How does a problematic weight—whether it’s too high or too low—affect fertility? A recent study of 1,950 women currently attempting pregnancy found that being overweight or obese in adulthood, gaining weight in adulthood and being underweight at age 18 were associated with modest reductions in the ability to have children.
In the study, published in the journal Obstetrics and Gynecology, participants reported their own height, current weight and weight at age 18 and every three to six months thereafter. They also reported the current duration of their pregnancy attempt. Duration is a measure of fertility—the longer it takes to get pregnant, the less successful one is.
The study found that:
• For every 5-kilogram (11-pound) increase in body weight from age 18, current duration of pregnancy attempt increased by 5%.
• Compared with women who maintained their weight, the duration was 0.5 months shorter in those who lost weight, 0.3 months longer for those who gained between 4 and 19.9 kilograms (9 to 44 pounds), and 1.4 months longer for those who gained 20 kilograms (44 pounds) or more.
• Being underweight at age 18 years was associated with a longer current duration of pregnancy attempt compared with women of normal weight.
• Being overweight or obese at age 18 was not associated with a change in fertility rates.
The takeaway: If you are trying to get pregnant, be sure to work with your doctors on weight control.