Women with polycystic ovary syndrome (PCOS) and obesity have a higher risk of giving birth to babies smaller in terms of birth weight, length and head circumference, according to a recent study at the Norwegian University of Science and Technology ( NTNU). .

One in eight women is affected by the hormonal disorder PCOS. Common features are increased levels of male sex hormones, infrequent or irregular menstrual periods, and the formation of small cysts on the ovaries.

In the study, 390 children born to women with PCOS were compared with approximately 70,000 children from the Norwegian Mother, Father and Child Cohort Study (MoBa) (see fact box.)

The researchers found that, on average, babies born to mothers with PCOS weighed less, were shorter and had a smaller head circumference at birth. This was especially the case when the mothers were obese, meaning they had a BMI over 30.

The co-occurrence of PCOS and obesity has the worst impact.

In normal-weight women who have PCOS, we only find that their babies have a lower birth weight compared to women who don’t have PCOS. The group of children born to obese mothers stands out the most. These babies have a lower weight, shorter stature and smaller head circumference. Obesity places an additional burden on mothers who have PCOS and their children.”

Professor Eszter Vanky at the NTNU Department of Clinical and Molecular Medicine

PCOS is a disease that follows women throughout their lives and can trigger various metabolic diseases and challenges such as diabetes, high blood pressure and obesity. Women with PCOS are generally more likely to develop overweight and obesity.

“What’s unusual is that women who are generally overweight and gain a lot of weight during pregnancy usually have an increased risk of giving birth to large babies. This is also true for women who develop gestational diabetes. In On average, women with PCOS have a higher BMI, gain more weight during pregnancy, and 25 percent of them develop gestational diabetes, the placenta is affected in these women,” Vanky said.

Placenta in overdrive

Newly qualified doctors Maren Talmo and Ingvild Fløysand carried out the study as a master’s thesis, supervised by Eszter Vanky and Melanie Rae Simpson. Talmo explains that although the placenta in these women is smaller in size, it appears to deliver more nutrients relative to the baby’s body weight compared to a normal placenta. Vanky describes it as an excess placenta.

“The placenta provides 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 has to provide everything the baby needs, so it has to work very hard to However, sometimes the placenta can’t keep up, which can lead to placental insufficiency and, in rare cases, fetal death “.

Researchers don’t know why this is the case.

“There are many hypotheses, but I don’t think anyone has a definitive answer yet. Previously, we thought the cause was related to high levels of male sex hormones, but we haven’t been able to fully connect the two. I know that women with PCOS have a slightly different immune profile during pregnancy.”

Monitoring during pregnancy

The researchers believe this is important knowledge for both affected women and healthcare professionals.

“A newborn is not a blank slate. Much of our long-term health is established in the womb. Genes play a role, but so does what we are exposed to during the fetal stage and early in life,” said Vanky .

NTNU researchers now want to know more about what is happening to children’s health.

“What are the consequences of maternal PCOS diagnostic for the child? Is there anything that can be done before or during pregnancy to keep moms-to-be with PCOS from gaining too much weight? Can blood glucose monitoring and regulation be ensured so that the child achieves the best possible outcome? It all depends on knowing more about the mother’s situation,” Vanky said.

Affected throughout life

The NTNU researchers also followed some of the children when they reached the age of 7.

“We saw that children born to mothers with PCOS generally had more central obesity, meaning they were larger around the waist,” Vanky said.

Other studies have shown that children born to mothers with PCOS are at greater risk of developing overweight and obesity at an early age. Research has also shown that low birth weight is linked to the development of type 2 diabetes and cardiovascular disease later in life.

“We see differences in children as young as 7 or 8, where children born to mothers with PCOS have a larger waist circumference and a higher BMI. They show little signs that their mother has PCOS. So it might be an advantage to know about it so that we can provide lifestyle and dietary guidance,” Vanky said.