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Dr. Tim, MD
Dr. Tim, MD, Board Cert. OB/GYN
Category: OB GYN
Satisfied Customers: 1007
Experience:  General OB/GYN, complicated obstetrics, complicated GYN
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Paternity, I want to know how accurate a first trimester

Customer Question

Customer: paternity
JA: Thanks. Can you give me any more details about your issue?
Customer: I want to know how accurate a first trimester ultrasound is
JA: OK got it. Last thing — JustAnswer charges a fee (generally around $18) to post your type of question to OB GYN Experts (you only pay if satisfied). There are a couple customers ahead of you. Are you willing to wait a bit?
Customer: yes but if i give you the possible dates of conception and the date of the first ultrasound will that help
JA: OK. Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: OB GYN
Expert:  Dr. Tim, MD replied 1 year ago.

Thank you for the question - can you give me more details so that I can help?

Dr. Tim

Customer: replied 1 year ago.
I had an ultrasound at 6 weeks which was (August 20) they said I was six weeks pregnant. I had sex on 8/8/15 with a different man and am concerned it is possible that he could be the father. My estimated conception date was around the second or third week of July. Is this possible?
Customer: replied 1 year ago.
Do you need more information?
Expert:  Dr. Tim, MD replied 1 year ago.

Thank you and I am sorry about the delay.

1. If you were 6 0/7 wks pregnancy on 8/20

2. Your due date = 4/14/2016

3. You conceived on 7/23/2015 (+/- 3 days)

An ultrasound at this early point in pregnancy is extremely accurate. Even taking into account that sperm can live in the cervix for up to 72 hours AND the small error in ultrasound, I would say that the 'window' within which you got pregnant was about 7/18-7/28. Interourse on 8/8 could NOT have produced a pregnancy that was visible on ultrasound on 8/20. It just could NOT happen.

Does this answer your question?

Dr. Tim

Customer: replied 1 year ago.
That makes sense. I have been wracking my brain and counting days and it just didn't add up. On 8/20, there was a heartbeat that they let me listen to. And from lots of research online, it says the heartbeat does not even START beating until 6 weeks. So if it was 8/8, then I would only be 4 weeks pregnant... I just want to be assured that I should not waste money on a test and tell my significant other that we need one if it's just not possible.....
Customer: replied 1 year ago.
I am just weary to tell my OBGYN considering I'm already almost 24 weeks... I'm sure he will tell me the same. If I ask him in confidence, he cannot tell my partner?
Customer: replied 1 year ago.
Do I get charged for each question?
Expert:  Dr. Tim, MD replied 1 year ago.

Thank you for the followup - I am sorry about the delay.

That is correct, the heartbeat cannot be heard until you are 4 weeks from conception, or 6 weeks pregnant. If you had conceived on 8/8, this is only 2 weeks after conception.

Also, ANYTHING that you tell your doctor CANNOT be discussed with other persons. You should, however, make sure that when you discuss this with them that they keep any of this discussion out of the medical record. It is possible that anything documented in your record might carry over to the child's record, to which he would have access as the parent.

I hope that this answers your question - please take a moment to provide a POSITIVE rating.

Finally, you can ask followup questions within this question stream until we are done and you will not have additional charges.

Dr. Tim