Are risk factors for preterm and early-term live singleton birth the same? A population-based study in France

Abstract

ObjectivesTo investigate whether risk factors for preterm (<37 weeks gestation) and early-term birth (37 and 38 weeks gestation) are similar.DesignNationally representative cross-sectional study of births.SettingFrance in 2010.ParticipantsLive singleton births (n=14 326).Primary and secondary outcome measuresPreterm and early-term birth rates overall and by mode of delivery (spontaneous and indicated). Risk factors were maternal sociodemographic characteristics, previous preterm birth, height, prepregnancy body mass index (BMI) and smoking, assessed using multinomial regression models with full-term births 39 weeks and over as the reference group.ResultsThere were 5.5% preterm and 22.5% early-term births. Common risk factors were: a previous preterm delivery (adjusted relative risk ratio (aRRR) 8.2 (95% CI 6.2 to 10.7) and aRRR 2.4 (95% CI 2.0 to 3.0), respectively), short stature, underweight (overall and in spontaneous deliveries), obesity (in indicated deliveries only), a low educational level and Sub-Saharan African origin. In contrast, primiparity was a risk factor only for preterm birth, aRRR 1.8 (95% CI 1.5 to 2.2), while higher parity was associated with greater risk of early-term birth.ConclusionsMost population-level risk factors were common to both preterm and early-term birth with the exception of primiparity, and BMI which differed by mode of onset of delivery. Our results suggest that preterm and early-term birth share similar aetiologies and thus potentially common strategies for prevention.

Epidemiology of late preterm and early term births – An international perspective

“…These suggest that there could be shared mechanisms, with some differences. In spontaneous deliveries, diabetes mellitus was a strong determinant of late preterm and early term birth (aOR > 2), as well polyhydramnios, oligohydramnios, placental ischemia, other hypoxia [39], and a previous preterm birth [39,43]. Infection and inflammation, on the other hand, were risk factors for spontaneous preterm but not early term birth [39].…”

“…The most recent US findings relate national income inequality to preterm birth time trends [48]. Research on associations of sociodemographic risk factors with early term birth are lacking, but a French study found many similar determinants including short stature, a low level of education, and foreign origin (for other European and Sub-Saharan nationals), although the impact of risk factors was greater for preterm than for early term births [43]. Primiparity was a risk factor for preterm birth, but not early term birth [43], as also found by Brown et al in Canada [39,42].…”

“…Most of the research on the social and behavioral determinants of early delivery has focused on preterm birth; however, some studies find similar associations for early term births. For instance, in France, underweight mothers were at greater risk of preterm and early term spontaneous delivery, whereas obese mothers were at greater risk of indicated preterm and early delivery [43]. One study found that women with high anxiety were more likely to deliver late preterm as well as early term [57].…”

The epidemiologic characteristics and associated risk factors of preterm birth from 2004 to 2013 in Taiwan

“…The study methods have been published previously [20,21]. Briefly, this study is based on data from the National Health Insurance Research (NHIR) database provided by the Taiwan National Health Research Institute.…”

“…hypertension), as well as obstetric complications (e.G. placenta abruptio) during the pregnancy period [21,24].…”