INTRODUCTION
Fetal growth is one of the signs of fetal health. Maternal inflammatory and thrombotic factors can affect the fetus through feto-placental-maternal circulation (1). For the determination of fetal growth abnormalities, definitions of small for gestational age (SGA) and large for gestational age (LGA) are applied using weight percentiles according to the gestational week (2). Premature birth is defined as birth <37 weeks and is associated with maternal inflammation (3). SGA, LGA, and prematurity negative perinatal outcomes are closely related. Fetal growth may also be affected by ethnic and racial factors (4).
There are significant changes in the maternal hematological system throughout the process of pregnancy (5, 6). The most frequently seen hematological change is anemia (Hb<12 g/dL), the cause of which is increased plasma volume resulting in hemodilution (7). Another variable is an increase in white blood cells. Leukocytosis develops because of physiological stress in pregnancy. Major leukocytes are neutrophils. While the leukocyte count decreases in the first and second trimester of pregnancy, it increases in the third trimester (8). In platelet count, especially because of platelet aggregation occurring in the 8th week of pregnancy, a significant decrease is seen from the 32nd week onwards (7). The role of these variables on fetal growth has still not been fully clarified.
There are studies in literature which have reported that the neutrophile to lymphocyte ratio (NLR) is associated with gestational diabetes, pre-eclampsia, the severity of pre-eclampsia, PPROM and hyperemesis gravidorum (9-13). In addition, the NLR and platelet to lymphocyte ratio (PLR) are known to be a sign of several inflammatory processes, primarily various malignancies (14-23). There may also be an association with healthy pregnancies without any pathological conditions (24, 25).
Deviations in hematological variables may become significant problems in pregnancy and afterwards, but if variations in hematological parameters are known, these negative events can be minimalised from the beginning.
In a recently published study it was suggested that all these variables have an effect on infant birthweight and gestational age (25).
The aim of this study was to investigate whether the NLR and PLR have an effect on birthweight, gestational age and the severity of prematurity.