I was in between relationships and I'm not sure who the father is...

[Ashley_Tyler]

Ok so me and my ex had been broken up a little over a year and I started dating this guy I went to school with.We really hit it off and carried out a sexual relationship for close to 6 months. All the while me and my ex still felt with eachother only having sex MAYBE once a month.Well I'm October I really backed off of both of them...had that months period on the 12th...regular,last 4/5 days. In November I had sex with New Guy on 11/4. I'm like 95% sure I came on like the next day (11/5) or sometime in that 2nd week of November. Me and my ex had sex 2/3 times between 11/11-11/15.me and the New guy had sex in 11/19.On 12/14 I had a positive test and vaginal ultra sound at the hospital and they said I was 4w 6d pregnant. Is my ex the father or the new guy more likely to be the father? New guy knows EVERYTHING.

[AnnieBrooke]

4w6d is pretty early for an ultrasound to see enough to get a good measurement. If possible, get another ultrasound this week. The embryo will be easier for the ultrasound tech to measure, but not so big that the growth rate can't be trusted. A late 6th week or early 7th week ultrasound is more useful for measuring an embryo and trying to guess at a conception date, than is a 4w6d ultrasound.

Also, let's review.
1. Do you know that a count of "weeks" in pregnancy begins on the first day of your last period, NOT on the presumed date of conception? (Or from a calculated first day of your last period if you don't know for sure?)
- To keep from getting confused by GA counts (the count in weeks), ask for an estimated due date whenever you get an ultrasound. You can count back 266 days from that date to get to an estimated conception date, and it keeps you from getting confused about what weeks pregnant means.
2. Did you know sperm can live 4-6 days in your reproductive tract? This means you would have had living sperm from both guys in your body at the same time, on the 19th and possibly even the 20th.

If your weeks "pregnant" count that you got at your December 14 ultrasound is totally correct, you would have conceived on November 24. But this isn't a sure thing, since you had such an early ultrasound. I strongly recommend getting a second one this week. After a while in pregnancy, embryos' growth rates can vary, meaning that ultrasounds can't be relied on when trying to do this kind of analysis after the first trimester. But at week 6 or 7 (and again, that number is measured from the last period, not from a guess at when conception was) an ultrasound can be pretty helpful.