Journal/Magazine Articles
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This collection contains original research articles, review articles and case reports published in local and international peer reviewed journals by the staff members of the Faculty of Medicine
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Item Ultrasound estimation of birthweight in twin pregnancy: comparison of biometry algorithms in the STORK multiple pregnancy cohort.(Wiley, 2014) Khalil, A.; D'Antonio, F.; Dias, T.; Cooper, D.; Thilaganathan, B.; Southwest Thames Obstetric Research Collaborative (STORK)OBJECTIVES: The aims of this study were first, to ascertain the accuracy of formulae for ultrasonographic birth-weight estimation in twin compared with singleton pregnancies and second, to assess the accuracy of sonographic examination in the prediction of birth-weight discordance in twinpregnancies. METHODS: This was a retrospective cohort study including both singleton and twin pregnancies. Routine biometry was recorded and estimated fetalweight (EFW) calculated using 33 different formulae. Only pregnancies that delivered within 48 h of the ultrasound scan were included (4280 singleton and 586 twin fetuses). Differences between the EFW and actual birth weight (ABW) were assessed by percentage error, accuracy in predictions within ± 10 % and ± 15% of error and use of the Bland-Altman method. The accuracy of prediction of the different cut-offs of birth-weight discordance intwin pregnancies was also assessed using the area under the receiver-operating characteristics curve (AUC). RESULTS: The overall mean absolute percentage error was ≤ 10 % for 25 formulae in singleton pregnancies compared with three formulae in twinpregnancies. The overall predictions within ± 10% and ± 15% of the ABW were 62.2% and 81.5% in singleton and 49.7% and 68.5% in twinpregnancies, respectively. When the formulae were categorized according to the biometric parameters included, those based on a combination of head, abdomen and femur measurements showed the lowest mean absolute percentage error, in both singleton and twin pregnancies. The predictive accuracy for 25% birth-weight discordance using the Hadlock 2 formula, as assessed by the AUC, was 0.87. CONCLUSIONS: Ultrasound estimation of birth weight is less accurate in twin than in singleton pregnancies. Formulae that include a combination of head, abdomen and femur measurements perform best in both singleton and twin pregnancies.Item Ultrasound diagnosis of fetal renal abnormalities(Elsevier, 2014) Dias, T.; Sairam, S.; Kumarasiri, S.Development of the urogenital system in humans is a complex process; consequently, renal anomalies are among the most common congenital anomalies. The fetal urinary tract can be visualised ultrasonically from 11 weeks onwards, allowing recognition of megacystis at 11-14 weeks, which warrants comprehensive risk assessment of possible underlying chromosomal aneuploidy or obstructive uropathy. A mid-trimester anomaly scan enables detection of most renal anomalies with higher sensitivity. Bilateral renal agenesis can be confirmed ultrasonically, with empty renal fossae and absent bladder filling, along with severe oligohydramnios or anhydramnios. Dysplastic kidneys are recognised as they appear large, hyperechoic, and with or without cystic spaces, which occurs within the renal cortex. Presence of dilated ureters without obvious dilatation of the collecting system needs careful examination of the upper urinary tract to exclude duplex kidney system. Sonographically, it is also possible to differentiate between infantile type and adult type of polycystic kidney diseases, which are usually single gene disorders. Upper urinary tract dilatation is one of the most common abnormalities diagnosed prenatally. It is usually caused by transient urine flow impairment at the level of the pelvi-ureteric junction and vesico-ureteric junction, which improves with time in most cases. Fetal lower urinary tract obstruction is mainly caused by posterior urethral valves and urethral atresia. Thick bladder walls and a dilated posterior urethra (keyhole sign) are suggestive of posterior urethral valves. Prenatal ultrasounds cannot be used confidently to assess renal function. Liquor volume and echogenicity of renal parenchyma, however, can be used as a guide to indirectly assess the underlying renal reserve. Renal tract anomalies may be isolated but can also be associated with other congenital anomalies. Therefore, a thorough examination of the other systems is mandatory to exclude possible genetic disordersItem Risk of stillbirth at term and optimum timing of delivery in uncomplicated south Asian singleton pregnancies(Sri Lanka Medical Association, 2014) Dias, T.; Kumarasiri, S.; Wanigasekara, R.; Cooper, D.; Batuwitage, C.; Jayasinghe, L.; Padeniya, T.OBJECTIVES: Aims of this study were to compare the perinatal mortality rate and the prospective risk of stillbirth for each given gestational age and to ascertain whether it is safe to continue the pregnancy beyond 40 weeks of gestational age and induce labour at 41 weeks in low risk singleton pregnancies. METHODS: This was a retrospective study. The perinatal mortality and prospective risk were calculated per 1000 total births and 1000 on going pregnancies respectively in well dated singleton pregnancies. 