Patients with

• Advanced maternal age
• Previous child with mental retardation, developmental delay or with malformation
• Previous child with chromosomal abnormality like Down Syndrome
• Previous child with metabolic disorder like Phenylketonuria
• Previous child with haematological disorder like Sickle cell anemia and Thalassemia
• Previous child with Neural tube defect
• Pregnancy with BOH
• Prenatal exposure to teratogenic drugs and infection
• Prenatally — anomaly diagnosed on scan
• Women with metabolic disorder like Diabetes and Hypothyroidism
• Women with any chronic medical disorder
  Family history of chromosomal abnormality
• Family history of Single gene defects
• Family history of Neural tube defects
• Family history of any other congenital structural abnormalities
• Twin or Multiple gestation
• Previous History of Preterm Delivery