Smoking and pregnancy-related pelvic pain


K Biering MHSc, Department of Occupational Medicine, Herning Regional Hospital, DK-7400 Herning, Denmark. Email


Please cite this paper as: Biering K, Aagaard Nohr E, Olsen J, Hjollund N, Nybo Andersen A-M, Juhl M. Smoking and pregnancy-related pelvic pain. BJOG 2010;117:1019–1026.

Objective  To investigate possible associations between smoking and pregnancy-related pelvic pain.

Design  Nested case–control study.

Setting  Denmark 2000–2001.

Population  The Danish National Birth Cohort.

Methods  The women were interviewed twice in pregnancy and twice after childbirth. The first pregnancy interview provided information on smoking and possible confounding factors, whereas the first interview after birth addressed case identification. Cases (n = 2302) were defined on the basis of self-reported pelvic pain, and controls were selected among women who did not report pelvic pain (n = 2692). Logistic regression analysis was used to estimate associations between smoking and pelvic pain.

Main outcome mreasue  Pregnancy-related pelvic pain.

Results  Compared with non-smokers, women who smoked during pregnancy had an adjusted odds ratio of 1.2 (1.0–1.4) for overall pelvic pain, similar to women who stopped smoking in early pregnancy 1.3 (1.1–1.7). The equivalent adjusted odds ratio for severe pelvic pain was 1.2 (1.0–1.5) for smokers, and 1.5 (1.2–1.9) for women who stopped smoking. Smoking intensity, measured as number of cigarettes smoked per day, was associated with pelvic pain in a dose–response pattern. Information about smoking was collected prospectively, which makes it unlikely that differential recall alone explains the results.

Conclusions  Smoking was associated with pregnancy-related pelvic pain, with a dose–response pattern between reported smoking intensity and pelvic pain. These findings suggest a possible new risk factor for a common ailment during pregnancy.