Being thin worse for IVF success than being overweight

Thinner women could find it harder to fall pregnant with fertility treatment than those who are obese, a new study reveals.

Posted: 21 October 2011
by Jenny Bamberger

Underweight? It may play a role in your chances of having a baby by IVF

Being too thin causes more problems for your chances of conceiving by IVF than being overweight, a study has shown.

Women with a healthy weight have a 50% chance of falling pregnant with IVF. While those who are overweight have a slightly lower chance than this, those who are too thin have just a 34% chance of conceiving.

So what is too thin? In the study, this was a Body Mass Index (BMI) of 14 to 18.

The Advanced Fertility Centre of Chicago studied 2,362 IVF cycles of women under the age of 40. They divided the women into three groups:

Thin, with a BMI of 14 to 18
Normal, with a BMI range of 19 to 28 (this would include women considered to be overweight in the UK, as the NHS puts a healthy BMI at 18.5 to 24.9)
Obese, with a BMI of 29 to 43

“There may be differences in the womb's receptiveness to an embryo depending on a woman’s weight. It was possible that being too thin means the body does not think it is the best time to reproduce, even with IVF,” said lead researcher Dr Richard Sherbahn, reports the Metro.

“The take-home message is to have a healthy BMI if possible,” added Dr Richard.