Obstetrics and Gynaecology for NEET-PG
Contraception for NEET-PG
Contraception refers to methods that prevent pregnancy, classified into barrier, hormonal, intrauterine, surgical, and natural methods. For NEET-PG, the highest-yield material is the mechanism, failure rate expressed as the Pearl index, contraindications, and specific side effects of each method. Combined oral contraceptive pills contain oestrogen and progestogen, act mainly by suppressing ovulation through inhibition of the hypothalamic-pituitary axis, and carry a risk of venous thromboembolism, which makes them contraindicated in smokers over 35 and in women with a history of thrombosis. Progestogen-only methods, including the minipill, injectable depot medroxyprogesterone, and implants, work by thickening cervical mucus and are safe in breastfeeding women. Intrauterine devices include the copper T, which acts as a spermicide and prevents implantation, and the levonorgestrel-releasing system, which thins the endometrium and is used therapeutically in menorrhagia. Emergency contraception with levonorgestrel or ulipristal is effective up to 72 to 120 hours, and the copper IUD is the most effective emergency method. Permanent methods include tubal ligation and vasectomy, the latter requiring confirmation of azoospermia before it is relied upon. The lactational amenorrhoea method offers protection when strict criteria are met. Knowing the most effective reversible method, the copper T lifespan, and the WHO medical eligibility contraindications are recurrent exam themes.
MedNext Academy | 3 min read
Contraception for NEET-PG
Contraception refers to methods that prevent pregnancy, classified into barrier, hormonal, intrauterine, surgical, and natural methods. For NEET-PG, the highest-yield material is the mechanism, failure rate expressed as the Pearl index, contraindications, and specific side effects of each method. Combined oral contraceptive pills contain oestrogen and progestogen, act mainly by suppressing ovulation through inhibition of the hypothalamic-pituitary axis, and carry a risk of venous thromboembolism, which makes them contraindicated in smokers over 35 and in women with a history of thrombosis. Progestogen-only methods, including the minipill, injectable depot medroxyprogesterone, and implants, work by thickening cervical mucus and are safe in breastfeeding women. Intrauterine devices include the copper T, which acts as a spermicide and prevents implantation, and the levonorgestrel-releasing system, which thins the endometrium and is used therapeutically in menorrhagia. Emergency contraception with levonorgestrel or ulipristal is effective up to 72 to 120 hours, and the copper IUD is the most effective emergency method. Permanent methods include tubal ligation and vasectomy, the latter requiring confirmation of azoospermia before it is relied upon. The lactational amenorrhoea method offers protection when strict criteria are met. Knowing the most effective reversible method, the copper T lifespan, and the WHO medical eligibility contraindications are recurrent exam themes.
Contraception refers to methods that prevent pregnancy, classified into barrier, hormonal, intrauterine, surgical, and natural methods. For NEET-PG, the highest-yield material is the mechanism, failure rate expressed as the Pearl index, contraindications, and specific side effects of each method. Combined oral contraceptive pills contain oestrogen and progestogen, act mainly by suppressing ovulation through inhibition of the hypothalamic-pituitary axis, and carry a risk of venous thromboembolism, which makes them contraindicated in smokers over 35 and in women with a history of thrombosis. Progestogen-only methods, including the minipill, injectable depot medroxyprogesterone, and implants, work by thickening cervical mucus and are safe in breastfeeding women. Intrauterine devices include the copper T, which acts as a spermicide and prevents implantation, and the levonorgestrel-releasing system, which thins the endometrium and is used therapeutically in menorrhagia. Emergency contraception with levonorgestrel or ulipristal is effective up to 72 to 120 hours, and the copper IUD is the most effective emergency method. Permanent methods include tubal ligation and vasectomy, the latter requiring confirmation of azoospermia before it is relied upon. The lactational amenorrhoea method offers protection when strict criteria are met. Knowing the most effective reversible method, the copper T lifespan, and the WHO medical eligibility contraindications are recurrent exam themes.
Key points
- **Pearl index:** Number of pregnancies per 100 woman-years of use. A lower index means a more effective method. Implants and IUDs have very low indices.
- **Combined pill mechanism:** Oestrogen plus progestogen suppresses ovulation by inhibiting the hypothalamic-pituitary axis, and also thickens mucus and thins endometrium.
- **COC contraindications:** Avoid in women over 35 who smoke, history of thromboembolism, migraine with aura, and active breast cancer due to thrombotic and oestrogen risk.
- **Progestogen-only safety:** Minipill, DMPA injection, and implants are safe during breastfeeding and in women where oestrogen is contraindicated.
- **Copper T:** Acts as a spermicide and prevents fertilisation and implantation. CuT 380A is effective for up to 10 years. Can worsen menorrhagia.
- **Levonorgestrel IUS:** Releases progestogen locally, thins the endometrium, reduces menstrual loss, and is therapeutic in menorrhagia and dysmenorrhoea.
- **Emergency contraception:** Levonorgestrel up to 72 hours, ulipristal up to 120 hours. The copper IUD is the most effective emergency method, up to 5 days.
- **DMPA effect:** Depot medroxyprogesterone delays return of fertility and reduces bone mineral density with prolonged use, which is reversible.
- **Vasectomy confirmation:** Not immediately reliable. Azoospermia must be confirmed by semen analysis, usually after about 3 months or 20 ejaculations.
- **Lactational amenorrhoea:** Effective only when the mother is fully breastfeeding, amenorrhoeic, and within 6 months postpartum, all three criteria required.
- **Most effective reversible:** Long-acting reversible contraceptives, the implant and intrauterine systems, have the lowest failure rates among reversible methods.
Frequently Asked Questions
What is the Pearl index?
The Pearl index is the number of accidental pregnancies per 100 woman-years of use. A lower value indicates a more effective contraceptive method.
When are combined oral contraceptive pills contraindicated?
They are avoided in women over 35 who smoke, those with prior thromboembolism, migraine with aura, or active breast cancer because of thrombotic and oestrogen-related risks.
Which is the most effective emergency contraceptive?
The copper intrauterine device is the most effective emergency contraceptive and can be inserted up to 5 days after unprotected intercourse.
How long does the copper T remain effective?
The CuT 380A copper device provides contraception for up to 10 years, though it may increase menstrual bleeding and cramping.
Which contraceptives are safe during breastfeeding?
Progestogen-only methods such as the minipill, DMPA injection, and implants are safe while breastfeeding because they do not affect milk supply.
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