Q.How do oral contraceptives prevent pregnancy? OR What is the difference between vasectomy and tubectomy?
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Contraceptive methods fall into a handful of categories, each blocking pregnancy at a different point. Natural/traditional methods (periodic abstinence during the fertile window, withdrawal, lactational amenorrhea) avoid conception without any device or hormone. Barrier methods (condoms, diaphragms, cervical caps) physically stop sperm and egg from meeting — and they're the only category NCERT credits with also reducing the risk of sexually transmitted diseases, since they block pathogen transmission along with sperm. IUDs (intrauterine devices) are inserted into the uterus; the copper-releasing type (Cu-T) works mainly by increasing phagocytosis of sperm within the uterus, alongside making the uterine lining less suitable for implantation — notably, Cu-T does not work by stopping ovulation. Hormonal contraceptives (pills, injectables, implants) primarily inhibit ovulation, with cervical-mucus alteration and endometrial effects as secondary, supporting mechanisms. Surgical methods — vasectomy (blocking the vas deferens in males) and tubectomy (blocking the fallopian tubes in females) — are permanent.
Hormonal contraceptives share one active ingredient family (progestogens, sometimes combined with estrogen) but differ in delivery route. A pill is taken daily; an injectable is given periodically; an implant is placed under the skin and releases hormone gradually. All three achieve the same primary effect — ovulation inhibition — the only difference is how often the user needs medical intervention to maintain it. …
Oral contraceptive pills deliver steady doses of hormones that act on the hypothalamus-pituitary axis, so they prevent pregnancy chiefly by suppressing the hormones that trigger ovulation, backed by effects on cervical mucus and the endometrium. …
OCPs (synthetic estrogen ± progesterone) prevent pregnancy chiefly by blocking ovulation, plus secondary barrier effects on mucus and the endometrium.
(Answering the primary part; the OR alternative on vasectomy/tubectomy is not required.)
Oral contraceptive pills (OCPs) contain synthetic estrogen and progesterone (combined pills) or progesterone alone, taken daily, usually starting within the first five days of the menstrual cycle, for 21 days. They prevent pregnancy through several linked mechanisms:
- Inhibition of ovulation: the steady dose of estrogen/progesterone suppresses the hypothalamus-pituitary axis, reducing FSH and LH secretion. Without the normal LH surge, follicles do not mature fully and ovulation does not occur.
- Altered cervical mucus: progesterone thickens the cervical mucus, making it hostile to and blocking the entry of sperm into the uterus. …
Showing the 12 most recent of 48 on this concept.
- CBSE 2026Set ZOOLOGY1 markMCQQ.MTP is safest during which period of pregnancy?(a) Second trimester(b) Third trimester(c) First trimester(d) Before parturition
›Reveal solutionSolution
MTP (abortion) carries the least risk of complications when carried out during the first trimester (up to 12 weeks) of pregnancy.
Medical Termination of Pregnancy involves the deliberate ending of a pregnancy before full term. It is considered safest during the first trimester (the first 12 weeks of gestation) because the embryo/foetus is smaller, the uterus is less developed, and the procedure carries a much lower risk of haemorrhage, infection, and other complicati …
- CBSE 2026Set ANNUAL1 markQ.Fill in the blank: 'Saheli' named contraceptive pill was developed by Central Drug Research Institute of ______ city in India.
›Reveal solutionSolution
Saheli, the non-steroidal oral contraceptive, was developed by the Central Drug Research Institute (CDRI) in Lucknow.
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- CBSE 2026Set ANNUAL1 markQ.Note the relationship between the first two words and find a suitable word for the fourth place. LNG - 20 : Hormone releasing IUD Multiload 375 : ________
›Reveal solutionSolution
LNG-20 is a hormone-releasing IUD; Multiload 375, like Cu-T and Cu7, is a copper-releasing IUD.
Intra Uterine Devices (IUDs) used as contraceptives are grouped by what they release into the uterus:
- Non-medicated IUDs — e.g. Lippes loop.
- Copper releasing IUDs — e.g. CuT, Cu7, Multiload 375. The Cu ions released increase phagocytosis of sperms and also suppress sperm motility and fertilising capacity of sperm. …
- CBSE 2026Set ANNUAL1 markQ.Name the oral pill which is taken by Indian women once a week.
›Reveal solutionSolution
The oral contraceptive pill taken once a week by Indian women is Saheli.
Saheli is a non-steroidal oral contraceptive developed by scientists at the Central Drug Research Institute (CDRI), Lucknow. Its active compound is Centchroman. Unlike most steroidal oral pills that need to be taken daily, Saheli has a weekly dosi …
- CBSE 2026Set ANNUAL1 markMCQQ.Assertion (A) : Medical termination of pregnancy (MTP) is done to get rid of unwanted pregnancies. Reason (R) : It is usually done after 24 weeks of pregnancy.(a) Assertion (A) and Reason (R) both are true and Reason (R) is the correct explanation of Assertion (A).(b) Assertion (A) and Reason (R) both are true, but Reason (R) is not the correct explanation of Assertion (A).(c) Assertion (A) is true, but Reason (R) is false.(d) Assertion (A) is false, but Reason (R) is true.
