A 29 yrs old woman with a pregnancy of 17 week has a 10 years old boy with down syndrome. She does not want another down syndrome kid; best advice to her is
No test is required now as her age is below 35 years
Ultra sound at this point of time will definitely tell her that next baby will be down syndromic or not
Amniotic fluid samples plus chromosomal analysis will definitely tell her that next baby will be down syndromic or not
blood screening at this point of time will clear the exact picture