Women With PCOS Have A Better Chance At Getting Pregnant With A Frozen Embryo
作者：Dr Ambar Rafique
Experts from Shandong University, China, and University of Pennsylvania have recently conducted a study which carries significant findings for women who wish to get pregnant but are suffering from polycystic ovarian syndrome (PCOS). According to this multi-central study, in vitro fertilization (IVF) from frozen embryo transfer yields higher live births than fresh embryo.
Women who underwent frozen embryo transfer had 49.3% live births while it was recorded 42% for women who underwent fresh embryo transfer.
The study which was conducted from 2013 to 2015 brings a better understanding about how the state of embryo affects greatly on the IVF treatment outcome for women with PCOS. The study’s findings were published by the New England Journal of Medicine (NEJM) on 10th August. They may have been successful in proposing a better streamlined IVF treatment for women with PCOS.
Previously, using fresh embryos for in vitro fertilizations has been preferred for years. The last decade, however, has seen a shift in trends and this study has further validated the use of frozen embryo transfer. The newly conducted study accumulated a large scale data solely for the women with PCOS.Affecting about 10% women in their childbearing age, this hormonal imbalance is often a result for infertility which causes the women to seek help from IVF procedures. However, miscarriages, preterm births, low live birth rates or other complications remain a cause of distress for couples who go through expensive and painful procedures just to witness futile results.
In this study, a total of 1,508 infertile women were divided into two groups by a randomized method to either undergo frozen embryo transfer or fresh embryo transfer in IVF procedure. Prior to the transfer, the fresh embryos and the cryopreserved embryos were developed in laboratory for three days. By the end of regular follow-up visits, it was found that live birth rates were better with frozen embryo transfer.
The women who underwent frozen embryo transfer had a lower rate of pregnancy loss, which was as low as 22%, as opposed to the pregnancy loss in fresh embryo transfer which was 32.7%.
Up to 70% of women undergoing IVF treatment have a tendency to develop a complication known as ovarian hyperstimulation syndrome (OHSS). Characterized by ovarian enlargement (due to ovarian cysts) and fluid shift in extravascular cavity. This condition can range from mild to severe symptoms. Disrupting the blood flow and causing swelling in the ovaries, this causes abdominal pain in the women who are already under constant medications, exogenous hormones and stress. However, no effect on the fetal health has been reported in successful IVF implantations.
While the researchers observed the effect of embryo transfer on OHSS incidence rate, it was found that in frozen embryo transfer group, the rate was 1.3% as opposed to 7.1% in fresh embryo transfer. While these statistics give using frozen egg transfer an edge over fresh egg transfer, an anomalous finding suggested that higher frequency of preeclampsia (hypertension during pregnancy) was found in frozen egg transfer cases which were recorded to be 4.4% as compared to 1.4%. However, further investigation proved that these cases of preeclampsia were mild and posed no serious threat to the fetal health.
It is worth noting that the other pregnancy and neonatal complications in both cases remained constant and had no statistical effect on the final results. However, 5 neonatal deaths were observed in frozen embryo transfer while no neonatal deaths were recorded in fresh embryo transfer group. But no explanation was given on this. Further research is warranted to understand if these neonatal deaths had a correlation to the egg transfer method.
Link Between PCOS And Infertility?
PCOS is a common endocrine system disorder which disrupts the levels of female sex hormones. Women with PCOS have enlarged ovaries containing small collections of fluid in the form of cysts that are spread over the ovaries. These cysts produce varied levels of hormones and adversely affect the women’s reproductive abilities. Marked commonly by irregular and painful menstrual cycle, obesity, facial hair, acne, bloating and tenderness, the hormonal imbalance in PCOS tends to affect ovulation leading to infertility issues.
Fresh Embryo Transplant vs Frozen Embryo Transplant
Fresh embryo transplant is a process in which the embryo is implanted back into the uterus of the women who is undergoing IVF treatment without any delay. On the contrary, in frozen embryo transplant (FET), successfully fertilized eggs are frozen below a temperature of 190 C under laboratory conditions, only to be thawed and implanted into the woman’s uterus when she is ready to get pregnant.
The success rate of FET was low some time ago as freezing facilities were not as good as they are now. This low rate of success was because of the compromised embryo quality which resulted by crystallization of ice residues which consequently etched to the egg, following the process of embryo freezing.
But with improved cryopreservation techniques, the success rate has been overwhelming. This can help achieve recovery from hyperstimulation of ovaries. This, in turn, will be a predictor for high success rate of implantation and an eventual live birth.
In this regard, Richard Legro, professor of obstetrics and gynecology and public health sciences at Penn State College of Medicine, commented, “This protocol potentially offers immediate benefits to women with PCOS, so practitioners should consider freezing all embryos for these patients. By electing to freeze all the embryos, you create a healthy environment for the best embryos, as opposed to putting them back in a disturbed environment.”
This study certainly brings hope to millions of women across the globe who are living with PCOS, which in turn is a leading cause of infertility for women.