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Pregnancy tests

Revisado: 4 de octubre de 2026

Solo en inglés por ahora

Most home pregnancy tests work from the first day of a missed period. A positive result is almost always right; a negative one is less certain if you test early.

How pregnancy tests work

Pregnancy tests look for a hormone called human chorionic gonadotrophin (hCG). It is made by the placenta, which grows in the womb and feeds the baby. Your body starts making hCG around 6 days after an egg is fertilised. Home tests check your pee. Blood tests at a clinic can pick up smaller amounts of hCG, sometimes before a missed period.

When to test

Most home tests work from the first day of a missed period. Some more sensitive tests can be used before a missed period, but the result is more reliable if you wait until your period is late. If you do not know when your period is due, test at least 21 days after you last had sex without contraception. Your first pee of the morning usually has the most hCG. Avoid drinking a lot of fluid before testing, because it can dilute the hormone. You can log your result in Ciclo next to your period dates.

Reading the result

Follow the instructions that come with your test, including how long to wait. After you pee on the stick, the result shows within a few minutes. Used the right way, home tests are reliable. Any line or plus sign you can see, even a faint one, most likely means you are pregnant. A faint line can mean the pregnancy is early and your hCG level is still low. Home urine tests are about 97% to 99% accurate when done a week or two after a missed period.

If the test is negative

A negative result is less reliable, especially if you tested early. Your body may not have made enough hCG yet for the test to find it. If you still think you might be pregnant, wait a few days and test again. Some medicines can also affect the result, so check the leaflet or ask a pharmacist. If a second test is negative and your period still has not come, see a doctor or nurse.

After a positive test

Whatever you decide, it helps to see a doctor, nurse or midwife soon. If you plan to continue the pregnancy, getting care early matters. If you are not sure what you want to do, a sexual-health or family-planning clinic can talk through your options. If you could be pregnant, contact a doctor or nurse the same day if you have pain low down on one side of your tummy or any bleeding. Get emergency help for sudden, severe tummy pain, pain in the tip of your shoulder, heavy bleeding, or feeling very dizzy or faint. These can be signs of an ectopic pregnancy.

This is general information. If your result is unclear or your period still has not come, talk to a doctor, nurse or sexual-health clinic.