- Effectiveness
- How likely is it to get pregnant while on the pill?
- Are birth control pills more effective than condoms?
- How long does it take for birth control pills to work?
-
Pill Failure
- What causes the failure of birth control pills?
- How would you know if you were pregnant while taking the pill?
- Related Resources
- Related Resources - How Likely Is It to Get Pregnant While on Birth Control Pills?
How likely is it to get pregnant while on the pill?
Birth control pills are over 99% effective when taken correctly and regularly as prescribed.
None of the methods used for birth control are 100% effective. There is a possibility, although rare, of getting pregnant while on birth control pills. Birth control pills are over 99% effective when taken correctly and regularly as prescribed.
What causes the failure of birth control pills?
Several factors that may be directly or indirectly related to the failure of birth control pills, causing pregnancy, are:
- Taking the pills irregularly or at a different time each day
- Vomiting and diarrhea for more than 48 hours
- Some antibiotics, antifungals and anti-seizure medicines
- Some HIV medications
- The herb St. John’s Wort
- The pill may not work for people who are overweight
How would you know if you were pregnant while taking the pill?
If a woman on birth control pills gets pregnant, she may notice the following symptoms:
- Missed periods
- Nausea and/or vomiting
- Aversions to certain foods and smells
- Appetite changes
- Bloating or water retention
- Breast pain or tenderness
- Change in breast size or appearance
- Fatigue
- Increased urine frequency
- Bodyache
- Mood swings
- Occasional spotting or bleeding
If you experience any of these symptoms, get a pregnancy test done at home or in a clinic/lab.
Are birth control pills more effective than condoms?
Yes, the typical effectiveness of a pill ranges from 91% to 99%. The failure rate for the pill is 1% to 9%, whereas for male condoms, it is 13% and for female condoms it is 21%.
How long does it take for birth control pills to work?
The time it takes birth control pills to work depends on when you start taking them and what type of pills you use. You may begin taking the birth control pill any day of the month. It is; however, advisable to use a backup birth control method, such as condoms, for about a week once you start taking the pills.
Combination oral contraceptive pills (COCs)
- When started within five days after the first day of your period, the combined pill will protect you from pregnancy right away.
- If you get your periods on a Monday morning and you start taking the combined pills any time before Saturday morning, you will be instantly protected from a possible pregnancy.
- If the pills are started at any other time, it is best to use an additional method of birth control, like a condom, for the first week after you start taking the combined pills.
Progestin-only pills (Mini pills)
- Progestin-only pills, POPs or mini pills can be started any day of the month. They will protect you from pregnancy after 48 hours (two days) of taking the first pill.
- In this case, you must use another method of birth control (like a condom) to prevent pregnancy during the first two days.
You must always discuss with your nurse or doctor about which birth control pill option would be best for you.
QUESTION
Which of the following are methods for contraception? See AnswerReferences
Medscape Medical Reference
Do birth control pills cause birth defects if taken during early pregnancy?
Answer From Myra Wick, M.D., Ph.D.
Taking birth control pills during early pregnancy doesn't appear to increase the risk of birth defects.
Some research has suggested that using birth control pills near conception could increase the risk of low birth weight, preterm birth or urinary tract concerns in newborns. But in general, health care providers haven't seen those problems occur.
Birth control pills lower the risk of pregnancy. They also reduce the risk of a fertilized egg implanting outside the uterus (ectopic pregnancy). Ectopic pregnancies most often form in one of the tubes that carry eggs from the ovaries to the uterus (fallopian tubes). If you do conceive while taking a progestin-only birth control pill, sometime called the minipill, there is a slightly higher chance that the pregnancy will be ectopic.
As a precaution, if you suspect you're pregnant, take a home pregnancy test. If that test is positive, stop taking the pill. If taking a home pregnancy test isn't possible, stop taking birth control pills until you can see a health care provider to find out if you're pregnant. In the meantime, use another method of birth control, such as condoms.
If you're worried because you took birth control pills before you knew you were pregnant, talk to your health care provider. But know that there is little risk of birth defects.
With
Myra Wick, M.D., Ph.D.
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Aug. 16, 2022
- Wick MJ (expert opinion). Mayo Clinic. July 30, 2022.
- Kaunitz AM. Ectopic pregnancy: Epidemiology, risk factors, and anatomic sites. //www.uptodate.com/contents/search. Accessed July 15, 2022.
- Charlton BM, et al. Maternal use of oral contraceptives and risk of birth defects in Denmark: Prospective, nationwide cohort study. BMJ. 2016; doi:10.1136/bmj.h6712.
- Aronson JK, et al. Hormonal contraceptives — Oral. In: Meyler's Side Effects of Drugs. 16th ed. Saunders Elsevier; 2016. //www.clinicalkey.com. Accessed July 15, 2022.
- Kaunitz AM. Progestin-only pills (POPs) for contraception. //www.uptodate.com/contents/search. Accessed July 15, 2022.
See more Expert Answers
See also
- 1st trimester pregnancy
- Ovulation
- Fetal development: The 1st trimester
- Implantation bleeding
- Nausea during pregnancy
- Pregnancy due date calculator
- Prenatal care: 1st trimester
- Pregnancy exercises
- Pregnancy stretches
.