›Reveal solutionSolution
MTP does help end unwanted pregnancies (A is true), but it is NOT usually done after 24 weeks — it is medically safest and most commonly performed during the first trimester (up to 12 weeks); second-trimester MTPs carry more complications (R is false).
Medical Termination of Pregnancy (MTP), or induced abortion, is indeed carried out to terminate unwanted pregnancies — making Assertion (A) true. However, MTPs are considered relatively safe only during the first trimester (up to 12 weeks of pregnancy); second trimester abortions are associated with significantly more …
- CBSE 2026Set ANNUAL1 markQ.Write the full form of MTP.
›Reveal solutionSolution
MTP = Medical Termination of Pregnancy — the medical/surgical induced termination of an unwanted pregnancy.
MTP (Medical Termination of Pregnancy), commonly called induced abortion, is the intentional termination of pregnancy before full term, done by a qualified medical practitioner. In India, the MTP Act (1971, amended later) legalised abortion under specific conditions to check illegal and unsafe abortions, which were a major cause of maternal mortality and reproductive health complicatio …
- CBSE 2026Set ANNUAL1 markMCQQ.Which of the following contraception aids works by releasing hormones to prevent ovulation?(a) Diaphragm(b) Oral Contraceptive Pills(c) Vaults(d) Copper - T
›Reveal solutionSolution
OCPs contain synthetic estrogen and/or progestogen that suppress the pituitary's FSH/LH surge, blocking ovulation.
Oral contraceptive pills are taken daily and contain a combination of synthetic estrogen and progesterone (or progestogen alone — the 'mini-pill'). These hormones work mainly by inhibiting the release of FSH and LH from the pituitary (negative feedback), which prevents the LH surge needed for ovulation; they also thicken cervical mucus, hindering sperm entry.
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- CBSE 2026Set ANNUAL1 markQ.Give two examples of terminal method of contraception. (21+21=1)
›Reveal solutionSolution
Vasectomy and tubectomy are the two surgical sterilisation procedures that provide permanent contraception.
Terminal methods of contraception are surgical sterilisation procedures that provide permanent (irreversible, in practice) protection against pregnancy. In males, this procedure is called vasectomy, in which a small part of the vas deferens is cut and tied/sealed on each side, preventing sperm from being included in the ejaculate. In females, the corresponding procedure is called tubectomy, in whic …
- CBSE 2025Set X11 markMCQQ.Which one among the following is a contraceptive method that involves no medicine or device?(a) Condom(b) Saheli(c) Cervical caps(d) Coitus interruptus
›Reveal solutionSolution
Coitus interruptus (withdrawal) is a natural contraceptive method that uses no medicine or device.
Natural/traditional methods of contraception avoid meeting of sperm and ovum without any drugs or devices. Coitus interruptus is the withdrawal of the penis before ejaculation to avoid insemination—no medicine or device is involved. In …
- CBSE 2025Set ANNUAL1 markMCQQ.Terminal method to prevent pregnancies is -(a) Sterilisation(b) Periodic abstinence(c) Intra uterine devices(d) Diaphragms
›Reveal solutionSolution
Sterilisation (vasectomy in males, tubectomy in females) permanently blocks gamete transport and is therefore called a terminal method.
Contraceptive methods are grouped as barrier (diaphragms), IUDs (intra-uterine devices), natural/behavioural (periodic abstinence), and terminal (permanent) methods. Sterilisation involves a minor surgical procedure — vasectomy (cutting/blocking the vas deferens in males) or tubectomy (blocking the fallopian tubes in females) — which is highly effective but …
- CBSE 2025Set ANNUAL1 markMCQQ.IUD stands for(a) Inter Union Device(b) Intra Uterine Device(c) Infra United Device(d) Insta Uterine Device
›Reveal solutionSolution
IUD stands for Intra Uterine Device - a contraceptive device placed inside the uterus by a doctor or trained nurse.
IUDs are one of the widely used reversible contraceptive methods for women. They include non-medicated devices (e.g. Lippes loop), copper-releasing devices (CuT, Cu7, multiload 375), and hormone-releasing devices (progestasert, LNG-IUS). Copper ions released from copper-based IUDs suppress sperm motility and fertilising capacity, while hormone-releasi …
- CBSE 2025Set ANNUAL1 markQ.Name the oral contraceptive for female developed by CDRI.
›Reveal solutionSolution
Saheli, developed by CDRI, is India's own non-steroidal oral contraceptive for women, taken once a week rather than daily.
Among the various contraceptive methods available to couples, oral contraceptive pills are a chemical method used by women to prevent pregnancy. While most oral pills are steroidal (containing synthetic progestogen alone or in combination with an oestrogen), India's Central Drug Research Institute (CDRI), Lucknow, developed a non-steroidal oral contraceptive for females called Saheli, whose active compound is Centchroman. It has very few side effects, high contraceptive efficacy, …
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