Elevation of transforming growth factor-beta1 is associated with recurrent miscarriage.

To investigate the significance of transforming growth factor-beta1 (TGF-beta1) in reproduction we have compared plasma levels in normal pregnant women and patients suffering miscarriages. We examined 188 normal pregnant women and 12 pregnant women with miscarriages. Eight women with severe recurrent miscarriages (mean +/- SD of previous number of miscarriages; 10.4 +/- 2.4 times) were also examined before conception; 34 nonpregnant women served as controls. Plasma TGF-beta1 level increased with the gestational week and returned within the normal range 1 month after delivery. The levels among pregnant women with miscarriages (mean +/- SD; 2.44 +/- 0.83 ng/ml) were significantly higher than those of pregnant controls (1.74 +/- 0.95 ng/ml) of matched gestational weeks; levels among nonpregnant women with severe recurrent miscarriages were extremely elevated (4.1 +/- 3.04 ng/ml) compared to the control value (1.34 +/- 0.59 ng/ml). These data suggest that TGF-beta1 may be necessary to maintain pregnancy but also may be a risk factor for recurrent miscarriages.