China – A new study has concluded that women with polycystic ovarian syndrome (PCOS) who do In Vitro Fertilization (IVF) have a better success rate if impregnated with a frozen embryo.
Dr. Zi-Jiang Chen led the research recently published in the New England Journal of Medicine from the Center for Reproductive Medicine at Shandong Provincial Hospital in China.
The researchers studied one thousand and five hundred women who suffered from PCOS and were trying IVF for the first time. Collecting the data signify a group effort from fourteen medical centers throughout mainland China in the span of two years (2013-2015).
The participants were randomly selected in two different groups. The first group received frozen embryos, “harvested” a month earlier, while the second groups had fresh embryos implanted.
All the women were monitored during their pregnancy term. The study concluded that there was almost no difference in the pregnancy rates among users or frozen embryos and users of fresh ones.
The discovery, however, was the fact that 49.3% of the women who used frozen embryos gave birth to a baby, compared with 42% of women who selected fresh embryos.
This means that women who used frozen embryos had less chance of having an abortion, and the babies had a higher birth weight.
Although the research was not supposed to shed light on why frozen embryos are more successful, the team argues that the waiting period allows the woman body to cleanse the hormones that are used during the “eggs’ harvesting.”
Critiques
Dr. Owen Davis, associate director of in vitro fertilization at the Center for Reproductive Medicine at Cornell Medical College, said that the fact that all participants had PCOS gave an inevitable conclusion that frozen embryos have more probabilities in reaching the pregnancy’s term that the fresh ones.
However, the same homogeneity means that one can not apply them to the general population. Since the majority of women who try IVF do not suffer from PCOS, the study may not be useful for them.
Davis also noted that during the experiment occurred five neonatal deaths and two still births in the groups that used the frozen embryos, while none occurred in the group that used the fresh embryos.
“It could be a statistical blip, but they were responsible and fair with how they dealt with it […] It’s a small red flag and something that does require further investigation” stated Davis.
The Centers for Disease Control and Prevention and the Society for Assisted Reproductive Technology only monitors the birth rates of living babies, since that is the goal of the IVF procedure.
But the researchers from the Center for Reproductive Medicine at Shandong Provincial Hospital hope to change this, and that the Centers will begin to use all births as a way to measure success.
Test-tube babies
Almost four decades have passed since Louise Brown, the first test-tube baby, was born on 25 July 1978, in Oldham General Hospital, United Kingdom. Since that year, more than five million people around the world owe their conception to a petri dish.
For the IVF procedure, doctors “harvest” eggs from a woman, mixing them with sperm to fertilize them. Generally, after a few days, the fertilized egg becomes an embryo that is implanted in the uterus or can be frozen and stored.
Source: LA Times