Incidence and risk factors for velamentous umbilical cord insertion in singleton pregnancies after assisted reproductive technology

Singleton term pregnancies resulting from frozen-thawed embryo transfer in hormone replacement cycles increase the risk of aberrant placentation, including velamentous umbilical cord insertion

PURPOSE

The number of frozen-thawed embryo transfers (FETs) has recently increased, and FET must be completed in the ovulatory (NC-FET) or programmed hormone replacement cycle (HRC-FET). However, the relationship between FET and abnormal placentation is unclear. This study aimed to determine whether the two distinct endometrial preparation protocols affect the incidence of several pathologic conditions caused by abnormal placentation, such as placenta with velamentous umbilical cord insertion (VCI), hypertensive disorders of pregnancy (HDP), and placenta accreta spectrum (PAS).

METHODS

For this retrospective cohort study, the medical records of 1,161 singleton term FET-conceived and -delivered cases were reviewed from January 2016 to July 2024. The study population was categorized into HRC-FET (Group A: n = 846) and NC-FET (Group B: n = 315) cases. After adjusting for confounding factors, the odds ratios (ORs) of the investigated targeted variables in Group A compared to Group B were calculated using multivariate logistic regression.

RESULTS

The incidence of VCI and PAS in Groups A and B was 7.0% and 2.5% for VCI and 5.1% and 1.0% for PAS, respectively, with a significant difference (P < 0.01). The adjusted ORs for VCI, PAS, and HDP in Group A compared to those in Group B were 3.07 (P < 0.01), 5.73 (P < 0.01), and 1.24 (P = 0.42), respectively.

CONCLUSION

Pregnancies achieved through HRC-FET have higher risks of developing abnormal placentation (i.e., VCI and PAS) than those achieved through NC-FET. These pregnancies are high risk and should be managed carefully for a healthy perinatal course.

Risk Factors of Velamentous Cord Insertion in Singleton Pregnancies-A Systematic Review and Meta-Analysis

Objective: This meta-analysis aims to quantitatively summarize current data on various potential risk factors of velamentous cord insertion (VCI). A better understanding of these risk factors could enhance prenatal identification both in settings with routine screening and in those where universal screening for cord insertion anomalies is not yet recommended. Methods: A systematic search was conducted in MEDLINE, Cochrane Library, and Scopus from their inception until 7 February 2024. Eligible studies included observational studies of singleton pregnancies with VCI, identified either prenatally or postnatally, compared with pregnancies with central or eccentric cord insertion. Analyses were performed using DerSimonian and Laird random-effects models, with outcomes reported as risk ratios (RR) or mean differences with 95% confidence intervals (CI). Results: In total, 14 cohort and 4 case-control studies were included, reporting on 952,163 singleton pregnancies. Based on the cohort studies, the overall prevalence of VCI among singleton pregnancies was calculated to be 1.54%. The risk of VCI was significantly higher among pregnancies conceived using assisted reproductive technology (RR, 2.32; 95% CI: 1.77-3.05), nulliparous women (RR, 1.21; 95% CI: 1.15-1.28), women who smoked (RR, 1.14; 95% CI: 1.08-1.19), and pregnancies diagnosed with placenta previa (RR, 3.60; 95% CI: 3.04-4.28). Conclusions: This meta-analysis identified assisted reproductive technology, nulliparity, smoking, and placenta previa as significant risk factors of VCI among singleton pregnancies. These findings could inform screening policies in settings where universal screening for cord insertion is not routinely performed, suggesting a targeted approach for women with these specific risk factors.

Trophectoderm biopsy is associated with adverse obstetric outcomes rather than neonatal outcomes

BACKGROUND

With the wide application of preimplantation genetic testing (PGT) with trophectoderm (TE) biopsy, the safety of PGT has always been a concern. Since TE subsequently forms the placenta, it is speculated that the removal of these cells was associated with adverse obstetrical or neonatal outcomes after single frozen-thawed blastocyst transfer (FBT). Previous studies report contradictory findings with respect to TE biopsy and obstetric and neonatal outcomes.

