How long does it take for Levonorgestrel to affect your body?

Once Levonorgestrel is taken, it typically takes 24 to 48 hours to take effect. During this time frame, the hormone will begin to stop ovulation and make changes in your cervix that can impede sperm movement. 

It may also work by thickening cervical mucus so that sperm cannot pass through it and reach an egg.


It’s important to note that emergency contraception does not protect against sexually transmitted infections (STIs).

 In order for emergency contraception to be effective, it must be taken as soon as possible after unprotected sex. If you wait more than 72 hours after unprotected sex, Levonorgestrel may not be effective at preventing pregnancy.


If your menstrual cycle is regular and you have sex near the time of your ovulation, Levonorgestrel may not be effective in preventing pregnancy. However, it is still worth taking if you have had unprotected sex as it can reduce the risk of pregnancy by up to 90%.


Levonorgestrel is safe for most people, but there are some possible side effects that you should be aware of.

 These include nausea, abdominal pain, fatigue and headaches. In rare cases, more serious side effects such as blood clots or allergic reactions can occur. If you experience any of these symptoms after taking emergency contraception, contact a healthcare professional immediately.


Although Levonorgestrel works quickly to prevent pregnancy in most cases when taken correctly and within 72 hours after unprotected sex, it is always best to use a more reliable form of contraception in order to avoid any risk of pregnancy. Learn more about emergency contraceptive pills at If you are sexually active and looking for a form of birth control, talk to your healthcare provider about the options available to you.


In conclusion, Levonorgestrel takes 24-48 hours to take effect once taken. Although it can reduce the chance of pregnancy by up to 90%, it does not protect against STIs and should be used as soon as possible after unprotected sex – preferably within 72 hours. 

It’s also important to be aware of potential side effects, and if experienced seek medical advice immediately. Lastly, while Levonorgestrel can provide emergency contraception when needed, other forms of long-term contraception are more reliable.

Why is the morning after pill not 100% effective?


The morning after pill is not 100% effective for a number of reasons. First, it must be taken within 72 hours of unprotected sex in order for it to be effective. If you wait longer than this, the chances of the morning after pill being effective decrease dramatically. Additionally, the morning after pill is less effective the closer you are to ovulation.


 This is because Levonorgestrel, the active ingredient in most morning after pills, works by delaying ovulation. If you have already ovulated by the time you take the morning after pill, it will not be effective in preventing pregnancy. Finally, some women may simply be less responsive to the hormone in the morning after pill, making it less effective. Again, this is why it’s important to take emergency contraception as soon as possible after unprotected sex.

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