title: Marital status, cohabitation, and risk of preterm birth in Europe: where births outside marriage are common and uncommon.
abstract: This article explores whether the impact of marital status on the risk of preterm birth varies in relation to marital practices in the population, defined by the proportion of out-of-marriage births. Data come from a case-control study of the determinants of preterm birth in 16 European countries (5456 cases and 8234 controls). There is a significantly elevated risk of preterm birth associated with both cohabitation (OR = 1.29 [1.08, 1.55]) and single motherhood (OR = 1.61 [1.26, 2.07]) for women living in countries where fewer than 20 of births occur outside marriage. In contrast, there is no excess risk associated with marital status when out-of-marriage births are more common. This overall result does not apply to all subgroups of preterm births: different patterns emerge for early preterm births and preterm births induced for medical reasons. It is important to consider social context in the analysis of individual risk factors.
authors.affiliation: I.N.S.E.R.M, Epidemiological Research Unit on Perinatal and Women's Health, Paris, France. Zeitlin@cochin.inserm.fr
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Zeitlin
authors.forename: Marie-Josèphe
authors.initials: MJ
authors.lastname: Saurel-Cubizolles
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Ancel
mesh_terms: D016022:Case-Control Studies; D005060:Europe / Q000453:epidemiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D007745:Labor Onset; D017533:Marital Status; D007752:Obstetric Labor, Premature / Q000453:epidemiology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D012111:Residence Characteristics / Q000706:statistics & numerical data*; D012307:Risk Factors; D015406:Single Parent / Q000706:statistics & numerical data*