For every extra 1 cm of waist measurement, a woman's risk of infertility increases by 3 per cent, reveals an alarming study. 

Obesity and infertility are both growing health concerns worldwide. The high prevalence of these two diseases necessitates a more comprehensive understanding of their interrelationship.

Obesity has had significant implications for fertility and reproductive health. However, evidence linking abdominal obesity to female infertility has been limited and inconclusive.

To find out, the researchers from China included 3,239 women aged 18-45 years in the US.

The results, published in the journal PLoS ONE, showed that waist circumference was positively associated with female infertility independent of body mass index (BMI) after adjusting for BMI and other potential confounders.

For every 1 cm increase in waist circumference, the risk of infertility increased by 3 per cent. When waist circumference was divided into five equal groups, women in the highest quintile had 2.64 times the risk of infertility than that in the lowest quintile. However, physical activity was found to be protective.

The team found an inverted U-shaped relationship between waist circumference and female infertility in participants who had moderate recreational activities and a J-shaped relationship between waist circumference and female infertility in participants who had deficient recreational activities.

"Waist circumference is a positive predictor of female infertility, independent of BMI," said Jierong Ke from Huizhou Central People’s Hospital in China, along with other researchers in the paper.

"Moderate recreational activities can lower the risk of female infertility associated with abdominal obesity. Our results indicated that effective waist circumference management strategies and moderate recreational activities were required to reduce the risk of abdominal obesity and improve reproductive health," the team said.