ORAL CONTRACEPTIVE PILLS (OCPs) - KDT Simplified Notes

CLASSIFICATION OF OCPs

A. ORAL PREPARATIONS

1. Combined Pill (Monophasic)

• Taken daily for 21 days, starting 5th day of menstruation; 7-day gap for withdrawal bleed
• Third generation pills (desogestrel) - better tolerated, fewer androgenic side effects

2. Phased Pill (Triphasic)

• Estrogen kept constant (30-40 mcg), progestin increases progressively in 3 phases
• Mimics natural hormonal pattern
• Examples: TRIQUILAR (6+5+10 tabs), ORTHONOVUM 7/7/7

3. Progestin-only Pill (Minipill)

• Taken daily continuously WITHOUT any gap
• Ovulation still occurs in 20-30% women
• Acts mainly via hostile cervical mucus + endometrial changes
• Efficacy: 96-98% (less than combined pill's 98-99.9%)
• Suspect pregnancy if amenorrhoea > 2 months
• Not popular; used when estrogen is contraindicated

4. Emergency (Postcoital) Pill

• Levonorgestrel = first choice; nausea/vomiting ~6% only
• Ulipristal = failure rate 1-3% (vs levonorgestrel 2-4%); extended window
• To be used ONLY for unexpected/accidental exposure (rape, condom rupture)

B. INJECTABLE CONTRACEPTIVES

• Given during first 5 days of menstrual cycle
• Major drawback: Complete disruption of menstrual cycle / total amenorrhoea (more with DMPA)
• NOT suitable for adolescent girls or lactating mothers

C. IMPLANTS

• Subdermal; release steroid slowly over 1-5 years
• NORPLANT - 6 capsules of levonorgestrel 36 mg each (total 216 mg) - works 5 years
• Biodegradable or non-biodegradable types

D. TRANSDERMAL PATCH

• Norelgestromin + ethinylestradiol; weekly for 3 weeks, 1-week gap

MECHANISM OF ACTION (MOA)

Table Summary - Effects of Different Hormonal Contraceptives

MOA Details:

1. Inhibition of Gn release (via FSH & LH suppression) → follicles fail to develop → Suppression of ovulation - PRIMARY mechanism of combined pill
2. Hostile cervical mucus (progestin action) - prevents sperm penetration; works with ALL methods except postcoital pill
3. Endometrial changes - hyperproliferative/hypersecretory or atrophic → blastocyst fails to implant
4. Uterine & tubal contractions modified - disfavours fertilization
5. Postcoital pill may dislodge implanted blastocyst / interfere with fertilization

PRACTICAL CONSIDERATIONS

1. Missed pill: If 1 pill missed - take 2 next day; if >2 missed - stop course, use alternative contraception, restart on 5th day of next bleeding
2. Return of fertility: After OC - 1-2 months; After injectables - delayed by several months (may not normalize)
3. Pregnancy during OC use - terminate by suction-aspiration (risk of malformations, carcinoma in female offspring, undescended testes in male offspring)
4. Obese women need 50 mcg pill; cardiovascular risk/age >40 - use 20 mcg pill

ADVERSE EFFECTS

A. Non-serious Side Effects (common in first 1-3 cycles, then disappear)

1. Nausea & vomiting (like morning sickness)
2. Headache (mild); migraine may worsen
3. Breakthrough bleeding/spotting (switch to triphasic or higher estrogen dose)
4. Breast discomfort

B. Side Effects Appearing Later

1. Weight gain, acne, increased body hair (androgenic - older 19-nortestosterone progestins; newer ones like desogestrel - relatively free)
2. Chloasma - pigmentation of cheeks, nose, forehead
3. Pruritus vulvae (infrequent)
4. Carbohydrate intolerance/diabetes precipitation (high-dose only; current pills - unlikely)

C. Serious Complications

1. Leg vein thrombosis & pulmonary embolism - venous thromboembolism (2-3 per 1000 women years); risk in women >35 yrs, diabetics, hypertensives, smokers - due to estrogen component
2. Coronary & cerebral thrombosis - 2 to 6-fold increase (older data); low-dose pills have smaller increase; mechanisms: increased clotting factors, decreased antithrombin III, decreased plasminogen activator, increased platelet aggregation
3. Rise in BP - 5-10% women; both estrogen and progestin responsible (via angiotensinogen & renin-aldosterone pathway); normalizes in 3-6 months after stopping
4. HDL/LDL: Estrogen raises HDL (beneficial); progestin partially nullifies this
5. Genital carcinoma - NOT increased in general population; slight breast cancer risk in current users (rare in young, considered inconsequential); PROTECTIVE against endometrial carcinoma
6. Benign hepatomas - rare; slightly higher incidence
7. Gallstones - slightly higher in OC users

CONTRAINDICATIONS

Absolute Contraindications

1. Thromboembolic/coronary/cerebrovascular disease or history
2. Moderate-to-severe hypertension; hyperlipidaemia
3. Active liver disease, hepatoma, or jaundice during past pregnancy
4. Suspected/overt malignancy of genitals/breast
5. Porphyria
6. Impending major surgery (risk of postoperative thromboembolism)

Relative Contraindications (use under supervision)

1. Diabetes
2. Obesity
3. Smoking
4. Undiagnosed vaginal bleeding
5. Uterine leiomyoma (may enlarge with estrogen - use progestin-only)
6. Mentally ill
7. Age above 35 years
8. Mild hypertension
9. Migraine
10. Gallbladder disease

INTERACTIONS

Enzyme Inducers (reduce OCP efficacy)

