The Contraceptive Pill: Types and Side Effects

The contraceptive pill is one of the most widely used methods of contraception in the world. There are two main types, and choosing the right one depends on your health, age and preferences.

Imagine starting the combined pill and getting headaches and mood swings in the first month. You think about giving up altogether. Your nurse explains that early side effects often settle, and if not, there are many other pills and methods. By month three, you feel fine.

The two main types

• Combined pill: contains oestrogen and progestogen; stops ovulation. Can make periods lighter, more regular and less painful.
• Progestogen-only pill (“mini-pill”): no oestrogen; suitable for more people, including those who are breastfeeding, smoke over 35, or have migraine with aura.

With perfect use, pills are over 99% effective; with typical use (missed or late pills), about 91%.

Possible side effects

• Spotting or irregular bleeding, especially early on
• Breast tenderness, headaches and nausea
• Mood changes
• A small increased risk of blood clots with the combined pill

The combined pill isn’t suitable for everyone, including people with a history of blood clots, some types of migraine, uncontrolled high blood pressure, or smokers over 35. A health check before starting is important.

But what if I miss a pill?

Rules differ between pill types and brands. Check your leaflet or ask a pharmacist. You may need emergency contraception or extra protection like condoms. Vomiting, severe diarrhoea and some medicines can also reduce effectiveness.

Seek urgent help for calf pain or swelling, chest pain, breathlessness, or a sudden severe headache while taking the pill. The pill doesn’t protect against sexually transmitted infections.

Sources: World Health Organization (Medical eligibility criteria for contraceptive use), Faculty of Sexual and Reproductive Healthcare, US CDC (Contraception), NHS.