Infertility and Maternal Obesity Study

Infertility is a global public health issue, and research must focus on addressing the risk factors. In a study, researchers have found that sons born to pre-pregnant obese mothers were more likely to be diagnosed with infertility during adulthood than sons of mothers with normal weight. The research has been published in Acta Obstetricia et Gynecologica Scandinavica on November 15, 2020.

Overweight and obesity in pregnancy is increasing worldwide and may harm the developing fetus, including its future reproductive health. Approximately 12.5% of couples are affected by infertility, which is often defined as unsuccessfully attempting to conceive for a year or longer. Overall, one-third of couples' infertility cases are caused by male reproductive issues, one-third by female reproductive issues, and one-third is either a combination or due to unknown factors. However, the association between maternal overweight and infertility in offspring is unknown, as no studies have previously assessed this association. Therefore, Dr. Linn H. Arendt and colleagues of Denmark conducted a study to evaluate the association between in utero exposure to maternal overweight and obesity and infertility in adulthood.

It was a cohort study of adult sons and daughters whose mothers were enrolled in the Danish Healthy Habits for Two cohorts during pregnancy in 1984‐87. Researchers evaluated a total of 1203 (13%) sons and daughters who were born to mothers with a body mass index (BMI) >25 kg/m². Among 1203 participants, they identified 871 (9.4%) as being infertile during follow-up. They followed participants in the Danish In‐Vitro‐Fertilization‐Register and Danish National Patient Register until February 2018 for diagnoses of infertility.

Key findings of the study were:

• Upon analysis, researchers have found sons of overweight mothers had slightly increased odds of infertility compared with sons of mothers with normal body weight (BMI 18.5‐24.9 kg/m², adjusted odds ratio 1.4).
• Using Cubic spline analysis with continuous BMI levels, they found increasing odds with higher levels of BMI. However, for BMI >29 kg/m², they noted that the confidence intervals were too wide to conclude.
• They found no association between maternal overweight and infertility among daughters (aOR 0.9).

The authors concluded, "Sons born to overweight mothers had higher odds of infertility compared with sons of normal weight mothers. No association between maternal overweight and infertility was observed in daughters. Prevention of overweight during pregnancy may be an important tool to preserve fecundity in future generations".

For further information: https://obgyn.onlinelibrary.wiley.com/doi/10.1111/aogs.14045