In vitro fertilisation (IVF): process, steps and treatment
In brief
In vitro fertilisation (IVF) involves stimulating the ovaries, collecting the eggs, bringing them together with sperm in the laboratory, then transferring an embryo into the uterus. One cycle takes about three to four weeks, from the start of stimulation to the pregnancy test. Good-quality embryos that are not transferred can be frozen for a later attempt.
What is IVF and when is it recommended?
In vitro fertilisation is an assisted reproduction technique. The meeting of egg and sperm, which normally happens in the fallopian tube, takes place in the laboratory. The resulting embryo is then placed in the uterus.
It is offered in particular in cases of:
- blocked or damaged fallopian tubes;
- endometriosis, depending on its impact and the woman's age;
- sperm abnormalities (ICSI is then often used, see below);
- ovulation disorders that have not responded to simpler treatments;
- unexplained infertility, after unsuccessful inseminations or straight away depending on age;
- use of donor eggs or sperm, or preimplantation genetic testing.
It follows a complete fertility assessment of the couple.
How do I prepare for IVF?
Before the first attempt, several steps are needed:
- a complete assessment of the couple, with some tests needing to be less than a few months old: ultrasound, hormone tests including ovarian reserve, semen analysis, and the infectious disease blood tests required by regulations for both partners;
- a consultation with the fertility centre team, who explain the protocol, your chances of success, the risks and the practical demands;
- paperwork: written consent from the couple or from the single woman and, in France, an application for 100% coverage by the Assurance maladie (the French national health insurance);
- a meeting with a psychologist, offered in many centres and sometimes compulsory depending on the situation, particularly with donor eggs or sperm.
Lifestyle matters for both partners: stopping tobacco and cannabis, limiting alcohol to fewer than 5 drinks a week, a Mediterranean-style diet and regular physical activity. These measures are recommended by the French College of Gynaecologists and Obstetricians (CNGOF, 2022) for all infertile couples. Women are advised to take folic acid before conception.
According to the CNGOF, a polyp larger than 10 mm, a fibroid distorting the cavity (FIGO 0 to 2), adhesions inside the uterus (synechiae) or a swollen fallopian tube (hydrosalpinx) are operated on before IVF. Dr Kadoch can then refer you to a medically assisted reproduction centre suited to your situation.
What are the steps of IVF?
| Step | What happens | Approximate duration |
|---|---|---|
| 1. Ovarian stimulation | Daily hormone injections, monitored by blood tests and ultrasound scans | About 10 to 12 days, depending on the centre's protocol |
| 2. Trigger | An injection triggers the final maturation of the eggs | One injection, at a precise time |
| 3. Egg collection | Eggs are collected through the vagina under ultrasound guidance | About 36 hours after the trigger |
| 4. Sperm sample and fertilisation | Conventional IVF or ICSI in the laboratory | On the day of egg collection |
| 5. Embryo culture | The embryos develop in an incubator | 2 to 6 days |
| 6. Transfer | One embryo (sometimes two) is placed in the uterus; other good-quality embryos can be frozen | A few minutes |
| 7. Pregnancy test | Blood test for the hormone hCG | About two weeks after egg collection, on a date set by the centre |
How does ovarian stimulation for IVF work?
In a natural cycle, only one egg matures each month. Stimulation aims to mature several, to increase the chances of obtaining at least one good-quality embryo. It relies on subcutaneous injections of gonadotrophins (FSH, sometimes combined with LH), which patients learn to give themselves.
A second medicine prevents ovulation from happening too early. There are two main approaches:
- the antagonist protocol: stimulation starts at the beginning of the cycle, and a GnRH antagonist is added after a few days. It is now the most widely used, and the European Society of Human Reproduction and Embryology (ESHRE) generally recommends it because it reduces the risk of ovarian hyperstimulation;
- the agonist protocol (the "long" protocol): a GnRH agonist first puts the ovaries to rest for about two weeks, then stimulation begins.
Doses are adjusted to age, ovarian reserve and weight. Blood tests (oestradiol) and ultrasound scans are used to adjust treatment and choose the day of the trigger.
What happens during egg collection and fertilisation?
Egg collection
It takes place in the operating theatre, about 36 hours after the trigger injection. A fine needle guided by the vaginal ultrasound probe draws up the fluid from the follicles, which contains the eggs. It is done under local or light general anaesthesia, depending on the centre, and patients usually go home the same day. The practical arrangements are explained to you by the fertility centre.
