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A ntepartum haemorrhage of unknown origin and maternal cigarette smoking beyond the first trimester
Author(s) -
Altvorst Marlies E.W.A.,
Chan Eliza H.Y.,
Taylor Rennae S.,
Kenny Louise C.,
Myers Jenny E.,
Dekker Gustaaf A.,
North Robyn A.,
McCowan Lesley M.E.
Publication year - 2012
Publication title -
australian and new zealand journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.734
H-Index - 65
eISSN - 1479-828X
pISSN - 0004-8666
DOI - 10.1111/j.1479-828x.2011.01398.x
Subject(s) - obstetrics , first trimester , cigarette smoking , medicine , pregnancy , biology , genetics , gestation
Background Antepartum haemorrhage of unknown origin ( APHUO ) is associated with preterm birth and perinatal mortality. Aim To determine whether smoking beyond the first trimester of pregnancy was an independent risk factor for APHUO . Methods Rates of APHUO were compared between non‐smokers and smokers, and non‐smokers and ceased smokers. Participants were healthy nulliparous women recruited to the S creening for P regnancy E ndpoints ( SCOPE ) prospective cohort study in N ew Z ealand, A ustralia, I reland and U nited K ingdom. Logistic regression was used to compare adjusted odds ratio, 95% confidence intervals ( OR , 95% CI ) of APHUO between continued smokers and non‐smokers, adjusting for possible confounders. Results Of the 3513 participants, 77.9% ( n = 2737) were non‐smokers, 10.6% ( n = 371) ceased in the first trimester and 11.5% ( n = 405) continued smoking beyond the first trimester. APHUO rates were higher in smokers than non‐smokers (7.4%, n = 30 vs 4.5%, n = 122; P = 0.01), but there was no difference between ceased smokers and non‐smokers (4.3%, n = 16 vs 4.5%, n = 122; P = 0.90). Smoking was no longer significantly associated with APHUO after adjustment for confounders (adjusted OR = 1.28, 95% CI 0.76–2.14), but vaginal bleeding in early pregnancy (adjusted OR = 2.98, 95% CI 2.12–4.18) and overweight/obesity (adjusted OR = 1.43, 95% CI 1.02–1.99) were independent risk factors. First trimester folic acid use was associated with a reduced risk (adjusted OR = 0.44, 95% CI 0.25–0.77). Conclusion Smoking is not an independent risk factor for APHUO after adjustment for confounders, but other risk and protective factors have been identified.