Half a million children are born every year in the world thanks to in-vitro fertilization, but do you know what it is, how does it work and its possible risks?
In-vitro fertilization involves the fertilization of an egg with a sperm outside the mother’s uterus. This process, performed in a laboratory, allows couples with fertility problems to reach pregnancy.
Louise Brown, daughter of Leslie and John Brown, was the first person born thanks to in-vitro fertilization (IVF). This happened on July 25, 1978, at Oldham General Hospital, in Manchester, England.
Since then more than 8 million babies have been born worldwide as a result of this technique, according to data compiled by the European Society of Human Reproduction and Embryology presented in 2018.
The name of in-vitro fertilization has its origin in the first tests carried out in the 70’s, when fertilization of the oocyte was carried out in laboratory test tubes. For the same reason, the first children conceived thanks to IVF were called “test tube babies”.
When to use in-vitro fertilization?
Couples consider in-vitro fertilization when other less invasive methods fail.
Doctors suggest IVF when other less invasive methods of fertilization, such as hormonal treatments or intrauterine artificial insemination do not work. Doctors can use the ovules and semen of the couple, or with donors’ if either of them have problems.
The most common cases of infertility that can be remedied with in-vitro fertilization are the following:
Damage to the fallopian tubes
This hinders the fertilization of the ovule and if there is obstruction it makes it impossible for the embryo to move to the uterus, frustrating the pregnancy.
There is not enough egg production.
The fibroids are tumors in the wall of the uterus that hinder implantation of the fertilized ovum.
The uterine tissue grows outside the ovary.
It occurs when the ovaries do not produce enough eggs.
When the man or the woman have congenital diseases that can transmit to the children.
Problems in the semen
The sperm count is low or has little mobility.
Fallopian tubes attached
When the woman has been sterilized, IVF can be a way of conceiving.
Preservation of ovules
If the woman is going to receive oncological treatment that affects fertility, she can keep the frozen ovules for later in-vitro fertilization.
The process of IVF
Before starting in-vitro fertilization, doctors have to perform several tests to verify that both women and men are able to fertilize under this process.
These tests include disease detection, semen quality, women’s ovarian reserve, embryo transfer tests, and uterine cavity tests.
Once they get the approval, the woman starts taking medicines for the stimulation of the ovules and later for the maturation of the ocytes.
After about two weeks to a month of preparation, doctors perform a vaginal ultrasound and blood test to verify that the body and the eggs are ready for fertilization. At that time, the woman receives an injection of the hormone Hcg that induces the maturation of the ovum and 36 hours later the process can start.
Obtaining the ovules
Doctors extract the ovules with a puncture to subsequently mix with the sperm.
The extraction of the ovum goes with the means of a puncture in an operating room and under sedation. The process lasts about 15 minutes.
For extraction, doctors insert an ultrasound probe through the vagina. They then insert a thin needle into the ultrasound guidance until it reaches the follicles to suck the ovules through the needle.
In some cases, in which doctors cannot use a vaginal ultrasound, they use a laparoscopy, which consists of a small incision near the navel, through which they insert an optical fiber with the needle that will extract the ovules.
Once the ovules and the semen of the man have been obtained, the process of in-vitro fertilization begins. The man provides the semen through masturbation or, in complex cases, through testicular aspiration, which involves extracting the sperm directly from the testicles with a needle.
In IVF, doctors mix the mature ovules with the man’s sperm in a culture dish with maternal serum similar to that in the tubes. Another procedure is intracytoplasmic injection, which involves injecting a sperm directly into each ovule.
Doctors analyze the embryos resulting from fertilization daily and select which ones to transfer to the uterus.
Transfer of embryos to the uterus
Doctors mix the ovules with the sperm in a culture dish prior to implantation.
Between two and six days after fertilization, doctors place the embryo in the woman’s uterus to start the pregnancy. This procedure is done by inserting a catheter through the vagina to reach the uterus. Thus, one or more embryos are injected. This process is monitored through ultrasound.
If the fertilization is successful, the embryo will adhere to the walls of the uterus. Doctors determine the success of fertilization after 11 days. From that moment on, a normal pregnancy process will follow, with a regular follow-up of the pregnancy.
Doctors store the rest of the good quality embryos cryogenically to use them later without the need to repeat ovarian stimulation in case of another pregnancy. The embryo conservation protocols vary according to the legislations of each country.
Possible complications and risks
The success of in-vitro fertilization varies depending on many conditions. In developed countries an average birth rate is estimated between 41% and 43% in women under 40 years of age for each IVF process. In women over 40 years this percentage reduces to 18%.
The American Pregnancy Society warns about the following risks:
- Possibilities of multiple pregnancy caused by the stimulation of fertility and the implantation of several embryos. This brings risks of premature birth and low birth weight of babies.
- Rates of abortion slightly higher than normal pregnancy, especially in women over 40 years.
- Vaginal, renal or urinary tract infections due to puncture errors. It is not frequent but it can happen.
- Ectopic pregnancy, which is the implantation of the ovum outside the uterus.
Additionally, side effects may occur, such as light bleeding in the first days of pregnancy, dizziness, nausea and diarrhea or constipation. You should consult with the gynecologist, but generally these do not involve any risk.
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