Reproductive Health — Class 12 Biology NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 12 Biology chapter "Reproductive Health" — 8 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 12 Biology chapter "Reproductive Health" — 8 important questions with detailed answers for CBSE board exam…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
NCERT Solutions for Class 12 Biology — Reproductive Health. Step-by-step answers to all 8 textbook questions from this chapter, written for CBSE board preparation and free to use.
Reproductive Health — All 8 Questions Solved
Q1. Define contraception. Explain different contraceptive methods.
Contraception is prevention of conception/pregnancy using various methods and devices.
Contraceptive methods:
1. Natural methods: Avoid timing intercourse with ovulation
- Rhythm method: avoid intercourse during fertile period (3 days before and after ovulation)
- Coitus interruptus: withdrawal before ejaculation
- Lactational amenorrhea: exclusive breastfeeding
- Reliability: 50-80%
2. Barrier methods: Prevent sperm-egg contact
- Condom (male and female): latex sheaths; prevents STIs
- Diaphragm: covers cervix
- Reliability: 80-95%
3. Chemical methods: Kill/immobilize sperms
- Spermicides: applied in vagina before intercourse
- Reliability: 70-80%
4. Intrauterine methods: Prevent implantation
- IUD (Copper-T): prevents sperm entry and implantation; 95-99% effective
- Hormone-releasing IUD: releases progesterone
5. Hormonal methods: Prevent ovulation
- Oral contraceptive pills: estrogen + progesterone
- Injectable: medroxyprogesterone acetate
- Implants: subdermal rods
- Reliability: 99%
6. Surgical methods: Permanent sterilization
- Tubectomy (female): surgical ligation of fallopian tubes
- Vasectomy (male): surgical ligation of vas deferens
- 100% effective
Q2. What are sexually transmitted infections (STIs)? Name at least four STIs and explain their causative agents and transmission.
STIs are diseases transmitted through sexual contact with infected person. Caused by bacteria, viruses, protozoa, or fungi.
Common STIs:
1. Gonorrhea:
- Causative agent: Neisseria gonorrhoeae (bacterium)
- Transmission: sexual contact with infected person
- Symptoms: purulent discharge from urethra/vagina, dysuria
- Complications: sterility in females (PID), infertility
2. Syphilis:
- Causative agent: Treponema pallidum (bacterium)
- Transmission: sexual contact, blood transfusion, vertical transmission
- Stages: primary (chancre), secondary (rash), tertiary (systemic damage)
3. Genital herpes:
- Causative agent: Herpes simplex virus type 2 (HSV-2)
- Transmission: sexual contact; virus remains latent in nerves
- Symptoms: vesicles, ulcers, pain; recurrent episodes
4. Chlamydia:
- Causative agent: Chlamydia trachomatis (bacterium)
- Transmission: sexual contact
- Often asymptomatic; complications: pelvic inflammatory disease, infertility
5. AIDS:
- Causative agent: Human Immunodeficiency Virus (HIV)
- Transmission: sexual contact, blood exposure, vertical transmission
- Progressive destruction of immune system
Prevention: condom use, monogamy, screening, treatment of partners, safe practices
Q3. What is infertility? Explain the causes of infertility in males and females.
Infertility is inability to achieve pregnancy after 1 year of unprotected intercourse in couples of reproductive age. Affects 10-15% of couples globally.
Male infertility causes (40% of cases):
1. Azoospermia: absence of sperms due to:
- Obstruction of ejaculatory ducts
- Undescended testes
- Cryptorchidism
2. Oligospermia: low sperm count (<20 million/mL)
- Hormonal deficiency (low testosterone, FSH)
- Varicocele (varicose veins in scrotum)
- Heat exposure
3. Asthenospermia: reduced sperm motility
4. Teratospermia: abnormal sperm morphology
5. Sexual dysfunction: erectile dysfunction, ejaculation problems
Female infertility causes (50-60% of cases):
1. Ovulatory disorders:
- Hormonal imbalance (PCOS, thyroid disorders)
- Hyperprolactinemia
- Ovarian failure
2. Tubal factors:
- Blocked fallopian tubes (from infections, endometriosis)
- Tubal scarring
3. Uterine factors:
- Endometriosis
- Uterine fibroids
- Abnormal endometrium
4. Cervical factors:
- Cervical mucus abnormalities
- Cervicitis
5. Immunological factors: antibodies against sperm
Investigation: semen analysis, hormonal tests, ultrasound, laparoscopy. Treatment: medication, assisted reproductive techniques (ART, IVF).
