SN2
SHORT NOTE
5M
★ High-yield
Classify the methods of contraception. Describe the mechanism of the combined oral contraceptive pill.
Classification of Contraceptive Methods
| Group | Methods |
|---|---|
| Natural | Rhythm (calendar), basal body temperature, cervical mucus (Billings), coitus interruptus, lactational amenorrhoea |
| Barrier | Condom (male and female), diaphragm, cervical cap, spermicides |
| Hormonal | Combined oral pill, progestogen-only pill, injectables (DMPA), implants, hormonal IUD |
| Intrauterine device | Copper T 380A, LNG-IUS |
| Emergency | Levonorgestrel 1.5 mg within 72 h; copper IUD within 5 days |
| Permanent | Vasectomy (male), tubectomy (female) |
Combined Oral Contraceptive Pill — Mechanism
Oestrogen + progestogen taken daily → Negative feedback on hypothalamus and pituitary → ↓ FSH → no follicular growth; NO LH surge → ovulation inhibited
- Additional actions — thick cervical mucus blocks sperm; atrophic endometrium unsuitable for implantation; altered tubal motility
- Failure rate 0.3% with perfect use, 8% with typical use
Non-contraceptive Benefits and Risks
| Benefits | Risks |
|---|---|
| ↓ Ovarian and endometrial carcinoma | Venous thromboembolism (oestrogen) |
| ↓ Dysmenorrhoea, menorrhagia, anaemia | Hypertension |
| Regular cycles; treats PCOS and acne | Stroke and MI in smokers over 35 |
| ↓ Benign breast disease, ovarian cysts | Slight ↑ in breast and cervical cancer |
| ↓ Pelvic inflammatory disease | Nausea, weight gain, breakthrough bleeding |
- Absolute contraindications — pregnancy, undiagnosed vaginal bleeding, past thromboembolism, oestrogen-dependent tumour, active liver disease, smoking over the age of 35
Copper IUD
- Copper is spermicidal and causes a sterile inflammatory reaction in the endometrium
- Copper T 380A is effective for 10 years; failure rate below 1%
- Problems — menorrhagia, dysmenorrhoea, expulsion, pelvic infection, and an ectopic pregnancy if it fails
Applied Aspects
- Only the condom protects against sexually transmitted infection and HIV — the decisive advantage of barrier methods
- Progestogen-only methods are preferred in lactation and where oestrogen is contraindicated
- India's national programme has historically relied heavily on tubectomy; spacing methods are now being promoted
All questions in Reproductive System
- Q1Describe the ovarian and uterine changes of the menstrual cycle. Explain its hormonal control. ★
- Q2Define spermatogenesis. Describe its stages, the cells of the testis and the factors controlling it. ★
- Q3Describe the hormones of the placenta and the maternal physiological changes during pregnancy. Add a note on parturition. ★
- Q4Describe the actions and regulation of testosterone. Add a note on puberty in the male. ★
- Q5Describe the physiology of lactation. Explain why milk secretion begins only after delivery. ★
- SN1Describe the mechanism of ovulation and enumerate its indicators. ★
- SN2Classify the methods of contraception. Describe the mechanism of the combined oral contraceptive pill. ★
- SN3Define menopause. Describe the hormonal changes and clinical features. ★
- SN4Describe semen analysis with its normal values. Add a note on the composition of semen. ★
- SN5Describe the changes at puberty in boys and girls and the mechanism of its onset.
- SN6Describe the basis of pregnancy tests. Add a note on the causes of false results.
- SN7Define infertility. Enumerate its causes and outline the investigations. ★