Read the passage carefully and answer the questions that follow:
A discussion on reproductive health is incomplete without a mention of infertility. A large number of couples all over the world including India are infertile, i.e., they are unable to produce children in spite of unprotected sexual co-habitation. The reasons for this could be many – physical, congenital, diseases, drugs, immunological or even psychological. In India, often the female is blamed for the couple being childless, but more often than not, the problem lies in the male partner. Specialised health care units (infertility clinics, etc.) could help in diagnosis and corrective treatment of some of these disorders and enable these couples to have children. However, where such corrections are not possible, the couples could be assisted to have children through certain special techniques commonly known as assisted reproductive technologies (ART). Though options are many, all these techniques require extremely high precision handling by specialised professionals and expensive instrumentation. Therefore, these facilities are presently available only in very few centres in the country. Obviously their benefits are affordable to only a limited number of people. Emotional, religious and social factors are also deterrents in the adoption of these methods.
In an IVF-ET procedure, the embryo formed in the laboratory has already reached the 16-blastomere stage. Where should it be transferred to complete its further development, and what is this transfer called?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Into the uterus; IUT
In IVF-ET (in vitro fertilisation followed by embryo transfer), the zygote or embryo formed in the laboratory is put back into the female body. The stage of the embryo decides the site: up to 8 blastomeres it goes into the fallopian tube, and with more than 8 blastomeres it goes into the uterus. A 16-blastomere embryo is past the 8-blastomere limit.
Option (1) Into the uterus; IUT — Correct. IUT stands for intra uterine transfer. An embryo with more than 8 blastomeres, such as one with 16, is placed in the uterus, where it can implant and complete its development.
Option (2) Into the fallopian tube; ZIFT — Incorrect. ZIFT stands for zygote intra fallopian transfer. It is used for the zygote or an early embryo with up to 8 blastomeres, so it does not fit a 16-blastomere embryo.
Option (3) Into the fallopian tube; IUT — Incorrect. IUT, intra uterine transfer, is by its name a transfer into the uterus, so it cannot be a transfer into the fallopian tube. The fallopian tube is also the wrong site for an embryo past 8 blastomeres.
Option (4) Into the uterus; ZIFT — Incorrect. The site is right, but ZIFT (zygote intra fallopian transfer) is the name of the transfer into the fallopian tube. The transfer into the uterus is called IUT.
NCERT Extract:
Infertility – “… In vitro fertilisation (IVF–fertilisation outside the body in almost similar conditions as that in the body) followed by embryo transfer (ET) is one of such methods. In this method, popularly known as test tube baby programme, ova from the wife/donor (female) and sperms from the husband/donor (male) are collected and are induced to form zygote under simulated conditions in the laboratory. The zygote or early embryos (with upto 8 blastomeres) could then be transferred into the fallopian tube (ZIFT–zygote intra fallopian transfer) and embryos with more than 8 blastomeres, into the uterus (IUT – intra uterine transfer), to complete its further development.”