Q.Explain the mode of action of contraceptive pills taken by human females. Mention the schedule to be followed for effective outcome.
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🔒 Start your 14-day free trial to unlock the full solution →Concept understanding — Reproductive Health
Reproductive Health Significance — A First Look
Think of health as a state of complete well-being — not just the absence of disease. Now apply that to the part of your life that involves reproduction, the biological process by which new individuals are created. That is reproductive health: it is not merely about being free from infections or disorders of the reproductive system. It means having a healthy body, a clear understanding of reproductive processes, and the ability to make informed, responsible choices.
The NCERT textbook defines reproductive health as "a total well-being in all aspects of reproduction — physical, emotional, behavioural, and social." That is the core idea. It is not a narrow medical term; it is a broad, positive concept that touches every person, regardless of gender or age.
Why does it matter?
Reproductive health is significant because it directly affects the quality of life of individuals, families, and communities. When people are reproductively healthy, they can:
- Make informed decisions about marriage, family size, and childbearing.
- Prevent and manage sexually transmitted infections (STIs), including HIV/AIDS.
- Avoid unwanted pregnancies and unsafe abortions, which are major causes of maternal death.
- Ensure safe motherhood — proper care during pregnancy, delivery, and after birth reduces risks for both mother and child.
- Recognise and address problems like infertility, menstrual disorders, or reproductive cancers early.
Reproductive health is not only about problems. It also includes positive aspects like sexual well-being, the ability to have a satisfying and safe sex life, and the freedom to decide if, when, and how often to reproduce.
The bigger picture
On a national scale, reproductive health is linked to population control, maternal and child mortality rates, and the spread of diseases. The Indian government has run programmes like the Reproductive and Child Health (RCH) programme to improve access to services, education, and contraception. The goal is not just to reduce numbers — it is to ensure that every birth is wanted, every pregnancy is safe, and every child is healthy.
Reproductive health is a fundamental right, not a privilege. It requires awareness, access to healthcare, and the removal of social taboos that prevent open discussion.
Key components you should know
- Family planning — spacing and limiting births through contraception. …
Concept: Hormonal contraception — the use of synthetic hormones to prevent ovulation and implantation.
The pills contain a combination of estrogen and progestogen (or progestogen alone). They work by:
- Inhibiting ovulation — the hormones suppress the release of FSH and LH from the pituitary, so no egg is released.
- Thickening cervical mucus — making it harder for sperm to enter the uterus.
- Altering the endometrial lining — making it unfavourable for implantation if fertilisation somehow occurs. …
Contraceptive pills use synthetic hormones (estrogen + progestogen) to prevent ovulation by disrupting the natural hormonal feedback loop. They are taken daily for 21 days, followed by a 7-day break, during which withdrawal bleeding occurs.
The Concept: Tricking the Ovary into Silence
The menstrual cycle is controlled by a delicate hormonal conversation between the hypothalamus, pituitary gland, and ovaries. The key event — ovulation — is triggered by a surge of luteinizing hormone (LH) from the pituitary. Contraceptive pills work by supplying steady, low levels of synthetic estrogen and progestogen. This fools the pituitary into thinking the body is already in the luteal phase (post-ovulation) or pregnant. As a result, the pituitary stops releasing FSH and LH, and no egg matures or is released.
The pill does not kill sperm or eggs. It prevents the egg from ever being released. Without an egg, fertilisation cannot occur.
Mode of Action — Step by Step
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Suppression of FSH release
The synthetic estrogen in the pill inhibits the secretion of follicle-stimulating hormone (FSH) from the anterior pituitary. Without FSH, the ovarian follicles do not develop, and no dominant follicle matures.
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Blocking the LH surge
The progestogen component suppresses the mid-cycle surge of luteinizing hormone (LH). Even if a follicle somehow began to develop, the absence of an LH surge means ovulation cannot occur.
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Thickening of cervical mucus
Progestogen also makes the cervical mucus thick and sticky, forming a physical barrier that sperm cannot easily penetrate. This is a secondary, backup mechanism.
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Altering the endometrium
The hormones make the uterine lining thin and unreceptive, so even if an egg were somehow fertilised (a rare event), implantation would be unlikely.