Q4. Explain in vitro fertilization (IVF) and other assisted reproductive technologies (ART).
ART are procedures helping couples achieve pregnancy when natural conception fails. IVF is most common.
In Vitro Fertilization (IVF) steps:
1. Ovarian stimulation: FSH injections stimulate multiple follicle development (superovulation)
2. Oocyte retrieval: Mature oocytes collected from ovaries using needle aspiration under ultrasound guidance
3. Sperm collection: Semen collected by masturbation; processed to separate motile sperms
4. In vitro fertilization: Oocytes and sperms mixed in culture medium; fertilization occurs naturally or by ICSI
5. Embryo culture: Fertilized embryos cultured for 3-5 days in incubator maintaining optimal conditions
6. Embryo transfer: One or two healthy embryos transferred into uterus through cervix using catheter; excess embryos frozen
7. Luteal support: Progesterone given to maintain endometrium
Other ART procedures:
- ICSI (Intracytoplasmic Sperm Injection): single sperm injected into oocyte for severe male infertility
- GIFT (Gamete Intra-Fallopian Transfer): gametes transferred to fallopian tube
- ZIFT (Zygote Intra-Fallopian Transfer): zygote transferred to fallopian tube
- Surrogacy: embryo implanted in surrogate mother's uterus
Success rate: 30-40% per cycle depending on age and cause. Cost: significant, not always affordable. Ethical concerns regarding multiple embryos and selective abortion exist.
Q5. What is reproductive health? List the measures for promoting reproductive health at community level.
Reproductive health is state of complete physical, mental, and social wellbeing in reproduction, not merely absence of disease or infirmity. Encompasses sexual health, safe contraception, fertility, safe childbirth, and freedom from STIs and infertility.
Community-level measures for promoting reproductive health:
1. Education and awareness:
- Sex education in schools on anatomy, physiology, contraception, STIs
- Health awareness campaigns on reproductive health
- Counseling services on family planning
2. Healthcare services:
- Accessible antenatal care for pregnant women
- Safe childbirth facilities and trained birth attendants
- Postnatal care for mothers and newborns
- Emergency obstetric services
3. Family planning services:
- Free/subsidized contraceptive distribution
- Counseling on contraceptive choices
- Vasectomy and tubectomy services
4. STI prevention and management:
- Health checkups and screening programs
- Treatment of STIs
- Promotion of safer sexual practices
- Condom distribution
5. Maternal and infant health:
- Antenatal checkups and monitoring
- Vaccination during pregnancy
- Management of pregnancy complications
- Institutional deliveries
- Newborn care and immunization
6. Adolescent health:
- Reproductive health education
- Counseling services
- Prevention of early marriage and pregnancy
7. Combating gender-based violence:
- Legal protection against sexual abuse
- Support services for victims
- Awareness on rights and dignity
Goal: Reduce maternal mortality, infant mortality, and improve overall reproductive health outcomes.
Q6. Explain the hormonal control of female reproduction focusing on feedback mechanisms.
Female reproduction controlled by hypothalamic-pituitary-ovarian (HPO) axis with complex feedback mechanisms:
1. Hypothalamus: secretes GnRH (Gonadotropin-Releasing Hormone) in episodic pulses (frequency varies with cycle phase)
2. Anterior pituitary: GnRH stimulates release of:
- FSH (Follicle-Stimulating Hormone): stimulates follicle growth
- LH (Luteinizing Hormone): triggers ovulation and maintains corpus luteum
3. Ovarian feedback mechanisms:
Follicular phase (negative feedback):
- Growing follicles secrete estrogen
- Low estrogen inhibits GnRH, FSH, and LH (negative feedback)
- Maintains steady hormone levels
Ovulatory phase (positive feedback):
- Estrogen reaches threshold (~200 pg/mL for 48 hours)
- High estrogen stimulates GnRH surge
- GnRH surge triggers LH surge (LH spike 10-12 hours before ovulation)
- LH surge causes ovulation
Luteal phase (negative feedback):
- Corpus luteum secretes progesterone and estrogen
- High progesterone inhibits GnRH, FSH, and LH
- Maintains low hormone levels
- Prepares endometrium for implantation
- If fertilization fails, hormone withdrawal triggers menstruation
Prolactin: elevated in luteal phase; high levels can inhibit GnRH
Inhibin: produced by granulosa cells; selective FSH inhibitor
This coordinated feedback ensures rhythmic cyclic changes in ovarian and endometrial functions.
