Liter¬ally test tube baby means production of babies in a test tube. But in practice test tube baby means artificial fertilization of egg and sperm outside the body and implantation of the zygote into the womb of the mother. So far no one has succeeded in growing a human embryo completely into a child on culture media.
IVF is the original ‘test-tube’ baby technique. It was developed more than 30 years ago for the treatment of women with damaged Fallopian tubes, and this remains an important reason for treatment today. Test tube baby production is a highly complicated task requiring a high degree of skill and advanced facilities in the hospital.
Researches in the reproductive biology of human beings have yielded won¬derful results both for the control of the population and for production of children in cases where the parents are unable to produce children.
How does IVF work?
All IVF treatments begin with a course of hormone therapy to stimulate the development of several follicles in the ovary. These are collected as eggs, which are then fertilised in a test-tube (‘in vitro’) to create several embryos. After between two and five days in an incubator, one or two of these embryos are transferred through the vagina to the uterus, where implantation occurs and pregnancy begins. However, in IVF as in natural conception, not every embryo implants to become a pregnancy, which is why surplus embryos are frozen – so that a subsequent transfer might be tried if the first one fails. Freezing is now an essential part of every clinic’s IVF programme.
Single Embryo Transfer
Because the transfer of two or more embryos is associated with multiple pregnancies, there has been a determined effort in recent years to cut this multiple rate by transferring just one embryo and freezing the remainder. At the LWC we encourage single embryo transfer in patients with a good chance of success.
The most widely reported ‘side effect’ associated with IVF is a multiple pregnancy. There is also a very small risk that some women (1-2%) will over-react to the hormone drugs used to stimulate the ovaries, but ultrasound and hormone monitoring during this drug treatment phase usually ensures that any over-reaction is foreseen and any risk avoided. Egg collection can be uncomfortable, and is often performed with a local anaesthetic.
As with other type of fertility treatment, success rates in IVF decline once patients reach the age of 35 or so. Before that, IVF pregnancy rates at the LWC are around 50% per cycle
According to Dr. Chakravarthi the production of test tube baby involves the following 5 steps –
1. Ovulation (by natural cycle or hormonal stimulation)
2. Follicular aspiration (either by laproscopy or ultrasonographic technique)
3. In vitro fertilization (IVF)
5. Embryo transfer (ET)
The following procedure is adopted in the production of a test tube baby. A suitable ovum is obtained from the mother or any other donor woman. First an inert gas like carbon dioxide is pumped into a small cut made just below the naval of the woman. This will help the abdomen to drop which will allow the proper manipulation of instruments. Next, a laproscope is inserted through the cut and brought near the ovaries.
The laproscope has a provision for viewing the ovaries. When the ovary is spotted a syringe is inserted into a follicle on the surface of the ovary and eggs are sucked into the syringe. This procedure is performed on the woman under general anesthesia. (If there is any problem of ovulation, before laproscopy the woman is injected with gonadotropin hormones which will stimulate the production of eggs).
In vitro fertilization (IVF)
After the egg has been removed it increase carefully placed in culture medium containing calcium along with other necessary nutrients. The whole thing should be kept in completely sterile conditions. The spermatozoa of the husband (or of the donor) are introduced into the culture medium. Normally the egg is fertilised between 12-24 hours.
Cleavage begins within 38 hours and 2 cells are formed. The cleavage continues and within 72 hours after sperm entry, the zygote reaches the 8 celled stages. Within 5 days the embryo reaches the 16 celled blastocyst stages. The blastocyst is now ready for implantation.
Embryo transfer (ET)
The blastocyst stage of tem is now ready for transfer into the womb of the mother. Prior of the implantation of the blastocyst the uterus of the recipi¬ent mother should be made ready to receive the embryo. This is usually done with the hormonal treatment. The blastocyst is introduced into the uterus by one of the two methods – by using a catheter through the vagina and cervical canal to the womb or directly into the uterus through a cut made in the wall of the uterus.
The womb of the mother under the influence of the hormones develops the endometrium and the blastocyst gets im¬planted and the normal process of pregnancy continues.
The following precautings are to be taken for a successful delivery of a test tube baby.
a. The ovum that is taken out should be fully mature.
b. Culture conditions should be ideal providing normal body temperature.
c. Strict aseptic conditions must be maintained.
d. The uterine wall of the recipient mother should be prepared to allow for implantation.
e. After implantation there should be regular check up throughout the pe¬riod of pregnancy to prevent miscarriage.