Mast cells. Mast cells and basophils are generally thought to be the major sources of histamine and can themselves be modulated by histamine as they express H 1, H 2 and H 4 receptors, although how this varies between different mast-cell types is not yet clear.
3. The pill is to be taken soon after unprotected sex. It should be taken preferably within 24 hours and before 72 hours or else the pill may turn useless. 4. I-pill checks pregnancy by preventing ovulation or fertilisation or implantation of the fertilised egg. 5. I-pill is 95 per cent effective if taken in time.
EC pills work by preventing or delaying ovulation and preventing sperm from fertilizing the egg. You can use EC right away or up to five days after sex. The sooner you use it, the better it works. There are a bunch of EC pills currently on the market in the U.S. that are made with the hormone levonorgestrel. If you take EC pills within 24 hours after sex, they reduce your risk of pregnancy by up to 95%. Overall, they are 89% effective, meaning they prevent about 7 of 8 pregnancies that normally would have occurred. There are several side effects that you may experience when using an EC pill.