Higher risk of preterm birth and low birth weight following oocyte donation: A systematic review and meta-analysis

Objectives: To perform a systematic review and meta-analysis of the known literature to assess whether the perinatal outcomes are different after oocyte donation (OD) compared to autologous oocyte (AO) in vitro fertilization (IVF) pregnancies.

Study design: A systematic literature search was done for studies published in English from 1980 to 2016. Studies comparing perinatal outcomes of pregnancies following fresh or frozen OD and AO IVF were included. Meta-analysis was performed using the Rev Man 5.3 software (Cochrane Collaboration) for the perinatal outcomes of PTB (<37 weeks), early PTB (<32 weeks), LBW (<2500g), very LBW (<1500g), and SGA (<10th centile). Six studies provided data on PTB, three studies on early PTB, five studies on LBW, four studies on very LBW and three studies on SGA after fresh embryo transfer. Two studies provided data on PTB, early PTB, LBW and very LBW after frozen embryo transfer.

Results: There is an increased risk of PTB following fresh embryo transfer in OD pregnancies than in AO IVF pregnancies (OR 1.45, 95% CI 1.20-1.77). If the PTB risk is assumed to be to 9% for pregnancies following AO IVF, then OD pregnancies will have a PTB risk between 10.8% and 15.9%. Similarly, the risk of LBW is higher after fresh embryo transfer in OD pregnancies than AO IVF pregnancies (OR 1.34, 95% CI 1.12-1.60). If the assumed LBW risk is 9% for AO IVF pregnancies, then OD pregnancies have a LBW risk between 10.1% and 14.4%. There is an increased risk of early PTB (OR 2.14, 95% CI 1.40-3.25) and very LBW (OR 1.51, 95% CI 1.17-1.95) in a fresh embryo transfer after OD as compared to AO IVF pregnancies.

Conclusions: There appears to be a higher risk of adverse perinatal outcomes following fresh OD compared to AO IVF pregnancies.