Q7. What are testicular problems that lead to male infertility? Explain cryptorchidism and varicocele.
Testicular problems affecting male fertility:
1. Cryptorchidism (Undescended testis):
- Definition: testis fails to descend into scrotum during fetal development; remains in abdomen or inguinal canal
- Causes: hormonal defects (low testosterone/LH), anatomical obstruction
- Effects: reduced testosterone production, azoospermia (absent spermatogenesis), increased risk of testicular cancer
- Infertility mechanism: high intra-abdominal temperature (37°C) damages germ cells; normal spermatogenesis requires 2-3°C below body temperature
- Treatment: surgical correction (orchiopexy) before puberty to preserve fertility
2. Varicocele:
- Definition: abnormal dilatation and tortuosity of veins of pampiniform plexus in scrotum
- Cause: incompetent valves in testicular veins, more common on left side
- Effects: impaired venous drainage, increased temperature in testis, reduced sperm production
- Symptoms: pain, swelling, infertility; some asymptomatic
- Mechanism: chronic venous stasis increases local temperature and hypoxia, damaging spermatogenic epithelium
- Diagnosis: clinical examination, ultrasound
- Treatment: surgical ligation (varicocelectomy) improves sperm production in 50-70% cases
3. Other testicular problems:
- Orchitis: inflammation of testis from viral (mumps) or bacterial infection
- Testicular torsion: twisting of testis, medical emergency
- Testicular trauma: mechanical injury
- Hormonal deficiency: low testosterone from pituitary/hypothalamic disorders
- Chemotherapy/radiation: germ cell damage
Q8. Discuss the role of estrogen and progesterone in female reproduction and pregnancy.
Estrogen and progesterone are primary female sex hormones essential for reproduction:
Estrogen (produced by follicles, corpus luteum, placenta):
During menstrual cycle:
- Stimulates proliferation of endometrial glands and stroma
- Increases vascularity of endometrium
- Promotes thickening of cervical mucus
- Positive feedback at high levels triggers LH surge for ovulation
- Negative feedback at low-moderate levels inhibits FSH and LH
Secondary sexual characters:
- Breast development
- Widening of pelvis
- Fat deposition in hips and thighs
- Pubic and axillary hair growth
Progesterone (produced by corpus luteum and placenta):
During menstrual cycle:
- Converts proliferated endometrium into secretory endometrium
- Increases endometrial thickness and glandular secretions for implantation
- Makes cervical mucus thick and viscid (hostile to sperms)
- Suppresses GnRH, FSH, and LH (negative feedback)
- Maintains pregnancy
During pregnancy:
- Maintains endometrium and prevents menstruation
- Inhibits uterine contractions
- Promotes breast development and prepares for lactation
- Decreases immune response (prevents embryo rejection)
- Maintains basal body temperature elevation
- Prepares maternal behavior
Temperature effect: Progesterone raises basal body temperature by 0.3-0.5°C, used clinically to confirm ovulation
Withdrawal of progesterone triggers menstruation if pregnancy fails. Both hormones essential for establishment and maintenance of pregnancy; deficiency causes miscarriage.
Reproductive Health — Practice MCQs with Answers
Attempt these 20 multiple-choice questions after working through the solutions above. Each carries the correct option and the reasoning behind it, so a wrong answer tells you which idea to revisit.
MCQ 1. Which country was the first in the world to initiate 'Family Planning' programs?
- A. USA
- B. India
- C. China
- D. Germany
Answer: B. India — India was among the first countries globally to initiate action plans and programs at a national level to attain total reproductive health as a social goal, starting with 'Family Planning' in 1951.
