Which one of the following congenital malformation of the fetus can be diagnosed in first trimester by ultrasound?

Ans. is a, i.e. AnencephalyRef. Williams Obs. 21/e, p 1120; USG in Obs. and Gynae by Callen 4/e, p 284, Fernando Arias 3/e, p 64. 66, 69As discussed in the chapter, anencephaly can be diagnosed as early as 10 weeks/first trimester in experienced hards.Ref. USG in Obs and Gynae Callen 4/e, p 298, 299MicrocephalyIt is decreased head size.In these patients both brain mass and total cell number are reduced.There is disproportion in size between the skull and face.It is difficult to recognize this anomaly by ultrasound - A head circumference below 2 SD from the mean is used as a diagnostic criteria in midtrimester scan.Holoprosencephaly is the presence of a single centrally placed cerebral ventricle and may be associated with midline abnormalities of the face.With the use of vaginal probe it can be recognised in the beginning of midtrimester.Also Know: Encephalocele can also be recognised in first trimester and is seen as a bony defect with protrusion of Wm the brain tissue and meninges. Occipital encephaloceles are commonest. A genetic association of encephalocele and polycystic kidney and is called Meckel-Gruber syndrome, which is an autosomal recessive disorder.