Tumor necrosis factor-alpha in midtrimester amniotic fluid is associated with impaired intrauterine fetal growth

To investigate whether abnormal immune system activation is involved in the pathogenesis of some instances of impaired fetal growth, we compared tumor necrosis factor-alpha levels in midtrimester amniotic fluid samples obtained from appropriate-for-gestational-age and small-for-gestational-age pregnancies.

In a case-control study with the sensitive and specific WEHI cell assay, bioactive tumor necrosis factor-alpha levels in amniotic fluid samples from 24 gestations resulting in small-for-gestational-age infants were compared with levels in 35 samples obtained from gestations resulting in the birth of a term, appropriate-for-gestational-age infant. The two groups were not significantly different with regard to indication for amniocentesis, maternal age, race, smoking history, parity, or other factors.

Elevated amniotic fluid tumor necrosis factor-alpha activity was associated with small-for-gestational-age birth, p = 0.028. With a threshold of 10 pg/ml, elevated amniotic fluid tumor necrosis factor-alpha had a sensitivity of 48% for the detection of small-for-gestational-age birth, with a specificity of 83%.

Elevated tumor necrosis factor-alpha in midtrimester amniotic fluid is associated with impaired intrauterine fetal growth. Abnormal immune system activation, as manifested by increased amniotic fluid tumor necrosis factor-alpha activity, may mediate impaired fetal growth in some cases.