In vitro fertilization is the process used to conceive a child outside a woman’s body, and the baby so born is called as a test tube baby.
In vitro fertilization or IVF is a technique of child conception used by infertile couples. The term infertile couples constitutes that the man can be infertile, or the woman can be infertile, or both can be infertile. Infertility in a man is given by:
- Low sperm count
- Poor sperm motility (movement)
- Abnormal sperm shape
Whereas, infertility in women is given by:
- Problems with the uterus
- Problems with the fallopian tubes
- Problems with ovulation
In such a condition, when the male parent or the female parent, or both parents are considered infertile, IVF is one of the alternate measures through which the couple can bear a child.
IVF is a process by which a child is conceived out of a woman’s body. Before performing the IVF, a woman's eggs and man's sperm are placed together in a plastic dish for fertilization. Once the fertilization occurs, the eggs transform into embryos, which are then placed in the woman’s uterus with the hope that this process will be followed by a successful pregnancy.
In contrast to what many people think, IVF is not a one-step procedure. In fact, the process of IVF is divided into 4 stages that can last over several weeks. The four steps involved in the procedure of IVF are:
Stimulating the ovaries: In this stage, the ovaries of a woman are stimulated by administering her some hormone injections or tablets, etc. This is done to collect many eggs at once, instead of the usual one egg per cycle. The development of eggs is under constant scrutiny by blood tests and ultrasound scans, which provide the right time to collect the eggs.
Collecting the eggs: The second stage of IVF includes collecting the woman’s eggs from her body. For this to happen, an ultrasound probe is placed inside the vagina, while the woman’s under light sedation. The probe reveals the location of the follicles within the ovaries. After locating the follicles, they are pierced by a fine needle that is passed through the vaginal wall and ovaries, which pierces the ovaries to collect the woman’s eggs.
Fertilization: After at least two hours of the collection of eggs, the male partner of the woman provides his semen sample. If the male is also infertile, then another semen sample may be used for the process. In a standard IVF treatment, the eggs are mixed with the sperm in a culture dish. If an egg is fertilized by a sperm, a zygote or pre-embryo will begin to develop. The pre-embryo remains in the incubator for two to five days while it continues to grow and divide. There is also another alternate process of fertilization, which is known as the Intra-Cytoplasmic Sperm Injection (ICSI). For this process, an individual sperm is injected into the cytoplasm of each egg.
Embryo Transfer: This is the final stage of the process, and perhaps the most important one as well. To transfer the embryos into the woman’s body, the doctors first must ensure that the embryos have grown up to a requisite size. Once this is ensured, the embryos are passed inside the woman’s uterus by a fine plastic tube (catheter) through the cervix and into the uterine cavity, again under the guidance of an ultrasound probe. Though the transfer is generally painless and involves no anesthetic, it has to be made sure that the embryos are being transferred during the most feasible time of conception in the woman’s menstrual cycle. Finally, two weeks after the transfer, the pregnancy of the woman is determined by a blood test.
Usually, the success rate of the IVF depends upon the age of the woman, the IVF procedures, clinics, etc. Some clinics achieve pregnancies in about 90 per cent of women aged under 35 years, 85 percent of women aged 35 to 39, and 45 per cent of women aged 40 to 44. Besides the varying conversion rate, there are also some risks and side effects associated with IVF:
- In many cases, it has been experienced that the use of medicines to treat infertility, result in side effects such as breast tenderness, slight nausea, dizziness and abdominal swelling, because of an increase in estrogen levels. Some other side effects include birth defects and cancer. However, there is no clear evidence in support of the fact that these disorders are caused by the proper or improper use of such medicines.
- Occasionally, too many follicles develop and the levels of the hormone estrogen rise too high, causing a condition called ovarian hyperstimulation syndrome (OHSS). This is an unpleasant experience, which may include marked abdominal swelling, nausea, vomiting and diarrhea, lower abdominal pain and shortness of breath. OHSS is rarely severe enough to require hospitalization.
- Another associated risk with the IVF is that there can be chances of multiple pregnancies. Though this has been largely curbed by techniques like ICSI, cases of multiple pregnancies have still been reported. Moreover, the collection needle used for IVF is understood to cause damage to other organs, infections, or abnormal bleeding in a woman’s body.
Thus, there has been no consensus on the risks associated with IVF and its success rate. Nevertheless, it has proven to be an available and an alternate source of conception for infertile couples.
3D animation of how IVF works
Another Video for understanding IVF Process: