%0 Journal Article %T Serum activin A and follistatin concentrations during human pregnancy: a cross-sectional and longitudinal study %A O'Connor, A.E. %A McFarlane, J.R. %A Hayward, S. %A Yohkaichiya, T. %A Groome, N.P. %A de Kretser, D.M. %J Human Reproduction %V 14 %N 3 %P 827-832 %@ 0268-1161 %D 1999-03-01 %I Oxford University Press %~ DeepDyve