Emergency contraception

Duration of use and safety of COCs

Combined oral contraceptives (COCs) are completely safe provided they are properly selected. Many patients mistakenly believe the body periodically needs a "break" from hormones. In reality, long-term use does not increase the risk of complications. The drugs can be taken continuously right up until the onset of menopause. Moreover, artificial breaks in intake are not only unhelpful but also extremely risky, as they sharply increase the likelihood of unwanted pregnancy.

Transvaginal and transdermal contraception

For those who find daily pill intake inconvenient, alternative routes of administering ovulation-blocking hormones have been developed.

• NuvaRing vaginal ring. This is a flexible plastic device providing parenteral delivery of hormones. The ring is inserted deep into the vagina between the 1st and 5th day of the menstrual cycle. It remains inside for exactly 3 weeks, releasing 15 mcg of ethinylestradiol and 120 mcg of etonogestrel (a progestogen) into the systemic circulation daily. After removal, a 7-day break is taken (bleeding begins), and then a new ring is inserted. The Pearl index is 0.4. The ring does not fall out, does not interfere with an active lifestyle, sports, or swimming, and causes no discomfort for partners during sexual intercourse.
• Evra transdermal system. This is a patch applied to the skin of the abdomen, buttocks, or shoulders. One package contains 3 patches. Each is worn sequentially for exactly 7 days (applications on days 1, 8, and 15 of the cycle). On day 22, the patch is removed, a 7-day break is taken, and a new package is started. Daily through the skin, 20 mcg of ethinylestradiol and 150 mcg of norelgestromin are absorbed. The patch adheres securely, does not detach during water procedures and under the sun.

Advantages of non-oral methods

Using patches and rings has several significant advantages compared to classic oral administration:

1. Smooth hormone release. Substances penetrate the blood evenly throughout the day, guaranteeing good cycle control.
2. Absence of first-pass liver metabolism. This allows lower daily dosages and minimizes negative side effects.
3. No need for daily intake. Virtually eliminates errors in contraceptive use.

Note: Indications, contraindications, as well as positive and negative effects of NuvaRing and Evra are completely similar to those of COCs.

Oral progestogen-only contraceptives (mini-pills)

Oral progestogen-only contraceptives (OPCs) contain small doses of pure progestogens and lack the estrogen component. These include drugs such as Demulen (ethynodiol 0.5 mg), Microlut (levonorgestrel 0.03 mg), Exluton (linestrenol 0.5 mg), and Cerazette (desogestrel 0.075 mg).

Mechanism of action:

• Increased cervical mucus viscosity.
• Creation of unfavorable conditions in the endometrium for the implantation of a fertilized egg.
• Decreased contractility of the fallopian tubes.

The steroid dose in OPCs is insufficient for effective ovulation suppression, so more than 50% of women retain normal ovulatory cycles. Because of this, the efficacy of the method is lower than that of COCs (the Pearl index varies from 0.6 to 4).

Rules of administration and target groups Administration begins on the 1st day of menstruation and continues continuously at 1 tablet per day. OPCs are indicated for breastfeeding women (not contraindicated during lactation), smoking women of late reproductive age, and those for whom estrogens are contraindicated.

Disadvantages and contraindications The main drawback is strict time adherence. If intake is delayed by 3–4 hours, efficacy drops, and additional contraceptive methods are required for at least 2 days. The absence of estrogens (which normally prevent the endometrium from shedding prematurely) leads to frequent intermenstrual spotting. OPCs are contraindicated in a history of ectopic pregnancy (progestogens slow down egg transport) and ovarian cysts (they promote the formation of retention structures).

Injectable contraceptives

For prolonged protection, the drug Depo-Provera, containing medroxyprogesterone, is used. Its Pearl index does not exceed 1.2. The mechanism of action and contraindications are similar to OPCs, but the method has its advantages: absence of estrogen-dependent complications, duration of action, and no need for daily administration.

Administration rules:

• The drug is administered intramuscularly.
• The first injection is given within any of the first 5 days of the menstrual cycle.
• Subsequent injections are performed every 3 months.
• After an abortion, the injection can be given immediately.
• After childbirth, the injection is given immediately (if the woman is not breastfeeding) or after 6 weeks (during lactation).

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• A detailed breakdown of the Pearl index: how it is calculated and why it differs among various contraceptive methods.
• Mechanism of progestins' influence on the formation of functional ovarian cysts.
• Pharmacokinetics of ethinylestradiol via transdermal and transvaginal routes of administration.
• Effect of progestins on fallopian tube peristalsis and the risks of ectopic pregnancy.
• Comparative characteristics of progestin-only drugs (levonorgestrel, desogestrel, lynestrenol).

Other topics in the "Gynecology" section

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