Ultrasound accuracy dating
There are various ways to estimate the day of ovulation.You can estimate your date of ovulation and conception from the length of your menstrual cycle if this is fairly regular.You should still have a ultrasound between 18 and 22 weeks because more detail can be seen as your baby grows bigger.The dating ultrasound will also show if you're expecting twins, triplets or more.For example, about one in 20 women will appear to be at high risk from the nuchal translucency ultrasound to assess the risk of Down's syndrome, but most of these babies will turn out not to have Down's syndrome. Now that you know all about ultrasounds scans, test your new-found knowledge by taking our quiz! It's up to you whether you have an ultrasound - you don't have to if you don't want to. Having an ultrasound in the first trimester of pregnancy can be a thrilling experience. Bear in mind that you may need a second ultrasound before you know for certain if all is well.
If you can determine that day, you will come close to identifying your date conception.
The LMP is used because most women know when their last period was, but may not know when they actually conceived.
If you do know the conception date, this is classed as day 14 and not day one.
It may show a very minor problem, or something which may get better on its own.
As with all screening tests, there can be false positive and false negative results.