Demographic, lifestyle, and reproductive risk factors for ectopic pregnancy

Smoking, alcohol intake, diethylstilbestrol exposure in utero, oral contraceptive use at young age, history of infertility, intrauterine device use, and tubal ligation are associated with higher risk of ectopic pregnancy.

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Volume 110, Issue 7, Pages 1328–1337


Audrey J. Gaskins, Sc.D., Stacey A. Missmer, Sc.D., Janet W. Rich-Edwards, Sc.D., Paige L. Williams, Ph.D., Irene Souter, M.D., Jorge E. Chavarro, M.D., Sc.D.



To evaluate the relationship between demographic, lifestyle, and reproductive factors and the risk of ectopic pregnancy (EP).


Prospective cohort.


United States.


Nurses' Health Study II cohort comprising 41,440 pregnancies from 22,356 women.


Demographic, lifestyle, and reproductive factors self-reported in 1989 then updated every 2 years. Multivariable log-binomial regression models with generalized estimating equations were used to estimate adjusted risk ratios (aRR).

Main Outcome Measure(s)

Ectopic pregnancy.


Incident EP was reported in 411 (1.0%) pregnancies. Former and current smokers had 1.22 (95% confidence interval [CI], 0.97–1.55) and 1.73 (95% CI, 1.28–2.32) times, respectively, the risk of EP compared with never smokers. The risk of EP 10 years after quitting was similar to never smokers (aRR 0.90; 95% CI, 0.60–1.33). Women consuming ≥10 g/day of alcohol had 1.50 (95% CI, 1.08–2.09) times the risk of EP compared with never consumers. In utero exposure to diethylstilbestrol (aRR 3.55; 95% CI, 2.51–5.01), earlier initiation of oral contraceptives (aRR 2.64; 95% CI, 1.70–4.09 for <16 years vs. never), intrauterine device use (aRR 3.99; 95% CI, 2.06–7.72), or history of infertility (aRR 3.03; 95% CI, 2.48–3.71) or tubal ligation (aRR 16.27; 95% CI, 11.76–22.53) also were associated with a higher risk of EP.


Women who were current or former smokers, consumed ≥10 g/day of alcohol, were exposed to diethylstilbestrol in utero, initiated oral contraceptives at earlier than age 16 years (which may be a marker of riskier sexual behaviors), and who had a history of infertility, intrauterine device use, or tubal ligation had a higher risk of EP.

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Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders.