Effect of older maternal age on the risk of spontaneous preterm labor: a population-based study

Author
McIntyre, Safina
Newburn-Cook, Christine V.
O’Brien, Beverley
Demianczuk, Nestor N.
Faculty Advisor
Date
2009
Keywords
women , older maternal age , first birth , nulliparous women , pregnancy complications , perinatal data , risk models , spontaneous preterm labor , risk factor , cohort study
Abstract (summary)
To determine if older maternal age (35 years and older) at first birth was an independent risk factor for spontaneous preterm labor, we conducted a retrospective population-based cohort study. Using provincial perinatal data, we developed separate risk models for low- and high-risk women using multivariate logistic regression. We found that older maternal age exerted a direct and independent effect on spontaneous preterm labor for both nulliparous women with no preexisting chronic illnesses or pregnancy complications (low-risk) and nulliparous women who did not have any preexisting chronic illnesses, but developed one or more pregnancy complications (high-risk). Over the past several decades, the proportion of women delaying the birth of their first child until 35 years and older has increased significantly in developed countries, both in North America and Europe. In the United States, for example, births to nulliparous women 35 to 39 years of age and women 40 to 44 years increased by 36% and 70%, respectively (Cnattingius & Stephannson, 2002; Heffner, 2004). With increasing numbers of women postponing childbearing until their later reproductive years, there is increased awareness and concern among women and health care providers about the impact of advanced maternal age on maternal morbidity, the increased risk of obstetric interventions, and adverse pregnancy outcomes, including preterm birth. The results of studies on the relation between increased maternal age and preterm birth have led to inconsistent conclusions. One limitation was the failure by most researchers to investigate the heterogeneity of preterm birth. Therefore, we conducted a retrospective population-based cohort study to determine if older maternal age (35 years and older) at first birth was an independent risk factor for spontaneous preterm labor. To our knowledge this was the first such study designed specifically to examine if older maternal age acts directly or indirectly on the risk of spontaneous preterm labor. Realizing that not all women of older maternal age are a homogeneous group, we developed separate risk models for low- and high-risk women. We found that older maternal age exerted a direct and independent effect on spontaneous preterm labor for both nulliparous women with no preexistisng illnesses or pregnancy complications (low-risk) and nulliparous women who did not have any preexisting chronic illnesses but developed one or more pregnancy complications (high-risk). It is important to identify risk factors for preterm birth that are amenable to change; resulting interventions possibly could have long-lasting and far-reaching effects.
Publication Information
Hassan McIntyre, S., Newburn-Cook, C. V., O'Brien, B., & Demianczuk, N. (2009). Effect of older maternal age on the risk of spontaneous preterm labour: A population-based study. Health Care for Women International, 30, 670-689. DOI: 10.1080/07399330802596473
DOI
Notes
Item Type
Article
Language
English
Rights
All Rights Reserved