Gynecology Topic 12. Hormonal contraception. Intrauterine devices

I. Basic Concepts and Effectiveness

Pearl Index

• Pearl index: number of contraceptive failures/pregnancies per 100 women-years of use.
• Lower Pearl index → higher contraceptive effectiveness.
• Examples: OCP 0.1-2.5, postcoital pill 0.5-2.5, IUD 0.5-5, condom 3-28 in classic exam notes.
• LARC: IUDs and subdermal implant → high efficacy, low compliance burden, reversible.

Before Prescribing / Inserting

• History: thrombosis, migraine with aura, smoking, HT/CVD, liver disease, breast cancer, abnormal bleeding, medications, pregnancy risk.
• Measure BP before combined hormonal contraception; exclude pregnancy if uncertain and before IUD insertion.

II. Combined Hormonal Contraceptives

Definition and Mechanism

• Combined hormonal contraceptives (CHC): estrogen + progestin.
• Estrogen examples: ethinylestradiol, estradiol.
• Progestin examples: desogestrel, drospirenone, levonorgestrel, norethisterone.
• Mechanism: negative feedback on GnRH/FSH/LH → no follicle maturation + no LH surge → ovulation inhibition.
• Additional effects: thick cervical mucus → blocks sperm; endometrial changes.

Forms and Regimens

• Combined oral contraceptive pill (OCP): daily oral use; classic regimen = 21 active pills + 7 placebo/pill-free days.
• Monophasic OCP: fixed estrogen-progestin dose through active pills.
• Multiphasic OCP: biphasic/triphasic dose changes → lower total hormone exposure/cycle control.
• Transdermal patch: estrogen + progestin; apply weekly for 3 weeks → 1 patch-free week; abdomen, buttock, upper arm, upper torso.
• Vaginal ring: estrogen + progestin; inserted for 3 weeks → removed for 1 week; steady vaginal absorption.

Benefits and Indications

• Contraception with good cycle control.
• Non-contraceptive uses: dysmenorrhea, PMS/PMDD, endometriosis, PCOS/hirsutism/acne, heavy bleeding.
• Risk reduction: ovarian, endometrial and colorectal cancer.

Adverse Effects and Contraindications

• Common side effects: nausea, breast tenderness, breakthrough bleeding, headache, mood change, mild BP increase.
• Serious estrogen-related risks: venous thromboembolism, stroke/MI and hypertension.
• Contraindications: unexplained vaginal bleeding, current breast cancer, severe liver disease, previous/current thromboembolism or thrombophilia, stroke/ischemic heart disease, migraine with aura, smoker age ≥35 years, severe uncontrolled HT.
• Enzyme-inducing drugs may lower efficacy: rifampicin, phenytoin, carbamazepine, barbiturates.

III. Progestin-Only and Emergency Contraception

Progestin-Only Methods

• Main indication: when estrogen is contraindicated or undesirable, e.g. lactation, thromboembolic/cardiovascular risk, smoker age >= 35 years.
• Mechanism: thick cervical mucus; variable ovulation suppression; endometrial thinning/atrophy.
• Progestin-only pill / minipill: taken every day without hormone-free interval; same-time adherence is important.
• DMPA / Depo-Provera: depot medroxyprogesterone acetate IM every 3 months; useful for low compliance.
• DMPA side effects: irregular bleeding/amenorrhea, weight gain, delayed return of ovulation, reversible bone mineral density decrease.
• Subdermal implant: etonogestrel rod in upper arm/biceps groove; product duration varies, classic notes often list 5 years.
• General progestin side effects: irregular bleeding, acne, breast tenderness, headache, weight change.

Emergency Contraception

• Use: after unprotected intercourse or contraceptive failure.
• Levonorgestrel: 1.5 mg PO as soon as possible, best within 72 h.
• Ulipristal acetate: 30 mg single dose up to 120 h.
• Copper IUD: most effective emergency contraception; insert within 5 days after unprotected intercourse/estimated ovulation.
• Mechanism of emergency pills: delay/inhibit ovulation; they do not interrupt an established pregnancy.

IV. Intrauterine Devices

General Advantages

• IUDs: long-acting reversible contraception with very low failure rate and no daily user compliance issue.
• Advantages: low systemic side effects, removable anytime, rapid fertility return after removal.

Copper IUD

• Mechanism: copper ions + sterile endometrial inflammatory response → toxic to sperm/egg, impairs sperm motility and fertilization.
• Duration: commonly 10 years, depending on product.
• Advantages: hormone-free; also emergency contraception.
• Side effects: heavier bleeding, longer menses, increased dysmenorrhea/cramps.

Levonorgestrel IUD / Intrauterine System

• Mechanism: levonorgestrel → thick cervical mucus + endometrial atrophy → prevents fertilization; mainly local hormone effect.
• Duration: classic notes often list 5 years; current duration varies by product.
• Bleeding pattern: irregular spotting initially → lighter periods or amenorrhea later.
• Clinical uses: heavy menstrual bleeding, dysmenorrhea, endometrial protection/treatment in selected cases, endometriosis symptom control.
• Contraindication specific to LNG-IUD: current breast cancer.

IUD Contraindications and Complications

• Contraindications: pregnancy, unexplained bleeding, acute pelvic/cervical infection, postpartum/postabortal sepsis, distorted uterine cavity, genital tract malignancy.
• Insertion complications: pain, bleeding, vasovagal reaction, uterine perforation, failed insertion.
• Later complications: expulsion, missing strings, endometritis/salpingitis/PID, tubo-ovarian abscess, ectopic pregnancy if contraception fails.