The pill does not protect against sexually transmitted infections (STIs). Only barrier methods like condoms do that. …
Showing the 12 most recent of 18 on this concept.
- CBSE 2026Set 57/2/11 markMCQQ.How many of the following features are related to Nirodh – a popular brand of condoms ?(i) Prevention of sexually transmitted infections.(ii) Phagocytosis of sperms.(iii) Male contraceptive device.(iv) Acts as chemical barrier.(v) Physiological changes in cervical mucus. (A) (i), (ii),(iv) (B)(i) and(iii) (C) (i), (ii),(v) (D)(ii) and (iv)
›Reveal solutionSolution
Nirodh is a male contraceptive device (condom) that prevents sexually transmitted infections by acting as a physical barrier; it does not involve phagocytosis, chemical action, or physiological changes in cervical mucus.
Nirodh holds a special place in India's reproductive health history as one of the earliest and most widely promoted brands of condoms under the national family planning programme. Launched in the 1960s, the name itself—derived from the Sanskrit word for "prevention"—reflected the government's effort to make contraception culturally acceptable and accessible. Understanding what condoms actually do, versus what they don't, is essential to answering this question correctly.
Condoms are barrier contraceptives. They work by creating a physical sheath that prevents sperm from entering the female reproductive tract. Because they block direct contact between genital surfaces and bodily fluids, they also offer protection against sexually transmitted infections (STIs) including HIV, gonorrhea, and syphilis. This dual function—contraception and disease prevention—makes them unique among contraceptive methods. So feature (i) Prevention of sexually transmitted infections is absolutely correct for Nirodh.
As a device worn by the male partner during intercourse, Nirodh is clearly a (iii) Male contraceptive device. This is straightforward and indisputable.
Now let's examine what condoms do not do. Feature (ii) Phagocytosis of sperms refers to the engulfing and destruction of sperm cells by immune cells—a biological process that has nothing to do with barrier methods. Phagocytosis occurs naturally in the female reproductive tract as part of the immune response, but it is not a mechanism employed by condoms. Condoms simply block sperm mechanically; they don't trigger or involve any cellular immune activity. …
- CBSE 2026Set ANNUAL1 markQ.Fill in the blank: ______ a contraceptive tablet developed by the Central Drug Research Institute of Lucknow in India.
›Reveal solutionSolution
The contraceptive tablet developed by CDRI, Lucknow is Saheli.
Saheli is an important indigenous contraceptive achievement of India. It is a non-steroidal, once-a-week oral pill developed by the scientists of the Central Drug Research Institute (CDRI) at Lucknow. It has few side e …
- CBSE 2026Set ANNUAL1 markMCQQ.Diaphragms are contraceptive devices used by females. Which of the following statement is correct about diaphragm?(a) They are introduced into the uterus to prevent implantation.(b) They are placed to cover the cervical region and act as a physical barrier for sperm entry.(c) They act as spermicidal agents.(d) They prevent ovulation by hormonal regulation.
›Reveal solutionSolution
A diaphragm is a barrier contraceptive that fits over the cervix and physically stops sperm from entering the female tract, so (b) is correct.
In the CBSE/NCERT Reproductive Health chapter, contraceptives are grouped as natural, barrier, IUD, hormonal (pills), and surgical. Diaphragms, cervical caps and vaults are barrier methods made of rubber that are inserted to cover the cervix, physically blocking sperm entry. They are reusable and are often used with a spermicidal cream/jelly for extra effect — but the diaphr …
- CBSE 2026Set ANNUAL1 markQ.Write True or False. Surgical methods of contraception prevent gamete formation.
›Reveal solutionSolution
False — sterilisation surgery blocks the vas deferens or fallopian tubes so gametes cannot meet; sperm and eggs are still formed.
In the CBSE/NCERT Reproductive Health chapter, surgical (terminal) contraception means:
- Vasectomy — the vas deferens is cut and tied, so sperm cannot travel out (though the testes keep producing sperm).
- Tubectomy — the fallopian tubes are cut and tied, so the ovum cannot travel down (though the ovary keeps ovulating). …
- CBSE 2025Set 57/4/11 markMCQQ.Assertion (A) : 'Saheli', an oral contraceptive inhibits ovulation and increases phagocytosis of sperms. Reason (R) : It is a non-steroidal preparation.
