LMP and Ultrasound Accuracy?? Help?

[Kerry222]

Hi girls, I need a bit of help. I've gotten myself into a bit of a mess and just need to ease my mind. My last period was March 12th and it lasted to the 15th. I slept with an old flame March 13 through March 16 (he pulled out). On March 17th my husband and I got back together and had sex at least once a day throughout the rest of the month. On April 12th, I found out I was pregnant. My cycles are generally 28-30 days long with my ovulation being around day 16 or so. (I tracked my cycles for a few months.)

Based on my LMP, my due date is December 17th. I went for an ultrasound at 13 weeks and the babies measurements put me at December 18th. Is this reliable? It seems really unlikely that my flame would be the father, I just need some other opinions. Please don't judge me, I know I made a mistake:(

[JoyRenee]

It honestly sounds like it is your husband's baby. But it's good you're getting a paternity test just to make sure.

It's a shame he'd want to divorce you if it wasn't his baby (understandable, but still). I wish you both much luck and love.

[Kerry222]

We plan on getting a paternity test...and if the child isn't his, there is a good chance we will divorce. I just want to know if you think this is something that sounds likely:/

[JoyRenee]

BTW- to answer your question. Yes, early sonograms are very reliable at dating pregnancies because at this point embryos tend to grow at the same rate (whereas as they get bigger they being to grow at their own rates depending on their genetic makeup and the mother's diet and health, etc.). Also, it's a lot easier to measure a tiny little jelly bean compared to a larger fetus.

[JoyRenee]

It's only off by one day. Implantation can occur from 7-12 days post ovulation so your baby probably just implanted a day later then you thought.  

A DNA test is the only way to know who the father of the baby is. I don't want to put a guess on something so very important.