First Trimester / Dating Ultrasound

Keep it with your so your midwife and anyone else involved in your care can see it. I am sure about my period dates. This ultrasound will check if your pregnancy is developing normally within the uterus.

How accurate are conception dates? It will not harm you or your baby. Am J Obstet Gynecol 1996; 174:278.

How Accurate Are Conception Dates? - How big will my baby be at the dating ultrasound? The purpose of this is to help with education and create better conversations between patients and their healthcare providers.

Of all of these uses, dating the pregnancy ultrssound the most common reason to use ultrasound, particularly when the expectant mother cannot remember the date of her last period as in breast-feeding or irregular cycles. When an ultrasound is performed, measurements of the head, abdomen, thigh, and amount of amniotic conception are done. This creates error in that the baby will compute out to be further along than he or she really is. For dating, say you normally have eight and nine pound babies. Then your baby at 37 weeks will have bigger measurements than babies destined to weigh seven or eight pounds at birth. This may then indicate that your 37-week baby is two weeks overdue! Therefore, measurements taken later on, when babies begin to grow at different rates among pregnancies, yield increasingly inaccurate dating of pregnancy. Although the dating of pregnancy accuracy takes a dive, still ultrasound is indispensable for the other uses. Nevertheless, this measurement is fairly accurate. In the ultrasound trimester, past the first 12 weeksthe other measurements can ulfrasound added. Two ultrasounds taken one month apart that agree with each other on when the due date is, yield a very accurate and reliable answer. So how accurate is ultrasound? Babies have their own clock and can come anywhere from three weeks before this exquisitely determined due date till two weeks after. So in this arithmetic test, the baby sets the curve.