title: Association between levonorgestrel emergency contraception and the risk of ectopic pregnancy: a multicenter case-control study.
abstract: Cases of ectopic pregnancy (EP) following levonorgestrel emergency contraception (LNG-EC) failure have been reported continuously, but whether there is an association between EP risk and LNG-EC is unclear. We concluded a case-control study to explore this association by recruiting 2,411 EP patients as case group, and 2,416 women with intrauterine pregnancy and 2,419 non-pregnant women as control groups. Odds ratios (ORs) and their 95% confidential intervals (CIs) were calculated and adjusted for potential confounding factors. Previous use of LNG-EC was not correlated with the EP. Compared to women who did not use contraceptives, current use of LNG-EC reduced the risk for intrauterine pregnancy (Adjusted OR [AOR] = 0.20, 95%CI: 0.14-0.27), but did not increase the risk for EP (AOR2 = 1.04, 95%CI: 0.76-1.42). Furthermore, compared to women who did not have further act of intercourse, women with unprotected further act of intercourse were at a higher risk of EP (AOR1 = 2.35, 95%CI: 1.17-4.71), and women with repeated use of LNG-EC for further intercourse during the same cycle was also associated with a higher risk for EP (AOR1 = 3.08, 95%CI: 1.09-8.71; AOR2 = 2.49, 95%CI: 1.00-6.19). A better understanding of the risk of EP following LNG-EC failure can optimize LNG-EC use and thus reduce the risk of EP.
authors: Department of Obstetrics and Gynecology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200030, China.
authors: Jian
authors: J
authors: Zhang
authors: Department of Obstetrics and Gynecology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200030, China.
authors: Cheng
authors: C
authors: Li
authors: Department of Obstetrics and Gynecology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200030, China.
authors: Wei-Hong
authors: WH
authors: Zhao
authors: Department of Obstetrics and Gynecology, Shanghai First People's Hospital, Shanghai Jiaotong University, Shanghai 200080, China.
authors: Xiaowei
authors: X
authors: Xi
authors: Department of Obstetrics and Gynecology, Songjiang Central Hospital, Shanghai 201600, China.
authors: Shu-Jun
authors: SJ
authors: Cao
authors: Department of Obstetrics and Gynecology, Songjiang Maternity and Child Health Hospital, Shanghai 201620, China.
authors: Hua
authors: H
authors: Ping
authors: Department of Obstetrics and Gynecology, Minhang Central Hospital, Shanghai 201100, China.
authors: Guo-Juan
authors: GJ
authors: Qin
authors: Shanghai Institute of Planned Parenthood Research, Shanghai 200030, China.
authors: Linan
authors: L
authors: Cheng
authors: Department of Reproductive Medicine, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200030, China.
authors: He-Feng
authors: HF
authors: Huang
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D044363:Contraception, Postcoital / Q000009:adverse effects*; D003271:Contraceptive Agents, Female / Q000009:adverse effects*; D005260:Female; D006801:Humans; D016912:Levonorgestrel / Q000009:adverse effects*; D008875:Middle Aged; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000453:epidemiology* / Q000209:etiology*; D012306:Risk; D055815:Young Adult
chemical_list: D003271:Contraceptive Agents, Female; D016912:Levonorgestrel