Patrick F. W. Chien

How useful is uterine artery Doppler flow velocimetry in the prediction of pre-eclampsia, intrauterine growth retardation and perinatal death? An overview.

Objective To evaluate the clinical usefulness of Doppler analysis of the uterine artery velocity waveform in the prediction of pre‐eclampsia and its associated complications of intrauterine growth retardation and perinatal death.

Ultrasonographic endometrial thickness for diagnosing endometrial pathology in women with postmenopausal bleeding: a meta-analysis

Our aim was to determine the diagnostic accuracy of endometrial thickness measurement by pelvic ultrasonography for predicting endometrial carcinoma and disease (hyperplasia and/or carcinoma) during an investigation of postmenopausal bleeding. We performed a systematic quantitative review of the available published literature, which consisted of online searching the MEDLINE and EMBASE databases (1966–2000) coupled with scanning of bibliography of known primary and review articles. The selection of studies, assessment of study quality, and extraction of data were performed in duplicate under masked conditions. Included in the analyses were 57 studies with 9031 patients . Accuracy data were summarized using likelihood ratios for various cut‐off levels of abnormal endometrial thickness. The commonest cut‐offs were 4 mm (9 studies) and 5 mm (21 studies), measuring both endometrial layers. None of the nine studies using the ≤ 4 mm cut‐off level were of good quality. Only four studies (out of the 21) used the ≤ 5 mm cut‐off level, which employed the best‐quality criteria. Using the pooled estimates from these four studies only, a positive test result raised the probability of carcinoma from 14.0% (95% CI 13.3–14.7) to 31.3% (95% CI 26.1–36.3), while a negative test reduced it to 2.5% (95% CI 0.9–6.4). In conclusion, ultrasound measurement of endometrial thickness alone, using the best‐quality studies cannot be used to accurately rule. However, a negative result at ≤ 5 mm cut‐off level measuring both endometrial layers in the presence of endometrial pathology rules out endometrial pathology with good certainty.

Validity of ultrasound estimation of fetal weight.

Objective To assess the validity of ultrasound estimation of fetal weight at term. Methods We conducted a prospective observational study whereby all ultrasonic biometric measurements were done by a single observer. Fifty pregnant women at term had ultrasonic measurement of various fetal biometric parameters performed within a week of delivery. Fetal weight was estimated by the use of four reported methods (Aoki, Campbell, Shepard, and Hadlock formulas). We compared estimated weight with the birth weight after the estimated fetal weight was adjusted by adding 25 g for each day between the ultrasound measurements and delivery. Results The adjusted estimated fetal weight obtained from all four formulas tended to be lower than measured birth weight. The smallest mean difference was obtained with the Shepard and Aoki formulas (51.4 g and 60.5 g, respectively), whereas the Campbell and Hadlock formulas produced larger mean differences (141.8 g and 190.7 g, respectively). The Aoki formula generated the smallest range between the limits of agreement (−324.2 to 445.2 g) whereas the Campbell formula produced the largest range (−286.5 to 570.1 g). The range between the limits of agreement generated with the Shepard and Hadlock formulas were intermediate between those produced by the Aoki and Campbell formulas. The intraclass correlation coefficients generated with the Aoki and Shepard formulas were identical (0.90). The intraclass correlation coefficients obtained with the Hadlock (0.84) and Campbell formulas (0.85) were lower. Conclusion The validity of ultrasonic estimation of fetal weight at term with all four formulas was high.

Pre-eclampsia and the later development of type 2 diabetes in mothers and their children: an intergenerational study from the Walker cohort.

Aims/hypothesisStudies have shown a relationship between pre-eclampsia and later coronary artery disease. This study investigated whether there is a relationship between pre-eclampsia and the development of type 2 diabetes in mothers and their babies and how this is affected by infant birthweight.Subjects and methodsThis was an intergenerational cohort study. The study population comprised 7,187 mothers who gave birth and 8,648 babies who were born in Dundee, Scotland between 1952 and 1958. Their later diabetic status was defined from 1980 to 2003 by linkage to population-based datasets.ResultsThere were 810 (11.3%) mothers with pre-eclampsia and 745 (10.4%) who subsequently developed type 2 diabetes. Logistic regression showed an increased risk of developing type 2 diabetes for mothers with pre-eclampsia, unadjusted odds ratio (OR) 1.37 (95% CI 1.10–1.71), p = 0.005. This relationship persisted after adjustment for infant birthweight, OR 1.40 (95% CI 1.12–1.75), p = 0.003. Of the babies born between 1952 and 1958, 221 (2.6%) had developed type 2 diabetes, 137 of them male (2.9% of male subjects in study population) and 84 female (2.2% of female subjects). The relationship between pre-eclampsia in the mother and the risk of type 2 diabetes in the offspring did not reach statistical significance, OR 1.38 (95% CI 0.90–2.10). Babies with birthweight in the lowest quintile (adjusted for sex, gestation and birth order) had an increased risk of developing type 2 diabetes, OR for lowest quintile vs highest quintile 1.84 (95% CI 1.24–2.72), p = 0.002.Conclusions/interpretationPre-eclampsia is associated with increased risk of developing type 2 diabetes in the mother, but birthweight is a more important determinant of future risk for the offspring.

