Termination, Infections and Infertility: Quick Revision

A brief note on Termination, Infections and Infertility. Read it before a test. Try each question at the end before you open its answer.

Amniocentesis and MTP

• Amniocentesis: a test of the amniotic fluid. It can detect Down syndrome, haemophilia and sickle-cell anaemia. Its use for finding the sex of the unborn child is banned by law.
• MTP: the voluntary ending of a pregnancy before full term, also called induced abortion. Legalised in India in 1971 with strict conditions.
• Safety: relatively safe in the first trimester, up to 12 weeks. The second trimester is very risky.
• Numbers: nearly 45 to 50 million MTPs a year in the world, about one fifth of the conceived pregnancies.

Sexually transmitted infections

• List: gonorrhoea, syphilis, genital herpes, chlamydiasis, genital warts, trichomoniasis, hepatitis-B and HIV.
• Cure: all are completely curable if detected early, except hepatitis-B, genital herpes and HIV.
• Other spread: hepatitis-B, genital herpes and HIV also spread by needles, by blood and from mother to foetus.
• Late finding: early signs are mild, females may have none, and stigma delays care.
• Complications: PID, abortions, stillbirths, ectopic pregnancies, infertility and cancer of the reproductive tract.
• Prevention: avoid unknown and multiple partners, always use condoms, and see a qualified doctor.

Infertility and ART

• Causes: physical, congenital, diseases, drugs, immunological and psychological.
• IVF: fertilisation in a dish, then embryo transfer. The test tube baby method.
• ZIFT: a zygote or an embryo of up to 8 blastomeres into the fallopian tube. More than 8 blastomeres: into the uterus.
• GIFT: the ovum of a donor into the fallopian tube.
• Not in the NEET text: ICSI (one sperm into an ovum), AI and IUI (semen into the vagina or the uterus).

A worked example

A zygote divides 3 times. Where is the embryo transferred?

1. After 3 divisions there are $2^3 = 8$ blastomeres.
2. Eight is the limit for the tube, so it can go into the fallopian tube (ZIFT).

Practice with new numbers

A program to try

The program gives the site of the transfer for an embryo of a given age.

Mistakes to avoid

• Saying that amniocentesis may be used to find the sex of the baby. The law bans it.
• Saying that all STIs are completely curable. Hepatitis-B, genital herpes and HIV are not.
• Mixing up GIFT and ZIFT. GIFT places an ovum in the tube. ZIFT places a zygote or an early embryo in the tube.
• Saying that IVF fertilisation is in the body. It is in the laboratory.

Check yourself

1. Up to how many weeks is MTP relatively safe?

2. Which three infections can also spread by needles?

3. Where is an embryo of 16 blastomeres transferred?

4. What is transferred in GIFT?

Sources

• NCERT (2023). Biology, Textbook for Class XII, chapter 3.
• World Health Organization (2023). Infertility prevalence estimates, 1990 to 2021.