Reference intervals of gestational sac, yolk sac and embryo volumes using three-dimensional ultrasound
Article first published online: 22 OCT 2009
Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Ultrasound in Obstetrics & Gynecology
Volume 34, Issue 5, pages 503–509, November 2009
How to Cite
Bagratee, J. S., Regan, L., Khullar, V., Connolly, C. and Moodley, J. (2009), Reference intervals of gestational sac, yolk sac and embryo volumes using three-dimensional ultrasound. Ultrasound Obstet Gynecol, 34: 503–509. doi: 10.1002/uog.7348
- Issue published online: 22 OCT 2009
- Article first published online: 22 OCT 2009
- Manuscript Accepted: 3 JUN 2009
- crown–rump length;
- embryo volume;
- first trimester;
- gestational sac diameter;
- gestational sac volume;
- reference intervals;
- three-dimensional ultrasound;
- yolk sac volume
To create reference intervals of gestational sac volume (GSV), yolk sac volume (YSV), embryo volume (EV), crown–rump length (CRL) and gestational sac diameter (GSD) in the first trimester of pregnancy using three-dimensional ultrasound.
Women in the first trimester of pregnancy were invited to participate in the study. Inclusion criteria were well-established dates, and that the women were non-smokers and healthy, without any medical disorders. Three-dimensional ultrasound volumetric data (GSV, YSV, EV) were collected together with standard two-dimensional measurements of CRL and GSD. For each measurement separate regression models were fitted to estimate the mean and SD at each gestational age. The 5th, 50th and 95th centiles were derived using a combination of these regression models.
One hundred and sixty-six women at between 6 and 12 weeks' gestation were scanned once. The mean ( ± SD) maternal age was 29.4 ( ± 5) years. There were no miscarriages and no congenital abnormalities were noted. Mean gestational age at delivery was 39.3 ( ± 1.4) weeks and mean birth weight was 3.3 ( ± 0.4) kg. The CRL centiles fitted a cubic model and the GSD centiles fitted a linear model. The centiles for YSV fitted a quadratic model on the modified log-transformed data. The centiles for GSV and EV were modeled using quantile regression.
Reference intervals and centile charts for first-trimester GSV, YSV and EV have been created in addition to CRL and GSD using rigorous methodology. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.