Baby Daddy Confusion

Question

This may sound like a stupid question, but I REALLY want to make sure of this..
I had unprotected sex on August 20th, 2011. 
My last menstrual cycle was on August 27th, 2011.(At least what I believed to be a menstrual cycle).
I had unprotected sex with someone else on September 10, 2011.
I went to the emergency room on September 15, 2011. They said they took a pregnancy test to make sure they could give me medication, I guess it came out negative, because they prescribed me painkillers. (strong ones)
On September 29th I took a pregnancy test and it was positive.
I went to the doctor October 10th and they told me i was 6 weeks 4 days pregnant (plus or minus 2 days).
So I guess my question is... can I be 100% sure that the baby daddy is the second guy I had sex with in September? My doctor tried to reassure me the pregnancy was definitely from September, but I just want to make sure they ultrasounds are really that accurate, and could the bleeding have been not really a period? What's the likelihood of that? And if the pregnancy was from August, would it have shown up when I went to the ER? I want to know because the baby daddy affect my decision to keep this baby or not. I'm hoping it's September guy.
P.S. I have taken Plan B in recent months, so I don't know if that would mess my ovulation cycle..
Any input? Thanks :)

rmmoye · Accepted Answer

Ok, Yes it is September guy!!!! I will explain how. the first two weeks are the time period in which your body is preparing to get pregnant. it is when your folliclies are growing to release and egg for the sperm to go in and make the baby. so at aroudn day 14 of your cycle ( cycle day one is the 1st day of your period) if u have a normal 28 day cycle, later then day 14 if u have a longer cycle, you concieve or get pregnant. then the baby latches on.  14 days after u concieve u get a + home pregnancy test  or u start your period. so because u started your period on the 27 of august then on teh 20th when u have sex with guy A that egg was long gone. it would have been ready on the 13th of August. Now u said u went to the er on the 15th of sept. so if u had gotten pregnant on the 20th then u would have been 4 weeks after conception putting u at 6 weeks pregnant. a pregnancy test would have been ++. 

now if it were guy B Which it was u would have had sex on cycle day(cd) 15 which is perfect timing for conception. 2 weeks after your period started.  now 5 days later u went to the emergancy room which would have been to early for even a blood test to show up positive because the baby  latches and implants between cd 5-10. once it latches and implants it then starts producing hcg which is what gives u the + hpt but it starts out producung so slowly that most women cant even get a + home pregnancy test until cd 28 at the earliest.  

I hope this helps. If u need more confirmation then go to due date calculator

baby center . com and they will tell u based on your period u conceved on the 10th of sept putting u right on the mark.

GL

bgeek167 · Answer

Thank you guys sooooooo much!!!!
I can sleep again!!!! lol Thanks!!!

RippedonScotch · Answer

You have to remember that when they say that you are 6weeks and 4 days that it really means that you conceived 4 weeks and 4days ago. The first 2 weeks are from your last cycle. So it is for sure the September guy.

Heather5 · Answer

Ultrasounds are very accurate this early, and yes, your pregnancy test at the ER would have been positive if you did in fact get pregnant in August. So I agree, definitely the September guy!