Hello,

Thanks for your consult at DoctorSpring.com.

Totally 6 ultrasounds have all given you the same EDD - 11/12.
Based on this EDD, the last date of your period would have been 5th of February.

According to this period date, the most likely date of conception would be around 14 days after the period, that is around the 19th of February.
Ultrasound has intrinsic error of upto maximum 5 - 7 days, so the probable dates of sex would have been a week before or after the 19th of February, but in NO WAY as early as January 18th.

Abdominal ultrasound is not as reliable as vaginal scan, however ALL first trimester ultrasounds are accurate in estimating the gestational age, and have maximum error upto a week.

All of them cannot be way off by a month, so do not worry.
Also, you had a condom as protection, took Plan B, and then were on probable birth control too - so chances of conception are nil.

If the embryo had lived through the withdrawal bleeding, and then measured small in the first abdominal scan, subsequent scans at 11 weeks, 14 weeks etc would have definitely picked up the discrepancy.

You had ultrasound pretty frequently, so that possibility can be ruled out.
Please do not worry, as I strongly opine that you DID NOT conceive from the January 18th episode.

Hope this helps, please feel free to discuss further.
All the best.

Hi,

When taken within 72 hours, Plan B is still 90 % effective in preventing a pregnancy, plus condom was used.

It is very less likely that the bleeding was implantation bleeding, as it does not corelate with your period pattern ( please mention the date of the period BEFORE 5th February if you recall it ).

Also the ultrasounds are supportive of the fact that the bleeding was withdrawal bleed, not implantation bleed.

If you deliver early for some reason ( the disparity is a month ), then in that scenario, if you DID conceive from January 18th the baby would be normal, while if you conceived later, the baby would be premature (36 weeks) and a paediatrician could tell the difference.

All said and done, odds of conception from January 18th encounter are almost zero, only a DNA paternity test would conclusively put this doubt to rest.
Do not stress out, as you can already understand.

Take care.

Hello,

All the things are against conception from January 18th.

The ONLY possibility ( and this is like a science fiction movie, as I am just adding together improbable hypothetical situations ). The bleeding experienced on February 5th was implantation bleeding ( not withdrawal from birth control ) - Least Likely.

The Birth control, AND plan B AND condoms failed ( Least Likely )
The first scan was ONE month off the mark ( least likely ).
ALL the remaining scans continued to be one month off the mark (least likely)
This is the only situation , and it is impossible.

Yes, I would suggest a DNA paternity test if you cannot forget the thing on your own, and it is continuing to bother you to this great extent.

Regards

Yes, apart from the absolutely irrefutable peace of mind it would offer you, DNA testing is quite unnecessary to establish the paternity, as all given facts clearly point to conception that occurred AFTER the 5th of February.

All the best.
Enjoy your pregnancy and motherhood!

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