Morphological Parameters of Blood Platelets in Small for Gestational Age Newborns.

Abstract 4466

Platelets demonstrate many activities, e.g. hemostasis, integrity of blood vessels and phagocytosis. Hemostasis in newborns is characterized by a low efficiency in comparison to adults. The regulation of fetal growth is multifactorial and complex. Intrauterine fetal conditions, as well as maternal and environmental factors can lead to intrauterine growth restriction (IUGR). In small for gestational age (SGA) newborns, platelet dysfunction may be more expressed. On the other hand, there are some data indicating that blood platelet functions have some relation to their morphology. We have concentrated our attention on the determination of the count and morphological parameters of blood platelets in SGA newborns. Sixty-one SGA newborns: 31 girls and 30 boys were introduced to our study. They fulfilled all the criteria for SGA newborns, including clinical state and laboratory findings. The newborns were divided into two groups: < 5^th centile – 35, and < 10^th centile – 26 newborns. The birth weight for females ranged from 1850 to 2780 g and for male newborns from 2000 to 2900 g, at 37-41 weeks gestation. The Apgar score ranged from 8 to 10 points at 1-5 minutes of life. 22 full term newborns (FTN) were introduced to our study. Blood samples were collected from the umbilical artery within 5 minutes of cutting the umbilical cord. The first 0.5 ml of blood was discarded prior to collecting the blood sample for analysis. Within 10 minutes, the blood was transferred to the laboratory, and the platelet count and morphological parameters were determined using a hematologic analyzer, Advia ^TM 120 System. The platelet count in SGA newborns was lower than in FTN 238 × 10³ /μL vs. 282 × 10³ /μL, females demonstrated a higher number of platelets than males, SGA 243 × 10³ /μL vss 231 × 10³ /μL, FTN 311 × 10³ /μL vss 258 × 10³ /μL. In SGA, newborns < 5^th centile 218 × 10³ /μL, < 10^th centile 263 × 10³ /μL. MPV (mean platelet volume) was nearly the same in both groups SGA 8.1 fl, FTN 7.8 fl, gender did not exhibit any effect on MPV in the tested newborns: SGA female 7.9 fl, male 8.4 fl, FTN: female 7.9 fl, male 7.8 fl. The IUGR index did not affect MPV: < 5^th centile 8.2 fl, < 10^th centile 8.0 fl. PCT (platelet hematocrit) in SGA 0.19 %, in FTN 0.22%. Practically no difference was noted in SGA between female 0.19 %, male 0,18 %; whereas, in FTN female 0.24 %, male 0.21 %. SGA newborns < 5^th centile 0.18 %, < 10^th centile 0.20 %. PDW (platelet anisocytosis) index was the same in SGA 47 % and FTN 46 %. Higher values were observed in female 48 %, male 45 % SGA newborns, in FTN female 49 %, male 44 %. An evident decrease of PDW was found in SGA newborns < 5^th centile 43 %, < 10^th centile 52 %. The large platelets (LP) are significantly lower in SGA newborns (4.75 %), in comparison to FTN (6.23 %). Male newborns demonstrated a decrease in the percentage of LP, in SGA: male 4.2 %, female 5.3 %, in FTN: male 4.5 %, female 8.3 %. In SGA newborns < 5^th centile 4.9 %, < 10^th centile 4.3 %. Some authors suggest that platelet count is related to birth weight, and the degree of placental dysfunction corresponds to our findings in SGA newborns. One can suggest megakaryocytes are not able to produce a satisfactory platelet count. Small differences in the platelet count in relation to gender may result from restricted maturity of the thrombopoietic system. Therefore, it may predispose to a higher risk of bleeding tendency. A low number of LP may increase this risk. An increase of MPV in SGA newborns may indicate platelet consumption and activation. Lower PCT in SGA newborns results from a decreased platelet count. PDW may be used as a marker for bacteriaemia, schistocytosis, or platelet consumption. Evidently, a lower percentage of LP may be considered a symptom of thrombopoiesis immaturity. Our results in the SGA newborns may indicate incomplete development of thrombopoiesis.