The association of platelet parameters with morbidity and mortality in infants of preeclamptic mothers

Preterm birth is the leading determinant of neonatal morbidity and mortality. Infants born before 32 weeks of gestation represent a high-risk group in which the adverse effects of prematurity are most pronounced. Preeclampsia, characterized by systemic inflammation, is a major cause of both maternal and neonatal morbidity and mortality. Changes in platelet parameters during systemic inflammatory responses have been well-documented in recent years, and there is a substantial body of literature exploring how these parameters are altered in preeclamptic mothers. However, there is a limited number of studies that comprehensively evaluate all platelet indices in preterm neonates born to preeclamptic mothers and examine their possible associations with morbidity and mortality. This study aimed to compare hematologic parameters, morbidity, and mortality outcomes of early preterm infants born to preeclamptic mothers with those of infants born to non-preeclamptic mothers. A secondary aim was to investigate the frequency of morbidity and mortality related to prematurity, the impact of platelet indices on these outcomes, and various demographic characteristics of early preterm neonates. Medical records of infants born at our hospital between January 1, 2018, and December 31, 2022, were retrospectively reviewed via the hospital's electronic data system. Among the infants included, 66 (35%) were born to preeclamptic mothers (study group), while 119 (65%) comprised the control group. The mean gestational age in the study group was 28.1 weeks (range: 26.3–29.5), and the mean birth weight was 1020.5 ± 268 grams. The control group had comparable demographic characteristics. No significant differences were observed between the groups regarding maternal age, antenatal steroid administration, APGAR scores, or other basic parameters. However, the rate of cesarean delivery (92.4%) and the incidence of small for gestational age (SGA) infants (27.3%) were significantly higher in the study group. Within the first 24 hours of life, the study group exhibited significantly lower white blood cell, neutrophil, and lymphocyte counts compared to the control group. The frequency of thrombocytopenia was notably higher in the study group, with lower platelet counts and platelet mass index (PMI), but higher platelet distribution width (PDW) and hemoglobin levels. Mean platelet volume (MPV) was similar between the groups. Apart from a significant association between low PMI and the incidence of intraventricular hemorrhage (IVH), no significant relationship was found between platelet indices and other morbidities or mortality. The most common morbidities were respiratory distress syndrome (RDS) (75.6%), hemodynamically significant patent ductus arteriosus (PDA) requiring treatment (49.2%), and moderate-to-severe bronchopulmonary dysplasia (BPD) (27.6%). Early-onset sepsis (EOS) and late-onset sepsis (LOS) were observed in 7,5% and 29,1% of cases, respectively, with an overall mortality rate of 16.2%. There were no statistically significant differences between the study and control groups in terms of morbidity (PDA, IVH, BPD, necrotizing enterocolitis [NEC], retinopathy of prematurity [ROP], sepsis), mortality, duration of mechanical ventilation, length of hospital stay, or time to achieve full enteral feeding. However, a weak negative correlation was noted between platelet count and the duration of non-invasive ventilation in the study group. The median time to full enteral feeding was 10 days (range: 7–15), invasive mechanical ventilation duration was 4 days (range: 1–10), non-invasive ventilation duration was 11 days (range: 3–27), and median length of hospital stay was 56 days (range: 34–80). No significant differences were found between the groups for these parameters. Notably, among the study group, infants born SGA had significantly lower platelet counts. This study demonstrates that early preterm infants born to preeclamptic mothers exhibit distinct hematologic alterations, including leukopenia, neutropenia, thrombocytopenia, low PMI, and elevated hemoglobin and PDW levels. However, these changes were not found to be directly associated with neonatal morbidity or mortality, and no significant differences in morbidity or mortality outcomes were observed between infants born to preeclamptic and non-preeclamptic mothers. These findings emphasize the importance of monitoring hematologic parameters in early preterm neonates and suggest the need for multidisciplinary approaches to improve clinical outcomes. The study's retrospective design, potential limitations in data collection, single-center setting, small sample size, and heterogeneous clinical characteristics may affect the generalizability and statistical power of the findings. Future prospective studies involving larger cohorts are needed to further investigate the long-term neurodevelopmental outcomes of infants born to preeclamptic mothers and the dynamic changes in their hematologic profiles. Keywords: Early preterm, preeclampsia, hematological, morbidity