›Reveal solutionSolution
Saheli is a non-steroidal, once-a-week oral contraceptive, so the Reason (R) is true. But "increasing phagocytosis of sperms" is an action of intrauterine devices (IUDs), not of Saheli, which makes the Assertion (A) false. The correct assertion–reason code is therefore (D): A is false, R is true.
This assertion–reason question, a common NCERT-based CBSE Class 12 pattern, tests whether you can separate the mechanism of the oral pill 'Saheli' from the mechanism of an IUD.
What NCERT actually says about Saheli
Saheli is described as a 'once-a-week' oral contraceptive for females that contains a non-steroidal preparation, with very few side effects and high contraceptive value. NCERT does not credit Saheli with increasing phagocytosis of sperms. General oral pills act mainly by inhibiting ovulation and implantation and by altering the cervical mucus so that the entry of sperms is retarded — not by phagocytosis of sperms.
Where 'phagocytosis of sperms' really belongs
In NCERT, the phrase "increase phagocytosis of sperms within the uterus" is used specifically for intrauterine devices (IUDs). Copper-releasing IUDs increase the phagocytosis of sperms in the uterus, and the released Cu ions suppress sperm motility and the fertilising capacity of sperms. Hormone-releasing IUDs additionally make the uterus unsuitable for implantation and the cervix hostile to sperms.
Evaluating the statements …
- CBSE 2025Set 57/5/11 markMCQQ.Assertion (A) : Cu-T, Cu-7 and LNG-20 are the most widely used copper-releasing IUDs. Reason (R) : Cu-ions in IUDs effectively suppress sperm motility and the fertilising capacity of sperms.
›Reveal solutionSolution
Copper-releasing IUDs work by releasing Cu²⁺ ions that impair sperm function and prevent fertilisation; both the assertion about widely used IUDs and the reason explaining their mechanism are correct and linked.
The question tests your understanding of intrauterine devices (IUDs) as a contraceptive method, specifically the mechanism by which copper-releasing IUDs prevent pregnancy. This is a classic assertion-reason question where you need to evaluate two statements: whether each is true, and whether the reason correctly explains the assertion.
Let's first understand what makes copper IUDs effective. When a copper-releasing IUD is placed in the uterus, it continuously releases cupric ions (Cu²⁺) into the uterine and tubal fluids. These ions create a hostile environment for sperm in multiple ways: they damage sperm membranes, reduce sperm motility (movement), and critically impair the sperm's ability to undergo capacitation and the acrosome reaction—both essential for fertilisation. The copper ions also trigger a local inflammatory response that further enhances the contraceptive effect. Importantly, this is primarily a spermicidal mechanism, not an abortifacient one; fertilisation itself is prevented.
Now let's evaluate each statement:
Evaluating Assertion (A):
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Cu-T is indeed one of the most common copper IUDs, shaped like the letter T with copper wire wound around the stem.
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Cu-7 (also called Copper-7) was historically significant and widely used, though it has been largely replaced by newer models in many countries. It had a "7" shape.
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LNG-20 refers to the levonorgestrel-releasing intrauterine system (Mirena being a brand name), which releases 20 μg of the hormone levonorgestrel per day. Here's the critical point: LNG-20 is not a copper-releasing IUD—it's a hormonal IUD.
The assertion mixes copper IUDs (Cu-T, Cu-7) with a hormonal IUD (LNG-20). While all three are IUDs, only the first two release copper. More accurate examples of copper IUDs would be Cu-T 380A, Cu-375, or Multiload 375.
Watch outA common confusion: not all IUDs work the same way. Copper IUDs release Cu²⁺ ions, while hormonal IUDs like LNG-20 release progestogen. They have different mechanisms of action.
Evaluating Reason (R):
The reason states that Cu-ions suppress sperm motility and fertilising capacity. This is absolutely correct. The mechanism includes:
- Direct toxic effect on sperm
- Inhibition of sperm motility
- Interference with sperm metabolism
- Prevention of sperm capacitation
- Alteration of cervical mucus
- Changes in the endometrium that prevent implantation (secondary mechanism) …
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- CBSE 2025Set 57/6/11 markMCQQ.Assertion (A) : Male contraceptive 'Nirodh' works on the principle of avoiding chances of ovum and sperm meeting. Reason (R) : It is made of thin rubber/latex sheath and is used to cover the penis before coitus.
