Being overweight or obese may reduce a woman’s fertility due to irregular or infrequent menstrual cycles
Obesity may also cause an increased risk of miscarriage and decreased success with fertility treatments. When pregnancy is achieved, women with excessive weight increase their risks associated with pregnancy, such as high blood pressure, gestational diabetes, birth defects, high birth-weight infants and an increased risk of Cesarean section. Weight loss may improve fertility and pregnancy outcome. A body mass index (BMI) of 25 to 29.9 is considered overweight, and obesity is defined as a BMI of 30 and above. Weight loss of 5% to 10% may dramatically improve ovulation and pregnancy rates.
Adversely, patients who are underweight can also have problems achieving pregnancy. Underweight women are unable to produce the necessary hormones to trigger ovulation, which is essential for conception. Eating disorders, such as anorexia and bulimia, can also lead to abnormal menstrual cycles and infertility. Low body fat percentages, common in female athletes, can interfere with ovulation and cause irregular periods or no period at all. It is not uncommon for dancers, professional athletes and runners to have ovulation problems.