Journal of Clinical Neonatology

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 8  |  Issue : 3  |  Page : 137--140

Relation of low birth weight and low-density lipoprotein cholesterol of neonates with postpartum maternal body mass index


Mohammad Kamrul Hassan Shabuj, Varsha Verma, Sanjoy Kumer Dey, Ismat Jahan 
 Department of Neonatology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh

Correspondence Address:
Dr. Mohammad Kamrul Hassan Shabuj
Department of Neonatology, Bangabandhu Sheikh Mujib Medical University, Dhaka
Bangladesh

Abstract

Objectives: This study was undertaken to compare the relation of low birth weight (LBW) categories and level of low-density lipoprotein (LDL) of LBW neonates with maternal postpartum body mass index (BMI). Materials and Methods: This was a hospital-based observational cross-sectional study conducted in the Department of Neonatology and in the Department of Obstetrics and Gynecology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh. Results: A total of 81 LBW neonates and mothers pairs were included in the study. There was no difference in LBW categories with maternal postpartum BMI categories (P = 0.15, post hoc). There was an increase in LDL level in the neonates of the obese mother (P = 0.02), but the difference of LDL level was not significant in the neonates of the normal and overweight mother. Conclusion: LBW categories do not differ with maternal BMI categories, but the LDL level is more in the neonates of obese mother than that of overweight mothers and normal weight mother.



How to cite this article:
Shabuj MK, Verma V, Dey SK, Jahan I. Relation of low birth weight and low-density lipoprotein cholesterol of neonates with postpartum maternal body mass index.J Clin Neonatol 2019;8:137-140


How to cite this URL:
Shabuj MK, Verma V, Dey SK, Jahan I. Relation of low birth weight and low-density lipoprotein cholesterol of neonates with postpartum maternal body mass index. J Clin Neonatol [serial online] 2019 [cited 2019 Aug 21 ];8:137-140
Available from: http://www.jcnonweb.com/text.asp?2019/8/3/137/264033


Full Text



 Introduction



There is a significant role of birth weight in the infant mortality and morbidity, childhood development, and adult health.[1] Low birth weight (LBW) is an important risk factor for adverse health outcomes, including many childhood diseases.[2] Reduced weight at birth is related to the risk of type 2 diabetes and ischemic heart disease in later life.[3] It is known that maternal glucose intolerance and hypertension is related to birth weight[4],[5] and birth weight is of the neonates also related to maternal weight gaining during pregnancy, with low weight gain in the first and second trimesters or in the second and third trimesters were associated with significant decreases in birth weights of the neonates.[6],[7] The serum lipids are low and have a unique quality of profile in human fetuses and LBW has less serum lipoprotein than that of normal birth weight neonates. Low-density lipoprotein cholesterol (LDL-c) is the dominant cholesterol carrier[8] and lipid is an essential component in lung development. The triglycerides from low-density lipoprotein (LDL) are essential for surfactant synthesis. Several studies showed that intrauterine growth restriction is an important determinant of cardiovascular risks in later life.[9] The mean concentration of LDL-c of the large for gestational age newborns was significantly higher than that of appropriate for gestational age (AGA) and small for gestational age (SGA) neonates.[10] In this study, we aimed to see the relation of LBW categories, such as LBW, very LBW (VLBW), and extremely LBW (ELBW) and the relation of the level LDL of these neonates with the postpartum maternal BMI categories (underweight, overweight, and obese).

 Materials and Methods



This was a hospital-based observational cross-sectional study conducted in the Department of Neonatology and in the Department of Gynaecology and Obstetrics of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh. The duration of the study was from February 2018 to September 2018.

The sample size was calculated using the formula N = (z2 × s2)/d2, where S is the standard deviation for the concentration of the LDL, obtained from the previous study,[11] which was 28 mg and “d” is the accuracy of measurement of LDL, considering 10 mg, z – value of at 95% of confidence interval is 1.96, requiring sample size is 30 but considering statistical power we included 81 LBW neonates in the study. The neonates and mother pairs were selected conveniently on the basis of the inclusion criteria of birth weight <2500 g irrespective of gestational age. We excluded those neonates with major congenital anomalies, perinatal asphyxia, and parents refused to participate in the study. Written informed consent was obtained from the parents, and the study was approved by the Institutional Review Board of BSMMU. Mother's anthropometry was measured as a routine at on admission and it was also measured within the 72 h of the postpartum period by Salter digital bathroom scale (model: 9141 WH3R Salter digital bathroom scale). BMI was calculated and expressed in kg/m2. The birth weight of the neonates was measured after initial stabilization. The blood sample of the neonates was sent within 24 h of the postnatal age before starting the feed. Two milliliters of the venous blood sample was collected in EDTA vials and was sent to the Department of Biochemistry, BSMMU. In the biochemistry laboratory, the sample was first centrifuged at a rate of 4000 rpm for 5 min for preparation of the serum and about 10 μL of serum was taken and then, the sample was kept on the operation area of the automated computerized biochemical analyzer. The unit of measurement of lipid profile was mg/dl. The estimation of lipid profile was carried out by automated analyzer: Architect Plus ci8200, which was first designed in the United States in the year 2003. We classified the maternal body mass index (BMI) as underweight (BMI <18.5 kg/m2), normal (BMI = 18.5–24.9 kg/m2), overweight (BMI = 25.0–29.9 kg/m2), and obese (BMI ≥30 kg/m2). Moreover, the LBW was categorized as LBW 1500–2499 g and VLBW 1000–1499 g and ELBW was <1000 g.

