Safe Healthy Pregnancies
1. These are all high risk pregnancies with likely complications and health problems for mother and babies that are significantly reduced in singleton pregnancies.
PFC has been a long-time proponent of single embryo transfer and healthy pregnancies and we have developed two strategies that help us maintain high pregnancy rates following the transfer of just one embryo. First, we were one of the early adopters of an embryo freezing technology called vitrification back in 2006. Vitrification is a much more efficient method of preserving embryos for future use and it works so well that patients can transfer just one embryo knowing that their others will be safely stored and available for use at any time. The older slow freeze method was less reliable and patients were more inclined to transfer multiple embryos in case remaining embryos didnt survive freezing and thawing. The second innovation was offering widespread chromosome screening on embryos, which allows patients to transfer only embryos that have the normal number of chromosomes. Before 2010 this testing was not as reliable or as accurate as current methods, so patients opted for two or more embryos at transfer to allow for potential loss due to chromosomal abnormalities. Therefore, a patient at age 38 for example, where we know that 50% of embryos are abnormal, would transfer two embryos. The outcome would be zero, one or two embryos implanting, so twins happed too often. By testing the embryos in advance, we eliminated the need to transfer multiple embryos.
As a result of these strategies, we have had NO triplet pregnancies for the last three years among both fresh and frozen cycles. In addition, we gleaned the following information.
With our fresh embryo transfers (ETs), we transfer:
- 1 embryo 64 percent of the time
- 2 embryos 25 percent of the time
- More than 2 embryos less than 10 percent of the time
The small number of cases where we end up transferring more than two embryos tend to be patients that dont want genetic testing and are transferring whatever small number of embryos they have.
Since January of 2015, we performed 277 fresh ETs from 1,373 retrievals. These are roughly split 50:50 between cleavage-stage and blastocyst-stage transfers. Eighty-eight percent of the pregnancies from fresh embryo cycles were singletons.
With our frozen embryos;
- 1,249 (91 percent) of these were single embryo transfer (SETs)
- 127 (9 percent) were double embryo transfers (DETs).
Among frozen embryos transfers, 889 (65%) were elective SETs (i.e. the patients had more than one embryo in the freezer but chose to thaw and transfer only one). Ninety-two percent of the pregnancies from our frozen embryo cycles were singletons.
At PFC, building healthy families, one healthy baby at a time, has long been our mantra. These data reflect that, by and large, we are being successful in this effort.