A systematic review and meta-analysis suggests that in pregnancies conceived via assisted reproduction, risk of adverse perinatal outcomes may be higher with donated than with autologous oocytes. The findings, by researchers from the UK and India, were published in the European Journal of Obstetrics & Gynecology and Reproductive Biology.
For the research, the authors performed a systematic literature search for studies in English published between 1980 and 2016 that compared perinatal outcomes of pregnancies following in vitro fertilization (IVF) with fresh or frozen donated or autologous oocytes. Using Cochrane Collaboration software, meta-analysis was done for preterm birth (PTB) (< 37 weeks), early PTB (< 32 weeks), low birthweight (LBW) (< 2500 g), very LBW (< 1500 g) and small-for-gestational-age (SGA) (< 10th percentile. There were 6 studies on PTB, 3 on early PTB, 5 on LBW, 4 on very LBW, and 3 studies on SGA after fresh embryo transfer. Data on frozen embryo transfer were from 2 studies on PTB, early PTB, LBW, and very LBW.
The analysis showed a higher risk of PTB after fresh embryo transfer in pregnancies using donated oocytes than in pregnancies created through IVF with autologous oocytes (OR 1.45, 95% CI 1.20-1.77). Assuming that PTB risk is 9% for pregnancies after IVF with autologous oocytes, that translates to a PTB risk between 10.8% and 15.9% for pregnancies using oocyte donation. A similar increase in risk with donated oocytes was seen for LBW (OR 1.34, 95% CI 1.12-1.60). If the assumed risk of LBW is 9% for IVF with autologous oocytes, then donated oocytes are associated with an LBW risk of 10.1% to 14.4%. The same relationship was seen for early PTB (OR 2.14, 95% CI 1.40-3.25) and very LBW (OR 1.51, 95% CI 1.17-1.95).