Oocyte Freezing – Process & Benefits
“We report the first pregnancy and birth in India after the transfer of embryos generated from frozen- thawed oocytes. A 29-year-old woman with previous bad obstetric history and an abnormal karyotype, necessitating a donor oocyte programme. Embryos were generated by microinjection of frozen-thawed sperms into thawed human oocytes (intracytoplasmic sperm injection). This resulted in an healthy male baby with a birth weight of 2.54 kg which was born by cesarean section at 35-36 weeks of gestation with normal follow-up.
This was published in January 2009, and it happened in Chennai, as mentioned the mother had a difficult obstetric history but was still able to give birth to a healthy baby from Oocyte freezing.
Till now more than 5000 babies have been born with frozen eggs, more recently on October 31 2022 , Lydia and Timothy Ridgeway were born from what may be the longest-frozen embryos to ever result in a live birth. The embryos were frozen on April 22, 1992. For nearly three decades, they sat in storage on tiny straws kept in liquid nitrogen at nearly 200 degrees below zero.
When freezing is done at 200 degrees below zero, the biological processes slows down to almost nothing, hence being frozen at that level it doesn’t matter if it was a week, a month , a year or a decade
Freezing of one’s eggs is catching up globally since a decade, and more recent times, in India. But there is still a certain uneasiness related to it due to lack of proper information and knowledge about the same. It is considered as unnatural and unconventional, just like all the other modern techniques which came in and were initially shunned, this process too may take a little thawing in people’s mind till it is normalized in society.
Egg freezing, or oocyte cryopreservation is a process in which a woman’s eggs (oocytes) are extracted, frozen and stored as a method to preserve future reproductive potential in women of reproductive age. Since the first birth in 1986 there has been an improved overall success of eggs surviving the freezing. Statistics say that although the freeze doesn’t affect the quality of the eggs, the age of the embryo shouldn’t affect the health of the child. What matters more is the age of the woman who donated the egg that went into the embryo.
The first step would be a visit to the gynecologist, who will start the screening process with ovarian reserve testing, which is a process that estimates the number of eggs a woman possibly has or can harvest for freezing, this is done usually through blood tests and an ultrasound. There will be other screening for diseases like HIV and hepatitis.
After the tests are cleared, doctors will have a better idea on how to proceed with a particular case as everyone’s hormone profiles are different. The menstrual cycle is tracked and the person will be injected with gonadotropin hormones to simulate their ovaries to produce more eggs. There might also be a need to prevent premature ovulation.
There will be constant monitoring via blood tests and ultrasound examinations to keep an eye on the growing follicles. This process takes anywhere between nine to 12 days.
The eggs are then harvested through a surgical procedure (usually a transvaginal ultrasound aspiration) conducted under short general anesthesia. These unfertilised eggs are then frozen to sub-zero temperatures (-196 degrees centigrade) to pause all its biological activity, and preserve it in its best state. When the patient is ready to attempt pregnancy (this can be several years later) the eggs are thawed, injected with a single sperm to achieve fertilization, and transferred to the uterus as embryos.
The reasons for egg freezing could be either social or clinical. A woman who might be suffering from cancer and would like to preserve her eggs before going in for her chemo, this would be a clinical reason. Women suffering from endometriosis or other ovarian disorders who might need surgery are also ideal candidates for oocyte freezing before surgery, as a survey might reduce egg count. There are several women who are not ready to embrace motherhood, might be due to higher education or professional pursuits; this is what would be a social reason. Eggs gradually reduce after a woman attains the age of 35, and by 40 the likelihood of miscarriage is about 45 percent and by the time they reach 45 the it is as high as 75 percent. As fertility declines by the time a woman turns 35 and significantly reduces by 40, the best age to freeze one’s eggs is in the late twenties or early thirties. The embryos formed from oocytes frozen at a younger age have bigger potential of giving a healthy and successful pregnancy.
Many Multinationals like Apple, Meta and Google have announced medical benefits for women who want to freeze their eggs, they regularly conduct seminars and workshops that spread awareness of the benefits of it. Early egg freezing gives women the freedom to live without the fear that their biological clock is ticking, it also ensures that the woman can bear her own genetic offspring whenever she wants.