Fertility experts, supported by extensive research, have long advised that obese women can potentially improve their fertility by losing weight.
Now, two new studies report that obesity decreases the success rates of in vitro fertilization (IVF).
One study found that compared to normal weight women, the birth rate decreased 19% by being either overweight or obese – from 42% for normal weight women to 23% in overweight or obese women.
The other study found that moderate obesity decreased the birth rate 8% – from 30% for normal weight women to 22% for moderately obese women.
Greater levels of obesity also correlated with poorer birth outcomes, with only 15% of severely obese women having successful pregnancies.
Though excess weight seemed to affect IVF outcomes, researchers found that short-term weight loss didnâ€™t actually help improve birth rates.
Researchers arenâ€™t sure why overweight women have less success with IVF. Â Therefore, further research into the field is needed to provide mechanistic insight into the correlation.