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ABSTRACT: To evaluate the performances of estimated fetal weight (EFW) and fetal growth velocity (FGV) in the prediction of birth weight>95th centile amongst women with impaired glucose tolerance (IGT); the prediction of neonatal hypoglycaemia was a secondary endpoint.
Two hundred and forty-two consecutive women (61 type 1 diabetes mellitus, 14 type 2 diabetes mellitus, 49 gestational diabetics and 118 with impaired glucose tolerance) receiving routine care at the combined diabetes/antenatal clinic, Jessop Hospital for Women, Sheffield. EFW was routinely calculated at approximately two-week intervals in the third trimester with the last EFW prior to delivery used in the analysis. FGV was calculated from two estimates of fetal weight between 21 and 35 days apart. EFW and FGV were both expressed as standard deviation (Z) scores.
The mean gestational age at delivery was 37 weeks (range 26-40 weeks). Sixty-five (27%) infants were of birth weight>95th centile. Mean EFW Z scores were 2.7 and 0.99 for >95th and <95th centile, respectively (p<0.001). Receiver operator characteristics (ROC) curve analysis gave area under the curve 0.8; using a cut-off Z score of 1.7 (=95.5 centile), EFW has sensitivity 80% and specificity 72% in predicting an LGA neonate (likelihood ratios 2.8 and 0.27 for positive and negative test). Mean FGV Z scores were 0.85 and 0.4 for >95th and <95th centile, respectively (p>0.05); ROC curve analysis indicated no discriminatory capacity. Estimates of fetal size and growth performed poorly in the prediction of neonatal hypoglycaemia.
In routine clinical practice, EFW has limited utility in the prediction of the LGA infant. FGV does not identify the LGA infant. EFW and FGV do not predict neonatal hypoglycaemia.
European Journal of Obstetrics & Gynecology and Reproductive Biology 07/2007; 132(2):189-92. · 1.97 Impact Factor
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ABSTRACT: To establish whether there is a relationship between estimated fetal weight (EFW) and umbilical artery Doppler waveform impedance indices in the third trimester.
The pulsatility index (PI) and S/D (systolic/diastolic) ratio were obtained together with the EFW from 274 low-risk pregnancies. Measurements were made at fortnightly intervals from 30 weeks' gestation until delivery. A relationship between the two impedance indices and EFW was sought at gestational age ranges of 30-32, 33-35, 36-38 and 39-41 weeks.
There were 918 pairs of PI (with S/D) and EFW available for analysis. The mean of the impedance indices decreased with advancing gestational age as expected. There was no clinically relevant correlation between impedance indices and EFW within any of the gestational age ranges.
Impedance indices from the umbilical artery Doppler waveform decrease with advancing gestational age due, at least partially, to expansion of the placental vascular tree. Within narrow gestational age ranges in the third trimester, there is no meaningful correlation between fetal weight and impedance indices. It is therefore not necessary to adjust umbilical artery Doppler impedance indices to account for fetal size.
Ultrasound in Obstetrics and Gynecology 09/2003; 22(2):157-9. · 3.01 Impact Factor
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ABSTRACT: To determine if cervical length obtained with three-dimensional ultrasound correlated with the 'true cervical volume' and to evaluate the reliability and validity of transabdominal and transvaginal three-dimensional cervical volume measurement.
This was a prospective observational study. Three-dimensional cervical volume measurements were made prior to hysterectomy in 28 women. Following hysterectomy the amputated cervical volume was calculated using water displacement. For the assessment of intra- and interobserver reliability, the intraclass correlation coefficient (ICC) was used. The index of concordance between the sonographic cervical volumes and those obtained by the reference standard (true cervical volume) was assessed with the limits of agreement method and the ICC.
