Pregnancy Timeline: Calculating Due Date After Past Intercourse

Question
QUESTION: I had sex with my ex-girlfriend on November 14, 2006.  She just now told me that it could possibly be my child.  I think she is lying to me because everything I have read leads me to believe that she would have already had the child.

ANSWER: If the child was conceived on that date, she could very well still be pregnant but very close to her due date. If November 14th was the date of conception, she would be just a little over 40 weeks. Pregnancies can go on for longer than 40 weeks, many often going into 42 or 43 weeks.  In addition, sperm can stay in a woman's body, and active, for about 4-5 days. This means she could have conceived around November 19th, which would put her at 39-40 weeks.

If you are concerned about the paternity of the child, however, I would have a paternity test done when the baby is born.

Please let me know if I can help you further or with anything else.

Best wishes,
Helen =)

---------- FOLLOW-UP ----------

QUESTION: I have just received more information.  She is on 28 day cycles, and started periods on the 1st and 28th of December.  The 28th one she is not sure about.  She also told me that her boyfriend had sex with her on December 18th.  So if she is on twenty eight day cycles.  Her cycle for me would have started on November 3rd, making the due date around August 9th, and her doctor told her if she does not deliver in 1-2 weeks he will have to induce.  So my question is, with all of this information, I feel that it is impossible for it to be my child.  I am correct?

Answer
If she had a period on the 1st of December then I doubt it is your child. However, doctors don't normally induce right at 35 weeks, which indicates to me that she may be further along in the pregnancy.

While I would put the chances of you being the father as very low, I can't in good conscience say that it would be impossible. If she presses the issue, you may want to take a paternity test after the baby is born to give you peace of mind. In addition, a paternity test will provide you with legal protection should she later come back and try to place paternity on you.

Best wishes,
Helen =)