Sperm
The partner provides a sample on the day of egg collection, after the abstinence period specified by the laboratory. The laboratory selects the most motile sperm. Frozen or donor sperm can also be used.
Conventional IVF or ICSI?
- Conventional IVF: the eggs are placed with many sperm, which fertilise them on their own.
- ICSI (intracytoplasmic sperm injection): a single sperm is injected directly into each mature egg. It is mainly used for significant sperm abnormalities or after failed fertilisation with conventional IVF.
The next day, the embryologists check fertilisation, then follow the embryos' development until transfer.
What happens during embryo transfer?
Transfer takes place between day 2 and day 6 after egg collection, depending on the embryo's stage. A thin, flexible catheter passed through the cervix places the embryo in the cavity. The procedure is quick, usually painless and needs no anaesthetic.
Transferring a single embryo limits the risk of a multiple pregnancy, which exposes mother and babies to more complications (prematurity in particular). According to a Cochrane review (2020), in women with a good prognosis, transferring one embryo, followed if needed by the transfer of a frozen embryo, gives cumulative live birth chances close to transferring two embryos, with far fewer twins. The number of embryos transferred is decided with the team, according to age and the couple's history.
Progesterone treatment, usually given vaginally, supports the phase after transfer. Good-quality embryos that are not transferred can be frozen and transferred in a later cycle, without new stimulation.
What are the risks of IVF and when is it an emergency?
- Ovarian hyperstimulation syndrome: the ovaries over-respond. Severe forms have become rare thanks to current protocols.
- Complications of egg collection: bleeding or infection, which are rare.
- Multiple pregnancy, especially if several embryos are transferred.
- Ectopic pregnancy: it is still possible after IVF, hence the follow-up ultrasound (see ectopic pregnancy).
Call your fertility centre straight away, or 15 (SAMU) or 112 in France, or your local emergency number, in an emergency, if you have:
- a very swollen or very painful abdomen, rapid weight gain of several kilos in a few days;
- breathlessness, or passing much less urine;
- fever after egg collection;
- heavy bleeding or feeling faint.
What happens after embryo transfer?
No sign can tell you in the following days whether the embryo has implanted. Pulling sensations or tender breasts are common and are often caused by the progesterone. You can live normally, with no need for strict rest.
A blood test for the hormone hCG is done on the date given by the centre. If it is positive, a second blood test checks how it is progressing, then an ultrasound confirms that the pregnancy is in the uterus. If it is negative, an appointment is arranged to review and plan the next step (transfer of a frozen embryo or a new attempt). After repeated failures, see what to do after several failed IVF attempts.
Frequently asked questions
Is IVF reimbursed in France?
Yes, in France it is covered at 100% on prescription, up to four IVF attempts. Egg collection is possible until the woman's 43rd birthday, and embryo transfer until the 45th birthday of the woman who will carry the pregnancy.
Is egg collection painful?
It is done under local or light general anaesthesia, so it is not very painful. Lower abdominal discomfort is common on the day and usually settles with a simple painkiller.
Can I work during IVF?
Yes, most women keep working. You need to be available for morning monitoring appointments and take the day of egg collection off.
How many embryos can be frozen?
All non-transferred embryos of sufficient quality can be frozen, with the couple's written consent. Their number depends on how many eggs were collected and how they develop in the laboratory.
References
- ESHRE Ovarian Stimulation Guideline Group, Ata B, et al. ESHRE guideline: ovarian stimulation for IVF/ICSI: an update in 2025. Hum Reprod, 2026. doi:10.1093/humrep/deag018 — PMID 41732035
- Kamath MS, et al. Number of embryos for transfer following in vitro fertilisation or intra-cytoplasmic sperm injection. Cochrane Database Syst Rev, 2020. doi:10.1002/14651858.CD003416.pub5 — PMID 32827168
- Sonigo C, et al. First-line management of infertile couple. Guidelines for clinical practice of the French College of Obstetricians and Gynecologists 2022. Gynecol Obstet Fertil Senol, 2024. doi:10.1016/j.gofs.2024.01.014 — PMID 38311310
Dr Olivier KadochObstetrician-gynaecologist and gynaecological surgeon in Paris (16th and 5th arrondissements). Former chef de clinique-assistant (senior registrar) at the Paris public hospitals (AP-HP); individually accredited by the French National Authority for Health (HAS). RPPS 10003957809. Background and practice locations
A question about your situation?Appointments at the practice or by video consultation, usually within one week to 10 days.
Book an appointmentGeneral information article: it does not replace a medical consultation. In an emergency, call 15 or 112 in France, or your local emergency number.