P-748 Cesarean scar defect does not predict embryo transfer outcomes: A retrospective cohort study

Study question

Is the presence of a cesarean scar defect associated with live birth outcomes at the time of embryo transfer?

Summary answer

The presence of a cesarean scar defect is not predictive of live birth rates at the time of embryo transfer.

What is known already

Cesarean delivery is associated with subsequent impaired fertility, with lower pregnancy and live birth rates and longer inter-pregnancy intervals, compared to patients who delivered vaginally. Studies exploring pregnancy rates after IVF and embryo transfer also suggest lower pregnancy rates among patients with prior cesarean delivery. A postulated mechanism by which a prior cesarean delivery may impact fertility is the cesarean scar defect, and prior studies have shown a possible association between a scar defect and suboptimal outcomes.

Study design, size, duration

We retrospectively identified a patient cohort based out of the Ottawa Fertility Centre in Ottawa, Ontario, Canada, between 2013 and 2019.

Participants/materials, setting, methods

This retrospective cohort study included 317 patients with a prior cesarean delivery. Embryo transfer outcomes compared between the two groups based on the finding of a cesarean scar defect. The primary outcome was live birth rate, secondary outcomes of positive hCG, clinical intrauterine pregnancy, miscarriage rate. We fit a multivariate log binomial regression model with a priori variables for the primary and secondary outcomes, adjusting for patient and cycle characteristics.

Main results and the role of chance

There was no statistically significant difference in live birth rate among patients with a cesarean scar defect compared to those without, 28.0% vs 29.5% respectively (adjusted RR 0.95, 95% CI 0.68-1.35). There was no statistically significant difference in any of the secondary outcomes. Area of the defect and subgroup analysis of fresh vs frozen embryo transfer did not demonstrate any difference. Secondary analysis of patients with retroverted uterus had significantly lower live birth rates compared to those with an anteverted uterus, 17.7% vs 32.4%, respectively (adjusted RR 0.56, 95% CI 0.34-0.91).

Limitations, reasons for caution

Although a multivariate log binomial model was used to adjust for clinically relevant confounders, there remains the possibility for residual confounding given the observational nature of our study.

Wider implications of the findings

The results of our study suggest that, after adjusting for patient and cycle characteristics, the presence of a cesarean scar defect may not impact live birth outcomes and secondary analysis of the impact of uterine retroversion requires more study.

Trial registration number

Not applicable

Association between Bell's palsy in pregnancy and pre-eclampsia

BACKGROUND

Previous published case series have suggested an association between the onset of Bell's palsy in pregnancy and the risk of pre-eclampsia and gestational hypertension.

AIM

To evaluate the period of onset of Bell's palsy in pregnancy and the associated risk of adverse maternal and perinatal events, including the hypertensive disorders of pregnancy.

STUDY DESIGN

Case series study of consecutive female patients.

METHODS

Women presenting with Bell's palsy during pregnancy or the puerperium were identified by a hospital record review at five Canadian centres over 11 years. Information was abstracted about each woman's medical and obstetrical history, period of onset of Bell's palsy, and associated maternal complications, including pre-eclampsia and gestational hypertension as well as preterm delivery and low infant birth weight (<2500 g). These rates were compared to those previously described for the province of Ontario or for Canada.

RESULTS

Forty-one patients were identified. Mean onset of Bell's palsy was 35.4 weeks gestation (SD 3.9). Nine (22.0%, 95%CI 10.8-35.7) were also diagnosed with pre-eclampsia and three (7.3%, 95%CI 1.4-17.1) with gestational hypertension, together (29.3%, 95%CI 16.5-43.9) representing nearly a five-fold increase over the expected provincial/national average. There were three twin births. The observed rates of Caesarean (43.6%) and preterm (25.6%) delivery, as well as low infant birth weight (22.7%), were also higher than expected, although the rate of congenital anomalies (4.5%) was not.

CONCLUSIONS

The onset of Bell's palsy during pregnancy or the puerperium is probably associated with the development of the hypertensive disorders of pregnancy. Pregnant women who develop Bell's palsy should be closely monitored for hypertension or pre-eclampsia, and managed accordingly.

Common C677T polymorphism of the methylenetetrahydrofolate reductase gene and the risk of venous thromboembolism: meta-analysis of 31 studies

BACKGROUND

Although the common 677 C --> T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene is implicated in the development of hyperhomocysteinemia, its correlation with venous thromboembolism (VTE) remains controversial. We conducted a meta-analysis of previously published studies to clarify the role of the MTHFR 677 TT homozygous genotype in association with VTE.

METHODS AND RESULTS

Relevant articles were retrieved from a systematic search of Medline and Embase from 1990 to September 2001. Two independent reviewers abstracted data on the characteristics of the cases with VTE and controls without VTE. We pooled the rates of the MTHFR 677 TT genotype in both groups, as well as the odds ratio (OR) of VTE in the presence of the TT versus CC or CT genotypes. In 31 published studies, comprising 4,901 cases and 7,886 controls, the pooled prevalence of the MTHFR 677 TT genotype was slightly higher among cases (14.3%) than controls (11.7%), conferring a borderline degree of heightened risk [pooled OR (OR(p)) 1.2, 95% confidence interval (CI) 1.1-1.4]. After excluding cases with a classic thrombophilia factor, the pooled prevalence rates of the MTHFR 677 TT genotype among 11 studies were 17.7 and 12.3%, respectively (OR(p) 1.5, 95% CI 1.2-1.9).

CONCLUSIONS

The classic MTHFR C677T gene polymorphism is weakly associated with an increased risk of VTE. It is unlikely that the purported relationship between hyperhomocysteinemia and VTE is mediated by this gene defect to a substantial degree, although other undiscovered gene polymorphisms may explain this association. Until more compelling data are made available, we do not recommend that testing for the MTHFR C677T polymorphism be routinely included as part of any clinical thrombophilia assessment.