Medicine
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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
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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 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 justified