• Phenytoin, carbamazepine, primidone, rifampicin, phenobarbitone, ritonavir
• Metabolism of estrogen (estrogenic component) increased
• Switch to preparation containing 50 mcg EE or use alternative contraception
• Rifampicin is such a potent enzyme inducer - always advise alternative contraception

Suppression of Intestinal Microflora

• Ampicillin, tetracyclines - interrupt enterohepatic circulation of estrogens → blood levels fall

OTHER HEALTH BENEFITS OF OCPs

• Lower menstrual blood loss (helps anaemia)
• Cycles become regular if irregular
• Dysmenorrhoea, premenstrual tension ameliorated
• Lower risk of endometrial and ovarian carcinoma
• Lower risk of developing colorectal cancer
• Protection from unwanted pregnancy

Memory tip for MOA: "CHUE" - Cervical mucus hostile, Hormonal suppression (LH/FSH), Uterine/tubal changes, Endometrial changes (out of phase)

Expected Viva Questions - OCPs (KDT Based)

🔴 MOST IMPORTANT / HIGH-YIELD QUESTIONS

A: Suppression of ovulation by inhibiting GnRH pulse → decreased FSH & LH → follicles fail to develop and rupture. Progestin reduces LH pulse frequency; estrogen suppresses FSH and abolishes midcycle LH surge.

A: Hostile cervical mucus (NOT ovulation suppression - ovulation still occurs in 20-30% women). Endometrial changes (out of phase) are also important.

A: Ulipristal is a Selective Progesterone Receptor Modulator (SPRM). Mifepristone is an antiprogestin. Both are used for emergency contraception, but ulipristal has extended window (120 hrs vs 72 hrs) and failure rate of 1-3% vs levonorgestrel's 2-4%.

A: Thromboembolism (leg vein thrombosis, pulmonary embolism, stroke, MI). Mechanisms: increased clotting factors, decreased antithrombin III, decreased plasminogen activator, increased platelet aggregation.

A:

• 1 tablet missed - take 2 tablets next day, continue as usual
• More than 2 tablets missed - stop course, use alternative contraception, restart on 5th day of next bleeding

A: (6 absolutes)

1. Thromboembolic/coronary/cerebrovascular disease (or history)
2. Moderate-severe hypertension / hyperlipidaemia
3. Active liver disease / hepatoma / jaundice in past pregnancy
4. Suspected/overt malignancy of genitals or breast
5. Porphyria
6. Impending major surgery (thromboembolism risk)

A: Enzyme inducers - Rifampicin, Phenytoin, Carbamazepine, Phenobarbitone, Primidone, Ritonavir. They induce hepatic enzymes → increased metabolism of estrogen → lower blood levels → contraceptive failure. Solution: Switch to 50 mcg EE pill OR use alternative contraception.

A: Depot Medroxyprogesterone Acetate - 150 mg i.m. deep injection, given during first 5 days of menstrual cycle, repeated every 3 months. Brand: DEPOT-PROVERA.

🟠 MODERATE IMPORTANCE QUESTIONS

A: Pigmentation of cheeks, nose and forehead seen as a late side effect of OCP - similar to that occurring in pregnancy.

A:

• Decreases: Endometrial carcinoma (progestin component is protective), ovarian carcinoma
• Slightly increases (minor): Breast cancer (only in current users; inconsequential in young women), benign hepatomas, gallstones

A: Increased risk of cardiovascular complications (thromboembolism, MI, stroke) especially if there are additional risk factors like smoking, hypertension, diabetes.

A: A subdermal implant containing 6 capsules of levonorgestrel (36 mg each = total 216 mg). Effective for 5 years. Slowly releases steroid from non-biodegradable rubber membranes. Discontinued in USA.

A: Older emergency contraception regimen using levonorgestrel 0.5 mg + ethinylestradiol 0.1 mg - two doses at 12-hour intervals within 72 hours. Now replaced by levonorgestrel-only regimen (2-3x more effective, better tolerated, nausea 6% vs 20-50%).

A: To reduce the risk of postoperative thromboembolism. Should be stopped 4 weeks before surgery (relative contraindication).

A:

• Estrogen - raises HDL (beneficial), lowers LDL
• Progestin - partially nullifies this benefit
• Overall: triglyceride level may rise marginally
• Low-dose pills: no significant adverse lipid changes

A: Ampicillin (and tetracyclines) destroy intestinal bacteria → suppression of intestinal microflora → deconjugation of estrogens in bile fails → enterohepatic circulation interrupted → blood estrogen levels fall → reduced contraceptive efficacy.

A: Triphasic pill where estrogen is kept constant but progestin dose increases progressively over 3 phases (mimicking natural hormonal pattern). Advantage: Reduces total steroid dose without compromising efficacy. Recommended for women >35 years or those with breakthrough bleeding on monophasic pill.

🟡 TRICKY / EXAMINER-FAVOURITE QUESTIONS

A:

• Progestin - reduces frequency of LH secretory pulses
• Estrogen - primarily reduces FSH secretion and abolishes midcycle LH surge

A: DMPA (Depot-Provera) - due to complete disruption of menstrual pattern, bone mineral density decrease, and permanent sterility risk.

A: 0.3% (quoted in KDT Table 22.3)

A: Third generation - Desogestrel (Novelon, Femilon) - free of androgenic side effects like weight gain, acne, hirsutism seen with older 19-nortestosterone progestins.

A: If pregnancy occurs, it should be terminated by suction aspiration because OCP use during pregnancy increases risk of:

• Malformations
• Genital carcinoma in female offspring
• Undescended testes in male offspring

QUICK RECALL TABLE

Pro tip for viva: Always mention "estrogen component" when asked about thromboembolism and "progestin component" when asked about protection against endometrial cancer - examiners love this specificity!