First- and second-trimester ultrasound assessment of gestational age

Kalish, Robin B.; Thaler, Howard T.; Chasen, Stephen T.; Gupta, Meruka; Berman, Seth J.; Rosenwaks, Zev; Chervenak, Frank A.

doi:10.1016/j.ajog.2004.06.053

« Previous Next »American Journal of Obstetrics & Gynecology
Volume 191, Issue 3 , Pages 975-978, September 2004

First- and second-trimester ultrasound assessment of gestational age

Robin B. Kalish, MD
- Department of Obstetrics and Gynecology, Weill Medical College of Cornell University, New York, NY and
- Reprint requests: Robin B. Kalish, MD, Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, 525 East 68th St, Room J-130, New York, NY 10021.
Howard T. Thaler, PhD
- Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY
Stephen T. Chasen, MD
- Department of Obstetrics and Gynecology, Weill Medical College of Cornell University, New York, NY and
Meruka Gupta, BA
- Department of Obstetrics and Gynecology, Weill Medical College of Cornell University, New York, NY and
Seth J. Berman
- Department of Obstetrics and Gynecology, Weill Medical College of Cornell University, New York, NY and
Zev Rosenwaks, MD
- Department of Obstetrics and Gynecology, Weill Medical College of Cornell University, New York, NY and
Frank A. Chervenak, MD
- Department of Obstetrics and Gynecology, Weill Medical College of Cornell University, New York, NY and

Objective

The purpose of this study was to evaluate and compare the accuracy of first- and second-trimester ultrasound assessment of fetal age.

Study design

Differences between ultrasound estimated gestational age and true gestational age were calculated between 11 to 14 weeks of gestation and 18 to 22 weeks of gestation for singleton, twin, and triplet pregnancies that were conceived by in vitro fertilization.

Results

One hundred four singleton pregnancies, 81 twin pregnancies, and 33 triplet pregnancies were included. First trimester ultrasound estimates overestimated gestational age by a mean (± SEM) of 1.3 ± 0.2 days (P < .0001) for singleton pregnancies, 1.4 ± 0.2 days (P < .0001) for twin pregnancies, and 0.8 ± 0.4 days (P=.027) for triplet pregnancies. Second trimester estimates were underestimated by a mean of −0.1 ± 0.4 days (P=.87) for singletons, −0.6 ± 0.3 days (P=.083) for twins, and −0.6 ± 0.5 days (p=0.21) for triplets.