### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
for trying to concieve does a female have to lie down for some time after coitus? wt is the ascending time for a sperm?wt is life span of a sperm?wt shud be exact timing for coitus after ovulation pain?hw much time does it take for an ovum to reach the tubes after it is released frm ovary following ovulation pain?any harm to fetus or difficulty in conceiving if liquid paraffin is used during coitus?does the drop of oil make the sperm heavy and prevent it frm ascending?

### output:

Hello, Welcome to Chat Doctor. If unprotected sexual intercourse is done around ovulation time, there is the 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. Be well.