title: Contraceptive Use and the Risk of Ectopic Pregnancy: A Multi-Center Case-Control Study.
abstract: To evaluate the association between the risk of ectopic pregnancy (EP) and the use of common contraceptives during the previous and current conception/menstrual cycle.
  
  
  
  A multi-center case-control study was conducted in Shanghai. Women diagnosed with EP were recruited as the case group (n = 2,411). Women with intrauterine pregnancy (IUP) (n = 2,416) and non-pregnant women (n = 2,419) were matched as controls at a ratio of 1∶1. Information regarding the previous and current use of contraceptives was collected. Multivariate logistic regression analyses were performed to calculate odds ratios (ORs) and the corresponding 95% confidential intervals (CIs).
  
  
  
  Previous use of intrauterine devices (IUDs) was associated with a slight risk of ectopic pregnancy (AOR1 = 1.87 [95% CI: 1.48-2.37]; AOR2 = 1.84 [1.49-2.27]), and the risk increased with the duration of previous use (P1 for trend <10-4, P2 for trend <10-4). The current use of most contraceptives reduced the risk of both unwanted IUP (condom: AOR = 0.04 [0.03-0.05]; withdrawal method: AOR = 0.10 [0.07-0.13]; calendar rhythm method: AOR = 0.54 [0.40-0.73]; oral contraceptive pills [OCPs]: AOR = 0.03 [0.02-0.08]; levonorgestrel emergency contraception [LNG-EC]: AOR = 0.22 [0.16-0.30]; IUDs: AOR = 0.01 [0.005-0.012]; tubal sterilization: AOR = 0.01 [0.001-0.022]) and unwanted EP (condom: AOR1 = 0.05 [0.04-0.06]; withdrawal method: AOR1 = 0.13 [0.09-0.19]; calendar rhythm method: AOR1 = 0.66 [0.48-0.91]; OCPs: AOR1 = 0.14 [0.07-0.26]; IUDs: AOR1 = 0.17 [0.13-0.22]; tubal sterilization: AOR1 = 0.04 [0.02-0.08]). However, when contraception failed and pregnancy occurred, current use of OCPs (AOR2 = 4.06 [1.64-10.07]), LNG-EC (AOR2 = 4.87 [3.88-6.10]), IUDs (AOR2 = 21.08 [13.44-33.07]), and tubal sterilization (AOR2 = 7.68 [1.69-34.80]) increased the risk of EP compared with the non-use of contraceptives.
  
  
  
  Current use of most contraceptives reduce the risk of both IUP and EP. However, if the contraceptive method fails, the proportions of EP may be higher than those of non-users. In the case of contraceptive failure in the current cycle, EP cases should be differentiated according to current use of OCPs, LNG-EC, IUDs, and tubal sterilization. In addition, attention should be paid to women with previous long-term use of IUDs.
authors.affiliation: Department of Obstetrics and Gynecology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200030, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Obstetrics and Gynecology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200030, China.
authors.forename: Wei-Hong
authors.initials: WH
authors.lastname: Zhao
authors.affiliation: Department of Obstetrics, Gynecology and Women's Health, School of Medicine, University of Missouri-Columbia, Columbia, MO, 65212, United States of America.
authors.forename: Chun-Xia
authors.initials: CX
authors.lastname: Meng
authors.affiliation: Department of Obstetrics and Gynecology, Songjiang Maternity and Child Health Hospital, Shanghai, 201620, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Ping
authors.affiliation: Department of Obstetrics and Gynecology, Minhang Central Hospital, Shanghai, 201100, China.
authors.forename: Guo-Juan
authors.initials: GJ
authors.lastname: Qin
authors.affiliation: Department of Obstetrics and Gynecology, Songjiang Central Hospital, Shanghai, 201600, China.
authors.forename: Shu-Jun
authors.initials: SJ
authors.lastname: Cao
authors.affiliation: Department of Obstetrics and Gynecology, Shanghai First People's Hospital, Shanghai Jiaotong University, Shanghai, 200080, China.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Xi
authors.affiliation: Department of Obstetrics and Gynecology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200030, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Department of Obstetrics and Gynecology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200030, China.
authors.forename: Xiao-Cui
authors.initials: XC
authors.lastname: Li
authors.affiliation: Department of Obstetrics and Gynecology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200030, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D003267:Contraception / Q000009:adverse effects; D003271:Contraceptive Agents, Female / Q000009:adverse effects*; D003274:Contraceptive Devices, Female / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007434:Intrauterine Devices / Q000009:adverse effects; D008875:Middle Aged; D012252:Natural Family Planning Methods / Q000009:adverse effects; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000209:etiology*; D012307:Risk Factors; D055815:Young Adult
chemical_list: D003271:Contraceptive Agents, Female