How soon can I test for pregnancy?

  If I think I may be pregnant, how soon after intercourse can I test?
  Thankyou
Dear Jenny:
Pregnancy occurs when an egg, released at ovulation, is fertilized by sperm released into the vagina during intercourse. Ovulation occurs in most women 12-16 days before menstruation begins (14 days is the average. Ovulation can be detected by urine ovulation detection kits and by basal body temperature graph plots (the shift from lower to higher temperature identifies ovulation). Ultrasound studies are a third test that identifies ovulation.
Research tests will detect pregnancy 8-10 days after ovulation. Standard clinical blood tests detect pregnancy reliably at 14 days from ovulation (the time of the missed menstrual period). Home pregnancy tests may be positive as soon as the day of the missed menstrual period (14 days from ovulation), but may give a "false" answer up to 17 days from ovulation.
I suggest to patients that they wait 3 days beyond the day they expect their flow to begin to do the test.
This material is provided for general information purposes only and should not be considered a formal medical consultation. If you have specific questions, please contact your physician.