PCOS in Mothers Linked to Reduced Growth in Newborns, With BMI Playing Key Role, finds study

In the cohort of mother-infant pairs, maternal PCOS status was linked to shorter birth length, reduced birth weight, and smaller head circumference in the infants.

"The observed growth restrictions became more pronounced when accounting for maternal BMI, offering deeper insight into the relationship between PCOS and body mass index. This study enhances our understanding of how PCOS impacts fetal growth and development," the researchers wrote in JAMA Network Open.

PCOS is a common endocrine disorder affecting women of reproductive age, characterized by irregular menstrual cycles, elevated androgen levels, and polycystic ovaries. The condition influences metabolic and reproductive aspects of women’s health. However, its impact on offspring growth has been less studied until now. To fill this knowledge gap, Maren Sophie Aaserud Talmo, Norwegian University of Science and Technology, Trondheim, Norway, and colleagues aimed to investigate the association between maternal PCOS and newborn anthropometrics and the modifying effects of maternal body mass index (BMI), PCOS phenotype, and gestational diabetes.

The cohort study tracked women from the early stages of pregnancy through to birth, integrating data from three clinical trials involving pregnant women with PCOS and a reference population from the Norwegian Mother, Father, and Child Cohort (MoBa) Study, along with the Medical Birth Registry of Norway. The clinical trials were conducted from October 1, 2000, to August 31, 2017, while the MoBa data covered the period from July 1, 1999, to December 31, 2008. The study included women with singleton pregnancies and live-born children, with data analysis between January 1 and June 15, 2023.

The exposure of interest was maternal PCOS status. Key outcomes measured included newborn birth weight, birth length, head circumference (both as continuous variables and z scores), ponderal index (calculated as birth weight in grams multiplied by 100 and divided by birth length in centimeters cubed), placenta weight, and the ratio of birth weight to placenta weight (BWPW).

The study led to the following findings:

• The cohort included 390 pregnant women with PCOS (mean age, 29.6 years) and 68 708 women in the reference group (mean age, 30.4 years).
• The offspring in the PCOS group had lower birth weight, birth length, and head circumference than in the reference group.
• The estimated mean differences in z scores were −0.26 for birth weight, −0.19 for birth length, and −0.13 for head circumference.
• The PCOS group also had a lower ponderal index (−0.04 g × 100/cm3) and placenta weight (−24 g), and a higher BWPW ratio (0.4).
• The association between growth restriction and PCOS was more apparent when additionally adjusting for body mass index.
• Neither PCOS phenotype nor gestational diabetes diagnosis was associated with neonatal anthropometry in women with PCOS.

The key discovery of the cohort study is that neonates born to mothers with PCOS show signs of growth restriction, including lower birth weight, shorter birth length, and smaller head circumference. This growth restriction was more evident when adjusting for BMI, particularly among women with overweight or obesity, though the impact of maternal BMI requires further investigation.

"Additionally, the study observed a smaller placenta and a higher BWPW ratio, indicating a potentially stressed but efficient placenta," the researchers added.

"This may help explain the increased perinatal mortality associated with PCOS. Further research is necessary to explore these findings in greater depth," they concluded.

Reference:

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