Medicine 3: Combined Oral Contraceptives

Medicine 3: Combined Oral Contraceptives

What is it?

Combination birth control pills, also known as the pill, are oral contraceptives that contain estrogen and a progestin.

Combination birth control pills come in different mixtures of active and inactive pills, including:

Conventional pack: One common type contains 21 active pills and seven inactive pills. Inactive pills do not contain hormones. Formulations containing 24 active pills and four inactive pills, known as a shortened pill-free interval, are also available. Some newer pills may contain only two inactive pills. You take a pill every day and start a new pack when you finish the old one. Packs usually contain 28 days of pills. Bleeding may occur every month during the time when you take the inactive pills that are at the end of each pack.

Extended-cycle pack: These packs typically contain 84 active pills and seven inactive pills. Bleeding generally occurs only four times a year during the seven days you take the inactive pills.

Continuous-dosing pack: A 365-day pill is also available. You take this pill every day at the same time. For some people, periods stop altogether. For others, periods become significantly lighter. You do not take any inactive pills.¹

How does it work?

Menstrual migraine occurs due to a decrease in the level of estrogen during the menstrual cycle, particularly 2 days before and 3 days after the period. Combined Oral Contraceptives prevent these drops of estrogen by providing consistent level of estrogen and therefore reduces the intensity and frequency of the attacks.²

What is the efficacy?

Method: A prospective randomized study was done to compare the efficacy of two regimens (21 active pills + 7 placebo pills vs. 24 active pills + 4 placebo pills) of combined oral contraception (COC), both containing 20 μg of ethinyl E₂ and 3 mg of drospirenone, in improving the severity of pure menstrual migraine without aura.

Results: Although both study groups demonstrated significant reduction in the intensity and duration of menstrual migraine, patients in group B (24/4 COC) reported a significant reduction in the intensity and a shorter duration of their menstrual migraine, compared with group A (21/7 COC).

Conclusion: The 24/4 COC regimen is recommended as the preferred treatment for patients suffering from pure menstrual migraine without aura.³

Side-effects:

Short-term effects: Breast tenderness, nausea, headaches, bloating, and unscheduled bleeding.

Long-term effects: Increased risk of venous and arterial thromboembolism (deep vein thrombosis, pulmonary embolism, myocardial infarction, stroke), mild increase in blood pressure, and possible increases in breast and cervical cancer risk.⁴

References

1. Cooper DB, Patel P. Oral Contraceptive Pills. [Updated 2024 Feb 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan– [cited 2025 May 16]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430882/

2. Nappi RE, Tiranini L, Sacco S, De Matteis E, De Icco R, Tassorelli C. Role of estrogens in menstrual migraine. Cells. 2022 Apr 15;11(8):1355.

3. De Leo V, Scolaro V, Musacchio MC, Di Sabatino A, Morgante G, Cianci A. Combined oral contraceptives in women with menstrual migraine without aura. Fertility and sterility. 2011 Oct 1;96(4):917-20.

4. Edwards M, Can AS. Progestins. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan [cited 2025 May 16]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK563211/