(HealthDay News) — Paper wheels are inaccurate for estimating date of confinement, according to a study published in the February issue of the American Journal of Obstetrics & Gynecology.
Linda R. Chambliss, MD, MPH, from St. Joseph’s Hospital and Medical Center in Phoenix, and Steven L. Clark, MD, from the Hospital Corporation of America in Nashville, TN, compared the estimated date of confinement of paper gestation wheels with electronic technique (APPs) wheels using a standard last menstrual period. The last menstrual period was set at January 1, 2013 and the date of confinement was estimated from 31 paper wheels and using 20 downloadable electronic APPs. The date given was compared with the expected date of October 8, assuming a pregnancy of 280 days.
The researchers found that 10 wheels (35%) gave an estimated date of confinement consistent with the standard pregnancy duration. The largest discrepancy seen with paper wheels was four days short of 280 days. The estimated date of confinement differed from one another by seven days in two wheels. There was no concurrence between wheels from the same source. All 20 APPs gave an estimated date of confinement of October 8, in accordance with pregnancy of 280 days. The APPs, but not the paper wheels, corrected for leap year.
“Precision in gestational age assessment is critical in a variety of clinical settings and heightened by the focus by payers and reporting agencies on elective deliveries before 39 weeks,” the authors write. “The use of paper gestational age wheels should be abandoned.”