How early can doctors do an amniocentesis?

14-15 weeks. Amnio carries procedure related risks including infection, amniotic fluid leak, vaginal bleeding and potential pregnancy loss. Amnio performed earlier than 14 weeks is associated with a significant increase in the complication rate and a significant increase in the risks of fetal limb defects. Amnio should not be performed less than 14 weeks; cvs can be performed for earlier genetic testing.
13 weeks. Amniocentesis can sometimes be performed as early as 13 weeks, but usually more common after 15 weeks. Alternatively nuchal cord ultrasound for down's syndrome can be performed between 9 and 12 weeks.