IVF: In Vitro Fertilization

Nicole Wendler holds a PhD in biology in the field of oncology and immunology. As a medical editor, author and proofreader, she works for various publishers, for whom she presents complex and extensive medical issues in a simple, concise and logical manner.

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IVF (In Vitro Fertilization) is the oldest method of assisted fertilization. The "classic" fertilization in the test tube was successfully used for the first time in 1978. Simply pouring egg cells and sperm cells together is not enough. An IVF treatment consists of several finely coordinated steps. Read here how IVF works, for whom it is suitable and what risks it entails.

What is IVF?

Organic processes that take place outside the body - namely in the test tube - are referred to as "in vitro". In IVF treatment, for example, the removed egg cell comes together with the man's sperm in a test tube. After successful fertilization outside the body, one or more fertilized egg cells are transferred into the woman's uterus.

With the birth of Louise Brown, now 38, in 1978, scientists Steptoe and Edwards first had success with IVF. At that time, however, the doctors removed the egg in a spontaneous menstrual cycle. Today, however, the ovaries of women are in the vast majority of cases stimulated with the help of hormones. This allows several egg cells to mature and be removed at the same time.

How does IVF work?

The IVF process can be roughly divided into the following sections:

hormonal stimulation of the ovaries
Triggering ovulation (induction of ovulation)
Egg retrieval
IVF of the egg cells
Cultivation of fertilized egg cells
Insertion of the embryo (embryo transfer)
Support of the corpus luteum phase (luteal phase support)

At the beginning of in-vitro fertilization, the woman's ovaries must be stimulated with the help of hormones (gonadotropin) to develop the egg cells. The doctor checks the progress with the ultrasound device. Once the egg cells have matured, ovulation can be triggered artificially (medicinally).

At best, the doctor can then remove between five and ten egg cells through the vagina (transvaginal follicular puncture) and transfer them to nutrient medium. There the egg cells then meet the partner's fresh sperm obtained through masturbation.

After a day in the warm incubator, you can check under the microscope whether the in vitro fertilization was successful. If this is the case, the reproductive medicine specialist can insert a maximum of two fertilized egg cells into the woman's uterus after one or two days. In order to increase the success of the implantation, the corpus luteum phase is supported hormonally (progesterone).

The entire IVF process from hormonal stimulation to the insertion of the egg cells can take several weeks.

Who is IVF suitable for?

On the one hand, IVF is an option for couples in whom the woman has a fallopian tube obstruction, endometriosis or antibodies against the partner's sperm cells. However, it is also suitable for couples in whom the man's sperm cells are so bad that an insemination has already been unsuccessful.

IVF: chance of success

The fact that IVF treatment now has significantly better success rates than in the past is mainly due to the removal of several egg cells or ovarian stimulation with gondotropins. How high the chances of success are can be found in the current yearbook of the German IVF Register:

According to this, pregnancy occurs in around 32 percent of cases after in vitro fertilization including embryo transfer. This number applies to the fresh transfer - i.e. the transfer of an egg cell (embryo) which has been "freshly" fertilized in the test tube. In contrast, the pregnancy rate with a cryo-transfer (transfer of a previously frozen and then thawed fertilized egg for the transfer) is around 29 percent.

The success of the pregnancy rate can be increased if the doctor transfers several embryos at the same time. Linked to this, however, is the possibility of a multiple pregnancy.

However, the pregnancy rate does not correspond to the birth rate, which is somewhat worse due to miscarriages - it is around 23 percent per embryo transfer. The proportion of multiple births is less than 20 percent.

In individual cases, the type of fertility disorder and age have a decisive influence on the success of in-vitro fertilization. For example, the older the woman, the worse the pregnancy and birth rate after embryo transfer.

Advantages and disadvantages of IVF

In-vitro fertilization only works with hormone treatment, and this can be emotionally and physically stressful for the woman. There is also the risk of ovarian hyperstimulation syndrome. It's potentially life-threatening, but luckily, it's very rare. According to the German IVF register (2019 yearbook), around 99 percent of IVFs are uncomplicated.

However, there are still risks. In 2019, vaginal bleeding (63 percent) or abdominal bleeding (14.4 percent) occurred relatively often during egg retrieval. Peritonitis (peritonitis; 4.6 percent) and intestinal injuries (0.2 percent) were also possible. Sometimes, as a result of IVF, inpatient treatment (1.3 percent) or surgical care (3.5 percent) was necessary.

If more than one embryo is implanted after in vitro fertilization, you can expect twins or triplets. A multiple pregnancy is generally associated with an increased risk of premature births and miscarriages.

IVF has been in use for a long time, but the influence on children's development is still being researched. Two studies recently showed that the culture medium used, in which the fertilized egg cells grow, influences the children's development. What exactly leads to this cannot be said, as the companies keep the exact composition of their nutrient solutions a secret. However, researchers have long been calling for the ingredients to be disclosed.

Despite the risks, in vitro fertilization is a relatively safe and promising method of artificial insemination.More than 900,000 IVF cycles are performed annually in Europe and around 200,000 children are born after out-of-body conception.

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