الفهرس 
Twin pregnancyOnly 14 pages are availabe for public view
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Abstract
Routine dating of pregnancy from a first-trimester crown rump length (CRL)is superior to the use of menstrual dates (1-2). Most countries now recommend routine ultra-sound dating of pregnancy (3, 4).There are several formulae available for calculating the gestational age from the CRL (5). The use of various CRL formulae introduces systematic differences,which are usually of limited clinical significance in the dating of singleton pregnancies (6).The particular formula chosen for routine use in many settings is often decided on the basis of consensus, rather than evidence of accuracy or reproducibility (7).Twin pregnancies are at increased risk of perinatal morbidity and mortality,compared with singletons, mainly as a consequence of both preterm delivery and fetal growth restriction. Accurate dating of twin pregnancies is therefore vital, but there are two particular areas of concern when trying to achieve this. Firstly, there has been no systematic evaluation of whether CRL charts derived from singleton pregnancies can be used to accurately date twin pregnancies. Secondly, there is a lack of consensus about whether the pregnancy should be date on measurements taken from the larger twin, smaller twin or on the mean measurement of the twins(8-9 We do our work is to determine the accuracy of singleton CRL formulae in dating twin pregnancies.There were 100 pregnancies seen during the study period that had undergone first trimester ultrasound assessment between 11 and 14 weeks of gestation These pregnancies comprised 75 singleton and 25 dichorionic diamniotic twins.Regarding the accuracy of ultrasound parameters in the first trimester to date the pregnancy, GA has 76% sensitivity, 75% specificity, 78% PPV and 72% NPV and accuracy of 75 while the CRL has 71% sensitivity, 75% specificity, 77% PPV and 70% NPV and accuracy of 73. Based on the result of our study we conclude that CRL is agood diagnostic parameter in assessment of gestional age of twin pregnancy There was no significant difference between twin and singleton pregnancies by measurement of CRL,therefore singleton CRL charts can be used to date twin pregnancies accurately