Division of pregnant period by multivariate analysis of all subjective symptoms - Hideaki Shono; Mayumi Kohara; Yuji Ito; Mitsuhiro Hirakawa; Hajime Sugimori; Hideaki Shono; Mayumi Kohara; Yuji Ito; Mitsuhiro Hirakawa; Hajime Sugimori (Acta Obstetricia et Gynecologica Scandinavica)