What is a test tube baby; how is it produced?
Researches in the reproductive biology of human beings have yielded wonderful results both for the control of the population and for production of children in cases where the parents are unable to produce children. Literally test tube bay 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.
Test tube bay production involves two main steps - in vitro fertilization (IVF) and embryo transfer (ET). Historically the first attempt to produce the test tube baby was by an Italian scientise Petrucci (1959). In his experiment he removed an ovum from a patient and put it in the middle of spermatozoa in a glass dome. One of the sperms fertilized the egg and a small embryo formed, but this survived only for 29 days.
However Petrucci's experiment opened up a new horizon and a new hope for infertile parents. In recent years two British scientists Edwards and Steptoe have done pioneering work in the field of test tube babies. The first scientifically recorded test tube baby in the world was born on July 25 1978 and the baby girl was named Louise Joy Brown.
In our country the first recorded instane of a test tube baby was under the supervision of Dr. Indira Hinduja in KEM Hospital Bombay in 1986. Subsequently test tube babies have been reported by Dr. Baidyanath Chakravarthi of Calcutta.
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 recipient 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 urider the influence of the hormones develops the endometrium and the blastocyst gets implanted and the normal process of pregnancy continues. Test tube baby production is a highly complicated task requiring a high degree of skill and advanced facilities in the hospital. 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 period of pregnancy to prevent miscarriage.