Parity, duration of lactation and prevalence of maternal metabolic syndrome: a cross-sectional study

Pregnancy is associated with insulin resistance in tissues. Although this condition is resolved after termination of pregnancy, subtle metabolic changes can remain and prompt incidence of metabolic syndrome. However, lactation causes increased metabolic load and energy needs and it may confer with unfavorable effects of pregnancy in metabolic status. We conduct this study to evaluate impacts of lactation on development of metabolic syndrome (MetS) among women.

In this cross-sectional study, we enrolled 978 women aged between 40 and 70 years who had at least one previous live birth, referred to population research center of Amol, Iran in 2011. We surveyed medical registries of participants of Amol health cohort and filled the checklist we had designed for our study. The checklist included main variables like age, number of pregnancies, life-time lactation duration, waist size, systolic and diastolic blood pressures, blood triglyceride level, and blood glucose level.

We included 978 women among which, the mean age of participants was 53.24±7.8 years. Calculated odds ratio (OR) for relationship of number of parities and metabolic syndrome (OR=1.14 [95% CI=1.02-1.28] p-value=0.017) was found to be statistically significant. However, calculated odds ratio for relationship of lactation duration and MetS (OR=0.99 [95% CI=0.99-1.00], p-value=0.322) was not statistically meaningful. Moreover, we calculated OR and Pearson correlation coefficient in different strata of number of parities, none of which were statistically significant and hence did not support protective roles of lactation in development of metabolic syndrome.

Our data did not support protective roles of lactation in development of metabolic syndrome, since in our study longer lactation durations as well as higher number of parities were seen among participants with metabolic syndrome.