Ischaemic placental disease risk lower with frozen vs fresh cycles
A frozen embryo transfer may be a safer approach compared with fresh transfer, as the former is associated with a lower risk of ischaemic placental disease (IPD), according to a study.
Researchers performed a secondary analysis of a retrospective cohort study involving 2,132 pregnancies (mean maternal age at conception, 36 years) resulting from autologous in vitro fertilization (IVF) cycles.
Of the pregnancies, 271 (12.7 percent) were from frozen embryo transfer and 1,861 (87.3 percent) from fresh embryo transfer. Frozen embryo transfer cycles were less likely to result in multifoetal gestations and lead to a preterm delivery.
The primary outcome was a composite outcome of IPD or intrauterine foetal demise (IUFD) due to placental insufficiency. IPD included pre-eclampsia, placental abruption and small for gestational age (SGA).
Results for the primary outcome were more favourable for frozen cycles than for fresh cycles (risk ratio [RR], 0.75; 95 percent CI, 0.59–0.97). In addition, frozen cycles were associated with a lower risk of SGA (RR, 0.58; 0.41–0.81).
On the other hand, there were no significant differences observed in the risks of pre-eclampsia (RR, 1.3; 0.84–1.9) and abruption (RR, 1.2; 0.56–2.4).
Researchers noted that the association between frozen embryo transfer cycles and a lower risk of IPD or IUFD from placental insufficiency was largely driven by a lower risk of SGA. Additional investigation should be conducted to elucidate the effect of IVF cycle parameters on pregnancy outcomes, especially in light of practice changes and improvements in the quality of frozen embryo transfer cycles.Ultimately, the present data may aid in determining guidelines for embryo transfer in high-risk groups, they added.