MCQ 2. Which of the following contraceptive methods is highly effective but generally considered irreversible?
- A. Oral pills
- B. IUDs
- C. Surgical methods
- D. Barrier methods
Answer: C. Surgical methods — Surgical methods like vasectomy and tubectomy are permanent methods of contraception, highly effective, but generally considered irreversible procedures for birth control.
MCQ 3. A woman has blocked fallopian tubes, preventing the ovum from reaching the uterus. Which Assisted Reproductive Technology (ART) would be most suitable for her if she wishes to conceive?
- A. GIFT
- B. ZIFT
- C. IUI
- D. ICSI
Answer: B. ZIFT — In ZIFT (Zygote Intra Fallopian Transfer), a zygote or early embryo (up to 8 blastomeres) is transferred into the fallopian tube, bypassing the blocked segment. GIFT and IUI require functional fallopian tubes.
MCQ 4. Which of the following is NOT a general measure to prevent Sexually Transmitted Infections (STIs)?
- A. Avoiding sex with unknown partners
- B. Using condoms during coitus
- C. Having multiple sexual partners
- D. Consulting a doctor for early symptoms
Answer: C. Having multiple sexual partners — Having multiple sexual partners significantly increases the risk of acquiring STIs, hence it is not a preventive measure. All other options are recommended practices for STI prevention.
MCQ 5. Medical Termination of Pregnancy (MTP) is considered relatively safe up to how many weeks of pregnancy during the first trimester?
- A. 8 weeks
- B. 12 weeks
- C. 18 weeks
- D. 24 weeks
Answer: B. 12 weeks — MTPs are considered relatively safe during the first trimester, i.e., up to 12 weeks of pregnancy. Beyond this period, they become riskier for the mother.
MCQ 6. Which of the following is a hormone-releasing Intrauterine Device (IUD)?
- A. Lippes loop
- B. Cu-T
- C. Cu-7
- D. Progestasert
Answer: D. Progestasert — Progestasert and LNG-20 are examples of hormone-releasing IUDs that make the uterus unsuitable for implantation and the cervix hostile to sperms. Lippes loop is non-medicated, while Cu-T and Cu-7 are copper-releasing IUDs.
MCQ 7. Oral contraceptive pills primarily inhibit which of the following processes?
- A. Fertilization
- B. Implantation
- C. Ovulation
- D. Spermatogenesis
Answer: C. Ovulation — Oral contraceptive pills, containing progestogens or progestogen-estrogen combinations, primarily work by inhibiting ovulation. They also alter cervical mucus and make the uterus unsuitable for implantation.
MCQ 8. What does RCH stand for in the context of reproductive health?
- A. Reproductive and Child Health
- B. Regional Contraception Hub
- C. Research and Clinical Help
- D. Regular Childbirth Healthcare
Answer: A. Reproductive and Child Health — RCH stands for Reproductive and Child Health, a program initiated by the Indian government to create awareness and provide facilities for reproductive health.
MCQ 9. The principle of 'Lactational Amenorrhea' as a contraceptive method is based on:
- A. Absence of menstruation during lactation
- B. Suppression of ovulation due to high prolactin levels
- C. Prevention of implantation by uterine changes
- D. Killing of sperms by vaginal secretions
Answer: B. Suppression of ovulation due to high prolactin levels — Lactational Amenorrhea works by the high levels of prolactin during intense breastfeeding, which suppresses the release of GnRH and subsequently inhibits ovulation, thus preventing conception.
MCQ 10. Which of the following STIs is characterized by the formation of painless ulcers (chancres) on the external genitalia?
- A. Gonorrhea
- B. Chlamydiasis
- C. Syphilis
- D. Genital herpes
Answer: C. Syphilis — Syphilis, caused by *Treponema pallidum*, is characterized by primary lesions called chancres, which are typically painless ulcers on the genitalia, mouth, or anus.
MCQ 11. Diaphragms, cervical caps, and vaults are barrier methods of contraception that are:
- A. Reusable
- B. Used by males
- C. Prevent fertilization by killing sperm
- D. Inserted into the uterus
Answer: A. Reusable — Diaphragms, cervical caps, and vaults are barrier methods that cover the cervix during coitus to prevent sperm entry and are reusable. They are typically used by females.
