OBJECTIVE:To investigate the effect of supraphysiologic estradiol levels during ovarian stimulation on placental pathology among singleton livebirths conceived with in vitro fertilization (IVF) and fresh embryo transfer.
DESIGN:Retrospective cohort study.
SUBJECTS:Six hundred twenty six IVF-conceived singleton livebirths with associated placental pathology.
EXPOSURE:Two separate analyses were performed, using the ≥75th (2588.75pg/mL), and ≥ 90th (3120.5 pg/mL) estradiol percentile as cut-offs. Livebirths were categorized as below or above the estradiol cut-off at time of trigger, and placental abnormalities were compared between groups.
MAIN OUTCOME MEASURES:Placental pathology (abnormalities classified as: anatomic, vascular, infectious, and inflammatory).
RESULTS:Mean (SD) age and body mass index were 35.2 (4.0) years and 24.8 (4.5) kg/m2. Most patients were identified as White (n = 482, 77.0%), and the most common infertility diagnosis was male factor (n = 178, 28.9%). Using the 75th percentile as estradiol cut-off, unadjusted rates of placental abnormalities did not differ between the two groups (anatomic: 63.7% vs. 65.9%; vascular: 72.0% vs. 66.1%; infectious:33.1% vs. 32%; and inflammatory: 14.6% vs. 20%, for ≥75th vs. <75th percentile, respectively). Adjusted risk ratio (adjRR) (95% confidence interval [CI]) was calculated to account for possible confounding factors (maternal age, body mass index, infertility diagnosis, stimulation protocol, gestational age at delivery, and infant sex). AdjRR (95% CI) did not show significant differences between groups in risk of anatomic or infectious abnormalities. In patients with estradiol levels ≥75th percentile, the risk of vascular abnormalities was higher vs. patients in the <75th percentile group (adjRR [95% CI] 1.14 [1.00-1.29]). Among patients with estradiol levels ≥75th percentile, the risk of inflammatory abnormalities was lower vs. patients in the <75th percentile group (adjRR [95% CI] 0.62 [0.38-0.99]). When using the 90th percentile as the cut-off, no significant differences were noted between groups in rates of anatomic, vascular, infectious, or inflammatory abnormalities (65.1% vs. 65.4%; 76.2% vs. 66.6%; 34.9% vs. 32%; and 15.9% vs. 19%, for ≥90th vs. <90th percentile, respectively). AdjRR (95% CI) did not show significant differences between groups in risk of anatomic, infectious, or inflammatory abnormalities. However, risk for vascular abnormalities was higher among patients with estradiol ≥90th vs. <90th percentile (adjRR [95% CI]: 1.19 [1.01-1.39]).
CONCLUSION:Our study did not reveal clinically increased risks of placental abnormalities. Higher serum estradiol during IVF was associated with a marginally higher risk for vascular placental abnormalities.