4Ko TM, Tseng LH, Hsu PM et al. Ultrasonography scanning of placen- tal thickness and the prenatal diagnosis of homozygous alpha thalassaemia in the second trimester [J] . Prenatal Diagnosis, 1995, 15:7 -10.
7Leibovitch L,Kuint J,Rosenfeld E,et al.Short-term outcome among term singleton infants with intrapartum oligohydramnios[J].Acta Paediatr,2012,101(7):727-730.
8Kodandapani S,Shreshta A,Ramkumar V,et al.Chorioangioma of placenta:a rare placental cause for adverse fetal outcome[J].Case Rep Obstet Gynecol,2012,2(2012):913878.
9Cao A, Galanclo R, Rosatelli MC. Prenatal diagnosis and screening of the haemoglobinopathies [ J ]. Baillleres Clin Haematol, 1998, 11 (1): 215-238.
10Yong KN, Wadsworth D, Langlois S, et al. Thalaascmia carrier screening and prenatal diagnosis among the British Co- lumbia (Canada) population of Chinese descent [ J ]. Clin Genet, 1999, 55 (1): 20-25.