How to determine the date of the conception?

Posted on Tue, 12 Jul 2016 in Sexual Health
Question: Hi,
Unfortunately in the moment I made the mistake of unprotected sex between the 20th-24th of august 2015, on the 30th of august the girl slept with another man.
I was lead to believe the concieved date was the 24th of august making the now born baby potentially mine, however the due date was XXXXXXX 16th (the baby was also born on the due date)
After spending endless hour's researching time frames I am unable to back track the pregnancy from the due date to her apparant concieved date of august 24th.
Is it possible that the women could of concieved on this date and still of had a due date of XXXXXXX 16th 2016? What's the chances of the child been mine, as she refuses to get her current partner (from August 30th to present) to do a dna test.

Many thanks
Answered by Dr. Chintan Solanki 11 minutes later
Brief Answer:
Provide more details

Detailed Answer:

Thanks for writing to us.

Due date is 16th XXXXXXX means she has conceived around 20-30 September 2015.

Let me know her last 3 menstrual period dates before pregnancy so I can give confirm date.

I will be happy to help further after your response.


Dr Chintan Solanki.
Above answer was peer-reviewed by : Dr. Veerisetty Shyamkumar
Follow up: Dr. Chintan Solanki 31 minutes later
unfortunately I can't get information as to her last 3 menstrual period dates. but with a due date of XXXXXXX 16th and say an irregular menstrual cycle either more of less than the average 28 days. would it appear possible to of concieved on 24th of august and still maintain the due date of XXXXXXX 16th?
Answered by Dr. Chintan Solanki 27 minutes later
Brief Answer:
Then it is post mature delivery

Detailed Answer:

Thanks for follow up.

If she has conceived on 24th August her due date should be around 17th May. If she delivered on 16th XXXXXXX with conceive date of 24th August delivery is called - post mature (one month more than expected and baby should be more in weight than normal). This is very rare possibility.

In case of lack of information about her menses dates, only DNA test can give confirm results about father.

Take care.
Above answer was peer-reviewed by : Dr. Sonia Raina
Answered by
Dr. Chintan Solanki


Practicing since :2007

Answered : 2406 Questions


The User accepted the expert's answer

Share on

Get personalised answers from verified doctor in minutes across 80+ specialties

142 Doctors Online

By proceeding, I accept the Terms and Conditions

HCM Blog Instant Access to Doctors
HCM Blog Questions Answered
HCM Blog Satisfaction