Incidence and causes of maternal thrombocytopenia in triplet gestation.

Objective: To determine the incidence, clinical significance and causes of maternal thrombocytopenia in triplet gestations.

Study Design: The study population consisted of 150 patients with triplet gestation that delivered at our department between 1990 and 2008. Thrombocytopenia was defined as a platelet count <150,000/μL. Patients were classified on the basis of the lowest recorded platelet count observed during pregnancy.

Results: A low platelet count was observed during the triplet gestation in 36 cases (24.0%), and after delivery in another 19 cases (12.7%). Thrombocytopenia was mild, moderate, and severe in 75% (27/36), 16.7% (6/36), and 8.3% (3/36) of the cases, respectively. During pregnancy, thrombocytopenia was associated with pregnancy-induced hypertension in 25.0% (9/36) of patients, while gestational thrombocytopenia was diagnosed in 72.2% of the cases (26/36). The mean platelet count showed a strong negative correlation with gestational age (r=-0.953, P<0.001), and at 36 weeks approached the limit of thrombocytopenia.

Conclusions: Thrombocytopenia occurs more frequently in triplet gestations than in the general pregnant population, and the rate of moderate and severe forms is higher. The distribution of causes is comparable to that of the general pregnant population. The average platelet count in triplet gestations decreases with gestational age.