Title:
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Preterm or not - an evaluation of estimates of gestational age
in a cohort of women from rural Papua New Guinea
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Author:
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Karl, Stephan; Li Wai Suen, Connie S. N.; Unger, Holger Werner; Ome-Kaius, Maria; Mola, Glen; White, Lisa; Wangnapi, Regina A.; Rogerson, Stephen John; Mueller, Ivo
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Abstract:
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BACKGROUND: Knowledge of accurate gestational age is required
for comprehensive pregnancy care and is an essential component
of research evaluating causes of preterm birth. In
industrialised countries gestational age is determined with the
help of fetal biometry in early pregnancy. Lack of ultrasound
and late presentation to antenatal clinic limits this practice
in low-resource settings. Instead, clinical estimators of
gestational age are used, but their accuracy remains a matter of
debate. METHODS: In a cohort of 688 singleton pregnancies from
rural Papua New Guinea, delivery gestational age was calculated
from Ballard score, last menstrual period, symphysis-pubis
fundal height at first visit and quickening as well as mid- and
late pregnancy fetal biometry. Published models using sequential
fundal height measurements and corrected last menstrual period
to estimate gestational age were also tested. Novel linear
models that combined clinical measurements for gestational age
estimation were developed. Predictions were compared with the
reference early pregnancy ultrasound (<25 gestational weeks)
using correlation, regression and Bland-Altman analyses and
ranked for their capability to predict preterm birth using the
harmonic mean of recall and precision (F-measure). RESULTS:
Average bias between reference ultrasound and clinical methods
ranged from 0-11 days (95% confidence levels: 14-42 days).
Preterm birth was best predicted by mid-pregnancy ultrasound
(F-measure: 0.72), and neuromuscular Ballard score provided the
least reliable preterm birth prediction (F-measure: 0.17). The
best clinical methods to predict gestational age and preterm
birth were last menstrual period and fundal height (F-measures
0.35). A linear model combining both measures improved
prediction of preterm birth (F-measure: 0.58). CONCLUSIONS:
Estimation of gestational age without ultrasound is prone to
significant error. In the absence of ultrasound facilities, last
menstrual period and fundal height are among the more reliable
clinical measures. This study underlines the importance of
strengthening ultrasound facilities and developing novel ways to
estimate gestational age. |
Subject(s):
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-Embaràs -Estadística mèdica -Edat gestacional -Part prematur -Pregnancy -Medical statistics -Gestational age -Premature labor |
Rights:
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cc by (c) Karl et al., 2015
http://creativecommons.org/licenses/by/3.0/es/ |
Document type:
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Article Article - Published version |
Published by:
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Public Library of Science (PLoS)
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