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Childbirth/conception calculation


Hello I wanted to know if you could tell me what date of intercourse most likely got me pregnant?

I had sex on 12/12/12 with one partner and sex with another on 12/16/12.

I found out I was pregnant on 1/7/13 the Dr. said I was 5w 5d.

My last menstrual was 11/28/12. I know the first 2w of pregnancy are calculated before conception takes place.

Who is more likely to be the father? I ovulated on 11/14/12 and 12/13/12 according to my period tracker.

Please Help, thanks.

It's too close to call without a paternity test.  Sperm can live in the reproductive tract for up to 5 days and the dates of intercourse are only 4 days apart, meaning that either man's sperm could have resulted in the pregnancy, especially if you ovulated later than the 13th which could be a possibility without an early transvaginal ultrasound to verify dates.


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Catherine Beier MS CBE


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.


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, 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.

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

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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