Idiopathic thrombocytopenic purpura in pregnancy: a randomized trial on the effect of antenatal low dose corticosteroids on neonatal platelet count.

OBJECTIVE: To determine the efficacy of antenatal low dose oral betamethasone in preventing neonatal thrombocytopenia and/or bleeding in infants of mothers with idiopathic thrombocytopenic purpura (ITP).

SETTING: Hospital department of obstetrics and gynaecology, referral centre.

PATIENTS: 41 pregnancies in 38 women were randomized. The results of 13 pregnancies were considered non-assessable. The final analysis involved 14 in the betamethasone group and 14 in the non-treatment group. All fulfilled the criteria for ITP.

INTERVENTIONS: The treated group received 1.5 mg betamethasone orally per day, from day 259 till day 273 and 1 mg from day 273 till delivery.

MAIN OUTCOME MEASURES: Effects of treatment were assessed in terms of maternal platelet counts after the first trimester and neonatal platelet counts at birth and the first week of life and neonatal bleeding episodes.

RESULTS: There were no significant differences in neonatal platelet counts at birth. Two infants in the betamethasone group and one in the untreated group had a severe thrombocytopenia either at birth or during the first week of life (less than 50 x 10(9)/l). Seven infants in the betamethasone group and six in the non-treatment group had a mild thrombocytopenia. The overall frequency of neonatal thrombocytopenia was similar: 64% in the betamethasone group and 57% in the untreated group (95% CI of the true difference: -43.5% to +29.5%). There was also no significant difference in neonatal bleeding episodes.

CONCLUSIONS: Low-dose betamethasone in pregnant women with ITP does not prevent thrombocytopenia or bleeding in their newborn infants.