Ultrasound concep.tion Date

All of the dates are estimates, honestly. They asked her the start date of her last period, the typical duration of her cycle and then divided it in half to "predict" when she ovulated. Having sex within 2 days on either side of that date can result in pregnancy. So... it could be yours... or the other guy. You'll have to have a DNA test done to find out.

Here's the bigger question... how stable is this relationship? You broke up and she immediately slept with another man? If the baby isn't yours, do you intend to raise the child? Think long and hard about this one...you don't have much time b/c if you "count months" she either just had the baby or is due any day!

The only way to really know is to have the test done. Be prepared for a response either way and know that you don't have to be a child's biological parent to be a wonderful father!

If you have doubts, then you need to have an open and honest discussion with your girlfriend. You two either need to find a way to trust each other or coparent or move on if the child is not yours.

She can put whatever name she wants on the birth certificate...so you can be presumed to be the father until proven othwerwise through a blood test.

Ultrasound is just a tool, not a test. It gives an estimate, not a result. It seems, by the information you gave, that the chances are equally yours and his to be the father.

Given the fact that there is unprotected sex and multiple partners, you should also get tested for STDs. I also hope y'all will look long and hard at whether or not y'all can be stable and mature enough to provide a home for this baby.

well the conception date states that it's POSSIBLE she concieved between 4/6-8 and she slept with 2 men between 4/3-12.

I'd say there is a highly likely possibility that this baby may not be yours.
At least 50/50 chance.

Because the conception dates on an ultrasound are not 100% accurate- it's just a GUESS based on the baby's size and growth, so honestly the conception date could be March 29 or it could be April 18. It can be off by weeks, however... since she slept with different partners that close together in time, she NEEDS to have a paternity test done.

Ultrasounds, last menstrual cycle, 'due dates' are ALL estimations and by far not accurate.

You will have to wait for a paternity test once baby is born.

There is no way you can know at this point whose baby it is. If you love your girlfriend and plan on marrying her either way, then just assume the baby is yours, ask her to marry you and start enjoying your family.
If you aren't sure about being with your girlfriend for the rest of your life then get a paternity test when the baby comes. 50/50 chance the baby is yours.