38+0 to 39+6 gestational age was taken as the reference. RESULTS: A total of 12,595 deliveries after 28 weeks of gestation were included. The risk of stillbirth at 38+0 to 39+6 weeks was 1.43 (95% CI, 0.9 to 2.4) per 1000 on going pregnancies. The perinatal mortality rate at 38+0 to 39+6 weeks was 2.9 (95% CI, 1.9 to 4.5) per 1000 total births. The perinatal mortality rate decreased throughout gestation and it was lowest at 40+0 - 41+6. In contrast, risk of stillbirth increased with advancing gestation and peaked at 40+0 - 41+6 (2.57, 95% CI, 1.4 to 4.7). However, risk of stillbirth at 40+0 - 41+6 was not statistically different from 38+0 to 39+6 (OR 1.79, 95% CI, 0.80 to 3.98). To prevent one stillbirth, 886 pregnancies should be induced at 38+0 to 39+6. CONCLUSIONS: Risk of stillbirth is more informative than perinatal mortality at term. Frequent antenatal fetal surveillance should be adopted towardsterm in order to identify high risk pregnancies. Elective delivery before 40 weeks in low risk pregnancies is not justifiedItem Timing of birth in multiple pregnancy(Elsevier, 2014) Dias, T.; Akoleka, R.Timing of delivery of twins should be decided when the benefit of prolonging the pregnancy outweighs the risk of stillbirth. Perinatal mortality of singletons is increased significantly after 42 weeks, whereas perinatal mortality in twins starts to increase significantly after 37 weeks. Recent, large cohort studies have showed significantly higher stillbirth rates near term even in apparently low-risk monochorionic twin pregnancies. Stillbirth risk in monochorionic twins is three-fold higher than in dichorionic twins, and this risk remains high throughout the pregnancy. In uncomplicated monochorionic twins between 32 and 37 weeks, no statistically significant increase of stillbirth occurs between 32 and 37 weeks; these pregnancies are usually monitored until delivery at 37 weeks. The risk of stillbirth in dichorionic twins does not seem to be different between 28 and 38 weeks, justifying a differential policy for the timing of delivery in monochorionic compared with dichorionic twin pregnancies. Therefore, uncomplicated dichorionic twins should be managed expectantly, and delivery can be arranged from 38 weeks. In cases of discordant fetal wellbeing at preterm gestations, timing of delivery should be based mainly on parameters and outlook for the healthy twin balanced against the condition of the compromised fetus. The threshold for early delivery may be lower in monochorionic twins because of the high mortality and morbidity in surviving twins with co-twin deathItem Weight discordance and perinatal mortality in twins: analysis of the Southwest Thames Obstetric Research Collaborative (STORK) multiple pregnancy cohort(Wiley, 2013) D'Antonio, F.; Khalil, A.; Dias, T.; Thilaganathan, B.; Southwest Thames Obstetric Research Collaborative (STORK)OBJECTIVES: The degree of actual intertwin birth weight (BW) or ultrasound estimated fetal weight (EFW) discordance that justifies elective delivery is yet to be established. The main aim of this study was to ascertain the performance of BW and ultrasound EFW discordance in the prediction ofperinatal loss in twin pregnancies. METHODS: This was a retrospective study of all twin pregnancy births from a large regional cohort of nine hospitals over a 10-year period. Intertwin BW and ultrasound EFW discordance were analyzed in relation to the occurrence of stillbirth or neonatal death of one or both twins from 26 weeks' gestation as obtained from a mandatory national register. Receiver-operating characteristics (ROC), survival and logistic regression analyses were performed to evaluate the contribution of weight discordance in determining perinatal loss. RESULTS: A total of 2161 twin pregnancies were included in the analysis. The area under the ROC curve for the prediction of perinatal loss was similar for BW and ultrasound EFW discordance (P = 0.62). Kaplan-Meier analysis showed that twins with BW or EFW of ≥ 25% discordance had a significantly lower