›Reveal solutionSolution
Both the assertion and the reason are correct, and the reason accurately explains how the male contraceptive 'Nirodh' prevents conception by acting as a physical barrier.
Reproductive health encompasses a state of complete physical, mental, and social well-being in all matters relating to the reproductive system, not merely the absence of disease or infirmity. A crucial aspect of reproductive health is family planning, which often involves contraception – methods designed to prevent unwanted pregnancies. Contraceptive methods work on various principles, but a fundamental one is preventing the union of male gametes (sperm) and female gametes (ova).
The Assertion (A) states that the male contraceptive 'Nirodh' works on the principle of avoiding the chances of ovum and sperm meeting. This is entirely correct. 'Nirodh' is a brand name for a male condom, which falls under the category of barrier methods of contraception. Barrier methods, as their name suggests, physically prevent the sperm from reaching the ovum. For conception to occur, a sperm must fertilize an ovum. By creating a physical obstruction, condoms ensure that the ejaculated semen, which contains sperm, does not enter the female reproductive tract, thereby effectively preventing the meeting of the gametes.
NoteBarrier methods are highly effective when used correctly and consistently. They also offer the added benefit of protecting against sexually transmitted infections (STIs), a crucial aspect of overall reproductive health.
The Reason (R) explains that 'Nirodh' is made of a thin rubber/latex sheath and is used to cover the penis before coitus. This statement accurately describes the composition and application of a male condom. The thin, elastic material (rubber or latex) is designed to be strong enough to contain the semen while being flexible and comfortable for use. When placed over the erect penis before sexual intercourse, it acts as a physical barrier. …
- CBSE 2025Set A1 markMCQQ.What is the age duration of adolescence?(a) 0 - 11 years(b) 12 - 18 years(c) 19 - 45 years(d) 45 - 70 years
›Reveal solutionSolution
Adolescence is the period of transition from childhood to adulthood, roughly the teenage years.
Adolescence is marked by the onset of puberty, rapid physical growth, and significant physiological, hormonal, and psychological changes as an individual matures from a child into an adult. Of the given options, the span that correctly represents this transitional teenage period is 12 to 18 years. This period is important in the study of reproductive health because reproducti …
- CBSE 2025Set A1 markQ.Fill in the blank with the correct answer: Physical, emotional, behavioural and social well being refers to ______.
›Reveal solutionSolution
Reproductive health is defined by the WHO as complete physical, emotional, behavioural and social well-being related to reproduction, not merely the absence of disease.
The World Health Organisation (WHO) defines reproductive health in a broad sense: a person (or couple) who is reproductively healthy has healthy reproductive organs functioning normally, and also experiences emotional and behavioural well-being in matters related to sex/reproduction, along with the social maturity and responsibility to make informed reproductive decisions. This is much more than the mere absence of disease or a functioni …
- CBSE 2025Set ZOOLOGY1 markMCQQ.Which of the following is not a terminal birth control method?(i) Vasectomy(ii) Tubectomy(iii) Hysterectomy(iv) Copper-T
›Reveal solutionSolution
Vasectomy, tubectomy and hysterectomy are permanent (terminal) methods; Copper-T is a reversible IUD, so it is the odd one out.
Terminal (permanent) methods are surgical sterilisation procedures that permanently prevent gamete transport:
- Vasectomy — cutting/tying the vas deferens in the male.
- Tubectomy — cutting/tying the fallopian tubes in the female.
- Hysterectomy — surgical removal of the uterus (permanent). …
- CBSE 2024Set 57/1/11 markMCQQ.The periodic abstinence by a couple for family planning should be from: (A) Day 5 to 10 of menstrual cycle (B) Day 13 to 15 of menstrual cycle (C) Day 10 to 17 of menstrual cycle (D) Day 16 to 20 of menstrual cycle
›Reveal solutionSolution
Periodic abstinence (the rhythm method) requires avoiding intercourse during the fertile window, which spans ovulation and the viable lifespan of sperm and egg. For a typical 28-day cycle, abstinence should be from day 10 to 17.
