When did I conceive ?

[Balavado18]

My LMP that I know was normal was June 29 of 2013 I had unprotected sex on July 17 with somebody I don't normally do it with an on the 19 of July I had sometype of bleeding period idk what it was ? But lasted for for days but it came early . I should have gotton it I the 29 of July anyways my due date is April 21 2014 I'm 36 weeks the doctors are saying most likely conceived July 29 but when I count back 40 weeks it takes me bak to the 21 I'm confused ?

[AnnieBrooke]

So, as I said, you use your estimated due date, not your number of weeks pregnant, for your figuring.  Since the estimated due date was given to you by an ultrasound early in the pregnancy it will be reliable.  From it, count back 266 days to reach the assumed day of conception, or plug your e.d.d. into a conception calculator online, and it will count back 266 days for you.  It says you conceived around the 29th.

[Balavado18]

I got my due date in my early ultrasound it has never changed since the.

[AnnieBrooke]

Kind of hard to understand what you mean when you say stuff like "if it was an early ultrasound coy back from those weeks of just by due date."  

Did you get your due date from one of your early ultrasounds, or was it given to you later in your pregnancy?

[Balavado18]

Okay so when yu mean early ultrasound which I did have whatyu mean by that? So basically if it was an early ultrasound coy back from those weeks of just by due date and I did use the calculator and it goes from what yu exactly said July 29-3of august . I asked about the CRL dating because that is what I got at 5 and 8 weeks ultrasound  but I. All the 17 is out of the question right so it is safe to say I conceived around the 29 or so ?

[AnnieBrooke]

Counting back 36 weeks 0 days using a calendar, I get the 18th.  If you want to check my work, here is how it came out:  33 weeks on March 6, 29 weeks on February 6, 24 weeks on January 2, 20 weeks on December 5, 16 weeks on November 7,11 weeks on October 3, 7 weeks on September 5, 2 weeks on August 1, and 0 on July 18.  

But counting backward by the weeks doesn't help unless the due date that gave you the start point of those weeks was gotten from an early ultrasound, which is why I asked.  Using your April 21 estimated due date, (if you got it from the early ultrasound), gives you the following:

     Assumed first day of last menstrual period:  July 15
     Probable date of ovulation:  July 29
     Possible dates of conception:  July 25 to August 2
     Due date:  April 21 (40 weeks)

In any case, whether your period began on July 15 or July 18, it still suggests strongly that your ovulation was long after the guy on the 17th, because you don't ovulate on the first day of your period or anywhere near it.

Regarding the CRL. crown-to-rump measurements of embryos are matched with the size of embryos of known development age and are used to count forward to an estimated due date and count back to an estimated start point.  

So, use your estimated due date, not your number of weeks pregnant, for your figuring, *if* the estimated due date was given to you early in the pregnancy.  From it, count back 266 days to reach the assumed day of conception.  Or just plug your e.d.d. into a conception calculator online, and it will count back 266 days for you.

I don't really see any point in counting forward 40 weeks from July 21 to April 21.

[Balavado18]

I got the 21 because I counted back 36 weeks back which iam today and it takes me back to the 21 so I'm a little confused how did yu get the 15 ?  I did have an early ultrasound at 5 weeks and 8 weeks and counting 40 weeks from July 21 to April 21 is 40 weeks that's where I'm confused are CRL dating the size of the baby from conception or LMP from the 19 ?

[Balavado18]

I got the 21 because I counted back 36 weeks back which iam today and it takes me back to the 21 so I'm a little confused how did yu get the 15 ?  I did have an early ultrasound at 5 weeks and 8 weeks and counting 40 weeks from July 21 to April 21 is 40 weeks that's where I'm confused are CRL dating the size of the baby from conception or LMP from the 19 ?

[AnnieBrooke]

Counting back 40 weeks should take you to about the 15th, you might try counting again.  But 40 weeks doesn't matter for counting back to the day of conception; it counts you back to the first day of your last period, not to the day of assumed conception.  The doc is right when he or she estimates July 29 for conception; you count back 38 weeks (266 days) to get to that assumed date.  The reason 40 weeks counts back to the first day of the last period is that is the day the doctors begin your week count.  They don't try to figure out when you conceived, they start on the first day of bleeding (or the assumed first day of bleeding) even though of course you are not pregnant on that day, you're having a period!  But it's a visible signal, and it has traditionally been the point where the weeks begin.  I'd expect that the period you had on July 19 was a real period.  Because you had a period after him, and also depending on how early you got the due date (the earlier in the pregnancy the more accurate), it seems pretty clear that your guy on the 17th is not the dad.

[Balavado18]

But if yu were to guess what would yur thoughts be ? We are getting a DNA test Its just driving me crazy thinking about it ?

[Carly1306]

Only way to know is a DNA test when baby is born.