Being the First Is Not Always Good

First-born children tend to have reduced insulin sensitivity that potentially exposes them to risks for diabetes and hypertension….

A recent study from a group of researchers in New Zealand shows that first-born children have reduced insulin sensitivity and higher blood pressure during the day compared with kids with older siblings.

Researchers studied 85 healthy children ranging in age from 4 to 11. The subjects for the study are younger children because puberty and adult lifestyles can affect insulin sensitivity. Thirty-two of those were first-borns. According to researchers, "all 32 first-born children had a 21 percent drop in insulin sensitivity and a 4 mm Hg increase in blood pressure levels compared with the other children."

After the first pregnancy, some physiological changes in the uterus help create better metabolic support for the fetus during subsequent pregnancies. Though having risk factors at birth does not necessarily translate into adult diabetes or hypertension, the findings have a significant impact in public health.

https://www.nlm.nih.gov/medlineplus/news/fullstory_133941.html