METHODS

We conducted a retrospective cohort study including 720 patients with singleton pregnancies from single FBT cycles who delivered at the same university-affiliated hospital between January 2019 and March 2022. The cohorts were divided into two groups: the PGT group (blastocysts with TE biopsy, n = 223) and the control group (blastocysts without biopsy, n = 497). The PGT group was matched with the control group by propensity score matching (PSM) analysis at a ratio of 1:2. The enrolled sample sizes in the two groups were 215 and 385, respectively.

RESULTS

Patient demographic characteristics were comparable between the groups after PSM except for the proportion of recurrent pregnancy loss, which was significantly higher in the PGT cohort (31.2 vs. 4.2%, P < 0.001). Patients in the PGT group had significantly higher rates of gestational hypertension (6.0 vs. 2.6%, adjusted odds ratio (aOR) 2.91, 95% confidence interval (CI) 1.18-7.18, P = 0.020) and abnormal umbilical cord (13.0 vs. 7.8%, aOR 1.94, 95% CI 1.08-3.48, P = 0.026). However, the occurrence of premature rupture of membranes (PROM) (12.1 vs. 19.7%, aOR 0.59, 95% CI 0.35-0.99, P = 0.047) was significantly lower in biopsied blastocysts than in unbiopsied embryos. There were no significant differences in regard to other obstetric and neonatal outcomes between the two groups.

CONCLUSIONS

Trophectoderm biopsy is a safe approach, as the neonatal outcomes from biopsied and unbiopsied embryos were comparable. Furthermore, PGT is associated with higher risks of gestational hypertension and abnormal umbilical cord but may have a protective effect on PROM.

Impact of velamentous cord insertion on perinatal outcomes: a systematic review and meta-analysis

OBJECTIVE

Velamentous cord insertion may be identified prenatally, but the clinical implications of this diagnosis remain controversial. This meta-analysis aimed to quantitatively summarize current data on the association of velamentous cord insertion and adverse perinatal outcomes.

DATA SOURCES

A systematic search was performed in MEDLINE, Scopus, and the Cochrane Library from inception until May 22, 2022 to identify eligible studies.

STUDY ELIGIBILITY CRITERIA

Observational studies including singleton pregnancies with velamentous cord insertion, either prenatally or postnatally identified, and comparing them with those with central/eccentric cord insertion were considered eligible.

METHODS

The quality of the studies was assessed with the Newcastle-Ottawa scale and the risk of bias with the Quality In Prognosis Studies (QUIPS) tool. The main outcome was small-for-gestational-age neonates. Heterogeneity of the studies was evaluated using a Q test and an I² index. Analyses were performed using a random-effects model, with outcome data reported as relative risk or mean difference with 95% confidence interval.

RESULTS

In total, 9 cohort and 2 case-control studies, of which 4 had prenatal and 7 had postnatal velamentous cord insertion diagnosis, were included. The overall prevalence of velamentous cord insertion was estimated to be 1.4% among singleton pregnancies. Compared with the central/eccentric cord insertion control group, pregnancies with velamentous cord insertion were at higher risk of several adverse perinatal outcomes, namely small-for-gestational-age neonates (relative risk, 1.93; 95% confidence interval, 1.54-2.41), preeclampsia (relative risk, 1.85; 95% confidence interval, 1.01-3.39), pregnancy-induced hypertension (relative risk, 1.58; 95% confidence interval, 1.46-1.70), stillbirth (relative risk, 4.12; 95% confidence interval, 1.92-8.87), placental abruption (relative risk, 2.94; 95% confidence interval, 1.72-5.03), preterm delivery (relative risk, 2.14; 95% confidence interval, 1.73-2.65), emergency cesarean delivery (relative risk, 2.03; 95% confidence interval, 1.22-3.38), 1-minute Apgar score <7 (relative risk, 1.53; 95% confidence interval, 1.14-2.05), 5-minute Apgar score <7 (relative risk, 1.97; 95% confidence interval, 1.43-2.71), and neonatal intensive care unit admission (relative risk, 1.63; 95% confidence interval, 1.32-2.02). In a subgroup analysis, prenatally diagnosed velamentous cord insertion was associated with small-for-gestational-age neonates (relative risk, 1.66; 95% confidence interval, 1.19-2.32), stillbirth (relative risk, 4.78; 95% confidence interval, 1.42-16.08), and preterm delivery (relative risk, 2.69; 95% confidence interval, 2.01-3.60). In a sensitivity analysis of studies excluding cases with vasa previa, velamentous cord insertion was associated with an increased risk of small-for-gestational-age neonates (relative risk, 2.69; 95% confidence interval, 1.73-4.17), pregnancy-induced hypertension (relative risk, 1.94; 95% confidence interval, 1.24-3.01), and stillbirth (relative risk, 9.42; 95% confidence interval, 3.19-27.76), but not preterm delivery (relative risk, 1.92; 95% confidence interval, 0.82-4.54).

