How Evolution Influences Pregnancy
Some ethnic groups are more genetically vulnerable to certain diseases than others, and diseases during pregnancy are no exception.
A study of pregnant women in New York City a few years ago found that women of European descent have the lowest risk of gestational diabetes, with African-American women at only slightly higher risk. The risk was much greater for women of South Asian descent – 14.3 per cent – with the highest risk reserved for Bangladeshi women: one out of every five pregnant women of Bangladeshi origin is affected by gestational diabetes.
In a study about to be published in Trends in Genetics, researchers think they’ve found why this happens: Evolution.
According to National Geographic:
Researchers argue that pregnancy has been one of the most important targets of natural selection in all of human biology. Mutations that raise the success rate of pregnancies let women have more offspring who can spread their genes throughout a population … A woman’s reproductive success depends not just on her newborn child surviving, but on her own survival as well.
European women’s ancestors adapted to a diet rich in carbohydrates – a diet that puts one at increased risk of gestational diabetes. As a result, they’re more likely to have genes adapted to ward off the disease.
However, women of Bangladeshi origin have ancestors who ate a diet low in carbohydrates (such as fish and unprocessed rice), and did not need to develop the adaptation. So when they eat a North American diet rich in carbs they are less likely to have the genes to ward off diabetes, and are more susceptible.
source: National Geographic