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How To Determine The Date Of Conception?

Posted on Mon, 9 Feb 2015

Question: I was wondering if a ultrasound can be off by 3 weeks. I had intercourse with my ex on September 13 and had a normal period on Sept 18 or 19. I had intercourse with my boyfriend after my period numerous times and found out I was pregnant in October. MY due date is XXXXXXX 25th can my ultrasound be off and possibly still be the exes baby???

Answered by Dr. Sameer Kumar (21 minutes later)

Brief Answer:
your ultrasound is uptodate...

Detailed Answer:
Hello,
Thanks for contacting healthcaremagic.
If your due date is XXXXXXX 25th , then as per Naegle's formula the LMP would be september 18 2014.
This is absolutely appropriate and there is no discrepancy.
Ultrasound indicates the date of conception which would be after ovulation period around 1 st week of october, which shows a general discrepancy of 2-3 weeks. So, its normal.
regards

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Sameer Kumar (4 minutes later)

Thanks for responding back. So I should stop worrying because the baby is my boyfriends and not my exes. Its such a stressful time and this would help out.

Answered by Dr. Sameer Kumar (21 minutes later)

Brief Answer:
explained....

Detailed Answer:
Hello,
so if your bf had intercourse in the 1st week of october, then it is likely that the conception is your boyfriend's.
you can stop varying.
regards

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar