家里没有唐氏症史的话，我建议你不要做，没什么必要。而且并不是每个孕妇的胎盘都适合做的。如果不适合硬要做的话，可能有流产的危险。
jiālǐ méiyǒu tángshìzhèng shǐ dehuà ，wǒ jiànyì nǐ bùyào zuò ，méi shénme bìyào 。érqiě bìng bù shì měige yùnfù de tāipán dōu shìhé zuò de 。rúguǒ bù shìhé yìng yào zuò dehuà ，kěnéng yǒu liúchǎn de wēixiǎn 。
If there's no history of Down's syndrome in your family, I'd suggest that you not do it. There's no need. And not every pregnant woman's placenta is suitable. If you're not suitable, but you insist on doing it, there's some risk of a miscarriage.