Risk factors for ectopic pregnancy in Lagos, Nigeria.

BACKGROUND: Ectopic pregnancy is an important cause of maternal deaths in Nigeria and in other developing countries. In Lagos, Nigeria, it is responsible for 8.6% of maternal deaths, and has a case fatality rate of 3.7%. The purpose of this study was to determine the risk factors for ectopic pregnancy in Lagos.

METHODS: A case-control study of 100 patients and 280 controls was performed in the three hospitals--Lagos University Teaching Hospital, Ayinke House Maternity Hospital, and Lagos Island Maternity Hospital--in Lagos from June 1999 to December 1999. Data were analyzed by using logistic regression.

RESULTS: The incidence was 23.1/1000 (1 : 43) deliveries and was responsible for 48.5% of gynecologic emergencies. Age, marital status, socioeconomic status, and parity were not the significant risk factors for ectopic pregnancy. An early age of sexual debut increased the risk of ectopic pregnancy almost two-fold (adjusted OR = 1.93; 95% CI = 1.71-2.93), whereas a late age of sexual debut was protective (adjusted OR = 0.37; 95% CI = 0.19-0.59). History of multiple lifetime sexual partners, induced abortions, pelvic inflammatory disease, sexually transmitted disease (STD), miscarriage, and pelvic surgery independently and significantly increased the risk of ectopic pregnancy. Induced abortion and STD increased the risk 14-fold and nine-fold, respectively. Previous use of intrauterine contraceptive device increased the risk almost four-fold (adjusted OR = 3.76; 95% CI = 2.12-6.69), whereas the use of condoms was protective (adjusted OR = 0.35; 95% CI = 0.17-0.71).

CONCLUSIONS: Proper sex education, prevention of unwanted pregnancy, and prevention and proper treatment of sexually transmitted infections will reduce the incidence of ectopic pregnancy.