Paternity Timeline: Calculating Due Date Based on Alleged Conception Date

Question
i started dating someone recently whos ex wife is pregnant( she had the baby June 1st and they stripped her membranes on May 24th) and he thinks the baby isn't his. They slept together on Sept 8th of 2005 and she says she got pregnant that night. He's in the military and thinks she was cheating on him. From this date could you please tell me when she would have been due?  

Answer
HI Jennifer,

Ok, based on this date I hate to tell you this but it is very possible that she did get pregnant on September 8th. This is why:

Ovulation in a normal, regular cycle takes place about 10-14 days after the first day of last period. So.... I worked backwards:

If we know that September 8th is the day she says she got pregnant, and we also know her delivery date of June 1st:

Working backwards from September 8th, assuming again her cycle is normal, she would have gotten her period "probably" around August 28th or so.

In a pregnancy, the due date is calculated by taking the first day of the last period, then going back 3 months and adding 7 days.

SO: if her last period started on August 28th, we go back 3 months= May 28th.... and add 7 days= June 4th. Her baby was born on June 1st. You said they stripped her membranes on May 24th, this is not usually done unless the mother is very very close to her due date. (So the doctor would  not have stripped her membranes if she wasnt due very soon)

Now, I dont know of course if she was cheating on your boyfriend... and it is TOTALLY possible that she slept with someone else right around that same time, and that they are the father, not your boyfriend... the only way you are going to know is a DNA test on the baby.

Also please remeember that these dates are not set in stone and are not perfect! This is just an average that I calculated based on the info you gave and what a normal cycle would  have been.

But, yes, it IS very possible that she did get pregnant on September 8th. Sorry! Please get the DNA test and this will solve the question of who is the father. I am sorry I couldnt rule out your boyfriend.

Good luck... and thanks to your boyfriend for protecting our country... I hope things work out for you all.
andi