羊膜穿刺术

定义

羊膜穿刺术 is a test that can be done during pregnancy to look for certain problems in the developing baby. 这些问题包括:

• 出生缺陷
• 遗传问题
• 感染
• 肺发展

选择的名字

Culture - amniotic fluid; Culture - amniotic cells; Alpha-fetoprotein - amniocentesis

如何执行测试

羊膜穿刺术 removes a small amount of fluid from the sac around the baby in the womb (uterus). It is most often done in a doctor's office or medical center. You do not need to stay in the hospital.

你会有一个 妊娠超声 第一个. This helps your health care provider see where the baby is in your womb.

Numbing medicine is then rubbed onto part of your belly. Sometimes, the medicine is given through a shot in the skin on the belly area. The skin is cleaned with a disinfecting liquid.

Your provider inserts a long, thin needle through your belly and into your womb. A small amount of fluid (about 4 teaspoons or 20 milliliters) is removed from the sac surrounding the baby. In most cases, the baby is watched by ultrasound during the procedure.

液体被送到实验室. 测试可能包括:

• 基因研究
• Measurement of alpha-fetoprotein (AFP) levels (a substance produced in the liver of the developing baby)
• 感染培养

Results of genetic testing usually take about 2 weeks. Other test results come back in 1 to 3 days.

Sometimes amniocentesis is also used later in pregnancy to:

• 诊断感染
• Check whether the baby's lungs are developed and ready for delivery
• Remove excess fluid from around the baby if there is too much amniotic fluid (羊水过多)

如何准备考试

Your bladder may need to be full for the ultrasound. 请咨询您的供应商.

Before the test, blood may be taken to find out your 血型 和Rh因子. You may get a shot of medicine called Rho(D) Immune Globulin (RhoGAM and other brands) if you are Rh negative.

为什么要进行测试

羊膜穿刺术 is usually offered to women who are at increased risk of having a child with birth defects. 这包括以下女性:

• Will be 35 or older when they give birth
• Had a screening test that shows there may be a birth defect or other problem
• Have had babies with birth defects in other pregnancies
• Have a family history of genetic disorders

Genetic counseling is recommended before the procedure. 这将允许您:

• 了解其他产前检查
• Make an informed decision about options for prenatal diagnosis

这个测试:

• Is a diagnostic test, not a screening test
• Is most often done between 15 to 20 weeks, but can be performed at any time between 15 to 40 weeks

羊膜穿刺术 can be used to diagnose many different gene and chromosome problems in the baby, 包括:

• 先天无脑畸形 (when the baby is missing a large portion of the brain)
• 唐氏综合症
• Rare metabolic disorders that are passed down through families
• Other genetic problems, like trisomy 18
• 羊水感染

正常的结果

正常结果意味着:

• No genetic or chromosome problems found in your baby.
• Bilirubin and alpha-fetoprotein levels appear normal.
• 没有发现感染迹象.

Note: 羊膜穿刺术 typically is the most accurate test for genetic conditions and malformation, 尽管罕见的, a baby may still have genetic or other types of birth defects, even if amniocentesis results are normal.

异常结果意味着什么

An abnormal result may mean your baby has:

• 基因或染色体问题，如 唐氏综合症
• 出生缺陷 that involve the spine or brain, such as 脊柱裂

Talk to your provider about the meaning of your specific test results. 询问你的供应商:

• How the condition or defect may be treated during or after your pregnancy
• What special needs your child may have after birth
• What other options you have about maintaining or ending your pregnancy

风险

风险很小，但可能包括:

• 婴儿感染或受伤
• 流产
• 羊水漏出
• 阴道出血

参考文献。

Driscoll DA, Simpson JL. 基因筛查和诊断. In: Landon MB, Galan HL, Jauniaux ERM, et al, eds. Gabbe's Obstetrics: Normal and Problem Pregnancies. 8日艾德. Philadelphia, PA: Elsevier; 2021:chap 10.

帕特森检察官，安达佐拉JJ. 羊膜穿刺术. 见:福勒GC编. Pfenninger and Fowler's Procedures for 初级护理. 第四版. Philadelphia, PA: Elsevier; 2020:chap 144.

韦伯杰，杜高夫. Prenatal diagnosis of congenital disorders. In: Resnik R, Lockwood CJ, Moore TR, Greene MF, Copel JA, Silver RM, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 8日艾德. Philadelphia, PA: Elsevier; 2019:chap 32.