It can be done before birth via chorionic-villus sampling or amniocentesis.

它可以前通过绒毛膜-绒毛取膜穿刺术完成。

This can also be done prenatally by testing fetal DNA obtained through either chorionic villus sampling or amniocentesis.

可以产前通过检测胎儿DNA完成，如绒毛膜绒毛取膜穿刺术。

A karyotype can be done before birth with an amniocentesis or at any time after birth with the blood test.

核型分析前就可以用膜穿刺术取后采血取。

In more serious cases, amniocentesis, where a sample is taken directly from the amniotic sac surrounding the fetus, can be performed.

严重的情况下，需行膜穿刺术，即直接从胎儿周围的膜囊穿刺取检查。