Mid-pregnancy circulating placental growth factor (PlGF) and obstetrical outcomes following nonovulatory and ovulatory frozen embryo transfer cycles.

Purpose: We compared serum placental growth factor (PlGF) concentration in pregnancies from ovulatory vs. non-ovulatory FET cycles and evaluated associations with obstetrical and neonatal outcomes.

Methods: We conducted a secondary analysis of a prospective single-center screening study at a large urban center in Canada where PlGF was performed between April 2020 and December 2022. Baseline characteristics were compared between FET ovulatory cycle and non-ovulatory cycle groups. We compared PlGF concentration in unadjusted and adjusted analyses using multivariable linear regression. Secondary outcomes were compared using chi square and Fisher exact tests for categorical variables and Wilcoxon rank sum tests for continuous variables.

Results: We identified 340 patients, 246 (72.4%) in the non-ovulatory group and 94 (27.7%) in the ovulatory group. The median gestational age (IQR) at PlGF testing was 27.9 weeks (26.6-28.3) in the non-ovulatory group and 27.7 weeks (25.6-28.1) in the ovulatory group (p = 0.07). Univariable analysis comparing the difference in PlGF showed no association between groups [β - 51.7 (95% CI - 43.7-384.1), p = 0.44]. After adjusting for maternal age, race, parity, pre-pregnancy BMI, gestational diabetes, gestational age of PlGF test, donor egg cycle, and maternal and previous obstetrical comorbidities, the difference in PlGF concentration remained non-significant. Obstetrical and neonatal outcomes were similar between groups.

Conclusion: Our findings indicate no significant difference in either mid-pregnancy circulating PlGF concentration or obstetrical outcomes comparing successful FETs in ovulatory vs. non-ovulatory cycles. Larger-scale prospective research should be prioritized to further elucidate the role of PlGF in predicting the potential risk of adverse pregnancy outcomes.