Can amniocentesis detect fetal lung maturity?
Fetal lung maturity amniocentesis can determine whether a baby’s lungs are ready for birth. This type of amniocentesis is done only if early delivery — either through induction or C-section — is being considered to prevent pregnancy complications for the mother in a nonemergency situation.
How can an amniocentesis determine lung maturity?
This test is undertaken by using thin-layer chromatography, and is technique dependent. The test takes advantage of the constant levels of sphingomyelin in the third trimester of pregnancy, as lecithin levels increase with a maturing lung. An L/S ratio of 2.0 is usually considered an indication of maturity.
What indicates fetal lungs are mature?
Fetal lung maturity is established during the 2 to 3 week interval when the L/S ratio increases to 2.2 or more, PI decreases, and PG becomes detectable. Because PG appears later in gestation, it is a good indicator of maturity (positive predictive value >95%).
What results do you get from amniocentesis?
Amniocentesis detects chromosome abnormalities, neural tube defects, and genetic disorders. Down syndrome or Trisomy 21 is the most common chromosome abnormality. Genetic disorders include disorders such as cystic fibrosis. The most common neural tube defect is spina bifida.
When does amniocentesis for fetal lung maturity occur?
Amniocentesis to determine fetal lung maturity is usually done after 32 weeks’ gestation because pulmonary maturity is unlikely before this gestational age. The amniotic fluid can be evaluated for a lecithin-to-sphingomyelin (L/S) ratio and the presence or absence of phosphatidylglycerol.
When is fetal lung maturity test done?
FLM testing & neonatal outcome. The 2008 American College of Obstetricians and Gynecologists (ACOG) practice bulletin concerning fetal lung maturity does not recommend FLM testing before 32 weeks of gestation or when delivery is mandated owing to fetal or maternal indications [22].
What can help determine lung maturity for a baby?
Laboratory tests can be performed on amniotic fluid before iatrogenic preterm birth to provide an indirect assessment of the likelihood of lung maturity (direct tests of fetal lung function are not possible), and can be a factor in planning the time of induction or cesarean delivery.
Are amniocentesis results ever wrong?
Amniocentesis is estimated to give a definitive result in 98 to 99 out of every 100 women having the test. But it cannot test for every condition and, in a small number of cases, it’s not possible to get a conclusive result. Many women who have amniocentesis will have a “normal” result.
How is fetal lung maturity determined in the last trimester?
What to look for in amniotic fluid for lung maturity?
When examining for fetal lung maturity in the final stages of pregnancy, the doctor might also recommend checking quantities of phosphatidyl glycerol (PG) along with the Lecithin/Sphingomyelin ratio (L/S ratio) in the amniotic fluid. Medical experts believe that lung maturity can be assessed more precisely if both L/S and PG levels are carried out.
Which is the most accurate test of fetal lung maturity?
This test actually counts the number of lamellar bodies in amniotic fluid. The higher the lamellar body count, the more likely it is that the fetal lungs are mature. Lecithin/Sphingomyelin Ratio This was the first test of fetal lung maturity ever developed and is more commonly known as the L/S ratio.
How can you tell if a fetus has mature lungs?
This is an agglutination test that uses antibodies to detect PG in amniotic fluid. If PG is present then visible agglutinates (clumps of particles) can be seen and the fetal lungs are considered mature.
When to use fetal lung maturity test for RDS?
The main value of fetal lung maturity testing is predicting the absence of RDS. An immature test result for fetal lung maturity is less reliable in predicting the presence of RDS. (1) Surfactant secretion into the amniotic fluid is minimal prior to 32 weeks gestation.