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Can One Determine The Time Of Conception Through An Ultrasound Scan?

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Posted on Thu, 14 Jul 2016
Question: Can ultrasounds really determine conception dates? I had a girl i slept with on march 30th and now she is pregnant. She also slept with a few other people after me. She had an ultrasound on XXXXXXX 7th,2016 and the baby CRL measured to be 2.03cm, how far along is she and how accurate is the measurementas it relates to gestational age?

Is the ultrasound more accurate than the last missed period because there are more guys involved than one? what is the margin of error here in days? If she conceived by me march 30th that would put her at gestational age at 11.6 weeks on XXXXXXX 7th during her first ultrasound, instead she got a CRL measurement of 2.03cm and was told she was 8 weeks 5 days along. Can there be that much error in the ultrasound if sperm lives 5 days that i could be the father? she did take plan b the day after and she admitted sleeping with two guys after me unprotected.

SO MY SPERM DIED APRIL 4TH, SAY SHE CONCEIVED APRIL 19TH, BECAUSE THE FIRST DAY OF HER LAST PERIOD WAS APRIL 5TH. THUS, THIS MEANS WITH THE PLUS MINUS OF 7 DAYS of errror ON THE ULTRASOUND THIS WOULD DATE THE CONCEPTION WINDOW TO APRIL 12TH TO APRIL 26TH, MY SPERM DIED ON APRIL 4-5TH. is THERE STILL any POSSIBILITY the child is mine?can the ultrasound at 8 weeks be off by two weeks or would there be a clear distinction on CRL. LASTLY, THERE WOULD BE A CLEAR DISTINCTION BETWEEN WEEK 8.5 AND WEEK 11 ON ULTRASOUND correct?

Do all babies grow at the same rate in the first trimester and if there is a three week gestational age difference
Can you help me through this?assuming the sperm lives 5 days mine died on april 4th.

I have attached the ultrasound from 8 week 5 days and 9 weeks 4 days. do these look consistent with the gestational age given. Moreover, none of the two scans could be father along by two weeks correct? Do all babies grow the same in the first trimester?
doctor
Answered by Dr. Manisha Jain (1 hour later)
Brief Answer:
No chances of you being the father

Detailed Answer:
Hello sir, thanks for trusting health are magic.
I understand your despair and issues.
There is absolutely no possibility that you can be the father as -
- she had periods on 5th so after you guys had sexual activity there were periods so totally negated the effect of intercourse between both of you
- she took plan B
- ultrasound is very accurate up to a disparity of 7 days only so that also negates the timing of pregnancy with the timing of intercourse between both of you.
So all in all no chances of you being the father.
Regards
Dr Manisha
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Manisha Jain (17 minutes later)

can a woman still get her period if she is pregnant is my only question. she state she had it for a week after me and I do believe this to be true.


the only reason im concerned is because of her symptoms 5 days after we were together, she stated she was throwing up and had stomach cramps symptoms. two weeks later she said she threw up 6 times.

did you look at the ultrasounds? do they look consistent with the gestational age
doctor
Answered by Dr. Manisha Jain (27 minutes later)
Brief Answer:
Not possible

Detailed Answer:
Yes dear, ultrasounds are consistent.
The symptoms she had were due to the emergency pill and are commonly seen.
Having periods (bleeding from vagina is a better term then) is associated with severe pain and usually passage of clots and ultimately leads to abortion.
Normal period like bleeding with minimal usual pain is not at all there is patient is pregnant.
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Manisha Jain (1 hour later)
Ok great so far! Thus, the first ultrasound looks to be accurate at 8 weeks and 5 days. There would be a clear size difference if she was 11 weeks you could actually see the babies head and clear legs and arms correct? So I don't need to work I'm reading online woman can still have their period when pregnant is that incorrect?
doctor
Answered by Dr. Manisha Jain (39 minutes later)
Brief Answer:
Misnamed

Detailed Answer:
This is not incorrect and is basically misnamed as it will be taken as bleeding from vagina and not her period at all.
So don't mix and be rather sure as 8 and 11 weeks have a lot of difference and totally negates the chance of you being the father
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Manisha Jain (30 minutes later)
Do you mean plan b causes the bleeding from the vagina to shed everything to reduce the risk of pregnancy? Thus that's the plan b and I'm not the father correct
doctor
Answered by Dr. Manisha Jain (10 hours later)
Brief Answer:
Plan B causes pregnancy like symptoms

Detailed Answer:
No dear, plan B causes pregnancy like symptoms because it has high dose progesterone.
Plus plan B causes changes in endometrium which lead to rejection of baby in case formed during the phase after unprotected sexual activity.
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
Answered by
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Dr. Manisha Jain

OBGYN

Practicing since :2007

Answered : 5136 Questions

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Can One Determine The Time Of Conception Through An Ultrasound Scan?

Brief Answer: No chances of you being the father Detailed Answer: Hello sir, thanks for trusting health are magic. I understand your despair and issues. There is absolutely no possibility that you can be the father as - - she had periods on 5th so after you guys had sexual activity there were periods so totally negated the effect of intercourse between both of you - she took plan B - ultrasound is very accurate up to a disparity of 7 days only so that also negates the timing of pregnancy with the timing of intercourse between both of you. So all in all no chances of you being the father. Regards Dr Manisha