CONCLUSION

Velamentous cord insertion is associated with several adverse perinatal outcomes, including stillbirth, and these associations persist when only prenatally diagnosed cases are considered and when vasa previa cases are excluded. According to these findings, the exact pathophysiology should be further investigated and an effective prenatal monitoring plan should be developed.

Effect Analysis of Degranulated Cell in Early Fertilization on FET Outcome and Offspring Safety with Data Mining

In vitro fertilization and embryo transfer is one type of assisted reproductive technology, although the technology is now more mature. Many factors, however, will have an impact on oocyte fertilization, embryo growth, pregnancy outcome, and child safety due to the journey from clinical to the laboratory. The influence of degranulated cells early in fertilization on frozen embryo transfer (FET) results is investigated in this study. This article analyzes 255 patients who underwent in vitro fertilization (IVF) and FET transplantation at the author's central unit from January 1, 2015, to June 30, 2021. Among them, IVF-assisted conception is the early degranulation of homologous oocyte fertilization. Correlation analysis is performed by observing the embryonic outcome of the early degranulation group and the overnight fertilization group and the clinical outcome after FET. Through data mining analysis, the results show that the polyfertilization rate and 0PN rate for the early degranulation group are significantly higher than the overnight fertilization group (9.87% vs. 8.24% and 3.14% vs. 1.69%). In terms of normal fertilization rate, there is no significant difference between D3 high-quality embryo rate and D5 high-quality blastocyst rate (64.07% vs. 65.15%, 27.5% vs. 26.5%, and 15.97% vs. 17.35%). There is no significant difference in the complete recovery rate of embryos after thawing (93.24% vs. 93.46%), and the implantation rate, clinical pregnancy rate, abortion rate, and live birth rate are not significantly different between the two groups after FET. The offspring outcomes of singletons do not differ significantly between the two groups; however, twins born early degranulate have much greater rates of ultralow birth weight and ultrapreterm children than twins born overnight fertilization (14.29% vs. 0). Therefore, it can be concluded that degranulation of cells early in fertilization is a desirable method to prevent fertilization disorders. However, under the premise of ensuring that no fertilization disorder occurs, it is not appropriate to degranulate all the oocytes of the patient at the early stage of fertilization.

Assisted Reproductive Technique and Abnormal Cord Insertion: A Systematic Review and Meta-Analysis

Abnormal cord insertion (ACI) is associated with adverse obstetric outcomes; however, the relationship between ACI and assisted reproductive technology (ART) has not been examined in a meta-analysis. This study examines the association between ACI and ART, and delivery outcomes of women with ACI. A systematic review was conducted, and 16 studies (1990–2021) met the inclusion criteria. In the unadjusted pooled analysis (n = 10), ART was correlated with a higher rate of velamentous cord insertion (VCI) (odds ratio (OR) 2.14, 95% confidence interval (CI) 1.64–2.79), marginal cord insertion (n = 6; OR 1.58, 95%CI 1.26–1.99), and vasa previa (n = 1; OR 10.96, 95%CI 2.94–40.89). Nevertheless, the VCI rate was similar among the different ART types (blastocyst versus cleavage-stage transfer and frozen versus fresh embryo transfer). Regarding the cesarean delivery (CD) rate, women with VCI were more likely to have elective (n = 3; OR 1.13, 95%CI 1.04–1.22) and emergent CD (n = 5; OR 1.93, 95%CI 1.82–2.03). In conclusion, ART may be correlated with an increased prevalence of ACI. However, most studies could not exclude confounding factors; thus, further studies are warranted to characterize ART as a risk factor for ACI. In women with ACI, elective and emergent CD rates are high.