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There are many types of birth control available. However, abstinence is the only birth control method that is 100 percent effective. All other forms of birth control can fail occasionally. When birth control fails, it is possible to become pregnant.
Not all birth control methods are equally effective, meaning that some have higher failure rates than others. In this article, learn about the effectiveness of each type of birth control, as well as what to do if you suspect that you are pregnant.
Different types of birth control have varying levels of effectiveness and fail for different reasons. Birth control options include:
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
According to the Centers for Disease Control and Prevention (CDC), the birth control injection tends to be the most effective form of hormonal birth control. Birth control pills, patches, and rings are about 91 percent effective with typical use.
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, while copper IUDs change the way that sperm swim. Both types of IUD also block sperm from entering the uterus.
According to the Association of Reproductive Health Professionals (ARHP), hormonal IUDs are more than 99 percent effective for up to 3 or 5 years, depending on the brand. The ARHP also state that the copper IUD is more than 99 percent effective for up to 12 years.
Hormonal IUDs can take up to a 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 of birth control work by physically blocking sperm from reaching the egg. These methods include:
- male condoms
- female condoms
- a sponge
The effectiveness of barrier methods vary. According to the CDC, barrier methods are 12–28 percent effective at preventing pregnancy. Diaphragms and male condoms are the most effective of these methods, while spermicide is the least likely to prevent pregnancy.
Barrier methods usually fail due to user error. In some cases, a person may not use a barrier method early enough, allowing sperm to enter the vagina.
Both types of condom may break or tear, and a diaphragm or sponge can sometimes slip out of place. Each of these incidents can allow sperm to get through and reach the egg.
Natural methods of birth control 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, which is withdrawing the penis before ejaculation occurs.
- Fertility-awareness methods, where a woman tracks her menstrual cycle and temperature to identify when she is fertile and infertile.
- Lactation amenorrhea, which is when a woman is infertile while breastfeeding and may not need to use contraception.
Natural methods of birth control have a very high failure rate. According to the CDC, withdrawal has a 22 percent failure rate, while fertility awareness methods fail 24 percent of the time.
- the baby is younger than 6 months
- the woman breastfeeds the baby at least every 4–6 hours
- the baby receives only breast milk and no formula
- the woman has not yet had a postpartum period
All natural methods of birth control rely heavily on body awareness. Some women may make errors in calculating when they are fertile or may not meet the criteria to make LAM an effective birth control method.
It is important to note that the withdrawal method often fails because the pre-ejaculatory fluid can contain sperm.
Women who get pregnant while using birth control may notice the following signs and symptoms:
Pregnancy is just one cause of the signs and symptoms above. Similar signs and symptoms can occur as a result of other conditions, including:
- premenstrual syndrome (PMS)
- a urinary tract infection (UTI)
- hormonal imbalances
- weight gain
- a change in birth control pill or method
- food poisoning
- gastrointestinal problems
- lack of sleep
- the common cold
A home pregnancy test can help confirm whether or not a woman is pregnant. Taking a pregnancy test is a quick and painless method of verifying a pregnancy.
Pregnancy tests are available at drugstores, some grocery stores, and online. It is essential to follow the instructions on the packaging.
Pregnancy tests look for the presence of a hormone called human chorionic gonadotropin (hCG), which indicates that a woman is pregnant.
Women should speak to a doctor as soon as possible if they suspect that they are pregnant or have had a positive result on a pregnancy test while on birth control.
Conversely, if a woman misses a period and gets a negative pregnancy test result, she should also seek medical advice unless she is 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 percent effective is abstaining from sexual intercourse.
Some methods of birth control are more reliable than others, so anyone who is concerned about their risk of pregnancy should speak with a doctor.