Association of multifetal gestation with obstetric and neonatal outcomes in gestational carrier pregnancies

Multifetal gestation is more frequent among gestational carrier pregnancies than non-surrogacy IVF pregnancies. We aimed to evaluate the association between multifetal gestation and obstetric and neonatal morbidity among gestational carrier pregnancies.

Pooled cross-sectional study of birth certificate data from gestational carrier pregnancies in Utah from 2009 to 2018. Our primary outcome was a composite of severe obstetric morbidity; secondary outcomes included cesarean delivery (CD), hypertensive disorders of pregnancy, preterm birth (PTB), and a neonatal morbidity composite. Logistic regression was utilized to compare odds of these outcomes between gestational carrier pregnancies with and without multifetal gestation.

A total of 361 gestational carrier pregnancies resulted in the delivery of 435 neonates during the study period. Of these, 284 were singleton pregnancies, and 77 were multifetal, a multifetal gestation rate of 21.3%. Baseline demographic characteristics did not differ between singleton and multifetal gestations. Multifetal gestation was not associated with higher rates of severe obstetric morbidity (odds ratio [OR] 1.87, 95% confidence interval [CI] 0.34-10.39). Multifetal gestation was associated with increased odds of neonatal morbidity (OR 9.49, 95% CI 5.35-15.83); PTB < 37, 34, and 32 weeks (OR 21.88, 95% CI 11.64-41.12; OR 11.67, 95% CI 5.25-25.91; OR 8.79, 95% CI 3.41-22.68); and CD (OR 4.82, 95% CI 2.81-8.27).

Severe obstetric morbidity did not differ between singleton and multifetal gestations among gestational carrier pregnancies. However, multifetal gestation was associated with increased odds of neonatal morbidity, CD, and PTB. This information may be useful when counseling prospective gestational carriers and intended parents.