Lipid levels after childbirth and association with number of children: A population-based cohort study

Abstract

ObjectiveLow parity women are at increased risk of cardiovascular mortality. Unfavourable lipid profiles have been found in one-child mothers years before they conceive. However, it remains unclear whether unfavourable lipid profiles are evident in these women also after their first birth. The aim was to estimate post-pregnancy lipid levels in one-child mothers compared to mothers with two or more children and to assess these lipid’s associations with number of children.MethodsWe used data on 32 618 parous women (4 490 one-child mothers and 28 128 women with ≥2 children) examined after first childbirth as part of Cohort of Norway (1994–2003) with linked data on reproduction and number of children from the Medical Birth Registry of Norway (1967–2008). Odds ratios (ORs) with 95% confidence intervals (CIs) for one lifetime pregnancy (vs. ≥2 pregnancies) by lipid quintiles were obtained by logistic regression and adjusted for age at examination, year of first birth, body mass index, oral contraceptive use, smoking and educational level.ResultsCompared to women with the lowest quintiles, ORs for one lifetime pregnancy for the highest quintiles of LDL and total cholesterol were 1.30 (95%CI: 1.14–1.45) and 1.43 (95%CI: 1.27–1.61), respectively. Sensitivity analysis (women <40 years) showed no appreciable change in our results. In stratified analyses, estimates were slightly stronger in overweight/obese, physically inactive and women with self-perceived bad health.ConclusionsMean lipid levels measured after childbirth in women with one child were significantly higher compared to mothers with two or more children and were associated with higher probability of having only one child. These findings corroborate an association between serum lipid levels and one lifetime pregnancy (as a feature of subfecundity), emphasizing that these particular women may be a specific predetermined risk group for cardiovascular related disease and death.

The association of female reproductive factors with history of cardiovascular disease: a large cross-sectional study

“…El Khoudary SR et al has found that postmenopausal women's decreased estrogen levels are believed to contribute to the rise in CVD in postmenopausal women [7]. Previous studies have shown that in addition to estrogen levels, CVD may also be influenced by other reproductive factors, including parity, lipid levels after childbirth, and miscarriage or recurrent miscarriage [8][9][10][11]. Bridger Staatz C et al also found that a variety of family factors, including the number of children, the age at first birth (AFB) and age of last birth (ALB), and the birth interval have been connected obesity and overweight [12].…”