Not only do pregnancy and childbirth exert important psychological and physiological effects on a woman's life but a mother's pregnancy and postnatal difficulties impact indelibly on her child and, reciprocally, the temperament health and behaviour of the child impact on the mother's well-being. The psychological fit between the two, in the context of the larger family, carries significant implications for both (Oates, 1996, 2001). Childbearing is associated with a marked increase in the incidence and prevalence of psychiatric disorder although exact causal mechanisms (such as hormonal changes) remain unclear. Postnatal depression is extremely common, being consistently found in 10–15% of mothers (O'Hara & Swain, 1996). Acute postpartum affective or schizoaffective psychosis is less common, affecting about 1–2 in every 1000 deliveries. Though rare, these illnesses are severe and usually require hospitalization with consequent mother–child separation, unless mother and baby units are accessible. In addition, about 2% of pregnant women suffer from chronic severe mental health problems which are exacerbated postpartum (Kumar & O'Dowd, 2000).

This chapter explores how childbirth can contribute to the onset or exacerbation of psychiatric disorder and discusses the relative contributions of aetiological factors, including biological, environmental and psychosocial factors. The potentially serious effects of perinatal mental health problems require specialist clinical services (see Asen & Schuff, Chapter 10; Seeman, Chapter 11; Puckering, Chapter 12), including specialist inpatient facilities for joint admission of mother and baby. Women with mental health problems, unless supports are in place, will have difficulties in caring for their babies.