BiologyCBSE Class 12 · Reproductive Health

Contraceptive Methods and Birth Control

Q: What are the main types of contraceptive methods?

Natural methods, barrier methods, intra-uterine devices, hormonal methods (pills, injections, implants), emergency contraceptives and surgical methods (vasectomy, tubectomy).

Q: How does a CuT work?

It increases phagocytosis of sperms in the uterus, and the copper ions it releases suppress sperm motility and fertilising capacity.

Q: How do oral contraceptive pills work?

They inhibit ovulation and implantation and alter the cervical mucus so that sperms are prevented or slowed.

Q: Why are natural methods not fully reliable?

They depend on timing and behaviour, so their chance of failure is high, even though they have almost no side-effects.

Q: What is the difference between vasectomy and tubectomy?

Vasectomy removes or ties a small part of the vas deferens in men; tubectomy removes or ties a small part of the fallopian tube in women. Both block gamete transport.

Updated 15 October 2026 · Fact-checked

Contraceptive methods prevent pregnancy. Natural methods avoid sperm meeting the ovum by timing; barriers such as condoms physically stop sperms; IUDs make sperms less motile and increase their phagocytosis; pills, injections and implants stop ovulation and implantation; and vasectomy or tubectomy permanently block gamete transport. An ideal method is safe, effective, reversible and easy to use.

Understand Contraceptive Methods and Birth Control

Why birth control. A rapidly growing population strains resources, so birth control and small families are encouraged. An ideal contraceptive is user-friendly, easily available, effective, reversible, with no or minimal side-effects, and does not interfere with sexual drive, desire or the sexual act.

1. Natural (traditional) methods: prevent the ovum and sperms from meeting, without any device or medicine.

Periodic abstinence: no coitus from day 10 to day 17 of the cycle, when ovulation is expected (the fertile period).
Withdrawal (coitus interruptus): the man withdraws before ejaculation.
Lactational amenorrhoea: during intense breastfeeding after childbirth, ovulation and the cycle do not occur; chances of conception are almost nil only while the mother breastfeeds fully, and only up to a maximum of six months after delivery.

Natural methods have almost no side-effects, but their failure rate is high.

2. Barrier methods: physically stop the ovum and sperms from meeting.

Condoms: thin rubber or latex sheaths that cover the penis (male) or the vagina and cervix (female) just before coitus, so semen does not enter the female tract. Nirodh is a popular brand for men. Condoms also protect against STIs and AIDS, and are disposable and easy to self-insert or use.
Diaphragms, cervical caps and vaults: rubber barriers inserted into the female tract to cover the cervix and block sperms; reusable.
Spermicidal creams, jellies and foams are usually used with these barriers to increase their efficiency.

3. Intra-uterine devices (IUDs): inserted into the uterus through the vagina by doctors or trained nurses.

Non-medicated: e.g. Lippes loop.
Copper-releasing: CuT, Cu7, Multiload 375.
Hormone-releasing: Progestasert, LNG-20.

*How they work*: IUDs increase phagocytosis of sperms in the uterus; copper ions suppress sperm motility and fertilising capacity; hormone-releasing IUDs also make the uterus unsuitable for implantation and the cervix hostile to sperms. IUDs are ideal for women who want to delay pregnancy or space children, and are among the most widely accepted methods in India.

4. Hormonal methods.

Oral pills: progestogens alone or progestogen-oestrogen combinations. Taken daily for 21 days, starting preferably within the first five days of the cycle, followed by a gap of 7 days (when menstruation occurs), then repeated. They inhibit ovulation and implantation and alter cervical mucus to stop or slow sperms. Very effective, with fewer side-effects.
Saheli: a non-steroidal, once-a-week oral pill with very few side-effects and high contraceptive value (developed at the Central Drug Research Institute, Lucknow).
Injections and implants under the skin: progestogens alone or with oestrogen; same mode of action as pills but effective for much longer.
Emergency contraception: progestogens or progestogen-oestrogen combinations, or an IUD, within 72 hours of coitus; useful after rape or casual unprotected intercourse.

