(RxWiki News) The invention of in vitro fertilization (IVF) has allowed many couples to become parents when it might not otherwise have been possible. But different factors can influence how well IVF works.
IVF is a process in which an egg is fertilized with sperm outside of a woman's body and then re-inserted into a woman's body.
Women can receive fertilized eggs that originally came from their own bodies or that came from an egg donor's body.
A recent study found that obese women receiving a donor's eggs were no less likely to conceive than women of a normal weight who received donor eggs.
"Discuss IVF options with your fertility doctor."
This study, led by E. S. Jungheim, of the Department of Obstetrics and Gynecology at Washington University School of Medicine, looked at whether being obese influenced how successful IVF was when the woman received donated eggs.
Past research has already shown that obese women receiving their own eggs have a lower chance of conceiving than women of a normal weight.
But this paper looked at all the studies related to obese women receiving donor eggs from someone else during IVF.
From a search of three medical research databases through December 2011, the authors identified 475 possible articles that dealt with IVF and body mass index (BMI).
BMI is a ratio of a person's height to weight. It is used to categorize people as having a healthy weight or being under- or overweight.
After excluding studies that did not meet their criteria, including ones that only looked only at frozen embryos (instead of both frozen and fresh ones), the researchers reviewed seven studies.
They were able to combine the data from five of these studies, along with data from the University of Washington involving 123 women. The data from the other two studies were not able to be extracted for inclusion in the overall analysis.
Overall, 4,758 women were included in the analysis of all the studies together.
From all these women, the researchers did not find women's weight to have any influence on whether the transferred embryo implanted in their uterus.
Even among women who were obese, the chances of the donated embryo implanting were just as good as they were for women of a normal, healthy weight.
Obese women were also no more or less likely to have a miscarriage or live birth than women with normal weights.
The authors said that these results meant it was possible that the quality of the egg matters more than the environment of the uterus.
In other words, obese women using their own eggs may have more difficulty with implantation because the eggs themselves are not as healthy, not because the woman's uterus is unfriendly to a fertilized egg.
This study was published July 11 in the journal Human Reproduction. The research was funded by the Women's Reproductive Health Research Program at the National Institutes of Health. The authors declared no conflicts of interest.