How does it work?

In vitro fertilization explained

In vitro fertilization

In vitro fertilization (IVF) is considered today to be one of modern medicine’s greatest achievements. It’s the most effective treatment in fertility clinics.

The IVF process

In vitro fertilization is a complex procedure involving a series of medical interventions that can make the experience physically and emotionally demanding. Remember that the goal of IVF is to fertilize an egg outside the uterus and to transfer it a few days later into the uterus.

The various steps in IVF are:

  • Overview
  • 1. Stimulating ovulation
  • 2. Retrieving the eggs
  • 3. Embryo development
  • 4. Microinjection (ICSI)
  • 5. Embryo transfer
  • 6. The luteal phase and pregnancy

  • This consists in triggering the simultaneous maturation of several eggs during the same cycle, the idea being to obtain enough embryos to be able to select the ones most likely to result in a successful pregnancy. The hormone manipulations required to do this cause various side effects for the patient that are generally very well tolerated.

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  • When the ultrasound shows follicles that are big enough (from 18 to 25 mm in diameter), the final maturation of the eggs is generally completed using a double injection of hCG and a GnRH agonist. The eggs will be ready for retrieval 35 hours later by puncture (aspiration) of the mature ovarian follicles. This procedure is carried out trans-vaginally, using a fine needle connected to an ultrasound probe.

  • The same day the eggs are retrieved, a sperm preparation is made using a sample of semen from the partner. In traditional in vitro fertilization, each egg is placed in a small plastic dish (a Petri dish) with 50,000 to 100,000 sperm. Around 18 hours later, fertilization can be seen under the microscope.

  • In order to reduce the risk of fertilization failure in the lab, at Fertilys, we usually carry out assisted in vitro fertilization, particularly when the semen does not contain enough sperm. The problem is solved by injecting a single sperm into each egg using a small glass needle.

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  • Between 3 to 5 days after fertilization, the embryo can be implanted by inserting a small, thin and flexible plastic tube into the vagina and depositing the embryo into the uterine cavity. This procedure only lasts a few minutes and is usually painless. A single embryo is transferred per attempt unless the doctor decides differently, due to the age of the patient or the quality of the embryos.

  • After ovulation, the uterine lining, the endometrium, becomes more receptive to the fertilized embryo, due to progesterone secretion by the corpus luteum. During IVF, progesterone supplements must be administered prior to the embryos being transferred, in order to encourage their implantation. An ultrasound will confirm the viability of the pregnancy in the 6th week of pregnancy.