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If unprotected sexual intercourse is done around ovulation time,there is highest possibility of pregnancy
in regular cycle.
It is preferable to lie down approx 1/2 hr after coitus during fertility
period but not always necessary.
Basically sperm is live for 3-5 days inside uterus or fallopian tube
and ovum is live 12-24hrs.
So you have to coitus within 5 days of exact ovulation date (means 12-17th day of regular cycle). Ovulation time is calculated 14 days before expected period date in regular cycle.
Sperm ascends through vaginal mucosa after deposition of semen by contraction. Alkali media is friendly environment for sperm and helps in ascending. 100-200 million sperms are together inside vagina.Velocity of sperm is 2-3 mm/min and approx 45 min is taken to ascend from cervix to ampullary-isthmic junction.Liquid paraffin
and oil are better to avoid as those may act as spermicide
I think you get proper knowledge.