Why some men develop signs of pregnancy

Psychoanalytical theory proposes that the syndrome evolves from the man’s envy of the woman’s procreative ability. The theory also proposes that for the male partner, the pregnancy acts as a catalyst for the emergence of ambivalence and the resurgence of oedipal conflicts. The event may cause regression — the man’s retreat to childhood feelings and conflicts triggered by his partner’s pregnancy, such as rejection, exclusion, ambivalence, and anxiety — with a sense of passivity and dependency that is intensified by the developing foetus and which conflicts with the man’s need for autonomy.

A second psychoanalytical theory proposes that expectant fathers may sometimes view the unborn child as a rival for maternal attention. Some have explained this as the expectant father’s interpretation of the unborn baby as a rival from whom attention is diverted. But this is expressed through a more socially acceptable outlet such as the syndrome. This interpretation would suggest that the syndrome has a protective function for the man because it enables him to identify with his pregnant partner and strengthens his protective instincts towards her and the baby.