Maternal PCOS Linked to Growth Restriction in Newborns

Maternal polycystic ovary syndrome (PCOS) was associated with growth restriction in offspring, a Norwegian population-based cohort study suggested.

Among 390 newborns of women with PCOS and 68,708 newborns of women without the condition, those in the PCOS group had lower birth weight, shorter birth length, and smaller head circumference compared with their counterparts in the reference group, reported Maren Sophie Aaserud Talmo, MD, of the Norwegian University of Science and Technology in Trondheim, and colleagues.

After adjusting for presumed confounding factors of maternal age, parity, smoking, educational level, and civil status, the estimated mean differences in z scores were -0.26 (95% CI -0.38 to -0.14) for birth weight, -0.19 (95% CI -0.33 to -0.05) for birth length, and -0.13 (95% CI -0.26 to -0.01) for head circumference, they wrote in JAMA Network Open.

The PCOS group also had a lower ponderal index — calculated as the birth weight in g × 100 divided by the birth length in cm³ — (-0.04 g × 100/cm³, 95% CI -0.07 to -0.004) and placenta weight (-24 g, 95% CI -43 to -5), as well as a higher ratio of birth weight to placenta weight (0.4, 95% CI 0.3-0.5).

Notably, after additionally adjusting for maternal BMI, the estimated mean differences in z scores between the PCOS group and reference group for birth weight, birth length, and head circumference were -0.39 (95% CI -0.51 to -0.27), -0.29 (95% CI -0.44 to -0.15), and -0.25 (95% CI -0.37 to -0.12), respectively. “This indicates an association between PCOS and growth restriction that may be partially camouflaged or counteracted by higher maternal BMI,” Talmo and team wrote.

“Hyperandrogenism, hyperinsulinemia, and early mobilization of cytokines with activated immune status are characteristics of PCOS that may influence the intrauterine environment, with a potential impact on fetal growth and offspring health,” Talmo and colleagues wrote. “While some studies report lower birth weight in children born to women with PCOS compared with controls, others find no association between PCOS and the rates of small-for-gestational-age or large-for-gestational-age babies or find that associations are no longer apparent after adjusting for presumed confounding factors.”

In an invited commentary, Mahnaz Bahri Khomami, BMid, MMid, PhD, and Helena Teede, MBBS, PhD, both of Monash University in Melbourne, Australia, noted that while the study addresses some limitations and advances knowledge by “highlighting associations between PCOS and newborn anthropometrics, independent of common confounders such as BMI … gaps persist, including the accurate capture of PCOS status in population studies.”

“Along with limitations in education and midwifery and ob/gyn resources and poor recognition of PCOS status in pregnancy, this underscores the need for greater investment in education, research, and clinical care,” Khomami and Teede wrote. “Ensuring that clinicians are well-educated about the diverse impacts of PCOS, accurately capture PCOS status, and are equipped to screen, prevent, and manage pregnancy complications will ultimately improve outcomes for both mothers and their babies.”

This study combined data from three clinical trials of pregnant women with PCOS and a reference population consisting of participants in the Norwegian Mother, Father, and Child Cohort (MoBa) study, with data from the Medical Birth Registry of Norway. Recruitment for the clinical trials lasted from October 2000 through August 2017, and for MoBa, from July 1999 through December 2008. Participants were women with singleton pregnancies and live-born children.

Mothers in the PCOS group had a mean age of 29.6 compared with 30.4 in the reference group. Mean BMI in the two groups was 27.9 and 24.5, respectively.

Study limitations included the fact that data on maternal weight and height in the PCOS group were measured, though they were self-reported in the reference group, Talmo and colleagues noted.

In addition, irregular menstruation as a proxy for PCOS in the reference group identifies only a proportion of women with PCOS. Also, because participants were mainly of Nordic ancestry, results may not be directly applicable to others.