In vitro fertilisation (IVF): a clear guide

The first successful IVF case was in 1978, when a British woman delivered a baby called Louise Brown on 25 July 1978, in Oldham, England, by caesarean section. The technique was developed by the physiologist Robert G. Edwards, who was awarded the Nobel Prize in 2010.

Most of the anxiety around IVF comes from not knowing which stage you are on, or what the next one is for. It helps to see the whole sequence at once.

What in vitro fertilisation means

Eggs are retrieved from the ovaries and fertilised in the laboratory in a dish. Sperm are added to it, after a special medium is used for semen washing. The dishes are placed in incubators until embryos form, and the embryos are then transferred into the uterus — which is done from 2 to 5 days later.

Who IVF is for

Unexplained infertility — mainly after 2 years of unprotected intercourse with no obvious cause.

Female causes

• Problems with the fallopian tubes: obstruction, salpingectomy following an ectopic pregnancy, or hydrosalpinx
• Endometriosis
• Ovulation problems, including polycystic ovarian syndrome (PCOS)
• Antibodies affecting both eggs and sperm

Male causes

• Defects in sperm quantity and/or quality
• Inability of the sperm to penetrate the cervical mucus
• No sperm seen in the semen fluid

Pre-implantation genetic diagnosis (PGD), to rule out genetic disorders.

The seven steps

1. Evaluation

Every couple is assessed before treatment, with investigations to find out whether the infertility can be treated without resorting to IVF. These include blood tests, semen analysis, evaluation of the fallopian tubes, and an ultrasound scan of the ovaries and uterus.

2. Ovulation induction

The aim is to produce several good follicles for fertilisation, using daily gonadotropin injections, most often with an antagonist protocol (recommended by ESHRE because it lowers the risk of ovarian hyperstimulation), or a long protocol in selected cases. Regular ultrasound monitoring follows the follicles as they develop, and the dose is adjusted accordingly. When they reach a certain size, final maturation is triggered with HCG, or with a GnRH agonist injection in women at high risk of ovarian hyperstimulation.

3. Egg retrieval

Egg retrieval is done 34 to 37 hours after the HCG injection. It is minor surgery, performed under general anaesthetic with ultrasound guidance, and takes 15 to 20 minutes. No more than two hours are needed to recover before going home. A needle aspirates all the follicles, and the fluid passes to the embryologist, who identifies and separates the eggs.

It is worth knowing that not every follicle seen on ultrasound contains an egg that can be fertilised. Up to 20–30% of follicles are empty.

4. Sperm and egg preparation

The eggs are stripped of the surrounding cells while the sperm are prepared in a special medium. Traditional IVF needs 10,000 to 100,000 motile sperm placed beside each egg in a dish.

This differs from intracytoplasmic sperm injection (ICSI), where only one sperm is injected into the cytoplasm of the egg — indicated for significant male-factor infertility (low sperm count, motility or shape), after failed fertilisation in a previous IVF cycle, and when sperm are retrieved surgically from the testes or epididymis.

5. Fertilisation

The prepared sperm and eggs are placed in the same dish. Where fertilisation fails with standard IVF, ICSI is recommended for the next cycle; if a problem with fertilisation is expected, ICSI is planned from the start.

6. Culture and grading

16 to 18 hours after fertilisation the eggs, now called zygotes, are cultured in incubators that support division and development. If the couple has a history of a genetic disease and the responsible gene has been identified, pre-implantation genetic testing (PGT) may be performed on a few cells taken from the embryo, usually at the blastocyst stage (day 5–6).

Grading of the embryos is done against specific criteria.

7. Embryo transfer

Embryos are transferred into the uterus 2 to 5 days after retrieval, depending on their quality and number, using a special transfer catheter. Drugs are given to support implantation. There is no need for a long hospital stay — one hour is usually sufficient — and patients from other countries can travel the next day if they wish.

Side effects and risks

During ovulation induction

Ovarian hyperstimulation syndrome (OHSS) occurs in less than 10% of ovulation induction cycles, whether for IVF or for other treatments. Mild OHSS is common and settles on its own; moderate OHSS occurs in about 3–6% and severe OHSS in about 0.1–2% of IVF cycles, and severe cases may need admission to hospital. In severe cases patients report:

• Lower abdominal pain
• Nausea and vomiting
• Reduced urine output
• Shortness of breath
• Fluid collecting in the abdominal cavity

If you notice any of these symptoms, contact the clinic immediately or go to the emergency department — severe OHSS also increases the risk of blood clots and needs prompt medical care.

During egg retrieval

• Anaesthetic complications
• Lower abdominal pain
• Mild vaginal spotting from the needle
• Intra-abdominal bleeding
• Genital tract infection
• Injury to bowel or bladder, in rare cases

If the cycle succeeds

There is a risk of multiple pregnancy and its complications, of miscarriage, and of ectopic pregnancy.

If the cycle fails

There is a real risk of depression for both partners — and the financial burden should not be forgotten either.

When to do the pregnancy test

2 weeks after embryo transfer. If the blood test is positive, the pregnancy sac can be seen one week later.

Success rates

For centre-specific figures and tables by age, see success rates of IVF, ICSI, TESA/TESE and IUI.

Success depends on several factors. The most important is the woman’s age: as age advances, the success rate declines. Egg and sperm quality, and the number and quality of embryos, matter too.

General success rates (international figures)

Age	General success rate
Under 35	41–43%
35–37	33–35%
38–40	23–27%
Over 41	13–18%

Our centre — clinical pregnancy rate per embryo transfer

Age	Our centre
30 and under	71%
35 and under	63%
40 and over	40%
Overall	53%

See also: our IVF success rates

Increasing the number of embryos transferred raises the success rate — and raises the risk of multiple pregnancy and of miscarriage along with it. A balance has to be struck, taking into account maternal age, previously failed attempts, and embryo grades.

For most women under 35 with a good-quality embryo, current international guidance (ASRM, ESHRE) recommends transferring a single embryo and freezing the rest, as this gives a similar chance of a baby with far fewer twin pregnancies.

Two further factors play a part: whether there is a genetic abnormality that will reduce implantation, and whether the endometrial lining of the uterus is of good quality.

What else affects the outcome

• Whether the cycle is regular
• Semen fluid analysis
• AMH, in some cases
• Smoking
• BMI and the percentage of body fat
• The health of the tubes

Additional techniques such as assisted hatching and intracytoplasmic morphologically selected sperm injection (IMSI) may be considered in selected cases, but current evidence (ESHRE 2023) has not shown that they increase the chance of a baby when used routinely.

If ovulation happens before retrieval

There are two options: cancel the cycle and start again the following month, or perform intrauterine insemination (IUI) if that is possible.

After the transfer

**[**You can return to normal daily activity straight after the embryo transfer** — rest does not improve the chance of pregnancy. Avoid very strenuous exercise until the pregnancy test; travel is possible when needed.

Fertilization / Fertility Potential | IVF and ICSI Videos | How to Increase Fertility for Men and Women (Guide to Preparing for IVF) | Treating Failed IVF (IVF/ICSI Failure)