Psychological factors and hyperemesis gravidarum.

Hyperemesis gravidarum (HG) is a condition of severe, intractable nausea and vomiting during pregnancy. It has long been held that HG is a psychosomatic illness reflective of a long-term psychological trait, that is, conversion disorder. We investigated this possibility by conducting a two-phase study: (1) a comparison of women with (n = 9) and without (n = 10) HG during pregnancy and (2) a comparison of nonpregnant women who did (n = 10) and did not (n = 12) have HG during their most recent pregnancies. The pattern of findings differed between experiments 1 and 2. During pregnancy, women with HG scored significantly higher on three scales associated with conversion disorder (all p values <0.01) than did women without HG. There were no significant differences between HG subjects and controls after pregnancy. We find no support for the theory that HG is a psychosomatic condition. Rather, it appears to be a complex interaction of biological, psychological, and sociocultural factors.