Transabdominal cervical length and transvaginal cervical length correlated moderately with actual cervical volume; correlation coefficients were 0.64 and 0.57 (P < 0.05), respectively. Intraobserver reliability for both transabdominal and transvaginal cervical volume assessment was good (> 0.75). Interobserver reliability for transvaginal cervical volumes was similarly good (ICC = 0.90). However, for transabdominal measurements the interobserver reliability was poor (ICC = 0.51). The validity of both methods of three-dimensional volume assessment was poor (ICC < 0.75). This was reflected in the wide limits of agreement, which ranged from approximately - 25 mL to + 30 mL.
The reliability and validity of three-dimensional cervical volume measurement are poor. Clinical introduction of cervical volume measurement should be avoided at this time.
Ultrasound in Obstetrics and Gynecology 07/2003; 22(1):49-52. · 3.01 Impact Factor
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ABSTRACT: To establish whether there is a relationship between the amniotic fluid index and estimated fetal weight in the third trimester. The presence of a relationship would require adjustment of amniotic fluid index to take account of estimated fetal weight with potential improvement in its prediction of adverse perinatal outcomes.
Paired measurements of amniotic fluid index and estimated fetal weight from 274 low-risk pregnancies enrolled in a longitudinal study of fetal growth. Measurements were made at fortnightly intervals from 30 weeks' gestation until delivery. A relationship between amniotic fluid index and estimated fetal weight was sought at gestational age week intervals of 30-32, 33-35, 36-38 and 39-41.
One thousand and three pairs of measurements of amniotic fluid index and estimated fetal weight were available for analysis. Mean amniotic fluid index decreased towards term as expected. There was no correlation between amniotic fluid index and estimated fetal weight. Furthermore, there was no correlation between amniotic fluid index and estimated fetal weight at any of the gestational age intervals.
There is no clinically relevant correlation between amniotic fluid index and estimated fetal weight. It should remain clinical practice to take account of gestational age when interpreting amniotic fluid index but it is not necessary to make adjustments for estimated fetal weight.
Ultrasound in Obstetrics and Gynecology 08/2002; 20(1):61-3. · 3.01 Impact Factor
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ABSTRACT: To evaluate the reliability and validity of two and three dimensional ultrasound volumetric measurements using balloon and uterine models.
Prospetive observational study.
Obstetric ultrasound department at a university teaching hospital.
Two and three dimensional ultrasound volumetric measurements (with 5, 10 and 15 ultrasonic slices) were performed on 30 different sets of ultrasound images obtained from 15 water filled balloons with volumes ranging from 19 to 697mL. The measurements were performed independently by two observers who were blinded to the true volumes of the balloons. For the uterine model, only three dimensional ultrasonic volume measurements were performed independently on 16 uteri by two observers who were again unaware of the definitive uterine volumes.
For the assessment of intra-and inter-rater reliability, the intraclass correlation coefficient was used. The index of concordance between the ultrasonic volumes and those obtained by the reference standard (validity) was assessed with the conventional Pearson's correlation coefficient, limits of agreement method and the intra-class correlation coefficient.
High levels of reliability and validity were obtained for both two and three dimensional ultrasound balloon volume measurements. For two dimensional ultrasonic volume measurements, the intra-class correlation coefficient ranged from 0.992 to 0.998 for reliability and validity whereas the Pearson's correlation coefficient for validity was 0.996. With three dimensional ultrasonic volume measurements, the intra-class correlation coefficient ranged from 0.991 to 0.999 for reliability and validity whereas the Pearson's correlation coefficient for validity was 0.999. Both two and three dimensional ultrasonic measurements tended to underestimate the true balloon volume with the largest observed mean difference obtained with three dimensional ultrasound measurements using five ultrasonic slices and the smallest value obtained with three dimensional ultrasound measurements employing 15 ultrasonic slices. The mean difference in volume measurement for two dimensional ultrasound was intermediate between these two values. However, two dimensional ultrasound volume measurement generated the largest range between the limits of agreement whereas the smallest range was obtained with three dimensional ultrasound using 10 ultrasonic slices. The intra-class correlation coefficient for reliability and validity with three dimensional ultrasonic uterine volume estimation ranged from 0.956 to 0.996 whereas the Pearson's correlation coefficient for validity ranged from 0.993 to 0.999). The use of three dimensional ultrasound also consistently under-estimated the actual uterine volumes. The larger the number of ultrasonic slices employed for three dimensional ultrasound, the smaller was the mean difference between the ultrasonic and true uterine volume measurements and the smaller the limits of agreement.