Magnesium sulphate in the treatment of eclampsia and pre‐eclampsia: an overview of the evidence from randomised trials

Objective To evaluate the effectiveness of magnesium sulphate in the treatment of eclampsia and pre‐eclampsia by a systematic quantitative overview of controlled clinical trials.

Evaluation of a clinical test. II: Assessment of validity.

Part one of this commentary dealt with the reliability of a clinical test; Part Two deals with the validity of a clinical test. Validity assesses whether the test is actually measuring what it is purporting to measure. In order to measure validity, the measurements obtained from the test under study are compared with those obtained from a recognised reference standard. There are three types of validity: content, criterion and construct validity. However, we will consider only criterion validity, which is more relevant to the evaluation of clinical tests. Content and construct validity are important in psychometric tests and quality of life measurements. It is important to note that reliability and validity are closely related, for a test which is unreliable cannot be valid. Validation involves comparing measurements obtained simultaneously, using the test under study and the reference test. One dif®culty with studies of validity is that the units of measurement may be different between the test under study and the reference standard. Examples are shown in Table 1. The measurements of bladder volume by both ultrasound and bladder catheterisation are on same scales (continuous) and their units of measurement (ml) are also identical. The comparison between pictorial menstrual blood loss and objective menstrual blood loss measurements using the alkaline haematin method have different scales: the pictorial menstrual blood loss method is in a scale of ordered categories; the alkaline haematin method is in a continuous scale. In the fetal ®bronectin test, preterm delivery can be considered the reference standard and cervical fetal ®bronectin is the test under scrutiny. Fetal ®bronectin is measured on a continuous scale, but this is converted to a dichotomous scale using an optimum cutoff value to predict for preterm delivery. This optimum cutoff value is determined by a receiver±operator characteristic curve.

The reliability and validity of three dimensional ultrasound volumetric measurements using an in vitro balloon and in vivo uterine model

Objective To evaluate the reliability and validity of two and three dimensional ultrasound volumetric measurements using balloon and uterine models.

Logistic regression models in obstetrics and gynecology literature.

OBJECTIVE To evaluate the reporting of multivariable logistic regression analyses and assess variations in quality over time in the obstetrics and gynecology literature. METHODS Methodologic criteria for reporting logistic regression analyses were developed to identify problems affecting accuracy, precision, and interpretation of this approach to multivariable statistical analysis. These criteria were applied to 193 articles that reported multivariable logistic regression in the issues of four generic obstetrics and gynecology journals in 1985, 1990, and 1995. Rates of compliance with the methodologic criteria and their time trends were analyzed. RESULTS The proportion of articles using logistic regression analysis increased over time: 1.7% in 1985, 2.8% in 1990, and 6.5% in 1995 (P < .001 for trend). Violations and omissions of methodologic criteria for reporting logistic models were common. The research question, in terms of dependent and independent variables, was not clearly reported in 32.1%. The process of variable selection was inadequately described in 51.8% of the articles. Among articles with ranked independent variables, 85.1% did not report assessment of conformity to linear gradient. Tests for goodness of fit were not given in 93.2% of articles. The contribution of the independent variables could not be evaluated in 36.2% of the articles because of a lack of coding of the variables. Interactions between variables were not assessed in 86.4% of articles. Analysis of variations in the quality of logistic regression analyses over time showed no increase in reporting of the criteria concerning variable selection and goodness of fit. However, the proportion of articles reporting one quality criterion concerning interpretation of the substantive significance of independent variables showed a trend toward improvement: 42.3% in 1985, 73.6% in 1990, and 75.4% in 1995 (P = .004 for trend). CONCLUSION The reporting of multivariable logistic regression models in the obstetrics and gynecology literature is poor, and the time trends of improvement in quality of reporting are not particularly encouraging.

The diagnostic accuracy of cervico‐vaginal fetal fibronectin in predicting preterm delivery: an overviev

Objective To determine the accuracy with which cervico‐vaginal fetal fibronectin predicts preterm delivery using systematic quantitative overview of the available literature.

Risk of hysterectomy after 1000 consecutive endometrial laser ablations

Objectives To determine the hysterectomy rate after endometrial laser ablation, allowing for variable follow up times, and to evaluate the factors that might predict outcome.