Objective: To compare adverse pregnancy and neonatal outcomes in twin pregnancies conceived by in vitro fertilization (IVF) to those conceived spontaneously.
Methods: Retrospective analysis of the Centers for Disease Control and Prevention, Natality Live Birth database for the years 2016-2019. All twin live births were included and stratified into two groups: those from pregnancies conceived via IVF and those from pregnancies conceived spontaneously. The incidence of several adverse pregnancy and neonatal outcomes were compared between the two groups. Statistical analysis included multivariable logistic regression to adjust for the following potential confounders: maternal age, race/ethnicity, body mass index, education level, type of medical insurance, chronic hypertension, pregestational diabetes, and prior preterm birth. Data were presented as adjusted odds ratios (aOR) with 95% confidence intervals (CI).
Results: Twin live births from pregnancies conceived via IVF comprised 9.5% of the study cohort (39,356 of 415,560). Baseline characteristics varied significantly between IVF and spontaneously conceived twins. After adjusting for these variables, IVF in twins was associated with an increased risk of multiple adverse outcomes including gestational diabetes (aOR = 1.35, 95% CI = 1.30-1.39), hypertensive disorders of pregnancy (aOR = 1.70, 95% CI = 1.65-1.75), preterm birth prior to 28 weeks (aOR = 1.53, 95% CI = 1.43-1.63), maternal intensive care unit admission (aOR = 2.03, 95% CI = 1.79-2.31), maternal blood transfusion (aOR = 2.97, 95% CI = 2.75-3.20), unplanned hysterectomy (aOR = 3.37, 95% CI = 2.73-4.16), and prolonged ventilation in newborns (aOR = 1.76, 95% CI = 1.69-1.82), compared to spontaneously conceived twin pregnancies.
Conclusions: Based on this large United States population-based cohort, twin pregnancies conceived via IVF represent a subgroup of twins that have an increased risk for several adverse pregnancy and neonatal outcomes, compared to those conceived spontaneously. With increased contemporary utilization of IVF, obstetricians should consider these risks while caring for patients with twin pregnancies conceived via IVF.
Keywords: ART; IVF; Twins; fertility treatment; maternal morbidity; neonatal morbidity.