The reliability and validity of balloon and uterine volume measurement by three dimensional ultrasound is high. This allows further research on three dimensional ultrasound for measuring pelvic organ volumes in the prediction of pelvic pathology.
BJOG An International Journal of Obstetrics & Gynaecology 07/2001; 108(6):573-82. · 3.41 Impact Factor
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Ultrasound in Obstetrics and Gynecology 01/2001; 16(7):667. · 3.01 Impact Factor
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ABSTRACT: To develop and validate a computerised algorithm for the interpretation of the characteristics of fetal heart rate monitoring in labour.
Prospective observational study.
Labour ward in a tertiary hospital.
Intrapartum cardiotocograms from 24 pregnancies.
A computerised algorithm was developed to assess the fetal heart baseline rate, variability, the number of accelerations and the number of decelerations. Twenty five minute segments of cardiotocograms were interpreted by the algorithm and also by seven expert reviewers independently. The reviewers were unaware of the outcome of labour. The reliability of the characteristics of cardiotocography and the validity of the computerised algorithm were assessed using the intraclass correlation coefficient and weighted kappa statistic for continuous and ordinal variables respectively.
The inter rater reliability of the baseline fetal heart rate and the number and type of decelerations was good (intraclass correlation coefficient 0.93, 0.93 and 0.79, respectively). The reliability of baseline variability (kappa = 0.27) and accelerations (intraclass correlation coefficient = 0.27) was poor. The computerised algorithm had good agreement with the reviewers for the baseline fetal heart rate (intraclass correlation coefficient 0.91 to 0.98) and the number of decelerations (intraclass correlation coefficient 0.82 to 0.91), but was less valid as regards the number of late decelerations (intraclass correlation coefficient 0.68 to 0.85) and the number of accelerations (intraclass correlation coefficient 0.06 to 0.80), and was invalid as regards baseline variability (kappa 0.00 to 0.34).
The high level of validity of the computerised algorithm for the estimation of the baseline fetal heart rate and the number of decelerations justifies its further technical development.
BJOG An International Journal of Obstetrics & Gynaecology 10/2000; 107(9):1130-7. · 3.41 Impact Factor
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ABSTRACT: Out-patient endometrial sampling is a commonly performed procedure in the investigation of post-menopausal bleeding. We hypothesized that an 'insufficient' Pipelle sample reliably reflected the absence of serious endometrial pathology.
A review of 141 consecutive cases reported as 'insufficient' for diagnostic purposes revealed 29 (20%) cases to have uterine pathology after secondary investigation. These included two cases of endometrial carcinoma and two other cases of uterine malignancy.
These results do not support the initial hypothesis and suggest that in women presenting with post-menopausal bleeding, an 'insufficient' sample is an indication for further investigation.
Acta Obstetricia Et Gynecologica Scandinavica 11/1999; 78(9):810-2. · 1.77 Impact Factor
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ABSTRACT: To evaluate the diagnostic prediction of intrapartum umbilical artery Doppler velocimetry for adverse perinatal outcomes using systematic quantitative overview of the available literature.
Online searching of MEDLINE database (January 1966-September 1997), scanning of bibliography of known primary and review articles, review of recent journal issues and that from personal files. Study selection, assessment of study quality and data extraction were all performed in duplicate under masked conditions.
2700 women (unselected, low, high, and combined low and high obstetric risk populations) included in eight studies selected for meta-analyses.
Likelihood ratios (LRs) for positive and negative test results were generated for the following outcome measures: Apgar scores < 7 at 1 and 5 minute following delivery, small for gestational age fetus; intrapartum fetal heart rate abnormality, umbilical arterial acidosis at delivery; and caesarean section for fetal distress.
