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.
And even though emergency contraceptive pills are often called âmorning after pillsâ or âday after pills,â they can be taken right away, and may be effective up to 5 days after unprotected sex. EC should be taken as soon as possible after unprotected sex. Sperm can live in a woman's body for 5 days after sex.