Dr. Sunil Eshwar, Lead Consultant – Laparoscopic Surgeon, Aster RV Hospital
Fertility preservation is an emerging field that provides the opportunity to maintain reproductive health to all those who have to receive medical treatment or want to preserve their gametes to postpone childbearing, age related fertility preservation.
What is egg freezing?
Egg freezing is a type of fertility preservation, also known as mature oocyte cryopreservation, is a method to save women’s ability to get pregnant in future. The eggs harvested from ovaries are frozen, unfertilized, and stored for later use. A frozen egg can be thawed, fertilized, and implanted later on.
Who are the candidates for egg freezing?
Anyone can freeze eggs. This is done for many non-medical and medical purposes. Today in the non-medical purpose of egg freezing there is a social trend towards delaying childbearing. This delay is due to factors related to development of a professional career or economic instability or absence of the right partner. As a consequence, these women may be affected by age related infertility when they plan for pregnancy and egg freezing is proposed as a solution for them.
When is the right time to freeze eggs?
Freezing eggs of a healthy fertile woman is stored to have pregnancy later in life. It should ideally be performed when the women are younger and less than 35 years in order to increase the chances of future pregnancy, but in reality, people come at an older age. The quality declines with age and this has an effect on the pregnancy rates.
What are the steps in egg freezing?
Elective oocyte freezing is done in multiple steps, includes –
Ovarian stimulation:
Ovaries are stimulated gonadotropin injections are given so that multiple eggs are produced, following which egg development is serially monitored with ultrasound. Once eggs are mature enough, injections of hcG / GnRh agonists are given to release the eggs.
Oocyte retrieval:
Once eggs are matured, they are retrieved under sedation or general anesthesia under ultrasound guidance using a needle guided through vagina. A suction device is connected to the needle to aspirate eggs.
Cryopreservation and storage:
Immediately after the eggs are harvested, they are cooled to subzero temperature so that they remain at the age at which they are frozen. This process is called as vitrification., where formation of ice crystals during freezing is prevented. The frozen eggs are then stored in liquid nitrogen until needed.
Are there any risks associated with egg freezing?
There are certain risks associated with ovarian stimulation and egg retrieval.
Injections given for stimulation are prone for ovarian hyperstimulation syndrome where ovaries become painful and swollen. Patient experiences abdominal pain, bloating, nausea, vomiting, diarrhea. This happens either during the stimulation period or after egg retrieval. Treatment depends on the severity of syndrome. First line treatment includes pain relief and adequate hydration.
During egg retrieval needle used for the same can puncture vessels and cause bleeding and infection.
What is the success rate of egg freezing?
The survival rate of eggs following freezing, and thawing is nearly 90-97 %, but egg survival doesn’t guarantee successful pregnancy. The quality of eggs cannot be determined during egg retrieval and age can impact overall success rate. The live birth rate among women who have their egg freezing at 20s or early 30s can be 85%. On the other hand, it falls to 70% among women at 36 or older at the time of freezing.
Generally, the greater number of eggs retrieved the higher the probability of pregnancy since several embryos may be available to choose from. Risk of miscarriage will be based on the age at the time of egg freezing and embryo transfer. Research studies have not found any increased risk of congenital anomalies or pregnancy complications with embryos from eggs that have been frozen for years.