For Apgar score < 7 at 1 minute following delivery, the pooled LR was 2.5 (95% CI 1.7-3.7) for a positive test and 1.0 (95% CI 0.9-1.1) for a negative test result. A positive test predicted an Apgar score < 7 at 5 minute following delivery with a pooled LR of 1.3 (95% CI 0.4-4.1) while a negative test had a pooled LR of 1.0 (95% CI 0.8-1.2). For the prediction of a small for gestational age fetus, the pooled LR was 3.4 (95% CI 2.3-5.1) for a positive test and 0.9 (95% CI 0.8-1.0) for a negative test. The prediction for fetal heart rate abnormality during labour was similarly disappointing: the pooled LR for a positive test result was 1.4 (95% CI 0.9-1.2) whereas a negative test result generated a pooled LR of 0.9 (95% CI 0.9-1.0). With umbilical acidosis at delivery, the pooled LR was 1.6 (95% CI 1.1-2.5) for a positive test and 1.1 (95% CI 1.0-1.2) for a negative test. The LRs for the prediction of caesarean section for fetal distress were 4.1 (95% CI 2.7-6.2) for a positive test result and 0.9 (95% CI 0.8-1.0) for a negative test result.
Intrapartum umbilical artery Doppler velocimetry is a poor predictor of adverse perinatal outcomes.
British Journal of Obstetrics and Gynaecology 09/1999; 106(8):783-92.
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ABSTRACT: This study evaluates the ability of two reviewers to detect independently an early diastolic notch in 1371 uterine artery Doppler velocity waveform recordings. Agreement between the two reviewers for the detection of uterine artery notching was assessed by using the Kappa statistic. The inter-rater reliability for the detection of unilateral notching was 0.75 (95% CI 0.70-0.80), whereas that for the presence or absence of bilateral notching was 0.66 (95% CI 0.60-0.71). The results suggest that there was good reviewer agreement for the presence or absence of a notch on uterine artery Doppler velocimetry.
British Journal of Obstetrics and Gynaecology 01/1999; 105(12):1308-11.
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ABSTRACT: Fetal movements were quantified in 182 low-risk women in early labour using the Hewlett-Packard M1350A (Boblingen, Germany) fetal heart rate monitor. There were no statistically significant differences in adverse intrapartum or neonatal outcomes detected by the fetal heart rate pattern or fetal movement profile. This study confirms the feasibility of obtaining, a measure of fetal movement in early labour but does not support its use as an admission test in low-risk pregnancies.
Clinical and experimental obstetrics & gynecology 02/1998; 25(1-2):23-5. · 0.43 Impact Factor
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ABSTRACT: This study was designed to evaluate the use of the biophysical profile and umbilical arterial Doppler in early labour in identifying the potentially compromised fetus. Two hundred and forty-two women attending the labour suite in early labour were studied. One hundred and fifty-one were in spontaneous labour and the remaining 91 had labour induced. All women had intrapartum biophysical profile assessment and umbilical arterial Doppler performed. Umbilical arterial Doppler and fetal movements were variously identified as being independently and significantly associated with adverse perinatal outcomes. Positive predictive values for adverse outcomes were however poor. Umbilical arterial Doppler used individually or in combination with clinical risk, gave no advantage over the use of clinically assigned risk alone in identifying fetuses at risk of subsequent adverse outcome. The assignment of clinical risk on admission in labour remains the most predictive 'test' for identifying the fetus at risk of subsequent adverse outcome. The routine addition of intrapartum biophysical parameters and umbilical arterial Doppler as methods of assessment is not justified.
Journal of Obstetrics and Gynaecology 09/1997; 17(5):452-6. · 0.54 Impact Factor
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ABSTRACT: To evaluate and compare third trimester ultrasound measurements of fetal size and growth velocity in the prediction of intrapartum operative delivery for fetal distress and admission to the special care baby unit in a low risk antenatal population undergoing labour at term.
