This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
1. To evaluate the effectiveness of antidepressant drugs in addition to standard clinical care in the prevention of postnatal depression.
2. To compare the effectiveness of different antidepressant drugs and with any other form of prevention for postnatal depression i.e. hormonal, psychological or social support.
3. To assess any adverse effects of antidepressant drugs in either the mother or the foetus / infant.