To evaluate in a national standardised setting whether the performance of ultrasound dating during the first rather than the second trimester of pregnancy had consequences regarding the definition of pre- and post-term birth rates. We determined the duration of pregnancy calculated by last menstrual period, crown rump length CRLbiparietal diameter 1 st trimesterBPD 2 nd trimesterand head circumference and compared mean and median durations, the mean differences, the systematic discrepancies, and the percentages of pre-term and post-term pregnancies in relation to each method. The primary outcomes were post-term and pre-term birth rates defined by different dating methods.
Researchers have mapped out the expected measurements for specific points in early pregnancyso an early ultrasound scan can give a doctor some important information. For this purpose, an ultrasound is considered a highly accurate means of dating a pregnancy. In a normal pregnancy, the ultrasound results can provide an estimate of the gestational age to within five to seven days of accuracy.
Most pregnant women will have an ultrasound scan during their pregnancy. This simple test is quite safe for both mother and baby and causes only minor, if any, discomfort. Ultrasound is a way of taking a look at the baby without using potentially dangerous X-rays.
Ultrasound scans use sound waves to create a picture of the baby in the womb. Most women have one or more ultrasound scans during pregnancy. The two scans routinely offered during pregnancy are the nuchal scan and the anatomy scan.
For many women, especially after 8 weeks gestation, sufficient information about the baby may be obtained with transabdominal ultrasound only. However, in the early pregnancy, the developing embryo is very small at 6 weeks gestation, the baby is only mm long and a transvaginal ultrasound may be required to get a better image of the baby. Transvaginal ultrasound is safe and commonly performed during all stages of pregnancy, including the first trimester.
Pettker, MD; James D. Goldberg, MD; and Yasser Y. This document reflects emerging clinical and scientific advances as of the date issued and is subject to change.
We at MUMS understand that the first few months of pregnancy can be quite an anxious time for many women with various concerns as to whether the pregnancy is developing normally or that it may result in a miscarriage or even an ectopic pregnancy. An Early Pregnancy Scan sometimes also called a Viability Scan or Dating Scan provides reassurance in this very early stage of your pregnancy. A pregnancy can be seen from as early as 6 weeks from the first day of your last period LMP and not the date of conception.
A dating scan is an ultrasound scan to determine how many weeks pregnant you are and your due date. Read on for more information about what a dating scan offers. A dating scan might be recommended to confirm your due date if you are unsure of your last menstrual period or your date of conception. It is usually offered to pregnant women from 10 weeks to 13 weeks gestation, but can be carried out any time from 6 weeks.
A dating scan is an ultrasound examination which is performed in order to establish the gestational age of the pregnancy. Most dating scans are done with a trans-abdominal transducer and a fullish bladder. If the pregnancy is very early the gestation sac and fetus will not be big enough to see, so the transvaginal approach will give better pictures.