The back-up plan

Women cannot stop the biological clock from ticking, but now they can do the next best thing: freeze time. Sanchita Sharma writes.

Freezing eggs indefinitely in a cryogenic vat till you are ready to have a baby is the brand new option for women who want to have a baby when they are ready for it. Technically known as oocyte cryopreservation, egg freezing is one way to tackle age-related barriers to childbearing. It extends fertility and raises the chances of conception even after a woman's fertility starts going down after the age of 35.

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The frozen eggs are used for conception using in vitro fertilisation (IVF), whenever a woman is ready.

"While most women go for egg freezing because they haven't found the right man, some opt for it because their partner may not be there for IVF cycles or if they are undergoing some cancer treatment. This allows them to have their own genetic children after 35, when fertility starts to wane," says Dr Abha Majumdar, head of the Centre of IVF and Human Reproduction at Ganga Ram Hospital.

Not all cancer treatments lead to infertility, but some types of chemotherapy and radiation can trigger premature menopause in young women. One such 19-year-old with uterine cancer was referred to Dr Majumdar from the Rajiv Gandhi Cancer Institute.

"Oocyte cryopreservation was the only option for her because after treatment she cannot ovulate," says Dr Majumdar.

Flash freezing
Until recently, the only method for freezing unfertilised eggs was a slow-freezing method. Unlike sperm, which has been successfully frozen and used for years, eggs contain a great deal of water, which causes ice crystals to form within the egg and these destroy the cell structure. The fertilisation and pregnancy rates for these slow-frozen eggs, once thawed, is low.

"New cryopreservation techniques use a flash-freezing process known as vitrification to chill the eggs to minus 196°C in less than a second. This does not allow ice crystals the time to form. The instant freezing preserves the quality of eggs and raises the chances of conception from 10% using the old method to 40%," says Dr Majumdar.

Since Ganga Ram introduced the technique, 13 women have opted for it. Of the seven who have undergone IVF, three have conceived, making the conception rate 42.8%. The average chance of conception in a normal IVF cycle is one in three.

Smriti, 36, a senior marketing executive at a pharma company, had planned to marry at 35, but her husband, who is the same age as her, is not ready for a child yet.

"I don't want to spend the next few years in a state of constant panic, or feel terrible every time I hear one of my friends is having a baby," she says. "Freezing my eggs made me feel as if I was in control of my future," she says.

Tough call
As in routine UIVF, women opting for egg freezing have to inject hormones for 11 days to ovulate.

"Unlike in the past, the new hormones have to be injected subcutaneously - in the fat tissue in the stomach, hips or thighs - which is not painful," says Dr Hrishikesh Pai, IVF specialist at Mumbai's Lilavati Hospital and Delhi's Fortis Group of Hospitals.

The process of harvesting eggs is the same as IVF - hormones are injected for a period of 11 days to stimulate the ovaries to release multiple eggs. All women produce some eggs that are unusable, and the percentage climbs with age.

For a woman in her mid-30s, it can take up to 10-12 frozen eggs to be reasonably sure of a single pregnancy, which means at least two cycles of injecting hormones for viable embryos.

Even then, there is no guarantee that every woman who goes for it will end up with a baby.

"While eggs that are obviously flawed are discarded after retrieval, it's not until the oocytes are combined with the sperms that their viability can be known. Even then there's no way to assure that a seemingly-healthy embryo will implant and result in a baby.

"And with a 40% success rate per IVF cycle, only two in three women go home with a healthy baby," says Dr Pai.

Women should not delay conception thinking they have egg-freezing as insurance, warn experts.

"But it's an option for many who have no other option," says Dr Majumdar.

And the option works for two in three women.

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