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Childbirth/Paternity Question

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Expert: - 8/16/2009


Question
QUESTION: Hello, I have a question I was hoping you could help me with. I was away for two months earlier this year and returned on February 22 of this year, on this day I had sex with my girlfriend and she is now pregnant.  Her due date is on November 4th is this due date about right from the time we had sex?  Reason I ask is I recently found out she was seeing someone else when I was gone and want to make sure this one is mine. Thank you.

ANSWER: Mark,

Based on her due date, she most likely conceived around February 11th, meaning it's quite possible you're not the father.


But, the accuracy of this will depend upon how her due date was calculated.  If it was measured from her last period, then the due date may be wrong.  If she had an early ultrasound that confirmed this due date, then it should be very accurate, meaning you're not the father.


So, at this point you need more information from her to know how her due date was calculated and if she has any confessions to make.


It seems that a paternity test may be in order to know for certain.



Best,
Catherine

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

QUESTION: Hi Catherine,  I found out that indeed the due date was confirmed by an ultrasound. But she says it is mine, that they usually count from her last period. Is this correct?

Answer
Mark,

Weeks of pregnancy are counted as 40 weeks from the first day of the last period.  However, conception occurs about two weeks AFTER the start of the last period.


So, actually a woman isn't even pregnant the first two weeks of her pregnancy.  I know it's completely confusing, but that is the method used to calculate pregnancy.


So, if her due date is November 4th, that would mean her last period most likely started around January 28th, meaning she conceived about two weeks after that, or around February 11th, which is 11 days before you had intercourse with her, meaning you would not be the father.


You can check dates using a due date calculator such as the one at http://www.givingbirthnaturally.com/calculating-due-date.html



Best,
Catherine

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Catherine Beier MS CBE

Expertise

I can provide evidence-based information and current research findings concerning childbirth and pregnancy. My specializations include natural childbirth, pregnancy and birth interventions, fetal positioning, labor induction, choosing a care provider, midwives, homebirth, unassisted birth, natural pain relief, medications in pregnancy and birth, informed consent, understanding the risks and benefits of childbirth choices, doulas, waterbirth, childbirth methods, childbirth education classes, cesarean section, and VBAC.

Experience

I have been a childbirth educator, mother, author, public speaker, researcher, and birth advocate for the past 9 years. I am also the author of Giving Birth Naturally, a site dedicated to natural childbirth and pregnancy information. I publish evidence-based articles on pregnancy, childbirth, newborn care, and post-partum care. I'm also a mother of three children, two daughters and one son all born naturally. To learn more about what normal birth looks like, view the natural childbirth video of my son being born at home unassisted.

Publications
My book, Birth Outside the Box, was published in 2007.

Education/Credentials
I hold a Master's degree in communication disorders with an emphasis in child development. I am also an independent childbirth educator.

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