IVF, ICSI and Egg Donation

IVF, ICSI and egg donation are the three main laboratory routes to pregnancy when natural conception fails. In vitro fertilisation (IVF) joins eggs and sperm outside the body; intracytoplasmic sperm injection (ICSI) injects a single sperm into each egg; egg donation uses another woman's eggs when a patient's own cannot achieve a pregnancy. The right route depends above all on the woman's age and the specific cause of infertility.

Dr. Parul Prakash, Head - Reproductive Medicine (IVF), Artemis Hospitals, Gurugram, India, built her masterclass on that sequence: first what normal fertility looks like, then why it fails, then which treatment answers which failure. This guide follows the same logic. The causes and the workup are covered in depth in causes of female and male infertility and how couples are evaluated, and the laboratory procedures in the IVF and ICSI process, from ovarian stimulation to embryo transfer.

Natural fertility: the baseline every treatment is measured against

Natural fertility is the capacity to produce a child. Dr. Prakash singles out one variable as more important than any other: the age of the woman.

The reason is biological arithmetic. A woman begins life with a fixed number of eggs, and that stock only falls. Dr. Prakash set out the trajectory:

• At 20 weeks of gestation, while she is still in her mother's womb, a female fetus holds her lifetime maximum of 6 to 7 million eggs.
• At birth, the number has fallen to 1 to 2 million.
• At puberty, roughly 300,000 to 500,000 remain.

Only a small fraction of these are ever ovulated. Over a typical reproductive life a woman releases around 400 to 500 eggs; the rest are lost through a continuous process of degeneration, until only a few remain at menopause. Both the number and the quality of eggs decline as a woman gets older, which is why fertility falls with age.

The age curve

Dr. Prakash places the highest pregnancy rates between 25 and 35, and describes a decline by 40. Her phrase for age was blunt: it is the time-limiting factor in a woman's fertility. No lifestyle change, medication or procedure restores eggs that have been lost, and this single fact shapes almost every decision that follows, from how long a couple should keep trying on their own to whether IVF with the woman's own eggs is realistic.

The fertile window

Within each cycle, the opportunity for conception is narrow. In a regular 28-day cycle, pregnancy rates are highest around ovulation. Dr. Prakash gave the two numbers that define the window: the egg survives 12 to 24 hours after release, while sperm survive 4 to 5 days in the female reproductive tract. Intercourse in the days before ovulation therefore matters as much as intercourse on the day itself.

The lining of the uterus has to be ready as well. On mid-cycle ultrasound, Dr. Prakash looks for a triple-line endometrium, the three-layered appearance of a well-prepared lining, which is associated with higher pregnancy rates.

How natural conception works

Every step of IVF replaces or bypasses a step of natural conception, so the sequence is worth stating precisely. Millions of sperm enter the female body at intercourse and travel up to the fallopian tube, where the egg waits after ovulation. One sperm penetrates the egg; its entry triggers a release of calcium ions inside the egg that activates it and completes fertilisation. The fertilised egg becomes an embryo that keeps dividing as it travels back down the tube, reaching the uterine cavity at around day five. If it implants in the lining, the pregnancy test turns positive.

Why infertility is becoming more common

Dr. Prakash reports that the incidence of infertility has increased over the last five to ten years. She attributes the rise to a cluster of modern factors:

• lifestyle habits;
• polycystic ovary syndrome (PCOS), a hormonal condition in which the ovaries carry many small follicles and ovulation becomes irregular;
• stress;
• couples trying to conceive at an older age.

Of these, she ranks two above the rest: the age of the woman, and obesity.

When a couple should see a fertility specialist

Dr. Prakash's threshold for referral is 12 months of regular, unprotected intercourse without conception, for a woman under 35. Standard guidance shortens this to 6 months for women aged 35 and over, because the age curve leaves less time to lose.

Where a cause is already known, such as tubal disease or a uterine problem, there is no reason to wait out the full period: the couple should be evaluated promptly. The same applies to irregular or absent periods, known endometriosis (tissue similar to the uterine lining growing outside the uterus), or a known male factor.

Dr. Prakash's practical point for referring doctors is that both partners are evaluated at the same time. Treating the woman for a year before anyone looks at the semen wastes exactly the time that age makes scarce. The full workup, including ultrasound, tubal testing and semen analysis, is set out in the companion article on causes and evaluation.

