Study case- Amniotic Fluid

Question 1

A 23-yea r-old female has had some bleed ing
during preg nancy and visited her obstetri cia n. The physician was concerned that the baby that she was carrying may have hemolytic d isease of the n ewborn . The mother was Rh-negative and had a positive indirect Coombs test She had not yet sought prenatal care and thought that she may h ave previously suffered a miscarriage. The physician estimated her preg nancy to be about
34 weeks along from questioning her. An amniocentesis was performed and the amn iotic fl uid was sent for a bilirubin sca n and
an US ratio . T h e bilirubin sca n showed a O.D. el evation o f 0 . 2 5 at 450 nm. The US ratio was 2.3. Using a Li l ey g raph, the p hysician esti mated her ba by’s risk to help him decide whether he should try intrauterine transfusion or del iver the i nfa nt early for
treatment

1. Does the bilirubin scan confirm the physician’s suspicion of hemolytic disease of the newborn?
2. What substances peak at 410 nm and 450 nm and what do
   these substances indicate?
3. Using the Liley graph, would you classify the fetal risk as
   nonaffected or mildly affected (zone I), moderately affected
   (zone II), or severely affected with intervention required
   (zone Ill).
4. Does the lecithin:sphingomyelin (LIS) ratio indicate
   fetal lung maturity if the physician decides to deliver this
   baby early?

Answer 1

1. Does the bilirubin scan confirm the physician’s suspicion of hemolytic disease of the newborn?
   =>Yes, the bilirubin is elevated.
2. What substances peak at 410 nm and 450 nm and what do these substances indicate?
   => The amount that the curve deviates from a straight line at 450 nm (the A450) is directly proportional to the amount of bilirubin in the amniotic fluid. The A410 corresponds to oxyhemoglobin, which is the major contaminant of concern
3. Using the Liley graph, would you classify the fetal risk as nonaffected or mildly affected (zone I), moderately affected (zone II), or severely affected with intervention required (zone Ill).
   =>Severely affected with intervention required
   (zone III).
4. Does the lecithin:sphingomyelin (LIS) ratio indicate fetal lung maturity if the physician decides to deliver this baby early?
   =>Yes, an lecithin:sphingomyelin (LIS) ratio of 2.0 or greater is associated with fetal pulmonary system maturity.