1. Objectifs

Intentions :
«We sought evidence to support the hypothesis that advancing maternal age is potentially causing a rise in preterm birth (PTB) rates in high-income countries.» (p. e33)

2. Méthode

Échantillon/Matériau :
«We undertook a historical cohort study of singleton live-born infants from Denmark (n = 1 692 794) and Quebec (n = 2 310 466) for 1981 through 2008. In Denmark, birth data are compiled in the Danish Medical Birth Registry, which contains linked data from national databanks including the National Patient Register and the Civil Registration System Register. […] The Quebec birth file is compiled directly from birth registration certificates, and ascertainment of births is considered complete.» (p. e33)

Type de traitement des données :
Analyse statistique

3. Résumé

«This comparative analysis of Denmark and Quebec made 2 new contributions to the literature on trends in maternal age and PTB rates over time. First, the findings revealed remarkably similar temporal trends for both high-income populations. The shift toward older maternal age and higher PTB rates occurred to a similar degree over time in both Denmark and Quebec. The notable difference was the 1 percentage point higher PTB rate in Quebec compared with Denmark. Second, we found that PTB rates declined in older women for both populations, whereas rates increased in younger women, especially for those younger than 30 years. However, trends in PTB rates among young women were offset by a shift toward older maternal age, leaving women aged 30 to 34 years responsible for most of the rise in overall PTB rates in both populations. The findings nonetheless suggest that interventions targeting women in their 20s are indicated. Their PTB rates increased, and obstetric practices are likely involved, because it is unlikely that younger women experienced a disproportionate increase in maternal comorbidities or other risk factors for PTB compared with older women.» (p. e36)