Adverse Perinatal Outcomes by Gestational Surrogacy Status among In Vitro Fertilization Pregnancies

Abstract

This study aimed to examine adverse perinatal outcomes by gestational surrogacy status among in vitro fertilization (IVF) pregnancies.

This was a retrospective cohort study of IVF pregnant women (2008–2023) who received obstetrical care at Kaiser Permanente Southern California, a large integrated health care system. Unstructured clinical notes abstracted from electronic health records were analyzed using natural language processing and chart reviews to identify IVF and surrogate pregnancy status. This study analyzed 997 (6.3%) surrogate pregnancies among 15,822 IVF pregnancies. Births at <20 weeks of gestation were excluded. Adjusted risk ratios (aRRs) derived from robust Poisson regression models were used to describe the magnitude of associations between surrogacy status and adverse perinatal outcomes among IVF pregnancies.

Compared with non-surrogate pregnancies, women with gestational surrogacy were younger (<35 years, 46.7% vs. 66.6%), non-Hispanic White (29.8% vs. 39.8%), Hispanic (38.3% vs. 45.8%), privately insured (11.3% vs. 21.4%), and had multiple gestations (10.9% vs. 16.5%), respectively. They were less likely to smoke (0.8% vs. 0.4%) or drink alcohol (31.0% vs. 18.9%) during pregnancy. IVF gestational surrogacy was not associated with an increased risk of placenta previa (aRR: 1.20; 95% confidence interval [CI]: 0.98–1.47), placental abruption (aRR: 1.07; 95% CI: 0.63–1.81), or preterm birth (PTB; aRR: 1.03, 95% CI: 0.91–1.16) but was significantly associated with decreased risk of gestational diabetes (aRR: 0.82; 95% CI: 0.69–0.97), small for gestational age/intrauterine growth restriction (SGA/IUGR; aRR: 0.72; 95% CI: 0.61–0.84), preeclampsia/eclampsia (aRR: 0.70; 95% CI: 0.56–0.87), preterm premature rupture of membranes (PPROM; aRR: 0.56; 95% CI: 0.40–0.77), and chorioamnionitis (aRR: 0.42; 95% CI: 0.22–0.79).

Gestational surrogacy had lower odds of selected adverse perinatal outcomes that were not previously reported. This information may be helpful to patients considering gestational surrogacy as a reproductive option.