5. Surgical methods (sterilisation): a terminal method for those who want no more children; they block gamete transport.

Vasectomy (men): the vas deferens is tied, or a short piece of it cut out, through a tiny cut in the scrotum.
Tubectomy (women): a small part of the fallopian tube is removed or tied up through a small incision in the abdomen or through the vagina.

Very effective, but reversibility is very poor.

Cautions. Contraceptives are not regular requirements for reproductive health; they are used to prevent, delay or space pregnancy, and the method should be chosen with a qualified medical professional. Their possible ill-effects (nausea, abdominal pain, breakthrough or irregular bleeding, even breast cancer) are not very significant but should not be ignored.

Choosing a method (decision flow):
Wants protection from STIs too? → condom.
Wants to space children / delay pregnancy? → IUD (CuT) or pills.
Forgets daily pills? → weekly pill (Saheli), injection or implant.
Unprotected intercourse in the last 72 hours? → emergency contraceptive.
Wants no more children? → vasectomy or tubectomy.

Draw and label (for awareness questions): positions of contraceptives. Checklist: outline of the female tract (vagina, cervix, uterus, tubes); show a CuT inside the uterine cavity, a diaphragm/cervical cap over the cervix, and a cut-and-tied segment on a fallopian tube. Labels: uterus, cervix, CuT (IUD), diaphragm, tubectomy site, fallopian tube.

Contraceptive Methods and Birth Control: key facts

Fertile period (periodic abstinence): $avoid coitus: day 10 to day 17$; Ovulation is expected in this window of a 28-day cycle.
Pill schedule: $21 days pills (start within days 1-5) + 7 days gap = 28$; Menstruation occurs in the 7-day gap; then repeat.
IUD action: $↑ phagocytosis of sperms; C u^{2 +} ↓ motility and fertilising capacity$; Hormonal IUDs also: uterus unsuitable for implantation, cervix hostile to sperms.
Pill action: $inhibit ovulation + inhibit implantation + alter cervical mucus$; Same for injections and implants, which last longer.
Time limits: $emergency: within 72 h; lactational amenorrhoea: up to 6 months$; Both are frequent 1-mark items.

How to answer Contraceptive Methods and Birth Control questions

Most questions are of three kinds: name the method and its mode of action, match devices with actions, or suggest a method for a case.

1Classify the method first: natural, barrier, IUD, hormonal, emergency or surgical.
2Give the mode of action in one line using the key verb: prevents meeting (natural, barrier), kills/immobilises/phagocytoses sperms (IUD), inhibits ovulation and implantation (hormonal), blocks gamete transport (surgical).
3For a case, read the need: STI protection, spacing, permanence, emergency, a nursing mother, forgetfulness. Match it using the decision flow.
4Justify every suggestion with the mode of action plus one advantage (reversible, reusable, protects from STIs, long-acting).
5For pill-use questions, quote the schedule (21 days, start within days 1-5, 7-day gap) and say that missing pills can allow ovulation.
6For sterilisation, name the tube cut (vas deferens or fallopian tube), the incision site, and note poor reversibility.

Contraceptive Methods and Birth Control in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Choosing a suitable contraceptive

Suppose a health worker in a village meets four people: Asha, newly married, who wants to delay her first child by two years; Ravi, who has casual partners and wants to avoid both pregnancy and infections; Meena, 38, with three children, who wants no more; and Rekha, who had unprotected intercourse yesterday.

Suggest a method for each and justify it with its mode of action.

