Not all contraceptive pills are the same. There are two main types: combined pills (estrogen + progestin) and progestin-only pills (the “mini-pill”). With perfect use, the pill is over 99% effective, but with typical use it is about 91% effective – meaning roughly 9 in 100 users may become pregnant in a year, usually due to missed pills. This guide explains the types, how well they work, side effects, and who should avoid them.
Last updated: 16 June 2026. Reviewed for medical accuracy by the Even team.
Key takeaways
- Two main types: combined (estrogen + progestin) and progestin-only (mini-pill).
- Effectiveness: over 99% with perfect use, about 91% with typical use.
- The pill does not protect against sexually transmitted infections (STIs).
- Combined pills are usually not advised for women over 35 who smoke, due to higher blood-clot risk.
- Choice of pill is individual – a doctor should help you pick the right one.
Types of contraceptive pills
| Feature | Combined pill | Progestin-only (mini-pill) |
|---|---|---|
| Hormones | Estrogen + progestin | Progestin only |
| Perfect-use effectiveness | Over 99% | Over 99% |
| Typical-use effectiveness | ~91% | ~91% |
| Timing | Once daily; 7-day break or placebo week | Same time daily (traditional: within 3 hours) |
| Good for | Many users; also helps acne, periods | Breastfeeding, smokers over 35, those who can’t take estrogen |
How effective is the pill?
With perfect use (taken correctly every day), the pill is more than 99% effective – fewer than 1 in 100 users become pregnant in a year. With typical use (allowing for missed or late pills), effectiveness drops to about 91%, or roughly 9 in 100 per year. Consistency is what makes the difference.
How to take it and what if you miss a pill?
If you start the combined pill within the first 5 days of your period it works immediately; otherwise use backup protection (such as condoms) for 7 days. If you miss one combined pill, take it as soon as you remember; if you miss two or more, use backup for 7 days and check the leaflet or your doctor. Traditional progestin-only pills must be taken within the same 3-hour window each day (some newer ones allow up to 24 hours).
Side effects and risks
- Common, usually temporary: nausea, headaches, breast tenderness, spotting, mood changes.
- Combined pills slightly raise the risk of blood clots – higher for smokers, especially those over 35.
- The pill does not protect against STIs; use condoms for that.
- Tell your doctor about migraines, high blood pressure, or a history of clots before starting.
Who should avoid the combined pill?
Combined pills are generally avoided if you are over 35 and smoke, have a history of blood clots, certain migraines with aura, uncontrolled high blood pressure, or some other conditions. In these cases a progestin-only pill or another method may be safer – a doctor can advise. Hormonal health also overlaps with conditions like diabetes, so share your full history.
Frequently Asked Questions
With perfect use the pill is over 99% effective; with typical use it is about 91%, meaning roughly 9 in 100 users may become pregnant in a year, usually from missed pills.
Combined pills contain estrogen and progestin; progestin-only pills (the mini-pill) contain only progestin. The mini-pill suits breastfeeding women, smokers over 35 and those who cannot take estrogen.
Take it as soon as you remember. If you miss two or more combined pills, use backup protection (like condoms) for 7 days and check the leaflet or your doctor. Traditional mini-pills must be taken within a 3-hour window.
No. The pill prevents pregnancy but does not protect against sexually transmitted infections – use condoms for STI protection.
Women over 35 who smoke, or those with a history of blood clots, migraine with aura, or uncontrolled high blood pressure should usually avoid the combined pill. A doctor can suggest a safer option.
Nausea, headaches, breast tenderness, spotting and mood changes are common and usually temporary. Combined pills slightly raise blood-clot risk, especially in smokers.
If you start the combined pill within the first 5 days of your period it works immediately; otherwise use backup protection for 7 days.
The bottom line
Contraceptive pills are safe and highly effective for most people when taken consistently, but the right type varies by individual. Talk to a doctor about your health history to choose well. Explore more women’s health topics in our Health section.
Choosing and reviewing contraception is easier with covered consultations: see health insurance with OPD cover, and women’s health care at Even Hospital in Bangalore.
Related reading
- Thriving after 50: a guide to women’s health
- Black grapes during pregnancy: benefits and safety
- Diabetes: types, symptoms and management
- More from the Even Health blog
References
- World Health Organization (WHO) – family planning and contraception effectiveness.
- U.S. CDC – contraception and effectiveness of methods.
- NHS – combined pill and progestogen-only pill.
