IVF involves a wide range of techniques, with the goal of helping infertile couples to have children. Since the birth of Louise Brown in 1978 -the first IVF baby, in Bourn Hall, England- thousands of couples have achieved that goal to date. This method offers a solution to female infertility (e.g. blocked Fallopian tubes) as well as male infertility (e.g. oligospermia) cases. The success rate per initiated cycle depends on many factors such as the female partner's age and the cause of infertility. Typically, the cumulative success rate can reach 60 to 65% after 3-4 attempts.

Preparation

During treatment, drugs are administered that are designed to stimulate ovarian function, in order to retrieve more eggs than the one produced by the female in any normal menstrual cycle. Monitoring is performed by ultrasound examination and blood sampling, usually every 2 to 3 days; thus, drug doses are individualized. The size of growing ovarian follicles is closely monitored by vaginal ultrasound; eggs are maturing within the follicles. The goal is to achieve development of multiple follicles larger than 18 mm in diameter; at this size, it is considered that the eggs in them have matured and are ready for retrieval. The increasing thickness of the endometrium is also monitored. The endometrium is the tissue lining the uterine cavity, where embryos will be trasferred. By means of a blood test, the levels of estradiol are also monitored; this hormone is produced by the follicles and is an indicator of egg maturity. When a sufficient number of follicles larger than 18 mm, a satisfactory endometrial thickness and adequate estradiol levels are achieved, the final stages of egg maturation are triggered by administering beta-chorionic gonadotropin (ovulation induction); egg retrieval is performed 34-36 hours later.

Egg collection

The egg collection procedure takes about 15 minutes and is done under sedation. The gynecologist aspirates the follicular fluid by means of a needle introduced, under ultrasound guidance, in each ovarian follicle. The follicular fluid is taken into the laboratory, where the embryologist identifies and isolates the eggs under a microscope.

Fertilization

After collection, eggs are placed in culture medium. Then, they are inseminated with sperm, previously isolated from the spouse's / partner's semen by the use of special techniques. The next morning, eggs are checked for fertilization; development of the embryos is monitored in the following days.

Embryo transfer

It's a simple procedure that does not require sedation. It is performed 2 to 3 days after egg collection. In certain cases, it may be performed when embryos reach the blastocyst stage, i.e. 6-7 days after egg collection. The embryos are placed inside the endometrial cavity by means of a thin plastic catheter, which is introduced through the cervix. The decision on how many embryos to transfer is made together with the couple. If there is a large number of supernumerary embryos available, some of them may be frozen and preserved for future attempts.

Pregnancy test

It is performed 12 days after ebryo transfer. Blood is drawn to measure the concentration of beta-chorionic gonadotropin. If the test is positive, an ultrasound scan is scheduled two weeks later, to detect the presence of gestational sac(s) in the uterus. If the test is negative, all medication is stopped and an attempt is made to analyse the possible causes of failure, in order to make further decisions.