The Use of Paper Based Obstetrics Wheel and Electronic Applications for Calculation of Estimated Date of Confinement and Gestational Age, Which is More Accurate?

This study demonstrates that the USS EDD is more in agreement with the date of spontaneous delivery than the EDD estimated from LMP. This highlights the importance of dating USS in all pregnancies which would be helpful in the management of pregnancy in late stages.

Background: During antenatal care, accurate determination of the gestational age and expected date of confinement are mandatory, for management decisions and birth plan. This could be achieved by the traditional Naegle’s rule, the mechanical obstetrics wheel, and recently the electronics applications.

Objective: To compare the accuracy and consistency of the mechanical or paper-based obstetrics wheel to that of electronics applications in calculating expected date of confinement and gestational age. It would also recommend the application that is most suitable for use in our environment, for the benefit of the patients and the health personnel.

Materials and Methods: An analytical study of 1200 pregnant women who presented for antenatal care on their booking visit. The study was carried out from May 2010 and April 2013, at the antenatal clinic of the department of obstetrics and gynaecology, Niger Delta University Teaching Hospital, Southern Nigeria. Women who presented in the antenatal clinic on the booking visit were identified, and consent was obtained from them. Relevant information concerning the first day of the last regular menstrual period and patient's bio-data were obtained for those who accepted to participate in the study. Using Naegle's rule as control, the expected date of confinement and gestational age were calculated using the mechanical obstetrics wheel and the electronics application. The results were then analysed.

Results: Using the mean gestational age by Naegle’s rule 27.6 ± 7.6 as control, the mean gestational age obtained by mechanical obstetrics wheel 28.4 ± 7.6, and electronics application 27.8 ± 7.6 were compared respectively using the student's t-test. The difference was statistically significant for the paper-based wheel, t = 2.62, p = 0.008 [0.21, 1.43], while that for the electronics applications was not significant, P = 0.48. Also, there was a higher tendency for the paper-based wheel to deviate from +1 to +5 days beyond the normal duration of pregnancy of 280 days, when used to calculate expected date of confinement.

Conclusion: The electronics applications are more accurate in calculating expected date of confinement and gestational age than the mechanical or paper-based obstetrics wheel. The mechanical wheel is less precise, with a high tendency to deviate when used to calculate expected date of confinement. The electronic applications are hereby recommended as first-line tools in all antenatal clinics.