羊膜穿刺术、羊膜腔穿刺术或羊水测试是一种医学上的产前诊断，诊断的样本是取自于发育中的胎儿周围的羊水。这项诊断主要是针对胎儿的唐氏症、镰刀型红血球疾病(sickle-cell disease)、囊肿性纤维化(cystic fibrosis)等先天遗传疾病和单基因遗传疾病的基因分析，还有胎儿成熟度的鉴定、开放性神经管缺损和子宫内胎儿溶血的诊断。对于脊髓性肌肉萎缩症(SMA)、大脑白质退化症(Adrenoleukodystrophy, ALD)、小脑萎缩症、杭廷顿舞蹈症(Huntington's disease)检测的准确度可达95%。

Amniocentesis (also referred to as amniotic fluid test or AFT) is a medical procedure used in prenatal diagnosis of chromosomal abnormalities and fetal infections, and also used for sex determination in which a small amount of amniotic fluid, which contains fetal tissues, is sampled from the amniotic sac surrounding a developing fetus, and the fetal DNA is examined for genetic abnormalities. The most common reason to have an "amnio" is to determine whether a baby has certain genetic disorders or a chromosomal abnormality, such as Down syndrome. Amniocentesis (or another procedure, called chorionic villus sampling (CVS)) can diagnose these problems in the womb. Amniocentesis is usually done when a woman is between 14 and 16 weeks pregnant. Women who choose to have this test are primarily those at increased risk for genetic and chromosomal problems, in part because the test is invasive and carries a small risk of miscarriage. This process can be used for prenatal sex discernment and hence this procedure has legal restrictions in some countries. Amniocentesis was first introduced by American obstetrician Fritz Friedrich Fuchs and Danish gastroenterologist Polv Riis in 1956 for fetal sex determination and up to mid 1970s amniocentesis were done 'blind‘. Doctors Jens Bang and Allen Northeved from Denmark were the first to report amniocentesis done with the guide of an ultrasound in 1972. Chorionic Villus Sampling (CVS) was first performed by Italian biologist Giuseppe Simoni in 1983. Now real-time ultrasound has been used during all invasive procedures because it provides the safety of the fetus and accuracy of results.