Class 12 Biology Notes

Unit VI: Reproduction · Chapter 3

Reproductive Health

India's efforts

  • India was one of the first countries to start a nationwide family planning programme, in 1951.
  • Today it is part of the RCH (Reproductive and Child Health Care) programme.
  • Schools teach sex education to remove myths and give correct information.

Population explosion

Year India's population
1947 (Independence) about 350 million
2000 (May) crossed 1 billion
  • Why it grew: fewer deaths, fewer mothers and babies dying (lower MMR and IMR), and more people reaching reproductive age.
  • Ways to control it: encourage small families, use contraceptives, and raise the marriage age. The legal marriage age is 18 for girls and 21 for boys.

Contraception (birth control)

There are 5 groups of methods: natural, barrier, IUDs, oral pills, injections and implants, and surgical (permanent).

How each method works

Method How it works Remember
Periodic abstinence Avoid sex on days 10–17 of the cycle, when ovulation is likely "Avoid the fertile window"
Withdrawal (coitus interruptus) Male withdraws before ejaculation Not very reliable
Lactational amenorrhea No periods (and no ovulation) while fully breastfeeding, up to 6 months after birth Works only while fully breastfeeding
Condoms Stop sperms from reaching the egg Also protect against STIs and AIDS
Copper IUDs Cu ions reduce sperm movement and ability to fertilise "Copper cuts sperm power"
Hormonal IUDs Make the uterus unsuitable for implantation and the cervix hostile to sperms
Pills Stop ovulation and implantation, and thicken cervical mucus Taken daily for 21 days
Saheli A non-steroidal, once-a-week pill made by CDRI, Lucknow Made in India
Emergency contraception Pills or an IUD within 72 hours of unprotected sex "Within 3 days"
Vasectomy Vas deferens is cut and tied, so sperms can't come out Vasectomy = Vas (male)
Tubectomy Fallopian tube is cut and tied, so the egg can't reach the uterus Tubectomy = Tube (female)

Medical Termination of Pregnancy (MTP)

  • MTP means ending a pregnancy on purpose, before the baby is fully grown.
  • Legal in India since 1971 (MTP Act), with an amendment in 2017 to reduce illegal abortions.
  • It is relatively safe during the first trimester (up to 12 weeks).
  • Big risk: illegal abortions by untrained people are dangerous and can kill.

Sexually Transmitted Infections (STIs)

Infections that spread through sexual contact. They are also called VD (venereal diseases) or RTI (reproductive tract infections).

STI Caused by Curable?
Gonorrhoea Bacterium Yes, if treated early
Syphilis Bacterium Yes, if treated early
Chlamydiasis Bacterium Yes, if treated early
Trichomoniasis Protozoan Yes, if treated early
Genital warts Virus Treatable
Genital herpes Virus Not completely curable
Hepatitis B Virus Not completely curable
HIV / AIDS Virus Not curable
  • Hepatitis B and HIV can also spread by sharing needles and blood transfusion, and from mother to baby.
  • If not treated, STIs can cause PID (pelvic inflammatory disease), abortions, stillbirths, ectopic pregnancy (the baby grows outside the uterus), infertility and even cancer of the reproductive tract.
  • Prevention: avoid sex with unknown or multiple partners, always use condoms, and see a doctor early if in doubt.

Infertility and ART (Assisted Reproductive Technologies)

Some couples can't have children. Science can help using ART, techniques that help the sperm and egg meet.

  • Low sperm count → AI / IUI: semen is placed in the vagina or uterus.
  • Sperm can't enter the egg → ICSI: a sperm is injected straight into the egg.
  • Female can't make eggs → GIFT: a donor egg is placed in her fallopian tube.
  • IVF + ET ("test tube baby"): the egg and sperm meet in the lab, then the embryo is transferred:
    • embryo with up to 8 cells → ZIFT (into the fallopian tube)
    • embryo with more than 8 cells → IUT (into the uterus)
Short name Full form In simple words
IVF In Vitro Fertilisation Egg and sperm meet in a lab dish ("test tube baby")
ET Embryo Transfer The embryo is put back into the mother
ZIFT Zygote Intra Fallopian Transfer Zygote or embryo with up to 8 cells → fallopian tube
IUT Intra Uterine Transfer Embryo with more than 8 cells → uterus
GIFT Gamete Intra Fallopian Transfer Donor egg → fallopian tube of a woman who can't make eggs
ICSI Intra Cytoplasmic Sperm Injection One sperm is injected straight into the egg
AI / IUI Artificial Insemination / Intra Uterine Insemination Semen from the husband or a donor is placed in the vagina or uterus

30-second revision

  • Family planning started in India in 1951; now under RCH.
  • Amniocentesis for sex determination is banned.
  • CuT reduces sperm motility; Saheli = weekly, non-steroidal (CDRI Lucknow).
  • Emergency contraception: within 72 hours.
  • MTP is legal since 1971 and safest in the first 12 weeks.
  • Incurable STIs: Herpes, Hepatitis B, HIV.
  • ZIFT (≤ 8 cells, tube), IUT (> 8 cells, uterus), GIFT (donor egg), ICSI (injected sperm).