Pregnancy outcome after levonorgestrel-only emergency contraception failure: a prospective cohort study

Hum Reprod. 2009 Jul;24(7):1605-11. doi: 10.1093/humrep/dep076. Epub 2009 Mar 31.


Background: Levonorgestrel (LNG), as a dedicated emergency contraception (EC) product, has been available over-the-counter in China for 10 years. Until now, only a small number of deliveries after LNG-EC failure have been documented.

Methods: This study was a prospective comparative cohort study. A group of 332 pregnant women who had used LNG-EC during the conception cycle was recruited, and matched to a group of 332 pregnant women without the exposure to LNG. Congenital malformations, perinatal complications and delivery circumstances were investigated in this study.

Results: There were 31 pregnant women in the study group and 28 in the comparison group miscarried within 14 weeks of gestation. In the study and comparison groups, four malformations were found in each group. In the study group, both birthweight (3416 versus 3345 g, P = 0.040) and the sex ratio of birth (boys/girls, 1.14 versus 0.90, P = 0.153) were higher than in the comparison group. There were no statistically significant differences in the incidence of miscarriage or malformation or in the neonatal outcome between the two groups.

Conclusions: There was no association between the use of LNG-EC pills and the risk of major congenital malformations, pregnancy complications or any other adverse pregnancy outcomes in our study.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abortion, Spontaneous / etiology
  • Adult
  • Cohort Studies
  • Congenital Abnormalities / etiology
  • Congenital Abnormalities / prevention & control
  • Contraception, Postcoital / adverse effects*
  • Contraceptive Agents, Female / pharmacology
  • Contraceptives, Postcoital / adverse effects*
  • Female
  • Humans
  • Levonorgestrel / pharmacology
  • Male
  • Pregnancy
  • Pregnancy Outcome*
  • Prospective Studies


  • Contraceptive Agents, Female
  • Contraceptives, Postcoital
  • Levonorgestrel