Background and Aims To determine whether there is an association between platelet counts and patent ductus arteriosus (PDA) incidence and/or closure in preterm newborns.

Methods Premature infants with hemodynamically significant PDA (n=154) and a control group without PDA (n=207) who were hospitalized in the NICU were eligible. Platelet counts and other platelet indices including mean platelet volume (MPV) and platelet distribution width (PDW) of the infants in both groups during the first 3 days of life were recorded. Ibuprofen was started in infants with hemodynamically significant PDA and echocardiography was repeated 48 hours thereafter to assess the closure of ductus.

Results Median gestational age and birth weight of the infants with PDA were 28 (range 26–29) weeks and 1060 (range 892–1250) gr respectively. Platelet counts were significantly lower in the patient group than in the control group (p<0,001). Multivariate analysis including gestational age, presence of RDS, presence of thrombocytopenia and PDW showed that platelet count < 150.000 (OR=2.13, 95% CI 1.26–3.61; p=0.005), high PDW (>17) (OR=2.68, 95% CI 1.41–5.09; p=0.003) and the presence of RDS (OR=2.25, 95% CI 1.41–3.59; p=0.001) were independently associated with higher risk of hemodynamically significant PDA. Baseline platelet counts of the infants in whom ductus closed or persisted after ibuprofen treatment were similar.

Conclusions Low platelet count was associated with ductus arteriosus patency in preterm infants while other platelet indices were not. We could not show an association between platelet counts and persistence or closure after medical treatment.