<s>[INST] My husband and I are trying to have a baby. Started my period today and calculated my ovulation days to be the 5th of march through the 15th. My most fertile days are the 6th through the 9th of march. He is away on a job right now and the only days we can have sex is the 28th-2nd and the 7th- 9th. I read that sperm stay in the vagina for 3-6 days. What are my chances of getting pregnant? [/INST] Hi, Welcome to Chat Doctor forum.  As you describe, it may be right, but need not be accurate.  For a woman with regular periods of 28 days, the ovulation may be on 14thday,say 5 days on both sides.  For 30 days period it may be on 16th day, and so on. Most probably 2 days on either side.  For exact calculation, there will be intraluminal thermometers, the temperature rises by 1 degree on the day of ovulation.  Take more of green leafy vegetables, pulses,sprouts, and protein rich foods to have blood, general health and resistance against infections.  Wishing for a quick and complete recovery. Thank you. </s>