survival trend than did those with lesser degrees of discordance (P < 0.001). The hazard ratios for the risk of total perinatal loss intwins with a BW or EFW discordance of ≥ 25% were 7.29 (95% CI, 4.37-12.00) and 7.28 (95% CI, 4.46-11.92), respectively. Logistic regression analysis demonstrated that BW discordance and gestational age, but not chorionicity or individual fetal size percentile, were independently associated with perinatal mortality. CONCLUSIONS: An EFW discordance of ≥ 25% represents the optimal cut-off for the prediction of stillbirth and neonatal mortality irrespective of chorionicity or individual fetal size. A policy of increased fetal surveillance commencing from 26 weeks' gestation might be reasonable for pregnancies beyond this cut-off, but this would require confirmation in large-scale prospective trials. Copyright © 2013 ISUOG. Published by John Wiley & Sons LtdItem Does antenatal ultrasound labeling predict birth order in twin pregnancies?(Wiley, 2013) D'Antonio, F.; Dias, T.; Thilaganathan, B.; Southwest Thames Obstetric Research Collaborative (STORK)OBJECTIVE: It is often assumed by obstetricians, neonatologists and parents that the prenatal nomenclature used to identify twins on ultrasound is consistent with twin labeling after their birth. The aim of this study was to use a large regional database of twin ultrasound scans to validate the effectiveness of a scan before delivery in predicting twin birth-order. METHODS: A large regional database of twin ultrasound scans with data from nine hospitals over a 10-year period was used to identify all ultrasound examinations carried out just before birth. The discordance in twin order between the last scan and birth was evaluated by observing discrepancies in fetal sex and weight. RESULTS: In total, 2103 twin pregnancies with ultrasound estimated fetal weights (EFWs) and birth weights were assessed. Of these, fetal sex was recorded in 149 different-sex pregnancies. Discrepancy between antenatal labeling and the anticipated birth order was noted in 37.6% (56/149) of cases when judged by sex discordance and in 36% (757/2103) of cases when judged by weight discordance. Multiple logistic regression analyses demonstrated that weight discordance, but not chorionicity, scan-to-delivery interval, gestation at scan or gestation at delivery, significantly influenced the change in birth order (P < 0.001). CONCLUSION: Antenatal ultrasound labeling does not predict twin birth-order in a significant proportion of twin deliveries. This finding should be borne in mind not only by parents, but also by physicians when delivering twins discordant for anomalies that are not evident on external examinationItem Sri Lankan fetal birthweight charts:validation of global reference for fetal weight and birthweight percentiles(Sri Lanka Medical Association, 2013) Shanmugaraja, Y.; Kumarasiri, S. G.; Wahalawatte, S. L.; Wanigasekara, R. V.; Begam, P.; Jayasinghe, P. K.; Padeniya, T.; Dias, T.INTRODUCTION: Small for gestational age (SGA) is defined as birthweight below the tenth centile at a particular gestational week. Birthweight centiles for different populations are varied. Generic reference for fetal weight and birthweight that could be adapted to local populations was recently described. The purpose of this study was to validate the reference for birthweights adapted to the local population. METHODS: This was a prospective validation study done between January 2012 and July 2012 in well dated pregnancies at General Hospital, Ampara. Observed frequencies of birthweights of 5th, 10th, 50th, 90th and 95th percentiles for Hadlock formula, World Health Organization (WHO)global survey data for Sri Lanka and India were calculated. The expected frequencies for each birthweight centile of our study were compared with observed frequencies. RESULTS: A total of 411 patients were recruited and 207 delivered at 40 weeks (40+0-40+6). The mean birth-weight (SD) at 40 weeks of gestation was 3140g (432g). Hadlock formula and WHO reference data for India overestimate and underestimate most of the birthweights respectively. WHO generic reference adapted to Sri Lanka fitted well with our data. The mean birthweight of our population is similar, and the adapted reference range would identify most of the small fetuses correctly. It would also identify almost all the babies with weight above the 90th centile. CONCLUSIONS: The findings of the study show that the observed distribution of birthweight fitted well with the reference range derived from the WHO global reference range adapted to Sri Lankan population. WHO reference charts can be used effectively in Sri Lankan populationItem Early fetal loss in