When IVF is recommended

IVF is not the first answer to every fertility problem. Lifestyle correction comes first where it is relevant (weight loss and stopping smoking and alcohol), and many causes are corrected surgically. Dr. Prakash lists the situations in which IVF becomes the indicated treatment:

• Severe endometriosis, where the disease is at an advanced stage.
• Genetic conditions, where a couple carries a high risk of passing on a hereditary disease and embryos need to be tested before transfer.
• Low ovarian reserve, where few eggs remain and time is short.
• Bilateral tubal block, where both fallopian tubes are blocked and egg and sperm cannot meet naturally.
• Severe male factor infertility, usually treated with IVF combined with ICSI.
• Repeated failure of ovulation induction, where several cycles of tablets or injections to trigger ovulation have not produced a pregnancy.
• Unexplained infertility, where every test is normal yet the couple has not conceived.

The list follows a single logic: IVF is indicated when the obstacle cannot be corrected inside the body, or when the cost of further waiting is too high.

IVF and ICSI in brief

IVF follows a predictable sequence. Dr. Prakash asks the woman to come in on day two or three of her menstrual cycle, gives about two weeks of injections to stimulate the ovaries, and retrieves the eggs when the follicles reach the right size. The eggs are fertilised in the laboratory, the embryos are grown to day three or day five, and an embryo is transferred into the uterus. A pregnancy test follows two weeks later.

ICSI changes only the fertilisation step. Instead of placing eggs with prepared sperm and letting fertilisation happen, the embryologist injects a single sperm directly into the cytoplasm of each egg. Dr. Prakash uses it when sperm are absent from the ejaculate and have to be retrieved surgically, when the count, motility or morphology is poor, when embryos are to undergo genetic testing, and when earlier IVF cycles have failed to fertilise. The step-by-step detail, from follicle size at retrieval to embryo grading and the micromanipulation technique of ICSI, is in the IVF and ICSI process article.

IVF with donor eggs

Because egg number and quality are the binding constraint, some women cannot achieve a pregnancy with their own eggs at any reasonable probability. IVF with donor eggs separates the source of the egg from the woman who carries the pregnancy: a donor undergoes ovarian stimulation and egg retrieval, her eggs are fertilised with the partner's sperm, and the resulting embryo is transferred into the recipient's uterus.

Who it is for

Donor eggs are the standard option for women whose ovaries no longer produce usable eggs:

• premature ovarian insufficiency or early menopause;
• severely diminished ovarian reserve, often in women at the upper end of the reproductive age range;
• repeated IVF failure attributable to poor egg quality;
• a high risk of passing on a genetic disorder through the woman's own eggs.

The chance of pregnancy with donor eggs depends largely on the age of the donor rather than the age of the recipient, because egg quality is the factor that age erodes. The recipient's uterus, in most cases, remains capable of carrying a pregnancy beyond the age at which her own eggs stop being viable, although obstetric risks rise with maternal age.

Egg donation rules under the ART Act

In India, egg donation is governed by the Assisted Reproductive Technology (Regulation) Act, 2021. Its central provisions for international couples considering treatment there are:

• Donor eligibility. An egg donor must be aged 23 to 35, must have been married, and must have at least one living child of her own who is at least three years old.
• Once in a lifetime. A woman may donate eggs only once in her life, and no more than seven eggs may be retrieved from her.
• Recipient age limits. Assisted reproduction may be offered to women above 21 and below 50, and to men above 21 and below 55.
• Banks and confidentiality. Donor gametes are sourced through registered ART banks, and the donor's identity is kept confidential.
• Parentage. A child born through assisted reproduction is deemed the biological child of the commissioning couple or woman, and the donor gives up all parental rights.
• No sex selection. Choosing the sex of an embryo is prohibited.

The upper age limit of 50 for the woman is worth confirming before travel.

Choosing between IVF, ICSI and egg donation

The decision comes down to three questions a couple and their doctor should answer in order. How old is the woman, and what does her ovarian reserve show? What is the specific cause, in her and in her partner? Can that cause be corrected inside the body, or does it need the laboratory? The answers point to lifestyle change, corrective surgery, IVF, IVF with ICSI, or IVF with donor eggs.

Treatment costs for international patients are set out on the IVF and fertility treatment cost page. For related masterclasses on obstetrics and reproductive medicine, see the obstetrics and gynaecology specialty hub, and for Dr. Prakash's background and practice, her doctor profile.