Objective To assess maternal-fetal outcomes of continued pregnancies after oral levonorgestrel (LNG) or mifepristone (MFP) contraceptive failure using Network meta-analysis.

Methods Relevant studies on continued pregnancy after failed oral contraception with LNG or MFP were retrieved from domestic and international databases (PubMed, ScienceDirect, CNKI, and Wanfang), and data were analyzed using RevMan 5.4 and Stata 16.0.

Results A total of 6 cohort studies were included, comprising 2,526 pregnant women in this Meta-analysis (541 women in the LNG group, 200 in the MFP group, and 1,785 in the control group). The results showed that compared with the control group, MFP significantly increased the risk of early pregnancy miscarriage and neonatal asphyxia (P<0.05); No significant increase in these risks was observed with LNG. There was no significant statistical difference (P>0.05) between MFP and LNG in the risk of spontaneous abortion and neonatal asphyxia in early pregnancy. No significant increase in the risk of fetal malformations or birth defects was observed for both drugs (P>0.05).

Conclusion Neither LNG nor MFP increased the risk of fetal malformations or birth defects following contraceptive failure, but MFP did increase the risks of first-trimester spontaneous abortion and neonatal asphyxia. Drug exposure alone is not an indication for pregnancy termination, and enhanced antenatal care is recommended for women who continue their pregnancy.

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