If you take birth control pills, you rightly expect a high degree of safety. Nevertheless, the thought of “could I still get pregnant?” can be consuming, especially if you’ve been late with a pill, had stomach problems, or are unsure if you’ve done it correctly. The chance of pregnancy depends heavily on whether the birth control pills are used correctly every single day, and whether there are factors that can reduce their effectiveness.

Below, you'll find practical, calm guidance to understand the risk and what you can specifically do if something has gone wrong.

The safety of birth control pills is often described with numbers that distinguish between “perfect use” and “typical use”. Perfect use means that the pill is taken correctly every day without delays, and that there are no factors such as vomiting or medication that affect absorption. Typical use covers the reality where many occasionally forget a pill or take it too late.

In healthcare summaries, birth control pills are generally stated as very safe with perfect use (low pregnancy rate), but the risk becomes higher with typical use. If you want to compare numbers, you can look for terms like “Pearl Index” from authoritative sources such as sundhed.dk (The Medical Handbook), which precisely explains the difference between perfect and typical use.

The Pearl Index is a way to indicate how many pregnancies occur among 100 people using a method over one year. The lower the number, the more effective the contraception.

If a method has a low Pearl Index with perfect use, it means that it protects very well when used entirely correctly. When the Pearl Index is higher with typical use, it practically tells us that most pregnancies on birth control pills are due to user error or factors that reduce effectiveness, not that the method “in itself” is unreliable.

The most common reasons for pregnancy on birth control pills are related to the hormone level not being kept stable enough. This can happen, among other things, due to:

• Forgotten pills or repeated delays (especially if it happens early in a pack).
• Vomiting and severe diarrhea shortly after intake, as the body may absorb less hormone.
• Interaction with certain types of medication or herbal remedies that can reduce effectiveness (always ask a pharmacist or doctor if you start new medication).
• Misunderstandings about pause weeks and starting a new pack (for example, too long a break).

If you recognize one of these situations, it's a good idea to look up precise instructions for your specific type of birth control pill in the package leaflet or get help from a pharmacy/doctor.

If you have forgotten a birth control pill, the most important thing is to act quickly and follow the instructions for your pill. Advice varies slightly depending on the pill brand and hormone dose, but a practical approach is:

1. Take the forgotten pill as soon as you remember (unless the package leaflet states otherwise).
2. Then continue as normal.
3. Use extra protection (e.g., condoms) for the period recommended by the package leaflet if you were too late.
4. Consider emergency contraception if you had unprotected sex around the time of the mistake and the package leaflet indicates you are not covered.
5. Take a pregnancy test if you do not get your period, or if you experience symptoms that concern you.

If in doubt, call the pharmacy or your doctor. It's completely normal to be unsure, and it's better to get clarity right away.

Birth control pills themselves can cause symptoms such as tender breasts, spotting, or nausea, which can resemble early pregnancy signs. Therefore, symptoms alone are not a reliable indicator.

Take a pregnancy test if:

• you have had a clear user error and then unprotected sex
• your period is absent, or you experience unusual pain
• you have a persistent suspicion of pregnancy

Seek urgent medical attention for severe abdominal pain, dizziness, or heavy, abnormal bleeding, as these should always be assessed.

If the test shows you are pregnant, or you are preparing for the postpartum period, a comprehensive postpartum solution can be good to have ready. One option is New Mum Care Pack, which gathers several practical items for the first time after childbirth.

Sources (further reading): sundhed.dk (The Medical Handbook, contraception/birth control pills), the package leaflet for your specific birth control pill, and advice from a pharmacy or your general practitioner.