pregnancy

[confused377]

How accurate are ultrasounds in confirming the due date? if you aren't to sure of your last period? had sex/cheated with a condom on the 3/19/010................Pretty sure almost positive i had my period on the 4-16-10, and had unprotected sex with my boyfriend after that..........according to my last period and the ultrasound it shows i am at 11weeks this friday 6-25-10........can you tell me if it could be of. a month. My guilty conscience will not let me rest. can you help with date of conception?

[k10road]

No...not bad.  The concept itself is quite confusing, and when you have a midwife or doctor who counts wrong, it doesn't help.  Plus....you have pregnancy brain!  :-)

[KarenDiane]

OK, Thanks! This is my 4th baby and I still can't wrap my head around it. LOL.
Pretty bad huh?

[k10road]

In a 40 week gestation, you are technically already 2 weeks pregnant when you actually conceive.  This is because in the medical profession, they count the first day of your last period as day 1 of your pregnancy.  So, if you ovulate 2 weeks later, and conceive then, you are already 2 weeks.  By the time your period is due, it is 4 weeks from your LMP, and then you are considered 4 weeks pregnant.  It is confusing.  Some doctors use a 38 week gestation.  In that case, they count from the time you conceived.  So you are due 38 weeks from the actual time that conception occured.  It is most common, however, for doctors to use a 40 week gestation timeline.  Technically, your due date should be 40 weeks from your LMP or 38 weeks from conception.

[KarenDiane]

Now if I count backwards from my due date to my date of conception, it's 40 weeks. And I am positive about both my LMP and my date of conception. Does this mean that my midwife counts differently or is my due date incorrect?

[gigi599]

your conception date should have been on april 23 (or something near to that date), so its your boyfried is the father.

[k10road]

If you are 11 weeks this Friday, conception would have occured around 4/23...and 4/9 would have been the approximate date of your last period.  Ultrasounds are usually pretty accurate when done early on in a pregnancy as the CRL (crown to rump length) shouldn't vary that much in early pregnancy.  As you get further along, the size of the baby can vary as some babies are bigger or smaller than others.  Since  your ultrasound was first trimester, it should be fairly accurate - not off by more than a week usually.  Since conception would have occurred around 4/23, and your "cheating" encounter was 3/19, I tend to think that you did not get pregnant on 3/19 since that is over a month off from the ultrasound.  A month is a bit drastic for an early ultrasound to be off by.  I would lean towards it being your boyfriends, but the only way to be certain is to have a paternity test done.  Good luck.

[gigi599]

ultrasounds are pretty acurrate specially on the first trimester, after the second and third your baby can measure right on track or about 1 or 2 weeks less or more.

but on the first trimester is really acurrate, i had an ultrasound at 12 weeks and it measured perfectley for my ovulation day.

remember that if you are 11 weeks now the actual conception date would have been 9 weeks ago

[KarenDiane]

u/s will give you an estimate, they aren't exact but they are usually only off by a week or so. Not a whole month. 11 weeks from this friday would be April 9th. That doesn't line up with either sexual encounter so you may need a paternity test after the baby is born.