The health of expectant mothers can significantly impact pregnancy outcomes and the well-being of their offspring. A recent study reveals that women with obesity and PCOS (Polycystic Ovary Syndrome) face a higher risk of giving birth to smaller babies.

Researchers at the Norwegian University of Science and Technology have found that, on average, babies born to mothers with PCOS face a higher risk of growth restriction. The offspring were lighter, shorter, and had smaller head circumferences at birth, and these effects were more pronounced in mothers who were obese.

The study published in the Jama Network Open used data from 390 children born to women with PCOS and compared it to around 70,000 children from the Norwegian Mother, Father, and Child Cohort Study.

"An association was found between maternal PCOS status and growth restriction in the newborn, expressed as low birth weight, shorter birth length, and smaller head circumference," the researchers wrote.

"In women of normal weight who have PCOS, we only find that their children have a lower birth weight compared to women who do not have PCOS. It is the group of children born to mothers with obesity that stands out the most. These babies have lower weight, shorter stature and a smaller head circumference. Obesity places an additional burden on mothers who have PCOS and their children," said Professor Eszter Vanky, a researcher of the study in a news release.

While being overweight and having gestational diabetes typically increases the risk of giving birth to larger babies, researchers noted that women with PCOS, who often have higher BMIs, face the opposite outcome. These women are more likely to give birth to babies who are smaller than average. According to researcher Professor Vanky, this may be due to the way PCOS affects the placenta resulting in an overdrive.

"The placenta delivers nutrients to the baby through the umbilical cord. In women with PCOS, we see that the placenta is generally smaller in size. At the same time, it must provide everything the baby needs, so it has to work very hard to meet these demands. Sometimes, however, the placenta can't keep up, which can lead to placental insufficiency and, in rare cases, fetal death," Professor Vanky explained.

However, the researchers do not know the exact mechanism by which PCOS affects the placenta. "Previously, we thought the cause was linked to the high levels of male sex hormones, but we have not been able to fully connect the two. We also know that women with PCOS have a slightly different immune profile during pregnancy," Professor Vanky added.

Studies have shown that children born to mothers with PCOS are at higher risk of developing obesity later in life. Research has also shown that having low birth weight raises the risk of type 2 diabetes and cardiovascular disease later in life.

The researchers hope the current findings will help healthcare professionals in offering additional support to pregnant women with PCOS, to reduce their risk of obesity and associated complications.

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