There are many types of birth control. No one type is 100% effective. It is possible to become pregnant while using birth control.

Not all birth control methods are equally effective. Some have higher failure rates than others.

In this article, learn about the effectiveness of each type of birth control and what to do if someone thinks they are pregnant.

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Yes, it is possible to get pregnant when using birth control such as the pill, implant, and barrier protection, including condoms.

Human error when using barrier methods, implant displacement, and mistiming treatment can all reduce the efficacy of birth control methods.

Different types of birth control have varying levels of effectiveness and fail for different reasons.

Birth control options include:

Hormonal methods

Hormonal methods of birth control work by releasing either a synthetic form of progesterone called progestin or a mixture of progestin and synthetic estrogen.

Hormonal birth control prevents pregnancy by:

  • stopping ovulation
  • thinning the lining of the uterus, which makes it difficult for an embryo to implant
  • thickening the cervical mucus, making it hard for sperm to enter the uterus

When hormonal birth control fails, this tends to be due to one of the following reasons:

  • failing to take the pill, get the next injection, or change the patch or ring on time
  • taking antibiotics
  • forgetting to take a pill

Intrauterine devices

An intrauterine device (IUD) is a T-shaped device that a doctor inserts into the base of the uterus.

Hormonal IUDs emit hormones to prevent pregnancy. Copper IUDs change how sperm swim. Both types of IUDs also block sperm from entering the uterus.

According to the Association of Reproductive Health Professionals, hormonal IUDs are more than 99% effective for up to 3 or 5 years, depending on the brand. The copper IUD is more than 99% effective for up to 12 years.

Hormonal IUDs can take up to 1 week to begin releasing hormones, so they are more likely to fail during the first week after placement.

Additionally, both hormonal and copper IUDs can become displaced and fall out of the cervix, making pregnancy possible on rare occasions.

Barrier methods

Barrier methods of birth control work by physically blocking sperm from reaching the egg. These methods include:

  • male condoms
  • female condoms
  • diaphragms
  • spermicides
  • sponges

The effectiveness of barrier methods varies. Diaphragms and male condoms are the most effective of these methods. Spermicide is the least likely to prevent pregnancy.

Barrier methods can fail due to user error. Male and female condoms may break or tear. A diaphragm or sponge can sometimes slip out of place. Each incident can allow sperm to get through and reach the egg.

Natural methods

Natural birth control methods do not rely on a pill or device to prevent pregnancy. Most natural birth control methods require careful planning and the strict cooperation of both partners.

Natural methods of birth control include:

  • Withdrawal: This involves withdrawing the penis from the vagina before ejaculation occurs.
  • Fertility awareness methods: A person tracks their menstrual cycle and body temperature to identify when they are most fertile.
  • Lactation amenorrhea: A person cannot conceive while nursing and may not need to use contraception.

Natural methods of birth control typically have a very high failure rate.

All natural methods of birth control rely heavily on body awareness. Some people may make errors in calculating when they are fertile or may not meet the criteria to make the lactation amenorrhea method an effective birth control method.

The withdrawal method often fails because the pre-ejaculatory fluid can contain sperm.

People who get pregnant while using birth control may notice the following symptoms:

Learn more about early pregnancy symptoms here.

It is a misconception that a pregnancy starting while a person is taking birth control can lead to complications.

Studies show that taking oral contraceptive pills around the time of pregnancy and during the early months does not increase the risk of birth complications nor pose a risk to the parent.

Pregnancy is just one cause of the symptoms above. Similar symptoms can occur as a result of other conditions, including:

People should speak with a doctor as soon as possible if they think they are pregnant or have had a positive result on a pregnancy test while on birth control.

Conversely, if a person misses a period and gets a negative pregnancy test result, they should also seek medical advice unless taking a form of birth control that prevents regular periods.

Although they are rare, false negatives are possible. There may be other underlying conditions causing missed periods or other pregnancy symptoms.

The only method of birth control that is 100% effective is abstaining from sexual intercourse.

Some methods of birth control are more reliable than others, so anyone concerned about their chances of pregnancy should speak with a doctor.