Variation in platelet count with gestational age, weight and sex in hospitalized newborns

Introduction: Platelet count & CRP are diagnostic markers of neonatal sepsis. Though the platelet count remains the same throughout the neonatal period, variations in platelet count have been noted based on gestational age, weight & sex of neonates. Beside other hematological findings, changes in platelet count induced by neonatal sepsis have been the focus of many studies. Objective: To analyze the variation in platelet count with gestational age, weight and sex in hospitalized newborns. Methods: This is a retrospective case analysis of 533 neonates between January-2012 to December-2014. The parameters examined were Baseline Platelet Count, Change In Platelet Count, (Baseline Platelet CountChange In Platelet Count)/ Baseline Platelet Count, Platelet Nadir, Incidence, Duration & Severity of Thrombocytopenia. Statistical Analysis: All data were collected in validated preformatted proforma sheet & analysed sing appropriate statistical methods. Results: 533 babies were studied. About 21.2% had Culture negative sepsis, 9.75% had culture positive sepsis & 69.04% had no sepsis. No difference in any platelet parameter was noted between female & male babies. The prevalence of early onset sepsis in our study was 17.44% & late onset sepsis was 13.50%. Significant variations of all platelet indices were noted among lower gestational age babies. Significant variations in the Incidence, Prevalence & duration of thrombocytopenia were noted depending on the weight of the baby. Conclusion: The baseline platelet count of the neonates remains uniform irrespective of sex, weight or gestational age. There are quantitative differences in the platelet response based on weight and gestational age


Introduction
Platelet count & CRP are diagnostic markers of neonatal sepsis [1,2]. Though the platelet count remains the same throughout the neonatal period, variations in platelet count have been noted based on gestational age, weight & sex of neonates. Neonatal Sepsis is infection with or without accompanying bacteremia [3]. It is most common in the smallest and most premature infants [4,5,6].

Objectives
To analyse the variation in platelet count with gestational age, weight and sex in hospitalized newborns.

Methodology
This is a retrospective case analysis between January-2012 to December-2014. Name, date of admission, age, platelet count, CRP levels, blood culture reports of 533 neonates during the study period were collected. The data was analysed for variation in platelet count with respect to gestational age and sex.

Severity of Thrombocytopenia: [7]
No Thrombocytopenia -Platelet count more than 1,50, 000/mm3 Mild Thrombocytopenia -Platelet count between 1,00,000 to1,50,000/mm3 Moderate Thrombocytopenia -Platelet count between 50,000 to 1,00,000/mm3 Severe Thrombocytopenia -Platelet count less than 50,000/mm3 Culture Negative Sepsis was defined as those with clinical signs and symptoms of sepsis, without growth of any pathogen from blood, but with presence of CRP > 6mg/L [8].  Analysis of variance was used to compare the groups, and data was expressed as mean ± standard deviation. No difference in any platelet parameter was noted between female & male babies. The mean Baseline platelet count was a little higher among male babies. The response to sepsis in the form of drop in platelet count was a little more in male babies, however platelet nadir was noted to be low in female babies who already had a lower baseline platelet counts. Female babies had a little higher incidence of thrombocytopenia with prolonged duration. However none of the differences in platelet parameters between male & female babies reached statistical significance Analysis of variance was used to compare the groups, and data was expressed as mean ± standard deviation. Chi Square was used to compare categorical variables. We observed that the Baseline platelet count was comparable among all gestational groups. However the severity of thrombocytopenia & incidence of thrombocytopenia was more among babies with lower gestational age as compared to more mature babies. Likewise the duration of thrombocytopenia was prolonged in babies with lower gestation as compared to more mature babies. We analyzed the platelet variations based on gestation using Anova & chi square. There was no statistical difference in the baseline platelet count among the babies with different gestaional age. However we noted a significant difference in all the other platelet parameters (change in count, nadir, incidence, prevalence & duration of thrombocytopenia) when we analysed the multiple gestational groups using anova. Significant variations of all platelet indices were noted among lower gestational age babies. Among the 533 babies in the study group majority (nearly 50%) were near term (35-37 weeks). The prevalence of thrombocytopenia was noted to be more in babies less than 32 weeks. Beyond 34 weeks early onset sepsis onset was more common than late onset sepsis, however in babies less than 32 weeks, late onset sepsis was more common than early onset sepsis.  [14] noted that the incidence of neonatal sepsis was higher in Pediatric Review: International Journal of Pediatric Research Available online at: www.pediatricreview.in 5 | P a g e male than female neonates. This is probably due to the fact that the factors regulating the synthesis of gamma globulin are situated on the X-chromosome and male has only one X-chromosome [11]. In Indian scenario we think high male:female birth ratio and neglected female neonates add to high rate of neonatal sepsis in male child. The male: female ratio was 1.36: 1 in a study by Ramesh Bhat Y et al [15].
In our study the mean incidence of Thrombocytopenia among neonatal sepsis was 0.  [28] observed that septicemia was more common in low birth weight and preterm babies. Higher incidence of sepsis in low birth weight is because of the low maternal acquired IgG and inherent susceptibility to infection.
Placental transport of IgG from maternal to fetal circulation increases with maturity, & this transport is hampered in Low birth weight babies neonates who are often the products of placental insufficiency [29].
Anil K Gupta et al [16] stated that LBW babies showed statistically significant (P 0.009) thrombocytopenia due to their limited ability to compensate for accelerated destruction of platelets.

Summary
No difference in any platelet parameter was noted between female & male babies. There was a statistically significant difference in all the platelet parameters except baseline platelet count among the gestational subgroups. Statistical significant difference was noted in the incidence, duration & prevalence of thrombocytopenia based on the weight of the newborns.

Conclusion
The baseline platelet count of the newborns remains uniform irrespective of sex, weight or gestational age. There are quantitative differences in the platelet response based on weight and gestational age which may help in prompt diagnosis and management of the newborns.