From ‘the only’ choice to ‘one of the choices’, today’s educated Indian woman has come a long way in her journey towards motherhood. Not so long ago, successful pregnancy used to be the most poignant issue in the life of married childless women post their late 20s. However, in the last decade or so, advances in assisted reproductive technology have helped, to a large extent, in taking off the mounting pressure of procreation before a certain age.
Egg freezing is one such reproductive technique that is fast becoming an option for the informed women of today, who are not ready for babies right now due to relationships, career, finances or a whole host of other reasons. Egg freezing, also known as oocyte cryopreservation, is a process in which a woman’s eggs (oocytes) are frozen (vitrified) and stored as a method to preserve their fertility. The technique has advanced greatly over the past few years leading to better egg survival rates, fertilisation and live birth rates when these eggs are thawed.
Egg freezing has allowed the modern woman a much greater degree of autonomy and control over her life than before. One of my patients, 36-year-old Anjali Bhagat (name changed), knew she wasn’t ready for marriage but she did know that she wanted to be a mother someday. She froze her eggs at the age of 32, determined that she didn’t want to be pushed into a marriage that she didn’t want, for the sake of maternity.
Egg freezing is particularly useful in IVF cases, as was discovered by Sheela Iyer (name changed), a 31-year-old from Matunga. Sheela’s husband was under tremendous pressure when they decided to go in for IVF. Stress on the day of egg collection was so great that he was unable to produce a semen sample. Luckily Sheela’s eggs could be frozen and they were able to complete the IVF process at a later date. Today Sheela is happily pregnant.
Egg freezing is also a recommended fertility preservation option for cancer patients. Cancer treatments are known to cause premature menopause. Egg freezing turned out to be a boon for 14-year-old Asha Patil who was diagnosed with borderline cancer of one ovary and this ovary had to be removed. We collected her eggs from the remaining ovary and froze them before chemotherapy. We were able to protect her fertility.
However, it is vitally important to know that freezing eggs does not guarantee a baby, and just offers a reliable insurance plan. When frozen eggs are used to create a baby, they must complete several steps, like surviving the thaw, fertilising, implant and hopefully a baby. Lastly, if a woman already has a partner but the couple is not yet ready for children, freezing embryos rather than eggs is a better option. Eggs are more delicate compared to embryos. More embryos survive the thawing process compared to eggs, resulting in better chances of pregnancy.
WHO NEEDS EGG FREEZING?
- Women requiring chemotherapy and/or pelvic radiation therapy for cancer that may affect their fertility.
- Surgery that may potentially cause damage to the ovaries.
- Women at risk of premature ovarian failure because of chromosomal abnormalities (eg: Turner syndrome, fragile X syndrome), or women with a family history of early menopause.
- Women with ovarian disease that may damage the ovaries. Eg: ovarian endometriosis, chocolate cysts.
- Women with genetic mutations that increase their risk of cancer where the advice is for prophylactic removal of ovaries (Eg: BRCA mutation).
- Fertility preservation for social or personal reasons to delay childbearing.
HOW ARE EGGS FROZEN?
- Assessment of the ovarian reserve by blood tests and pelvic ultrasound.
- Ovarian stimulation with injections and egg collection procedure like that for IVF. Egg collection is aspiration of the follicular fluid from the ovary with a needle to extract the eggs.
- Eggs are then preserved using vitrification. This is a method of ultra-rapid cooling using liquid nitrogen. Eggs are then stored in liquid nitrogen.
- When the woman is ready to achieve pregnancy, these vitrified eggs are thawed. Those that survive are then fertilised by the ICSI technique, where a single sperm is injected directly into the egg, and the fertilised eggs will grow in culture until the embryo(s) are ready to be transferred into the uterus to achieve pregnancy, typically 3-5 days after fertilisation.
1986: FIRST REPORTED HUMAN BIRTH FROM A FROZEN OOCYTE
- EGG FREEZING SUCCESS RATES
Two most important factors in determining the probability of a live birth are the woman’s age at the time of egg freezing and the number of available eggs. Clinical pregnancy rates quoted in world literature vary between 4-12 per cent per oocyte depending on age at freezing and whether the woman has any other medical issues.
- DO BABIES BORN OF FROZEN EGGS HAVE HIGHER RISK OF BIRTH DEFECTS?
Available data comparing births resulting from previously frozen oocytes with those from fresh oocytes have not shown an increased risk of congenital anomalies. More long-term data, however, will be needed to further assess risks if any.
- WHAT ARE THE RISKS OF EGG FREEZING?
Risks are similar to those associated with ovarian stimulation for IVF, which include small risks of ovarian hyper stimulation syndrome (enlargement of the ovaries and fluid accumulation in the pelvis and abdomen), infection, and bleeding related to the egg collection procedure.
- HOW LONG CAN THE EGGS BE STORED FOR?
Storing the eggs for longer durations does not appear to have negative effects. In India, the ICMR rules state that assisted reproductive treatment (ART) can be offered to a woman until her age of 50. Hence, the frozen eggs should be thawed, embryos created and transferred before the lady’s 50th birthday.
(Dr Rajalaxmi Walavalkar is a consultant, IVF and Reproductive Surgery at the Cocoon Fertility Centre)