Try it first, then show the solutionSolution

Asha: an IUD such as CuT (or oral pills). Copper ions reduce sperm motility and fertilising capacity; it is reversible and ideal for delaying pregnancy.
Ravi: condom. It stops semen from entering the partner's tract and also protects against STIs and AIDS.
Meena: tubectomy (or vasectomy for her husband). Cutting or tying the fallopian tube blocks gamete transport; it is terminal, which suits a couple wanting no more children.
Rekha: an emergency contraceptive (progestogen or progestogen-oestrogen pill, or an IUD) within 72 hours of coitus.

Answer: Asha: CuT or pills; Ravi: condom; Meena: tubectomy/vasectomy; Rekha: emergency contraceptive within 72 hours.

Memory hook: Delay → IUD, Disease → condom, Done → sterilise, Disaster → 72 hours.

Tricks to remember Contraceptive Methods and Birth Control

Short memory aids. Say each one aloud once, then use it on a question the same day.

10 to 17: the 'no-go' week
Ten to seventeen, keep it clean.
Use it when: Periodic abstinence window.
21-7, start by 5
Pills for 21, rest for 7, start by day 5.
Use it when: Oral pill schedule.
Vas for the man, tube for the woman
Vasectomy cuts the vas deferens; tubectomy cuts the fallopian tube.
Use it when: Surgical methods.

Contraceptive Methods and Birth Control: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Matching devices and actions · 1 mark · MCQBoard level

Match: (a) CuT (b) oral pill (c) vasectomy (d) condom with (i) blocks transport of sperms from the testes (ii) prevents semen entering the female tract (iii) inhibits ovulation (iv) suppresses sperm motility.

Try it first, then show the solutionSolution

CuT releases copper ions that suppress sperm motility; pills inhibit ovulation.
Vasectomy blocks sperm transport in the vas deferens; condom keeps semen out of the female tract.

Answer: (a)-(iv), (b)-(iii), (c)-(i), (d)-(ii).

Example 2: Vasectomy · 3 marks · Short answerBoard level

Name and explain a surgical method of contraception for the male partner. Why is it called a terminal method?

Try it first, then show the solutionSolution

Vasectomy (1 mark).
Through a tiny cut in the scrotum the vas deferens is tied, or a short piece of it cut out, so sperms cannot reach the ejaculate (1 mark).
It is terminal because reversibility is very poor; it is advised only when no more children are wanted (1 mark).

Answer: Vasectomy: vas deferens cut or tied; poorly reversible, hence terminal.

Example 3: Pills: mode of action and schedule · 3 marks · Short answerHarder board level

Explain the mode of action of contraceptive pills and the schedule to be followed. Why can wrong use of pills actually lead to conception?

Try it first, then show the solutionSolution

Pills (progestogens or progestogen-oestrogen) inhibit ovulation and implantation and alter the cervical mucus to prevent or slow sperm entry (1 mark).
Schedule: one pill daily for 21 days, starting preferably within the first five days of the cycle, then a 7-day gap (menstruation), and repeat (1 mark).
If pills are missed or started late, hormone levels fall, ovulation may not be suppressed and an ovum may be released, so unprotected coitus can lead to conception (1 mark).

Answer: Inhibit ovulation and implantation, thicken cervical mucus; 21 days from within day 1-5, 7-day gap; missing pills allows ovulation.

Example 4: How IUDs prevent pregnancy · 3 marks · Short answerHarder board level

Give three ways in which IUDs prevent pregnancy, naming the type of IUD responsible for each.

Try it first, then show the solutionSolution

All IUDs increase phagocytosis of sperms within the uterus (1 mark).
Copper-releasing IUDs (CuT, Cu7, Multiload 375): copper ions suppress sperm motility and fertilising capacity (1 mark).
Hormone-releasing IUDs (Progestasert, LNG-20): make the uterus unsuitable for implantation and the cervix hostile to sperms (1 mark).

Answer: Phagocytosis (all); Cu ions reduce motility (copper IUDs); unsuitable uterus and hostile cervix (hormonal IUDs).

