Comparison of Lamellar Body Counts Using Light Microscopy with Standard Coulter Counter Techniques to Assess Fetal Lung Maturity

Amniotic lamellar body count and congenital diaphragmatic hernia in humans and in a rat model

BACKGROUND

We examined the extent of fetal lung hypoplasia and lung maturation using the amniotic lamellar body count (LBC) in congenital diaphragmatic hernia (CDH).

METHODS

We obtained 30 amniotic fluid samples from human CDH cases during cesarean section. We assessed LBC, magnetic resonance imaging (MRI), and ultrasound findings for predicting the prognosis of CDH. We collected newborn amniotic fluid and lung tissue at embryonic day (E)21 from normal and nitrofen-induced CDH rats (administered 100 mg orally at E9). Amniotic LBCs in rats were measured using light microscopy.

RESULTS

In human CDH, LBC was significantly higher in the surviving than in the deceased group (P < 0.01). A significant positive correlation was observed between LBC and percentage of fetal lung volume on MRI (P < 0.001; r = 0.716). In rats, LBC was significantly higher in controls than in CDH rats (P < 0.01) and correlated with fetal lung weight.

CONCLUSION

We conclude that LBC is useful for predicting lung hypoplasia in human CDH after 35 gestational weeks and in a rat model of nitrofen-induced CDH.

Changes in the threshold of fetal lung maturity testing and neonatal outcome of infants delivered electively before 39 weeks gestation: implications and cost-effectiveness

OBJECTIVE

To compare the neonatal outcome of infants delivered before 39 weeks' gestation following documentation of fetal lung maturity before and after the lamellar body count (LBC) threshold was increased from 30,000 to 50,000 LB/ul. We discuss the algorithm employed for testing fetal lung maturity, the cost of testing and potential savings.

MATERIAL AND METHODS

We studied the outcome of infants delivered electively before 39 weeks' gestation after fetal lung maturity was documented by amniotic fluid analysis. We compared the outcome of neonates born before and after the LBC threshold was increased.

RESULTS

Our cohort included 527 neonates who were divided into two groups: 264 who underwent fetal lung maturity studies before the change in LBC threshold and 263 who underwent testing after the change. In the first group, 158 neonates met the criteria of LBC >30,000 LB/ul and were delivered without further testing. The second group included 154 neonates who were mature by LBC >50,000 LB/ul and were delivered. Seven of the neonates born in the first group required admission to the neonatal intensive care unit (NICU), whereas in the second group only two neonates required admission (P = 0.02). Additionally, 16 neonates in the first group required respiratory assistance compared with six in the second group (P = 0.04). The overall neonatal complication rate was significantly higher in the first group (P = 0.001).

CONCLUSION

Changing the LBC threshold resulted in a significant decrease in neonatal morbidity. Employing the algorithm, we described for testing fetal lung maturity is cost effective, and more importantly, represents sound evidence-based medical management.