Can trans-vaginal scan detect 2 months pregnancy?

Question

Hello doctor,

Is it possible for a girl to be two months pregnant? For example, we had unprotected sex five months ago and then four months ago. We went to the clinic to have trans vaginal ultrasound and it turns out to show that she is two months pregnant.

Please help.

Answer 1

Hello,

Welcome to icliniq.com.

I understand your concern.

No, it is not possible for a pregnancy from five months to be dated as two months (eight weeks) based on a transvaginal ultrasound.

Why?

Pregnancy dating is done from the first day of the last menstrual period (LMP), not the exact day of conception.

If you had unprotected sex five months back, the pregnancy would be around four weeks (not eight weeks) four months back if conception happened shortly after.

For the pregnancy to be two months (eight weeks), conception would have likely occurred around four months back.

What could explain this?

Earlier conception: If she was already pregnant, then the ultrasound would show a longer gestational age.
Incorrect ultrasound dating (± one week variability): While early ultrasounds are accurate, there can be slight variations.
Irregular ovulation: If she ovulated earlier than expected, conception might have happened before the date you assume.

I hope this has helped you.

Please feel free to reach out to me again if you have further queries.

Thank you.