This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intra Uterine Growth Restriction, Intrapaum and Antepaum Fetal Surviellance, Subject name: Gynaecology & Obstetrics
Which one of the following congenital malformations of the fetus can be diagnosed in the first trimester by ultrasound? 
Select and explain. 
A. Anencephaly, B. Dysplastic kidneys, C. Microcephaly, D. Holoprosencephaly
A: Anencephaly
Answer: A: Anencephaly 
Explanation: Ultrasound done in the first trimester helps in dating the pregnancy. Malformations are best looked for at 18-20 weeks of gestation. If there is a malformation that is not ble with a normal life, then a decision to do a termination of pregnancy can be taken at this time ( In India: MTP only <= 20 weeks) However, in the first trimester, i.e., around 9-11 weeks, gross malformations of the fetus like anencephaly, Acrania or spina bifida can be picked up. To detect specific deformities like holoprosencephaly or microcephaly, USG is to be done at 18-20 weeks of gestation and not in the first trimester.