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.
Using the morning-after pill may delay your period by up to one week after you normally expect it. If you don't get your period within three to four weeks of taking the morning-after pill, take a pregnancy test. Normally, you don't need to follow up with your health care provider after using the morning-after pill. Don't have sex until you start another method of birth control. 2  The morning-after pill doesn't offer lasting protection from pregnancy. 3  If you have unprotected sex in the days and weeks after taking the morning-after pill, you're at risk of becoming pregnant. 4  Be sure to begin using or resume use of birth control.