Was I most likely already pregnant?

[Livealittlelynn]

I had unprotected sex with someone other than my mate on Oct. 23rd ... My period was due Oct. 27th. It did not come on. Would my body know I was pregnant in just those 4 days or was I most likely already pregnant? I also had a ultrasound performed Dec. 19th ... exactly 8 weeks and 1 day later after my Oct 23rd encounter. However the ultrasound revealed the fetus to be 9 weeks and 3 days give or take 5 days in either direction. Was I already pregnant?

[Livealittlelynn]

It's so close I don't know and it does worry me sometime. However, you've given me excellent advice and that's what I'll do. I was never supposed to be able to have children so this is my miracle baby. I want to enjoy this .. I'm going too. Thanks for all your advice and insight and not being judgmental, I do appreciate it.

[AnnieBrooke]

So, although this is all a bit confusing because doctors use GA and you were using conception dates, I would advise you to try to put the question out of your mind and enjoy your pregnancy, assuming the guy from 8 weeks 1 day is not the father, and then get a DNA test with him when the baby is born, just to put the question to rest entirely.

[AnnieBrooke]

Well, Lynn, I don't know if you can absolutely and entirely rule out the guy you don't want to be the dad, but it looks promising.  No matter whether you were using a count from the first day of conception and the doctor was using a GA count, it does sound like the doctor thinks the baby is one week and two days further along than it would be if the wrong guy was the dad.  That is not the kind of margin where one would use the words "guaranteed" and "for sure," about but it is big enough.

[Livealittlelynn]

It always comes on Day 29 at the end of the month, no mater what calendar date that falls on.
I'm certain about what the doctors said as far the fetus being older than 8 weeks in the ultrasound. They said at 8 weeks I would have needed a transvaginal ultrasound, but they could see everything perfectly because I was 9 weeks and 3 days give or take 5 days which would be 8 weeks and 5 days or 10 weeks and a day. Each of those dates is way past the 8 weeks that I slept with Guy B. So even if I conceived that day meaning the blastocyst implanted itself in my uterus I believe it was already fertilized ... I hope. Guy B said he didn't ejaculate inside of me but I'm not to certain about that.

[AnnieBrooke]

Well, months on the calendar are different lengths, for example February only has 28 days most years.  Are you saying your cycle comes on January 28, then on February 24, then on March 28, then on April 30?  If so, you have a slightly variable cycle, which is important to know -- variability is important in trying to compute when you ovulate.  But if you are saying your period always comes on day 29 after the last one began, no matter what calendar date that falls on, then it would be regular enough for you to assume you couldn't have gotten pregnant on the 23rd if you expected your period on the 27th.

The problem I'm having is that if they gave you a due date of the 21st based on a relatively early ultrasound, this identifies your probable date of ovulation as being October 28.  It does give you a range of the 24th through November 1, but you already knew you were pregnant by most of those dates because you expected your period.  Are you certain of what the doctors told you?  And are you sure your periods are always on the end of the calendar month?

[Livealittlelynn]

The 12 weeks was based off my LMP I suppose. My ultrasound estimated 9 weeks 3 days give or take 5 days but at that time I had sex with that person exactly 8 weeks ago.
My cycle it's like clockwork. It never misses a beat. It always the last 4 days of the month.

[AnnieBrooke]

If the ultrasound doctors said there was no way you could have been 8 weeks, but they thought you were 12 weeks along before you had the ultrasound, what were they comparing to?

As far as your question about if you were expecting a period on the 27th, would sex on the 23rd get you pregnant, the answer is only if you ovulated on the 23rd.  In other words, it is possible to ovulate late sometimes. (If you had ovulated late, then your period would not have come when expected on the 27th even if you hadn't gotten pregnant.)  Are your cycles always exactly like clockwork or are they sometimes varied in length?

[Livealittlelynn]

I only asked how far along I was. My first estimated due date was July 4th based on the first day of my last period (Sept 27th)which would have made me almost 12 weeks at the time of the ultrasound. However after the ultrasound they gave me a due date of  July 21st. At the ultrasound the doctors said the was no way I could have just been 8 weeks from the look of the fetus in the ultrasound. But I had just slept with Guy B exactly 8 eeks ago at the time of the ultrasound. I'm just a little confused. And wouldn't my period still have came on Oct.27th if I only unprotected sex 4 days ago and wasn't already pregnant.

[AnnieBrooke]

Did you get an estimated due date?  Usually when the ultrasound person or the doctor gives you a date, the medical version of how pregnancy is counted (the gestational age, or GA) starts the count at the first day of your last period.  This would then mean you conceived around the 28th.  Did you ask specifically about conception, using that word, or did you simply ask how 'far along' you were?