Retrospective analysis of prospectively collected ultrasound data.
Ninewells Hospital, Dundee, Scotland.
Three hundred and ninety-eight women previously enrolled in a longitudinal study of intrauterine volume undergoing labour at a gestational age of > 37 weeks.
Fetal abdominal area (FAA) standard deviation scores (Z scores) were calculated for size at 32 and 36 weeks of gestation together with the growth velocity Z scores between these two gestational ages. Receiver-operator characteristics were calculated for fetal abdominal area Z scores at 32, 36 weeks and velocity Z scores in the prediction of caesarean section for fetal distress and/or admission to the special care baby unit.
Intrapartum caesarean section for fetal distress and admission to the special care baby unit with a diagnosis of perinatal hypoxia.
Pregnancies ending in caesarean section for fetal distress or admission to the special care baby unit (n = 17) had significantly lower fetal abdominal area Z scores at 36 weeks of gestation (mean Z score -0.71 vs -0.18) and lower fetal abdominal area growth velocity (mean Z score - 1.31 vs -0.01). Taking a cutoff Z score of -1.2 derived from the receiver-operator characteristic curve, fetal abdominal area velocity has a sensitivity of 65% and specificity 75% for caesarean section for fetal distress and/or admission to the special care baby unit.
Growth velocity of the fetal abdominal area in the third trimester is superior to a single measurement of the fetal abdominal area at either a mean of 32 or 36 weeks of gestation in the prediction of caesarean section for fetal distress and admission to the special care baby unit in low-risk women labouring at term. These results support the hypothesis that in the third trimester at least, growth rate in utero is more relevant to intrapartum performance and immediate perinatal outcome than estimates of fetal size alone.
British Journal of Obstetrics and Gynaecology 04/1997; 104(4):445-9.
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British Journal of Obstetrics and Gynaecology 10/1996; 103(9):926-8.
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ABSTRACT: Our goal was to test the hypothesis that the addition of fetal electrocardiogram time-interval analysis to conventional electronic fetal monitoring would significantly reduce the number of cases requiring fetal scalp blood sampling without an increase in adverse outcome.
A randomized prospective trial was performed in 214 women with high-risk labor.
There was a significant reduction in the number of cases that had fetal blood sampling performed in the fetal electrocardiogram plus electronic fetal monitoring group (risk ratio for electronic fetal monitoring alone 3.53; p < 0.01, 95% confidence interval 1.39 to 8.95). The fetal blood samplings performed in the electronic fetal monitoring alone group were less likely to be abnormal (pH < 7.25, base excess < -8.0) than those performed in the fetal electrocardiogram plus electronic fetal monitoring group (risk ratio for electronic fetal monitoring alone 0.62, p = 0.05, 95% confidence interval 0.35 to 1.10). There was a trend of more infants with an arterial umbilical pH < 7.15 and a base excess less than -8.0 mmol/L at birth being unsuspected and more instrumental deliveries for presumed fetal distress being performed in the electronic fetal monitoring alone than in the fetal electrocardiogram plus electronic fetal monitoring group.
The addition of fetal electrocardiogram analysis to conventional electronic fetal monitoring during labor can reduce significantly the number of parturients undergoing fetal scalp blood sampling and can simultaneously increase its efficiency without an increase in adverse outcome.
American Journal of Obstetrics and Gynecology 05/1996; 174(4):1295-9. · 3.47 Impact Factor
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ABSTRACT: Fetal movements were quantified prior to and after administration of intramuscular Diamorphine in thirteen labouring women. A significant reduction in the number of fetal heart rate accelerations was observed following Diamorphine. Thirty minutes after Diamorphine, all fetal movement parameters had returned to pre-Diamorphine values. If fetal movement detection is to be incorporated into an assessment of intrapartum fetal well being, the transient influence of narcotic analgesia must be allowed for.
Clinical and experimental obstetrics & gynecology 02/1996; 23(3):144-6. · 0.43 Impact Factor
