDM), placenta previa (PP), placental abruption (PA), postpartum hemorrhage (PPH), and elective and emergency cesarean sections than SC twin pregnancies. The absolute risks of these complications remained relatively low. We also found a slightly higher risk of respiratory distress syndrome (RDS) and congenital malformations in ART-conceived infants compared to the risks in SC infants. Finally, the risk of neonatal intensive care unit (NICU) admissions was significantly higher in ART-conceived infants than in SC infants, but with high heterogeneity.

CONCLUSION

We found associations between DCDA twin pregnancies conceived through ART and increased frequencies of adverse maternal outcomes. However, the absolute risks of these complications remained low, and the benefits of ART for achieving successful pregnancies may well outweigh the potential risks. Additionally, ART-conceived DCDA twin pregnancies may pose higher risks of RDS, congenital malformations and NICU, admissions than SC DCDA twin pregnancies.

Thick endometrium is associated with hypertensive disorders of pregnancy in programmed frozen-thawed embryo transfers: a retrospective analysis of 2,275 singleton deliveries

OBJECTIVE

To investigate whether endometrial thickness (EMT) acts as a contributing factor to adverse perinatal outcomes in programmed frozen-thawed embryo transfer (FET) cycles.

DESIGN

Retrospective cohort study.

SETTING

University-based reproductive medical center.

SUBJECT

The study included singleton live births resulting from programmed FET cycles that took place between January 2017 and April 2022 (N = 2,275 cycles).

EXPOSURE

The EMT measurement conducted on the day of progesterone initiation was utilized. Programmed FET cycles with EMT <7 mm were excluded from consideration. All included subjects were divided into 4 groups on the basis of the 10th, 50th, and 90th percentiles of EMT: group Ⅰ (EMT ≤8 mm, n = 193), group Ⅱ (EMT = 8.1-10 mm, n = 1,261), group Ⅲ (EMT = 10.1-12 mm, n = 615), and group Ⅳ (EMT >12 mm, n = 206). After adjusting for patient demographics and FET parameters, logistic regression analysis and restricted cubic spline were used to investigate the relationship between EMT and perinatal outcomes. The group Ⅱ (EMT = 8.1-10 mm) served as a reference.

MAIN OUTCOME MEASURE(S)

The primary outcome measure was the hypertensive disorders of pregnancy (HDP). Secondary outcomes included gestational diabetes mellitus, cesarean delivery, placenta previa, premature rupture of membrane, birthweight, preterm birth, low birthweight, macrosomia, small for gestational age, large for gestational age and neonatal morbidity.

RESULTS(S)

The incidence of HDP was substantially elevated in group Ⅳ when compared with the other groups (5.7% vs. 4.1% vs. 5.7% vs. 9.7% for groups Ⅰ-Ⅳ, respectively). In addition, group I displayed a higher incidence of cesarean deliveries, whereas both group I and group IV exhibited an elevated prevalence of placenta previa. After adjusting for confounding factors, patients in group IV exhibited a significantly increased risk of HDP (adjusted odds ratio [OR] = 2.03, 95% confidence interval [CI] 1.13-3.67) as compared with patients in the reference group. The restricted cubic spline model revealed a nonlinear association between EMT and the odds of HDP on continuous scales. In comparison to women with an EMT of 9.5 mm, there was no significant change in the risk of HDP in women with EMT between 7 and 11 mm, as indicated by adjusted ORs of 1.37 (95% CI 0.41-4.52), 1.34 (95% CI 0.73-2.47), 1.13 (95% CI 0.79-1.62), 1.04 (95% CI 0.87-1.25), and 1.46 (95% CI 0.81-2.65), respectively. However, the risk of HDP was significantly higher in women with EMT ranging from 12 to 15 mm, with adjusted ORs of 1.86 (95% CI 1.03-3.35), 2.33 (95% CI 1.32-4.12), 2.92 (95% CI 1.52-5.60), and 3.62 (95% CI 1.63-8.04), respectively.

CONCLUSION(S)

This study demonstrated a noteworthy association between EMT and adverse perinatal outcomes during the programmed FET cycles. Specifically, a thick endometrium (EMT >12 mm) was independently associated with an increased risk of developing HDP, whereas the optimal EMT for reducing the risk of HDP was at around 9-10 mm.

Perinatal Outcomes of Monochorionic Twin Pregnancies Conceived Naturally Versus through Assisted Reproductive Techniques

Objective: It has been reported that monochorionic twin pregnancies conceived through assisted reproductive techniques (ART) display a higher risk of second-trimester miscarriage, cesarean delivery, and neonatal death than those conceived naturally. The aim of this study was to compare the perinatal outcomes of monochorionic diamniotic (MCDA) twin pregnancies conceived naturally and through ART in a tertiary hospital. Methods: This was a retrospective cohort study of all MCDA twin pregnancies that received obstetric care and delivered at La Fe University and Polytechnic Hospital between 2015 and 2021. MCDA pregnancies that were referred to the tertiary hospital for specialized management, follow-up, and delivery were also included. The study was approved by The Health Research Institute Hospital La Fe (IIS La Fe). Results: Among the 184 MCDA pregnancies, 149 (81%) had a natural conception, and 35 (19%) were conceived through ART. Patients with an MCDA pregnancy who conceived through ART had a significantly older maternal age (38.0 [35.5-42.5] vs. 32.0 [29.0-36.0], p < 0.001) and an elevated rate of nulliparity (80.0% vs. 50.3%, p = 0.001). Regarding pregnancy complications, MCDA pregnancies through ART were associated with a significantly higher incidence of gestational diabetes (22.9% vs. 2.7%, p < 0.001), hypertensive disorders during pregnancy (22.9% vs. 9.4%, p = 0.04), and other pregnancy complications such as threatened labor or preterm prelabor rupture of membranes (14.3% vs. 36.2%, p = 0.015), than naturally conceived MCDA pregnancies. No differences were found in the incidence of twin-to-twin transfusion syndrome (20% vs. 33.6%, p = 0.155). MCDA pregnancies through natural conception had a greater rate of vaginal delivery than MCDA through ART (16.8% vs. 2.9%, p = 0.032). When adjusted for confounding factors, MCDA pregnancies through ART were only more likely to develop gestational diabetes than those naturally conceived (aOR 7.86, 95% CI 1.55-39.87). No differences were found regarding neonatal outcomes between groups. Conclusions: Compared with naturally conceived MCDA twin pregnancies, those conceived through ART displayed a significantly higher risk of developing gestational diabetes. No differences regarding other pregnancy complications, mode of delivery, or neonatal outcomes were found between groups.