MCQ 12. What is a popular slogan widely used in India to encourage smaller families?
- A. "Hum Do, Hamare Do"
- B. "One child, one family"
- C. "Small family, happy family"
- D. "Population control, nation's goal"
Answer: A. "Hum Do, Hamare Do" — "Hum Do, Hamare Do" (We two, our two) is a very popular and widely recognized slogan in India promoting the idea of having two children per couple to control population growth.
MCQ 13. The MTP Act of 1971 was significantly amended in which year to increase the gestation limit for MTP under certain conditions?
- A. 1986
- B. 1992
- C. 2017
- D. 2021
Answer: D. 2021 — The Medical Termination of Pregnancy (Amendment) Act, 2021, increased the upper gestation limit for MTP from 20 weeks to 24 weeks for certain categories of women and removed the upper limit in cases of substantial fetal abnormalities.
MCQ 14. In which of the following ART techniques are sperms directly injected into the ovum?
- A. IVF-ET
- B. ZIFT
- C. ICSI
- D. GIFT
Answer: C. ICSI — Intra Cytoplasmic Sperm Injection (ICSI) is a specialized procedure where a sperm is directly injected into the ovum in the laboratory to achieve fertilization, particularly useful for severe male infertility.
MCQ 15. Which of the following Sexually Transmitted Infections (STIs) is generally considered incurable but manageable with antiviral medications?
- A. Gonorrhea
- B. Syphilis
- C. Chlamydiasis
- D. Genital herpes
Answer: D. Genital herpes — Genital herpes, caused by Herpes Simplex Virus (HSV), is a viral STI that currently has no cure, although its symptoms can be managed with antiviral medications. The others are bacterial and curable.
MCQ 16. Vasectomy is a surgical contraceptive method performed in:
- A. Females, involving the fallopian tubes
- B. Males, involving the vas deferens
- C. Females, involving the uterus
- D. Males, involving the testes
Answer: B. Males, involving the vas deferens — Vasectomy is a male sterilization procedure where a small part of the vas deferens is cut or tied to prevent sperm from reaching the urethra.
MCQ 17. Emergency contraceptives are most effective if taken within how many hours of unprotected intercourse?
- A. 24 hours
- B. 48 hours
- C. 72 hours
- D. 120 hours
Answer: C. 72 hours — Emergency contraceptive pills are primarily progestogen-only pills or progestogen-estrogen combinations, and are most effective if taken within 72 hours (3 days) of unprotected coitus.
MCQ 18. How do copper-releasing IUDs primarily prevent conception?
- A. By inhibiting ovulation
- B. By making the uterus unsuitable for implantation
- C. By increasing phagocytosis of sperms within the uterus
- D. By blocking the fallopian tubes
Answer: C. By increasing phagocytosis of sperms within the uterus — Copper ions released by IUDs suppress sperm motility and the fertilizing capacity of sperms, and they also increase phagocytosis of sperms within the uterus.
MCQ 19. Infertility is defined as the inability to conceive or produce children even after unprotected sexual cohabitation for a period of at least:
- A. 6 months
- B. 1 year
- C. 2 years
- D. 5 years
Answer: B. 1 year — Infertility is medically defined as the inability to conceive after one year of regular, unprotected sexual intercourse.
MCQ 20. Which of the following STIs can also be transmitted by sharing injection needles, surgical instruments, and from an infected mother to her baby?
- A. Chlamydiasis
- B. Genital warts
- C. Hepatitis-B
- D. Gonorrhea
Answer: C. Hepatitis-B — Hepatitis-B and HIV are known to be transmitted through sharing of injection needles, surgical instruments, blood transfusions, and from an infected mother to her fetus.
How to Use These Solutions
Attempt each question yourself first and only then compare with the worked answer. Marks in the CBSE board exam are awarded for the METHOD as much as the final result, so reproduce the steps rather than memorising the last line. Where a solution states a law, a formula or a definition, learn that wording — examiners look for it.
Related practice for this chapter: chapter MCQs, previous-year questions, revision notes and sample papers.