Example 5: Lactational amenorrhoea · 3 marks · Short answerHOTS / competency

Suppose a mother who delivered four months ago is fully breastfeeding and believes she 'cannot get pregnant while feeding'. A friend who delivered nine months ago and now feeds the baby only twice a day believes the same. Evaluate both beliefs.

Try it first, then show the solutionSolution

During intense lactation ovulation and the menstrual cycle do not occur, so chances of conception are almost nil (1 mark).
First mother: fully breastfeeding and within six months of delivery, so her belief is largely valid, though the method has a high failure rate (1 mark).
Friend: beyond six months and not breastfeeding intensely, so ovulation can resume (even before the first period) and she can conceive; she should use another method (1 mark).

Answer: First mother is mostly right (full feeding, under 6 months); the friend is wrong (over 6 months, partial feeding).

Example 6: Suggest for each case · 3 marks · Short answerHarder board level

Suggest a contraceptive with justification for: (i) a woman who wants protection from both conception and STIs; (ii) a woman with two children who wants no more and does not want daily pills; (iii) a woman who wants to space her next child by three years.

Try it first, then show the solutionSolution

(i) Female condom (or her partner uses a condom): barrier keeps semen out and protects from STIs (1 mark).
(ii) Tubectomy: fallopian tube cut or tied, blocks ovum transport; terminal, no daily effort (1 mark).
(iii) IUD such as CuT: reversible and long-acting, ideal for spacing; copper ions reduce sperm motility and fertilising capacity (1 mark).

Answer: (i) condom (ii) tubectomy (iii) CuT.

Where students lose marks in Contraceptive Methods and Birth Control

The slips examiners see most often, and what to write instead.

Mistake: Saying IUDs stop ovulation
IUDs are confused with pills.
Wrong working
CuT prevents ovulation.
Right working
CuT: copper ions suppress sperm motility and fertilising capacity; IUDs increase phagocytosis of sperms.
Do this: Only hormonal methods inhibit ovulation.
Usually costs: 1 mark.
Mistake: Wrong pill schedule
Students write '28 days' or 'start on day 14'.
Wrong working
Pills are taken daily for 28 days from the 14th day.
Right working
21 days, starting within the first 5 days of the cycle, then a 7-day gap.
Do this: 21-7, start by 5.
Usually costs: 1 mark.
Mistake: Calling sterilisation easily reversible
Students know it can sometimes be reversed.
Wrong working
Vasectomy is a reversible method of family planning.
Right working
Very effective but reversibility is very poor; it is a terminal method.
Do this: Use 'terminal' and 'poor reversibility'.
Usually costs: 1 mark.
Mistake: Forgetting the 72-hour limit
Emergency contraception is described vaguely.
Wrong working
Emergency pills can be taken any time after intercourse.
Right working
Within 72 hours of coitus.
Do this: Always write '72 hours'.
Usually costs: ½-1 mark.

Exam tips

In 'suggest a method' questions, name the method, then justify with its mode of action; a name alone earns half marks at most.
Name examples for IUDs by type: Lippes loop (non-medicated), CuT/Cu7/Multiload 375 (copper), Progestasert/LNG-20 (hormonal).
Mention STI protection only for condoms.
Quote numbers exactly: day 10-17, 21 + 7 days, within 5 days, 72 hours, 6 months.
For Saheli, the two keywords are non-steroidal and once a week.

