A Cochrane review included 62 studies (6 428 women), half of which involved bromocriptine. Bromocriptine reduced the proportion of women lactating compared to placebo at or within seven days postpartum (RR 0.36, 95% CI 0.24 to 0.54, 3 trials, n=107). Trials involving oestrogen preparations (diethylstilbestrol, quinestrol, chlorotrianisene, hexestrol), most of which are unavailable nowadays, suggested that they significantly reduced the proportion of lactating women compared to no treatment at or within seven days postpartum. Trials comparing bromocriptine with other pharmacologic agents suggested similarity in their effectiveness. Side effects were poorly reported, though no case of thromboembolism was recorded in the 4 trials that reported it as an outcome.
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment, blinding and incomplete outcome data for adverse effects) .