Conception date/when you had sex to get pregnant

clpowers95

I need some advice I was told at my last ultra sound I was 9 weeks which would make me about 14 weeks and 6 days but I had a new ultrasound at a different place saying I'm actually 15 weeks and 5 days can anyone help me figure out when I had the sex that got me pregnant? Me and my boy friend broke up between March 17 and the 20 and I unfortunately spent a night with my ex... I just need to be sure I know who the father is and I need some advice because I know the conception date and the day you had sex are not exactly the same and they add a week or two to how far along you are but I don't quite understand it completely.

meggyme

Knottie1474915250 said:

I need some advice I was told at my last ultra sound I was 9 weeks which would make me about 14 weeks and 6 days but I had a new ultrasound at a different place saying I'm actually 15 weeks and 5 days can anyone help me figure out when I had the sex that got me pregnant? Me and my boy friend broke up between March 17 and the 20 and I unfortunately spent a night with my ex... I just need to be sure I know who the father is and I need some advice because I know the conception date and the day you had sex are not exactly the same and they add a week or two to how far along you are but I don't quite understand it completely.

A paternity test is the only reliable way to determine the father of your child.

harpseal135

Agree with PP, the reliable way to know is paternity test.

JennyColada

It can take 6-10 days from fertilization to implantation on average, and sperm can live up to 5 days, so I could be anywhere from 6-15 days between sex and the start of pregnancy. So you won't really get any reliable answers since you're cutting it a little close. A paternity test would be the only reliable way to tell for sure.

KLake42

You can get a blood test now that will collect fetal blood cells from your blood stream, and do a DNA test.

Mekimchiie

The gestational age starts from the first day of your last period. You ovulate 2 weeks before your period normally comes. If you are on a 28 day cycle, you typically ovulate around day 14. Sperm in theory can hang out for 5 days before ovulation occurs and still fertilize the egg. And the egg can in theory be fertilized up to 2 days after ovulation. So whatever your normal cycle is and go back 19 days. Starting 19 days before your period is due til 12 days before your period is due is in theory your fertile period. If your periods are irregular that will not help so then you have to go by ultrasound. The problem is ultrasounds have a margin of error. Earlier ultrasounds are more accurate than later ones. Your ultrasound dating is less than a week apart and could just be margin of error or so. If you haven't done paternity testing which is the surefire way of knowing, then go with your first ultrasound dating and whenever you were 1 week 2 days til 2 weeks and 1 day would be your theoretical conception window. 

eggplantface

With only a three day window between partners, a paternity test is the only reliable way to know, especially since you don't know for sure your ovulation date.