According to a study published in the Journal of Obstetrics and Gynecology, overweight and tall mothers are more likely to have fraternal twins. The
study shows that mothers with a BMI index of 30 or more are significantly more likely to have fraternal twins. (
BMI or Body Mass Index is a measure of body fat based on a height and weight ratio.) Researchers analyzed over 50,000 pregnancies, (561 twin) in the Collaborative Perinatal Project, which took place at several hospitals in the United States from 1959 to 1966. They compared the incidence of twinning with the mothers' prepregnant body mass index (BMI).
The study also showed that taller-than-average women also have an increased chance of having twins. The mother's stature did not impact her chances of having identical or monozygotic twins, according to the study. Fraternal or dizygotic twinning is influenced by a number of different factors, including the use of fertility drugs, heredity and maternal age.
More Resources:
• How to Have Twins
• What are the Odds?
• Quiz: Is it Twins?
• Readers Respond: Why I Had Twins