monochorionic and dichorionic twin pregnancies: analysis of the Southwest Thames Obstetric Research Collaborative (STORK) multiple pregnancy cohort(Wiley, 2013) D'Antonio, F.; Khalil, A.; Dias, T.; Thilaganathan, B.; Southwest Thames Obstetric Research Collaborative (STORK)OBJECTIVES: Monochorionic (MC) twins are at increased risk of early fetal loss secondary to vascular complications such as twin-twin transfusion syndrome (TTTS). This study compared the early perinatal loss rates between MC and dichorionic (DC) twins in an era of invasive treatment for TTTS. METHODS: This was a retrospective study of all twin pregnancies of known chorionicity from a large regional cohort of nine hospitals over a 10-year period. Ultrasound data were matched to hospital delivery records and to a mandatory national register of pregnancy losses. Prospective risk of pregnancy loss from 14 to 24 weeks' gestation was calculated and the survival trend of MC and DC twins was analyzed using Kaplan-Meier survival analysis. RESULTS: The analysis included 3117 twin pregnancies (605 MC and 2512 DC). The total risk of early pregnancy loss (miscarriage and neonatal death) before 24 weeks was significantly higher in MC twins (60.3 per 1000 fetuses) than in DC twins (6.6 per 1000 fetuses), with a relative risk of 9.18 (95% CI, 6.0-13.9). Survival analysis showed a significant difference in overall and early mortality between MC and DC twins (log-rank test, P < 0.0001), while no difference was noted after 24 weeks' gestation (log-rank test, P = 0.08). CONCLUSIONS: Early pregnancy loss is significantly more common in MC than in DC twins, but no difference in the prospective risk of mortality between MC and DC twins is evident after 24 weeks' gestation. The observed early mortality rate has almost halved in comparison with previous studies in the published literature. Early detection and prompt treatment of complications in MC twins are likely to have contributed to this improvement in outcome. Copyright © 2012 ISUOG. Published by John Wiley & Sons Ltd.Item Crown-rump length discordance and adverse perinatal outcome in twins: analysis of the Southwest Thames Obstetric Research Collaborative (STORK) multiple pregnancy cohort.(Wiley, 2013) Dias, T.; Thilaganathan, B.OBJECTIVE: Evidence for the role of first-trimester ultrasound in predicting outcome in twin pregnancies is conflicting. The aim of this study was to determine the association between crown-rump length (CRL) discordance and adverse perinatal outcome in twin pregnancies. METHODS: This was a retrospective study of all twin pregnancies of known chorionicity from a large regional cohort over a 10-year period. Terminations of pregnancy, cases with fetal or chromosomal abnormalities and monoamniotic pregnancies were excluded. Receiver-operating characteristics (ROC) curve and logistic regression analyses were performed to evaluate the association between CRL discordance and stillbirth, neonatal mortality, intrauterine growth restriction, preterm birth (PTB) at < 34 weeks' gestation and birth weight (BW) and ultrasound estimated fetal weight (EFW) discordance of ≥ 25%. RESULTS: A total of 2155 twin pregnancies were analyzed, of which 420 were monochorionic (MC) and 1735 dichorionic (DC). There were 42 fetal losses before 24 weeks' gestation and 23 perinatal deaths. CRL discordance was poorly predictive for fetal loss at < 24 weeks (area under the ROC curve (AUC), 0.54 (95% CI, 0.46-0.62)), perinatal loss (AUC, 0.52 (95% CI, 0.41-0.64)), BW discordance (AUC, 0.61 (95% CI, 0.56-0.65)), BW < 5(th) centile (AUC, 0.56 (95% CI, 0.53-0.59)), EFW discordance (AUC, 0.55 (95% CI, 0.51-0.60)) and PTB at < 34 weeks (AUC, 0.50 (95% CI, 0.47-0.54)). Overall mortality was significantly higher in MC (5.0%) than in DC (2.6%) twins (P = 0.016). Logistic regression analysis demonstrated that chorionicity (odds ratio 2.09 (95% CI, 1.06-4.10); P = 0.033) independently contributed to determining mortality, while CRL discordance (P = 0.201) did not. Adjusting for chorionicity did not improve the detection of adverse outcomes using CRL discordance. CONCLUSION: In the absence of aneuploidy or structural fetal abnormality, CRL discordance is of poor predictive value for adverse perinatal outcome in both MC and DC twin pregnancies. CRL discordance should not be used routinely to identify twin pregnancies at high risk of adverse perinatal outcome. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.Item Preterm delivery: current concepts(Sri Lanka College of Obstetricians and Gynaecologists, 2013) Rameez, M.F.M.; Lankeshwara, D.; Dias, T.; Khatri, M.; Lohana, R.No Abstract Available
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