The effect of low amniotic pressure without oligohydramnios on fetal lung development in a rabbit model

OBJECTIVE: Our purpose was to examine fetal lung development in reduced intraamniotic pressure without amniotic fluid loss. STUDY DESIGN: A circular portion of uterine wall measuring 1 cm in diameter was excised while the chorionic and amniotic membranes were left intact at the twenty-third day of gestation in Nez Zealand White rabbits. The chorionic and amniotic membranes herniated spontaneously through the defect. RESULTS: Amniotic pressure was significantly reduced after herniation. Lung weight/body weight ratios at term who significantly reduced in experimental fetuses compared with controls. Residual amniotic fluid volumes at term did not differ. Histopathologic examination of lung specimens showed that fetal lungs had not matured in the experimental group as fully as in the control group. CONCLUSION: This experimental study demonstrated that low amniotic pressure impaired fetal lung development, even without oligohydramnios.