The rhythm method relies on understanding when conception is actually possible during the menstrual cycle. A woman can conceive only when a viable egg meets viable sperm, so we need to map out this fertile window with some safety margins.
The biology behind the fertile window
Ovulation typically occurs around day 14 in a standard 28-day cycle (counting from the first day of menstruation). The released ovum remains viable for about 12–24 hours. However, sperm can survive in the female reproductive tract for up to 5 days under favorable conditions in cervical mucus.
This creates a window of fertility that extends before and after ovulation:
- Sperm deposited 5 days before ovulation can still be alive when the egg is released
- The egg remains fertilizable for about 1 day after ovulation
So the theoretical fertile period spans roughly 6 days: from 5 days before ovulation through 1 day after.
Calculating the safe period for abstinence
For a 28-day cycle with ovulation on day 14:
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Earliest possible fertilization: Intercourse on day 9 → sperm survive 5 days → meet egg on day 14
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Latest possible fertilization: Ovulation on day 14 → egg viable until day 15
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Adding a safety buffer: Because ovulation timing can vary by ±2 days even in regular cycles, we extend the window:
- Start abstinence a bit earlier: day 10 (accounting for early ovulation on day 12)
- End abstinence a bit later: day 17 (accounting for late ovulation on day 16, plus 1 day egg viability)
This gives us the day 10 to 17 window for periodic abstinence. …
- CBSE 2023Set 57/1/11 markMCQQ.Given below are two columns. In Column I the names of four contraceptive devices are given and in Column II the modes of action of the contraceptives are given. Select the option where the contraceptive devices are correctly matched with their respective modes of action. Column I (Contraceptive devices) Column II (Modes of action) P. Lippes loop i. Inhibition of ovulation Q. Multiload 375 ii. Phagocytosis of sperms in uterus R. Subcutaneous Norplant iii. Causes thickening of cervical mucous S. Saheli iv. Makes cervix hostile to sperms Options :(a) P-ii, Q-iv, R-iii, S-i(b) P-i, Q-ii, R-iii, S-iv(c) P-iii, Q-i, R-iv, S-ii(d) P-iv, Q-iii, R-ii, S-i
›Reveal solutionSolution
Lippes loop and Multiload 375 are IUDs that make the uterus hostile to sperm; Norplant thickens cervical mucus; Saheli inhibits ovulation by interfering with estrogen receptors.
Understanding how contraceptive devices work requires clarity on their mechanisms. Each method targets a different stage of reproduction—some prevent fertilization by creating barriers or hostile environments, others suppress ovulation, and some alter the uterine lining. The NCERT textbook describes these devices under reproductive health, emphasizing their modes of action.
Lippes loop (P) is an intrauterine device (IUD) made of plastic. Once inserted into the uterus, it triggers a local inflammatory response. This response increases the number of white blood cells in the uterine cavity, which phagocytose (engulf and destroy) sperms. The device also releases copper ions in copper-bearing IUDs like CuT or Multiload, but the Lippes loop itself primarily works through the inflammatory mechanism that makes the uterus hostile to sperm survival and movement. The textbook describes IUDs as devices that "increase phagocytosis of sperms within the uterus" and make the environment unsuitable for implantation.
Multiload 375 (Q) is a copper-releasing IUD. The copper ions it releases have a spermicidal effect and also make the cervix hostile to sperms by altering cervical mucus and creating an unfavorable environment. Copper IUDs are specifically noted for their ability to prevent fertilization by affecting sperm motility and viability, and by making the cervical environment inhospitable.
NoteBoth Lippes loop and Multiload 375 are IUDs, but they differ slightly in mechanism—Lippes loop works mainly through inflammatory phagocytosis, while Multiload 375 adds copper's spermicidal action and cervical hostility.
Subcutaneous Norplant (R) consists of small rods implanted under the skin that release progestin slowly over several years. Progestin-based contraceptives work by thickening cervical mucus, which creates a physical barrier that prevents sperm from entering the uterus. They may also suppress ovulation in some cases, but the primary and consistent mechanism is the thickening of cervical mucus that makes sperm penetration difficult. …
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