Depot progestogen is a safe, effective and widely used form of contraception which is often prescribed just after childbirth. There is uncertainty however about its effect on mood, some case series suggesting that proges- terone prevents postnatal depression, while randomised trials have shown that it does not help the premenstrual syndrome, a condition considered to be similar to post- natal depression. Theresa Lawrie and her colleagues (pages 1082–1090) report the first double-blind ran- domised trial of a depot progestogen in the puer- perium. The women were given a single injection of norethisterone enanthate or normal, the syringes being masked to disguise the oily nature of the depot progestogen. The risk of depression was measured by two validated psychometric instruments, the Montgomery-Asberg Depression rating Scale and the Edinburgh Postnatal Depression Scale. At six weeks women given the depot progestogen had greater scores for depression and were more likely to be at risk of severe depression; these differences had disappeared by three months, possibly because the women received one injection only of the progestogen. The depot progesto- gen caused a greater degree of suppression of oestra- diol and progesterone, but there was no association between the risk of depression and the concentrations of these hormones.
Because depot progestogen is used so commonly in the puerperium and beyond the results of this ran- domised trial are important. The authors conclude that all depot progestogens are likely to result in an increased risk of puerperal depression, but this requires further study for confirmation. Only one injection of depot progestogen was given in this trial, and it is possi- ble that depression becomes less likely with continued treatment. More research is required.