Maternal serum free α-human chorionic gonadotrophin levels in twin pregnancies: Implications for screening for Down's syndrome |
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Authors: | N J Wald J W Densem |
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Institution: | Department of Environmental and Preventive Medicine, Wolfson Institute of Preventive Medicine, St Bartholomew's Hospital Medical College, Charterhouse Square, London EC1M 6BQ, U.K. |
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Abstract: | Maternal serum free α-human chorionic gonadotrophin (free α-hCG) levels were determined in twin and singleton pregnancies at 15–22 weeks of gestation using a set of stored serum samples relating to 200 twin pregnancies and 600 singleton control pregnancies matched for gestational age and duration of storage. Free α-hCG values are, on average, 1·66 times greater in twin pregnancies than in singleton pregnancies (95 per cent confidence interval 1·56–1·76). If maternal serum free α-hCG is used in screening for Down's syndrome, values in twin pregnancies can be adjusted using this result so that screening can be performed in twin pregnancies as well as in singleton pregnancies. |
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Keywords: | Maternal serum screening Down's syndrome free α-hCG twin pregnancy |
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