Transferring just one – rather than multiple – fertilized donor eggs doubles the chances of a healthy birth, according to a new study.
Using IVF increases the odds of having twins or multiples, which in turn increases the likelihood that the babies will be born premature and underweight.
Many women choose to have multiple embryos transferred in IVF in order to save money and improve their chances of getting pregnant. But in light of the study’s findings, the authors urge women to use only one embryo.
The University of Colorado and Duke University study is the largest to date to look at outcomes of pregnancies using fresh and frozen donor eggs.
Using just one fertilized fresh or frozen donor egg in IVF doubles the chances of having a healthy baby, a new study finds
IVF – in vitro fertilization – has been around since the late 1970s, but with the advent of reliable cryogenic freezing technology, more and more women have been choosing to use cheaper frozen donor eggs, or even freezing their own.
In traditional IVF using fresh eggs, the donor egg is immediately fertilized with a semen sample and then inserted into the uterus of the hopeful mother. For the process to work, not only do donor, doctor, father and recipient have to move quickly, but the egg donor and recipient have to have their hormonal schedules synced up.
With more moving parts, IVF with fresh eggs can take more time, patience, work and money.
Frozen eggs can be cryogenically stored for up to 15 years, and are ready to be fertilized as soon as they have thawed.
Egg-freezing is now a commercially available service, but using them for IVF was still an ‘experimental’ procedure up until 2013, says Dr Jennifer Eaton, study co-author and Duke University medical director of reproductive technologies.
Women have even begun flocking to clinics to freeze their own eggs in order to focus on their careers while preserving their chances of having a healthy baby later in life.
Cryobanks, unsurprisingly have touted the practice as just as effective, and much affordable and simple than the use of live eggs. But, the practice is so new that there hasn’t been enough data to prove whether or not it works just as well as IVF with fresh eggs.
The Colorado and Duke study is the first comprehensive comparison of the two methods, comparing out comes for 30,000 patients who underwent IVF between 2012 and 2014.
‘We now know that using [frozen] bank eggs has no negative outcomes,’ as compared to using fresh eggs, Dr Eaton says.
According to her study, fresh donor eggs are slightly more likely to successfully implant in the recipient’s uterus and result in a live birth, but the outcome is not ‘clinically significant.’
There are elevated risks for multiple births, and babies that are premature and have low birth rates for both forms of IVF, but especially for those who use fresh donor eggs. This ‘deserves more attention,’ the study authors write.
Often, women opt to have more than one embryo fertilized and transferred, primarily because the process is so expensive, and doing so increases their odds of at least one successful pregnancy.
What’s more disconcerting is that clinic’s ‘success rates are published publicly, so there’s competitions between clinics to have the best pregnancies rates, and I think that drives some clinicians to transfer more embryos than they should,’ Dr Eaton says.
She adds that the American Society for Reproductive Medicine’s (ASRM) guidelines recommend that only one embryo should be transferred at a time. And yet, 22.5 percent of IVF procedures with frozen eggs and 31.9 percent of those with fresh eggs result in multiple births.
This, Dr Eaton says, ‘is concerning because multiple births are at risk for premature birth or low birth weights.’
Her team’s findings suggest that ‘women should strongly considering having one just one embryo transferred, because it’s going to give them the best odds of having a healthy baby.’