Practice questions on Contraceptive Methods and Birth Control

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
Periodic abstinence for family planning should be from:
(a) day 1 to day 5 (b) day 10 to day 17 (c) day 18 to day 25 (d) day 21 to day 28 of the menstrual cycle
Hint
Around ovulation.
Answer
(b) day 10 to day 17.
Q2 · 1 mark · Assertion-reasonHarder board level
Assertion (A): Saheli is a non-steroidal oral contraceptive pill.
Reason (R): Saheli has to be taken every day for 21 days.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Hint
How often is Saheli taken?
Answer
(c). Saheli is non-steroidal, but it is a once-a-week pill.
Q3 · 2 marks · Very short answerBoard level
Why are condoms considered better than other contraceptives for people with multiple partners? Name the popular brand for men.
Hint
Second benefit besides contraception.
Answer
They prevent conception and also protect the user from STIs and AIDS, which other methods (IUDs, pills) do not. Popular brand: Nirodh.
Q4 · 3 marks · Short answerHOTS / competency
Suppose a woman fitted with a hormone-releasing IUD asks why it works even on the rare occasion that a sperm reaches an ovum and fertilises it. Explain, and say how this differs from a non-medicated IUD.
Hint
Implantation.
Answer
A hormone-releasing IUD (Progestasert, LNG-20) makes the uterus unsuitable for implantation, so even if fertilisation occurs the embryo cannot implant and pregnancy is not established; it also makes the cervix hostile to sperms. A non-medicated IUD (Lippes loop) mainly increases phagocytosis of sperms in the uterus and does not alter the endometrium hormonally.
Q5 · 4 marks · Case-basedHarder board level
Read and answer.
Suppose a family-planning clinic records the following: Client P uses a rubber device inserted over the cervix and reuses it; Client Q received an injection that protects her for three months; Client R came to the clinic 60 hours after unprotected intercourse; Client S has had both fallopian tubes tied.
(a) Name the device used by P and one substance used with it to raise efficiency. (1)
(b) How does Q's method prevent pregnancy? (1)
(c) Is R within the time limit for emergency contraception? What can be given? (1)
(d) Why is S's method not advised for a young couple who may want children later? (1)
Hint
72 hours; reversibility.
Answer
(a) Diaphragm or cervical cap (vault); spermicidal cream, jelly or foam. (b) Progestogen (with or without oestrogen) inhibits ovulation and implantation and alters cervical mucus, like pills but longer-acting. (c) Yes, 60 h < 72 h; progestogen or progestogen-oestrogen pills, or an IUD. (d) Tubectomy has very poor reversibility; it is a terminal method.
Q6 · 3 marks · Short answerHarder board level
List the features of an ideal contraceptive. Which natural method meets most of them, and why is it still not recommended as the only method?
Hint
Side-effects vs failure rate.
Answer
Ideal: user-friendly, easily available, effective, reversible, few or no side-effects, does not interfere with sexual drive, desire or the act. Natural methods (periodic abstinence, withdrawal, lactational amenorrhoea) need no device or medicine and have almost no side-effects, but their chance of failure is high, so they are not reliable on their own.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.Name a copper-releasing IUD.Show answer
CuT, Cu7 or Multiload 375.
2.Within how many hours must emergency contraception be used?Show answer
72 hours.
3.Which contraceptive also protects from STIs?Show answer
Condom.
4.What is cut in tubectomy?Show answer
A small part of the fallopian tube (removed or tied).
5.How often is Saheli taken?Show answer
Once a week.
6.Up to how long after delivery can lactational amenorrhoea work?Show answer
A maximum of six months, with full breastfeeding.

Contraceptive Methods and Birth Control: frequently asked questions

What are the main types of contraceptive methods?

Natural methods, barrier methods, intra-uterine devices, hormonal methods (pills, injections, implants), emergency contraceptives and surgical methods (vasectomy, tubectomy).

How does a CuT work?

It increases phagocytosis of sperms in the uterus, and the copper ions it releases suppress sperm motility and fertilising capacity.

How do oral contraceptive pills work?

They inhibit ovulation and implantation and alter the cervical mucus so that sperms are prevented or slowed.

Why are natural methods not fully reliable?

They depend on timing and behaviour, so their chance of failure is high, even though they have almost no side-effects.

What is the difference between vasectomy and tubectomy?

Vasectomy removes or ties a small part of the vas deferens in men; tubectomy removes or ties a small part of the fallopian tube in women. Both block gamete transport.