A mother’s health problems pose a risk to her children
Obesity combined with the hormone disorder PCOS in mothers can cause health problems for her children both at birth and later in life.
Women with polycystic ovary syndrome (PCOS) and obesity are at a higher risk of giving birth to smaller babies in terms of birth weight, length, and head circumference, according to a recent study conducted at NTNU.
One in eight women is affected by the hormone disorder PCOS. PCOS is commonly characterized by elevated 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 to around 70,000 children from the Norwegian Mother, Father and Child Cohort Study (MoBa) (See the fact box.)
The researchers found that on average, the babies born to mothers with PCOS weighed less, were shorter, and had a smaller head circumference at birth. This was particularly the case when the mothers were obese, meaning they had a BMI over 30.
The Norwegian Mother, Father and Child Cohort Study (MoBa)
- The Norwegian Mother, Father and Child Cohort Study (MoBa) is one of the world’s largest health surveys.
- The survey includes 114,000 children, 95,000 mothers and 75,000 fathers.
- MoBa follows the participants throughout their entire lives and over generations. Both biological samples and responses to questionnaires are collected. An important aim is to identify the causes of serious illnesses.
Co-occurrence of PCOS and obesity has the worst impact
“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. Instead, the group of children born to mothers with obesity stands out the most. These babies weigh less, are shorter and have a smaller head circumference. Obesity places an additional burden on mothers who have PCOS as well as their children,” said Professor Eszter Vanky at NTNU’s Department of Clinical and Molecular Medicine.
“Obesity places an additional burden on mothers who have PCOS and their children,” said Professor Eszter Vanky at NTNU’s Department of Clinical and Molecular Medicine (pictured). Photo: Geir Mogen
PCOS is a disease that follows women throughout their lives and can trigger different metabolic diseases and problems such as diabetes, high blood pressure, and obesity. Women with PCOS are generally more likely to develop overweight and obesity.
“What is 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 also applies to women who develop gestational diabetes. On average, women with PCOS have higher BMIs, gain more weight during pregnancy, and 25 per cent develop gestational diabetes. However, the outcome is the opposite: these women give birth to babies who are smaller than average. We still don’t know why, but we see that the placenta is affected in these women,” said Vanky.
- You might also like: Saving lives in Sierra Leone – one C-section at a time
Placenta in overdrive
Maren Talmo and Ingvild Fløysand, both medical doctors, have carried out the study as part of their master’s thesis, with Eszter Vanky and Melanie Rae Simpson as their supervisors. Talmo explains that even though the placenta in these women is smaller in size, it seems to deliver more nutrients relative to the baby’s body weight compared to a normal placenta. Vanky describes it as a placenta in 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, foetal death.”
The researchers do not 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 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.”
Polycystic ovary syndrome (PCOS)
- PCOS is a common hormone disorder that is estimated to affect between 10 and 17 per cent of women.
- The condition is characterized by increased levels of male sex hormones, infrequent or irregular menstrual periods (which are a sign of infrequent, irregular ovulation) and many small cysts on the ovaries.
- The cause of PCOS is multifaceted and not fully understood. PCOS is hereditary, but genes only play a minor role in determining who will develop the condition.
- The secretion of hormones that control ovulation is disrupted. This leads to fewer ovulations and higher production of male sex hormones. The ‘cysts’ on the ovaries are not actual cysts, but follicles (eggs) where maturation has stopped.
- PCOS is associated with insulin resistance and elevated insulin levels in the blood (hyperinsulinemia). In turn, high levels of insulin can also contribute to increased production of male sex hormones. It can also contribute to central obesity (accumulation of fat in the abdomen and liver). This can result in the development of metabolic syndrome, which in turn can lead to type 2 diabetes and cardiovascular disease.
Source: (Great Norwegian Encyclopedia – SNL)
Follow-up during pregnancy
The researchers believe this is important information for both affected women and for healthcare professionals.
“A newborn baby is not a blank slate. Much of our long-term health is established in the womb. Genes play a role, but also what we are exposed to during the foetal stage and early in life,” said Vanky.
The NTNU researchers now want to learn more about what happens to the children’s health.
“What are the consequences of the mother’s PCOS diagnosis for the child? Is there anything that can be done before or during pregnancy so that expectant mothers with PCOS do not gain too much weight? Can follow up and good glucose regulation be provided so that the child gets the best outcome possible? All this depends on knowing more about the mother’s situation,” said Vanky.
Affected throughout life
The NTNU researchers have also followed up on some of the children when they were 7 years old.
“We saw that the children born to mothers with PCOS generally had more central obesity, meaning they were larger around the waist,” said Vanky.
Other studies have shown that children born to mothers with PCOS are at higher risk of developing overweight and obesity at a young 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 early as 7 or 8 years old, where children born to mothers with PCOS have a larger waist circumference and higher BMI. They show small signs that their mother has PCOS. It may therefore be an advantage to know more about this so we can provide guidance on lifestyle and diet,” Vanky said.
Source: Talmo MSA, Fløysand IS, Nilsen GØ, et al. Growth Restriction in the Offspring of Mothers With Polycystic Ovary Syndrome. JAMA Netw Open. 2024;7(8):e2430543. doi:10.1001/jamanetworkopen.2024.30543
