Does Obesity Reduce the Odds of Success After a Frozen IVF transfer?
Yes, another post about fertility and weight! But luckily, I bring some good news this time.
Studies have shown that in FRESH IVF cycles obese women have a lower success rate which is thought to be due to uterine receptivity issues.
Researchers from France wanted to know whether the same was true in frozen cycles (FET). In this particular study, 958 women were included who had a frozen embryo transfer between 2012 to 2017 at a French fertility clinic. All embryos were transferred on day 5, the blastocyst stage.
After dividing women into normal weight (BMI >18.5 and <25) and obese (BMI >30) groups -a BMI suggesting “overweight” of >25 and <30 was purposely excluded- the researchers set out to see how they compared. Both the normal and obese groups had similar embryo quality, and both groups of women had the same number of embryo’s transferred (84% were single embryo transfers).
So Does Obesity Reduce Success Rates?
The clinical pregnancy rate was the same (about 22%), the miscarriage rate was slightly higher among obese women but within the margin of error (10% vs 7%), and the live birth rate was almost the same too (19% vs 20%).
That’s not bad at all!
The researchers seem to think that these results might be explained by obese women’s uterus being less receptive in a fresh transfer due to ovarian stimulation hormones affecting their bodies differently. But, frozen transfer cycles don’t have this issue.
And although this research is preliminary and needs confirmation, it does suggest that among obese women, frozen transfers could be a good alternative to a fresh cycle.
Reference:
Prost et al. 2020. Female obesity does not impact live birth rate after frozen-thawed blastocyst transfer. Human Reproduction, 35(4), 589-865.
