DISCUSSION
The aim of this study was to investigate whether CBC variables were correlated with birthweight, gestational age at birth and severity of prematurity. The results demonstrated that there was a weak negative correlation of PLR with birthweight and gestational age at birth and NLR was a weak positive independent variable for birthweight.
The Hb value was determined to be lower in the preterm group. When the groups were separated on the basis of infant birthweight according to gestational week, the highest Hb value was observed in the SGA group and the lowest Hb value in the AGA group.
There is only one study in literature related to the effect of NLR and PLR on birthweight and gestational age at birth (25). In that study, it was concluded that an increased NLR was associated with early birth and low birthweight. In the current study, no correlation was determined between increased NLR and preterm births, but a weak positive relationship was determined with birthweight. When the increase in NLR is measured in the first trimester of pregnancy, it may be associated with various pregnancy complications as a link with underlying inflammatory processes (9-13).
For example, the NLR has been observed to be increased in pre-eclampsia and especially in the severe form. Therefore, it has been recommended that it could be a useful marker in the first trimester of pregnancy (26). Moreover, in healthy pregnancies with no complications, as in the current study population, no increased NLR values have been observed (27).
In a study by Akgun et al, a negative correlation was observed between the PLR and birthweight and gestational age at birth (25). In the current study, a similar result was obtained in this context. However, while there was no significant relationship in the comparisons made according to preterm, term, or birthweight, a correlation was determined when all the patients were examined independently of the groups. Furthermore, it was concluded in this study that low PLR was an independent risk factor for birthweight. While Akgun et al stated that PLR was related to early births because of prematurity rather than birthweight (25), the results of the current study showed that in contrast there was a greater relationship with birthweight according to gestational age rather than prematurity. In literature, it has been reported that maternal inflammation affects birthweight according to gestational age through various inflammatory cytokines, and leads to low birthweight (28). The results of the current study support these findings in literature.
In the current study, the lowest RDW value was observed in the SGA group, which was consistent with the findings of Akgun et al (25). In addition, in the comparison of the preterm subgroups, the lowest value was observed in the 31+0-32+6 weeks gestational age group, at a statistically signficant level (p=0.001). This suggested that the RDW was directly proportional to both gestational age and the severity of prematurity. In literature, some authors have reported a higher result of RDW in IUGR and preterm infants (29, 30), while others in studies of neonatal populations have shown a negative correlation of RDW and gestational age (31).
In the study by Akgun et al, although PDW and MPV values were observed to be lower in preterm and IUGR groups, a positive correlation was determined with birthweight (25). In the currrent study, while PDW and MPV values were observed to be lower in the preterm group, the highest value was seen in the LGA group. The relationship between PDW and MPV values and prematurity has been reported in literature (32, 33). However, no clear data have been obtained in respect of the effect on birthweight.
In the study by Akgun et al, the leukocyte value was determined to be higher in male fetal gender (25), and in the current study, although not statistically significant, a higher value was seen in female infants. These conflicting results lead to hesitation in suggesting that there could be a relationship between CBC variables and fetal gender.
There is only one study in literature about the effect of NLR and PLR on gestational age at birth and birthweight (25). However, the current study is the first to have evaluated whether or not there is an effect of NLR and PLR on the severity of prematurity. There are of course many factors affecting prematurity, but the patients included in this study were healthy pregnant patients with no other disease, and thus it was attempted to minimise additional factors. A limitation of the current study could be said to be that the study group was heterogenous as it included patients of different ethnic origins.
From the results of the current study, it was concluded that elevated NLR was an independent risk factor for birthweight. Although not statistically significant, the lowest NLR was obtained in the SGA group. This result is consistent with the only study in literature on this subject, but as Akgun et al also stated, this result should be investigated independently of gestational week, and there is a need for further studies on this subject. In the current study, no relationship was observed of the NLR with preterm or term pregnancies and no correlation was determined with the severity of prematurity. A negative correlation was determined between the PLR and both gestational age at birth and birthweight, and it was concluded that a decreased PLR was an independent risk factor for birthweight. Furthermore, although not statistically significant, the PLR was determined to be directly proportional to the severity of prematurity.
CONCLUSION
In conclusion, the results of this study revealed a negative correlation between NLR and gestational age at birth and birthweight, and although this does not support the findings of Akgun et al (25), in the first study published on this subject, similar results were obtained in respect of the negative correlation between PLR and gestational age at birth and birthweight. In addition, the current study results showed that although low Hb was associated with early births, there was no association with low birthweight and the highest Hb value was observed at low birthweight. There is a need for further studies to determine the effects of maternal CBC variables on perinatal outcomes, and this easily applicable method can be considered useful for the pre-determination of perinatal outcomes.
ACKNOWLEDGEMENT
None
CONFLICIT OF INTEREST
The authors certify that they have NO affiliations with or involvement any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affi liations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.
CONTRIBUTION TO AUTHORSHIP
Planning and writing carried out by A.N.Bulut
Data scanning carried out by V.Ceyhan
ETHICS APPROVAL
This study has received the approval of erciyes university ethics committee.
Date:29.01.2020. Referance number: 2020/53.
FUNDING
None
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