Preaching to the Choir
From: art fougner, md (evsono@pipeline.com)
Fri Feb 2 06:50:18 2001
this in the Feb Green Journal 2001 -
Predicting Delivery Date by Ultrasound and Last Menstrual Period in
Early Gestation
Pekka Taipale, MD, PhD,a,b,c and Vilho Hiilesmaa, MD, PhDd
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Objective: To compare last menstrual period and ultrasonography in
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predicting delivery date.
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Methods: We used ultrasound to scan 17,221 nonselected singleton
pregnancies at 8-16 completed weeks. The last menstrual period (LMP)
was considered certain in 13,541 and uncertain in 3680 cases. The
duration of pregnancy from the scan to the day of spontaneous delivery
was predicted by crown-rump length, biparietal diameter (BPD), and femur
length (FL) using linear regression models, and the results were
compared with estimates based on LMP.
Results: At all gestational ages, ultrasound was superior to certain LMP
in predicting the day of delivery by at least 1.7 days. When deliveries
before 37 weeks were excluded, crown-rump length measurement of 15-60 mm
(corresponding to 8-12.5 weeks) had the lowest prediction error of 7.3
days. After that time, BPD (at least 21 mm) showed a similar error (7.3
days) and was more precise than crown-rump length. Femur length was
slightly less accurate than crown-rump length or BPD. Regression models
using a combination of any two or three ultrasonic variables did not
improve accuracy of prediction. When ultrasound was used instead of
certain LMP, the number of postterm pregnancies decreased from 10.3% to
2.7% (P < .001).
Conclusion: Ultrasound was more accurate than LMP in dating, and when it
was used the number of postterm pregnancies decreased. Crown-rump
length of 15-60 mm was superior to BPD, but then BPD (at least 21 mm)
was more precise. Combining more than one ultrasonic measurements did
not improve dating accuracy.
aDepartment of Obstetrics and Gynecology, Jorvi Hospital, Espoo, Finland
bDepartment of Obstetrics and Gynecology, Kuopio University Hospital,
Kuopio, Finland
cNational Center for Fetal Medicine, Trondheim University Hospital,
Trondheim, Norway
dDepartment of Obstetrics and Gynecology, Helsinki University Central
Hospital, Helsinki, Finland
Supported by grants of Maud Kuistila Foundation, Helsinki, Finnish
Cultural Foundation, Helsinki, and Jorvi Hospital Research Foundation,
Espoo, Finland.
(Obstet Gynecol 2001:97:189-194. © 2001 by The American College of
Obstetricians and Gynecologists.)
art
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art fougner, md
A series of 1000 cases begins with but a single anecdote.
