Donor oocytes are associated with preterm birth when compared to fresh autologous in vitro fertilization cycles in singleton pregnancies

Objective To use a national registry to examine the role of oocyte donation on pregnancy outcomes in singleton pregnancies. Design Retrospective cohort. Setting Not applicable. Patient(s) Women undergoing autologous cycles and donor oocyte recipients in the United States from 2008–2010. Intervention(s) None. Main Outcome Measure(s) Preterm delivery, birth weight <2,500 g, small for gestational age birthweight, perinatal death. Result(s) The rates of preterm delivery and low birthweight for all members of this cohort were higher than the US national average. Pregnancies resulting from oocyte donation were significantly more likely to end before 34 weeks' and 37 weeks' gestation (adjusted odds ratio [OR] = 1.30, 95% confidence interval [CI] = 1.03–1.64 for 34 weeks' gestation, adjusted OR = 1.28, 95% CI = 1.12–1.46 for 37 weeks' gestation), and to result in infants weighing <2,500 g (adjusted OR = 1.21, 95% CI = 1.02–1.44). However, once gestational age at delivery is accounted for, these infants are actually at decreased risk of having a small for gestational age birthweight (adjusted OR = 0.72, 95% CI = 0.58–0.89) and of perinatal death (adjusted OR = 0.29, 95% CI = 0.09–0.94). Conclusion(s) Data from a national cohort indicate that donor oocyte recipients are more likely to deliver preterm when compared with autologous patients. The effect of donor oocyte donation on birthweight is likely a function of an increased rate of preterm delivery among this population.