Women who had their first child at age 25 or older were more likely to live to age 90 and women with two to four full term pregnancies were also more likely to live at least nine decades, found a large, 21-year University of California study.
The average age of a woman giving birth for the first time has risen dramatically in the US over the past 40 years, driven by factors like education or career. A new study by researchers at University of California San Diego School of Medicine found that women choosing to become first-time mothers later in life may increase their chances of living into their 90s.
The study is the first to look at age at first childbirth in relation to longevity. The researchers found an association between a woman’s age at childbirth and parity (the number of times a woman has been pregnant) with survival to age 90.
“We found that women who had their first child at age 25 or older were more likely to live to age 90,” said Dr Aladdin Shadyab, lead author of the study with the department of family medicine and public health at UC San Diego School of Medicine. “The findings indicate that women with two to four term pregnancies compared with a single term pregnancy were also more likely to live at least nine decades.”
Of the approximately 20,000 participants in the study, 54% of women survived to 90 years old. The participants were part of the Women’s Health Initiative, a national longitudinal investigation of women that began in 1991. The women were followed for up to 21 years. The study also found that women who lived to age 90 were more likely to be college graduates, married, have a higher income and less likely to be obese or have a history of chronic disease.
“Our findings do not suggest that women should delay having a child, as the risk of obstetric complications, including gestational diabetes and hypertension, is higher with older maternal ages. It is possible that surviving a pregnancy at an older age may be an indicator of good overall health, and as a result, a higher likelihood of longevity,” said Shadyab. “It is also possible that women who were older when they had their first child were of a higher social and economic status, and therefore, were more likely to live longer.”
Shadyab said further research is needed to determine which social factors might explain associations of age at first childbirth and parity with longevity.
“Our findings have several public health implications,” said Shadyab. “We hope this is a foundation to help identify targets for future interventions among women in the preconception and family planning phases of their lives, which may improve women’s healthy longevity in the long term.”
Objectives. To examine associations of maternal age at childbirth and parity with survival to age 90 years (longevity).
Methods. We performed a prospective study among a multiethnic cohort of postmenopausal US women in the Women’s Health Initiative recruited from 1993 to 1998 and followed through August 29, 2014. We adjusted associations with longevity for demographic, lifestyle, reproductive, and health-related characteristics.
Results. Among 20 248 women (mean age at baseline, 74.6 years), 10 909 (54%) survived to age 90 years. The odds of longevity were significantly higher in women with later age at first childbirth (adjusted odds ratio = 1.11; 95% confidence interval = 1.02, 1.21 for age 25 years or older vs younger than 25 years; P for trend = .04). Among parous women, the relationship between parity and longevity was significant among White but not Black women. White women with 2 to 4 term pregnancies compared with 1 term pregnancy had higher odds of longevity.
Conclusions. Reproductive events were associated with longevity among women. Future studies are needed to determine whether factors such as socioeconomic status explain associations between reproductive events and longevity.
Aladdin H Shadyab, Margery LS Gass, Marcia L Stefanick, Molly E Waring, Caroline A Macera, Linda C Gallo, Richard A Shaffer, Sonia Jain, Andrea Z LaCroix