Conception
January 8, 2015 | 15,00 EUR | answered by Dr. med. Frauke Gehring
Good day,
If a baby was born on 11.09.2014, the conception date would have been between 03.12.14 and 31.12.2014, right?
When would the last sexual intercourse have been? (Since sperm can survive in the body for several days)
That's right. It is not possible to determine the exact date of conception, because sperm can actually survive in the vagina for up to 5 days, and because the menstrual cycle is not always regular. In a 28-day cycle, subtracting 5 days from the expected date of conception, which would be on the 17th, would give us the 12th as the possible date of intercourse. However, since most sperm do not survive that long, we usually assume 3 days, so the likely date of intercourse would be from the 15th in a 28-day cycle.
It cannot be narrowed down any further, and in case of doubts, a paternity test would probably be necessary.
Sincerely, Dr. Höllering
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