Expert: Catherine Beier MS CBE - 7/27/2011

Question
Childbirth/Conception

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Expert: Dorothy H, LCCE - 7/12/2011

Question
QUESTION: Hi,i have irregular periods but i remember that my last lmp was on 11/16/10 and i found out i was preggo on the 16th of Dec with a blood test..At that time i was told i was 2 weeks..On 01/10/11 i had a vaginal ultrasound that said i was 7weeks and 6days which matched my lmp exactly with a due date of 8/23/11..Then on 04/06/11 i was 20weeks and 1day and the ultrasound said 20weeks with a due date of 8/24/11..I had sex with guy 1 on the 22nd of november while on my period but he did not ejaculate in me(pre-cum), then i had sex with guy 2 on 27th of november and he did ejaculate in me, and we continued to have sex until i found out i was pregnant..I bled until the 25th of november..Who is more likely to be the father? Was the bleeding still my period or was it ovulation/implantation bleeding? How accurate was my first ultrasound, I keep reading no more than 3 days off? Please help...Thank You

ANSWER: Hello Jordan,

It's the second man's baby.  The dates match perfectly.  If your LMP was 11-16-10, your most probable date of conception would be around November 30th, which makes it impossible for the first man to be the father, in addition to the fact that you had your period at the time making the chances slim to none that you were ovulating as soon as the 22nd.

Your first ultrasound was very accurate, and you are correct that it would be off by no more than 3 days in either direction.  The bleeding was most likely still your period as ovulation wasn't likely to occur until around the 30th.


Best,
Catherine Beier, MS, CBE

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

QUESTION: Thank you...so I  can be sure that guy 2 is the dad, I've been worried the whole pregnancy!? Even though my periods aren't regular does that change anything? I was thinking that I could ovulate at any time since they come at different times or not at all..thanx again

Answer
With irregular periods, the difference in timing happens before ovulation.  The time after ovulation remains very constant, from an average of 12-16 days.  This is called the luteal phase of your cycle.  So, once you ovulate, your period should come about 12-16 days later, every month that you have one.  Even with irregular cycles, it is not common to ovulate during your period as the uterine lining is being shed, hence the bleeding, and is not ready to support a pregnancy. Given the supporting measurements of your ultrasound, it's very likely that man #2 is the father.