A comparison of Leopold's maneuver, McDonald's measurement and
ultrasonic estimation of fetal weight
¡ÒÃà»ÃÕºà·Õº¡ÒûÃÐÁÒ³¹éÓ˹ѡ·Òá㹤ÃÃÀì´éÇÂÇÔ¸Õ Leopold's maneuver,
McDonald's measurement áÅСÒõÃǨ¤Å×è¹àÊÕ§¤ÇÒÁ¶ÕèÊÙ§
Thadpong Promvijit, D. of Obstetrics and Gynecology, F. of Medicine, PSU.
Thitima Suntharasaj, Asst. Prof., D. of Obstetrics and Gynecology, F. of Medicine, PSU.
Alan Geater, Epidemiology Unit, F. of Medicine, PSU
Corresponding e-mail : sthitima@ratree.psu.ac.th
Grant : Faculty of Medicine, PSU.
Presented : The 16th Annual Academic Meeting, Faculty of Medicine, PSU., Hat Yai,
Songkhla, 16-18 August 2000
Key words : Leopold's maneuver, McDonald's measurement, ultrasonic estimation,
fetal weight
Objective : (1) To compare the accuracy of Leopold's maneuver, McDonald's measurement
and ultrasonic estimation of fetal weight. (2) To compare the accuracy of various experience physi-cians in LeopoldÕs maneuver fetal weight estimation.
Method : The study sample included 232 singleton pregnancies admitted in labour room. Clinical and ultrasonic estimation of fetal weight were performed in the same day. Two methods of clinical fetal weight estimation, Leopold's maneuver and McDonaldÕs measurement were used. The McDonaldÕs measurement calculated fetal weight by formula as 3.4+0.16 (uterine length measure-ment (cm) + S-O-34) when S refer to station, coded as -1, 0 or 1, and O = 1 if maternal weight >90.5 kg. LeopoldÕs fetal weight estimation was seperately done by obstetric staff, resident and intern or extern. The ultrasonic estimation was done by experienced perinatologists. The accuracy of three methods was determined by median percentage error, median absolute percentage error and propor-
tion of estimates within 10% of actual birth weight. Statistic analysis was done by ANOVA, ScheffeÕs test, Wilcoxon signed rank test and McNemar chi square test.
Results : McDonaldÕs formula overestimated birth weight approximately 90% of cases and
was considered inappropriation for our population. (The median absolute percentage error = 15.6%
of actual birth weight). The median absolute percentage error of LeopoldÕs maneuver performed by obstetric staff was significantly smaller than that of the ultrasonic estimation. (6.4% VS 8.4%, P<
0.05). The highest proportion of estimates within 10% was LeopoldÕs maneuver done by obstetric
staff (78%). Comparing the experience level of examiners, obstetric staff had the smallest median absolute percentage error. A new formula of McDonaldÕs measurement the appropriate for our study samples was derived as birth weight (kg) = 3.28+0.12 (uterine length (cm) + S - 36.25).
Conclusion : LeopoldÕs maneuver of fetal weight estimation by obstetric staff was more accurate than ultrasonic and McDonaldÕs measuring formula. The experience of examiners have influenced the accuracy of LeopoldÕs maneuver.
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