Pregnancy dating criteria

30-Dec-2019 10:21

Caughey, MD, Ph D, Department of Obstetrics and Gynecology, University of California, San Francisco, 505 Parnassus Avenue, Box 0132, San Francisco, CA 94143, O: 415-514-9322, P: 415-443-0301, F: 415-476-1811, E: We conducted a retrospective cohort study of all term, singleton pregnancies delivered at our institution who had an OBUS at ≤24 weeks of gestation.

Those women who underwent an OBUS at ≤12 weeks of gestation (OBUS12) were compared to those who had an OBUS at 13–24 weeks of gestation (OBUS13–24).

Several studies have attempted to characterize subchorionic hemorrhage by conventional two-dimensional ultrasound which is not particularly well-suited for accurate measurement of small irregular hematomas.

The accuracy of h CG measurement in determining the week since conception was more than 93%.

Methods for establishing pregnancy duration vary in their accuracy and their GA estimates.

The difference between LMP estimates and estimates based on ovulation day or ultrasound was 9 and 12 days, respectively.

A uniform rise in h CG on each day of pregnancy was seen using all reference methods.

Several studies have attempted to characterize subchorionic hemorrhage by conventional two-dimensional ultrasound which is not particularly well-suited for accurate measurement of small irregular hematomas.The accuracy of h CG measurement in determining the week since conception was more than 93%.Methods for establishing pregnancy duration vary in their accuracy and their GA estimates.The difference between LMP estimates and estimates based on ovulation day or ultrasound was 9 and 12 days, respectively.A uniform rise in h CG on each day of pregnancy was seen using all reference methods.For Down’s syndrome, a blood test called the quadruple test is available from weeks 14-20 of pregnancy.