Accurate early ultrasounds dating pregnancy
There is no evidence that these ultrasounds were harmful to fetus. More than one ultrasound throughout your pregnancy may be required because ultrasounds are not always accurate.
They could be out as little as a couple of days by a matter of weeks.
My wife told her doctor she didn't know when her last mp was, so he sent her for an ultrasound!
Seeing the gestational sac, which looks like a black dot in the uterus, has several benefits: it confirms that a woman is pregnant, confirms that the pregnancy at a very early stage, making dating the pregnancy very accurate, and also confirms that the pregnancy is in the uterus rather than ectopic, or outside the uterus.
Our 1st baby measured within 5 days thru the entire pregnancy, and that was as early as 8 weeks and as late as 26!
Not very accurate yet, your best bet is to wait until about 20 weeks to get a accurate ultrasound Ultrasounds are always most accurate in the first trimester of pregnancy, within about 3-5 days, in the second usually off by 7-10 days after 20 weeks could be off by 2 weeks and in the third it could even be as much as 3 weeks!
It records high-frequency sound waves that create an image (see Reference 4).
Normally, ultrasounds before until week 4 of pregnancy shows nothing in the uterus and serve no purpose.