A review of longitudinal studies on antenatal and postnatal depression.

Antenatal depression is a known risk factor for postnatal depression; both are common disorders associated with negative impacts on child development. Few studies have followed up women from pregnancy and through the postnatal period to explore how rates of depression change. This review evaluates recent evidence on depression during pregnancy and after childbirth. A search of Embase, PsychINFO, MEDLINE and Cochrane Reviews was carried out to identify longitudinal studies on antenatal and postnatal depression. Studies that measured depression during pregnancy and up to 1 year after childbirth were evaluated against a set of criteria (e.g. less than 50 % attrition). Of the initial 523 studies identified, 16 studies met the final inclusion criteria with a total of 35,419 women. The average rate of antenatal depression across these studies was 17 and 13 % postnatal depression. The longitudinal nature of the studies revealed that on average 39 % of those who experienced antenatal depression went on to have postnatal depression. Similarly, on average, 47 % of those with postnatal depression had also experienced antenatal depression. On average, almost 7 % of women reported significant depressive symptoms in pregnancy that persisted after childbirth. The review provided evidence that rates of depression tend to be higher during pregnancy than in the first year following childbirth. Furthermore, the longitudinal data show that there is much movement between the groups categorised as depressed or not depressed. There is evidence that postnatal depression is often a continuation of existing antenatal depression.