A new study has added to a growing body of evidence that natural IVF results in healthier babies. The study, conducted by a group of American scientists, retrospectively analysed the birth weights of babies born to women through both conventional and natural IVF and found that babies from the natural IVF cohort had a significantly higher average birth weight.
Natural IVF is a form of IVF where no stimulating drugs are used. The ovaries are instead left unstimulated and the egg in the dominant follicle is collected. This is very different from conventional IVF which uses high doses of stimulating drugs in order to collect multiple eggs. Although natural IVF was the original form of IVF and used in the birth of the first IVF baby Louise Brown, it has since become less popular with IVF providers, who often prefer to offer conventional IVF as it is likely to result in the collection of more eggs. Conventional IVF has now been the norm for several decades and there has long been speculation as to whether this approach has any negative effects for resulting babies. There have been a few studies examining this question which have suggested that natural IVF may result in increased birthweight of babies compared to conventional IVF.
This most recent study retrospectively examined the cycles of 364 women, 174 of whom had undergone stimulated IVF and 190 of whom had undergone natural cycle IVF. The researchers examined the length of gestation and birthweight. They discovered that the average birthweight of babies born through natural IVF was significantly higher than the average weight of babies from the conventional IVF cohort. This was despite the natural IVF patients being slightly older on average. These results suggest that natural IVF may not just increase the likelihood of babies going to term but may actually change outcomes even for babies born early, perhaps due to a higher quality egg being collected without the use of stimulating drugs.
There are a few limitations with this study, including the small sample size of patients and the fact that information was studied retrospectively. However, the statistically significant results suggest that natural IVF could help to reduce the risk of low birth weight in babies born through IVF.
Mak, W; Kondapalli, L.A; Celia, G; Gordon, J; DiMattina, M; Payson, M. (2016). Natural cycle IVF reduces the risk of low birthweight infants compared with conventional stimulated IVF. [online], volume 31. Available from: http://humrep.oxfordjournals.org/content/31/4/789.abstract. [Accessed 20th July 2016].