Breastfeeding: A bystander marker of improvement in multiparity-induced cardiometabolic disease risk?

Abstract

Metabolic and cardiovascular changes in pregnancyThe cardiovascular system undergoes notable structural and haemodynamic changes during the course of pregnancy, such that some call pregnancy nature's stress test.1 Contrary to previous generally held belief, some recent studies demonstrated a progressive increase in blood pressure (BP) throughout gestation in women who were overweight before pregnancy.2 In a population-based cohort study, obese and overweight women had a higher BP throughout pregnancy.3 Substantial ethnic differences exist in the BP levels that are observed during pregnancy and the risk of gestational hypertension. 4 Childbearing was associated with incidence of the metabolic syndrome (MetS) among women with gestational diabetes mellitus (DM) and, after controlling for preconception body mass index (BMI) and MetS components, in primi-and multiparous women without gestational DM as well. 5Associations between higher parity and prevalence of DM have been mixed, and even an increased risk of DM with nulliparity was reported among Native American women.6 Multiparity is associated with coronary heart disease (CHD), showing a a J-shaped relationship with higher risk for nulliparous women. 7,8 Decreases in serum creatinine and uric acid values have been attributed to rises in glomerular filtration rates by the end of the first trimester. 9 Higher baseline levels of a measure of aortic stiffness have been observed in multiparous compared with nulliparous women.1 Both multiparity and nulliparity have been associated with higher insulin levels many years after childbearing.10 Viewed from the perspective of correlates of lipoprotein(a) (Lp(a)), 11 gestation may reflect underlying 'reduced' serum Lp(a) assays and autoimmune activation. Influence of lactationA prospective study on a relatively small sample examined the relationship between lactation and changes in maternal metabolic risk factors and found a tendency towards improved serum high-density lipoprotein cholesterol and fasting insulin, 12 changes that are potentially consistent with underlying rises in Lp(a) levels.11 Longer duration of lactation was associated with a lower incidence of the MetS years after delivery and after weaning among women with non-gestational DM, as well as with gestational DM pregnancies. Lactation may ameliorate the increased risk of the MetS that is associated with higher parity.5 Data from the Coronary Artery Risk Development in Young Adults (CARDIA) study provided evidence that lactation may have lasting favourable effects on the risk of the MetS among women, regardless of a history of gestational DM. 13 However, this protection seemed to be absent in overweight women and black women without gestational DM, suggesting a possible interaction with adiposity, given the generally inverse association between BMI and Lp(a) and the existence of two-fold higher Lp(a) levels in black compared with white women. 11In a cohort of 177,749 Korean premenopausal women, the risk of the development of hypertension was significantly reduce...