The time it takes for birth control to start working depends on the method. Some are effective at once, while others can take several months.

Barrier methods, such as condoms, work immediately when used correctly, while birth control pills may take several days to start working. A vasectomy usually takes at least 3 months to become effective, while tubal ligation works right away.

Below, learn more about these and other types of birth control, including when and how they start working and how effective they really are.

It is worth noting that no method of birth control is 100% guaranteed to work — there is always a chance of pregnancy, even with perfect use. With typical use, which take human error into account, the chances of pregnancy increase.

Also, health experts can only estimate how long these methods take to become effective. Use a backup type of birth control for at least as long as it is likely to take for a new method to start working.

Finally, keep in mind that some forms of birth control can have adverse effects. A healthcare provider can help make sure that a person is choosing the safest, most effective option for their needs.

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Oral contraceptives prevent ovulation and make it harder for the sperm to reach the egg. There several types, including progestin-only and combination pills.

It is worth noting that birth control pills are not suitable for everyone and may involve some risks. Discuss the pros and cons carefully with a doctor.

How long do they take to work?

A few factors, including the type of pill, influence how long the pills take to work.

Progestin-only pills

Sometimes called the “mini-pill,” this type can work immediately if the person takes it between days 1 and 5 of their menstrual cycle. In other words, they should take the first pill in the first 5 days after a period has begun.

However, these pills take 2 days to work if the person has a short cycle or starts taking the pills after day 5.

After having a baby, a person can take their first progestin-only pill on day 21 after delivery, and it will work at once.

After a pregnancy loss or termination, the pill starts working right away if a person takes it within 5 days. Otherwise, the pill takes 2 days to become effective.

Combination pills

Combination pills contain two hormones — estrogen and progestin — that prevent ovulation.

If a person takes the first dose within 5 days of their period starting, it is effective immediately. If they start at any other time, the pill takes 7 days to work.

After having a baby, most people can start taking these pills on day 21 after delivery, and they are effective immediately.

Following a pregnancy loss or termination, the pill starts working at once if the person starts taking it within 5 days. If not, the pill takes 7 days to become effective. However, it is best to speak with a doctor, because the trimester can influence the effectiveness of this pill.

Identifying the start of menstruation is not always easy. Here, find other telltale signs of a period and learn how pregnancy spotting is different.

How effective are they?

With perfect use, birth control pills are 99% effective.

However, most people miss a dose from time to time. As a result, the overall effectiveness is around 93%.

Learn more about the types of birth control pill.

A healthcare professional inserts an intrauterine device (IUD) into the uterus. It contains copper, which interferes with the process of fertilization.

Some IUDs, such as Liletta, Mirena, and Skyla, prevent ovulation by releasing the hormone progestin.

How long does it take to work?

A copper IUD, or “coil,” begins working immediately and can remain effective for up to 10 years.

An IUD that contains hormones becomes effective right away if a doctor inserts it within 7 days of a period starting. Otherwise, it takes 7 days. Depending on the type, these last 3–6 years.

How effective is it?

These devices are more than 99% effective.

Here, find some tips on choosing an IUD.

The birth control implant is a tiny rod that a doctor inserts under the skin in the upper arm. It releases progestin and prevents ovulation.

How long does it take to work?

If a doctor inserts the device during the first 5 days of a cycle, the implant works immediately. Otherwise, it takes 7 days to reach full effectiveness.

How effective is it?

Overall, these devices are more than 99% effective. As with all methods of birth control, however, there is always a small chance of pregnancy.

The birth control patch prevents ovulation by releasing estrogen and progestin. A person applies a new patch each week for 3 weeks. On the fourth week, they use no patch to allow for menstruation.

How long do they take to work?

If a person applies the first patch within 5 days of starting a period, it works immediately. Otherwise, it takes 7 days to become effective.

How effective are they?

These patches are 91% effective.

Barrier methods prevent fertilization by stopping sperm from reaching an egg. Male and female condoms, the diaphragm, and the sponge all create a physical barrier.

Spermicides are substances that contain chemicals that kill sperm. A person might use a cream, foam, film, suppository, or gel variety. Insert it into the vagina, near the cervix.

How long do they take to work?

Barrier methods and spermicide begin working immediately.

Learn more about other nonhormonal methods of birth control.

How effective are they?

With typical use:

  • diaphragms are 88% effective
  • female condoms are 79% effective
  • male condoms are 82% effective
  • spermicides are 72% effective
  • sponges are 88% effective for those who have never given birth and 76% effective for those who have given birth

Combining a physical barrier, such as a condom, with spermicide increases its effectiveness. Condoms need to fit properly to work, however.

Here, learn how to find the right size of condom.

A person inserts a vaginal ring into their vagina. They wear it for the first 3 weeks of their cycle, then remove it to allow menstruation to occur.

The ring releases estrogen and progestin, which prevent ovulation.

How long does it take to work?

If a person inserts the ring on the first day of their cycle, it works immediately. Otherwise, it takes 7 days to work.

How effective is it?

With typical usage, the vaginal ring is 93% effective.

Here, learn more about a type called NuvaRing.

Using the birth control shot involves having an injection of the hormone progestin every 3 months. This prevents ovulation.

How long does it take to work?

When a person has an injection within 5 days of a period starting, it works immediately. Otherwise, it takes 7 days.

How effective is it?

With typical usage, the success rate is 94%.

Male sterilization, a procedure called a vasectomy, prevents sperm from getting into semen. A person still ejaculates, but pregnancy cannot occur.

How long does it take to work?

It can take several months to work.

After a vasectomy, fertility declines slowly and steadily. In most people, semen contains no sperm by the end of 12 weeks, but an older study, from 2003, found that 17% of participants still had sperm after 24 weeks.

Use a backup method of birth control until tests show that semen contains no sperm.

How effective is it?

The success rate of vasectomy is nearly 100%.

Tubal ligation, what some people call having their “tubes tied,” is one surgical form of female sterilization.

It involves closing or blocking the fallopian tubes, which would otherwise carry eggs from the ovaries to the uterus.

How long does it take to work?

Tubal ligation is effective immediately.

How effective is it?

It is nearly 100% effective.

A wide variety of birth control options exist. Some, such as barrier methods, provide immediate protection, while others, such as a vasectomy, can take several months to work. Many take about a week to become effective.

It is worth noting that some forms are more effective than others, and certain types carry risks. After taking into account a person’s overall health and lifestyle, a healthcare provider can recommend the safest, most effective options.