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Emergency contraception side effects and period changes

Written by Hi Doctor clinical content teamPublished 19 July 2026

Headache, nausea, cramps and a temporary change in the next period can occur. Know when to test, seek help or expect your period.

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DIRECT ANSWER

An online consultation lets an EU-licensed doctor review your case and, if appropriate, issue an electronic prescription; each pharmacy decides whether it can dispense it.

Doctor reply in under 2 hours

Average doctor reply under 2 hours; at night and on public holidays it can take longer, always within 24 hours. A prescription only if appropriate.

EU-licensed doctors

Every case is reviewed by an EU-licensed doctor.

Electronic prescription

Each pharmacy decides whether it can dispense an approved prescription; some do not accept PDF prescriptions.

HOW IT WORKS

From consultation to collection

  1. 1

    Consultation

    Answer a secure medical questionnaire online.

  2. 2

    Doctor reviews

    An EU-licensed doctor personally assesses your case.

  3. 3

    Prescription only if appropriate

    The doctor replies in under 2 hours on average and issues a prescription only if it is clinically appropriate.

  4. 4

    Collect at the pharmacy you choose

    Take an approved prescription to the pharmacy you choose; each pharmacy decides whether it can dispense it.

Most effects after an emergency contraceptive pill are short-lived. They can overlap with premenstrual symptoms and anxiety, so it helps to know what is expected without assuming every change means pregnancy.

Common effects after an emergency pill

Nausea, headache, lower abdominal discomfort, tiredness, dizziness and period-like cramps can occur. The next bleed may come a little earlier or later and may be lighter or heavier than usual. Follow the leaflet if you vomit soon after taking the tablet, because another dose may be needed.

What an altered period can and cannot tell you

Bleeding after the pill is not a reliable pregnancy test, and a delayed period does not prove pregnancy. Cycle timing, stress and the emergency method can all shift bleeding. Use a pregnancy test at the interval advised by the pharmacist, clinician or leaflet, and test sooner if the period is clearly late or unusually light with pregnancy symptoms.

After copper-IUD insertion

Cramping and spotting can follow insertion, and periods may become heavier or more painful, particularly at first. Severe worsening pain, fever, offensive discharge, very heavy bleeding or inability to feel the threads when you were taught to check them warrants clinical advice.

When to seek help

Emergency contraception is time-sensitive. Seek a pharmacy, sexual-health service or clinician as soon as possible rather than waiting for symptoms. Urgent in-person care is needed for severe one-sided or lower abdominal pain, collapse, very heavy bleeding or a severe allergic reaction. Emergency contraception does not treat an established pregnancy and does not protect against sexually transmitted infections.

What to prepare for a medical review

Be ready to share when each episode of unprotected sex happened, the first day of the last period, usual cycle length, the contraception that failed, current medicines and supplements, breastfeeding, and whether a period was already late. These details help a professional compare oral options with a copper IUD and explain when regular contraception can be restarted.

A calm next step

Write down the date of the unprotected sex, treatment and expected period. That simple record makes follow-up clearer. If symptoms are severe or the pregnancy-test timing is uncertain, ask rather than guessing.

Clinical sources used: World Health Organization emergency-contraception fact sheet and European Medicines Agency product information for ulipristal acetate.

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Written by the Hi Doctor editorial team. General information, not individually reviewed by a doctor.

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