Statistical analysis

for the qualitative data, we did the Chi-square test and for quantitative data, we used mean and standard deviation and for multiple group comparison we did ANOVA test with Bonferroni correction, and for prediction of formula, we used linear regression equation. Statistical Package for the Social Science, SPSS version 20, IL, Chicago, USA, was used for the data analysis.

 Results



Among the 81 LBW neonates, their mean birth weight was 1535 ± 382.57 g and mean gestational age was 33.44 ± 2.29 weeks. The birth weight categories showed that LBW was the majority 50% and VLBW was 40%, and the mean BMI of the mother was 25.00 ± 3.38 kg/m2 and the mean concentration of the LDL was 36.38 ± 26.704 mg/dl [Table 1]. The mean birth weight and the concentration of the LDL according to the maternal BMI categories are shown in [Table 2], the difference of mean birth weight according to the maternal BMI categories showed that there was no statistical difference [Table 3], P > 0.05 after Bonferroni correction]. There was no statistical difference (P = 0.15 after correction of adjusted residual) of birth weight categories (LBW, VLBW, and ELBW) with the maternal BMI categories [Table 4].{Table 1}{Table 2}{Table 3}{Table 4}

With linear regression analysis our predicted birth weight formula for these LBW babies was, BW = 845.72 + 30.35 × maternal BMI, that with each unit change in the BMI of the mother, birth weight will increase 30.35 unit and our predicted formula for LDL concentration was, LDL = 21.15 + 0.69 × BMI of the mother, that is with each unit change in the maternal BMI there will 0.69 unit change in the concentration LDL of the neonates. There was statistically significant increased (P = 0.02) in the mean of LDL concentration in the neonate of obese mother with neonates of normal birth weight mother, but there was no difference in concentration of LDL with baby of overweight mother with that of normal weight mother (P = 1.00) and there was statistically significant increase in the LDL concentration in obese mother's baby than that of overweight mother (P = 0.007 after Bonferroni correction) [Table 5]. There was no difference in the LDL concentration with the weight categories of the neonates [P > 0.05 after post hoc test with Bonferroni correction, [Figure 1].{Table 5}{Figure 1}

 Discussion



This study reveals the relation of LBW and the relation of LDL-c concentration of the LBW neonates with the maternal postpartum BMI. The categories of LBW (LBW, VLBW, and ELBW) do not differ with maternal postpartum BMI categories (normal, overweight, and obese) and there is no difference of the birth weight mean with maternal postpartum BMI. It is known that the large baby is related to maternal obesity, and morbid obesity and SGA babies were more in the underweight group.[12] However, our research findings showed that the normal weight of the mother and even maternal obesity can lead to LBW, but the causes of LBW are not evaluated in this study. We predicted a formula for birth weight of the LBW neonates with maternal postpartum BMI. There was no such type of study was conducted previously. However, in our study, incidentally, there was no underweight mother and we have included only low birth neonates. A systematic review and meta-analysis compared pregnancy BMI and showed that preobese (BMI, 25–29.9) and obese (BMI, 30–34.9) women have a reduced risk for preterm birth 15% and 17%, respectively.[13] There was no study to be found to show the relation of the postpartum maternal BMI with an LBW of the neonates. This study showed the frequency of LBW and a mean difference of birth weight in three categories of postpartum BMI of the mother.

The present results also demonstrate the effect of birth weight, on the LDL-c profile. We did not find any difference of LDL among the LBW groups. In this study, the mean gestational age was 33.44 ± 2.29 weeks meaning all the neonates in our study were preterm. The concentration of the LDL-c is lower in these preterm neonates than that of term neonates 52.7 ± 14 mg/dl.[14] This finding was also in agreement with other studies.[14],[15] These studies reported that LDL-c concentration level of 53.09 ± 1.34 in IUGR newborns as compared to 56.58 ± 1.16 in AGA newborns (P value was not statistically significant).[16] As the liver is the main site of LDL cholesterol synthesis and due to the immaturity of hepatic function and storage, the low concentration of LDL in LBW newborns may be secondary to limited cholesterol pool of the fetus. It was revealed that in human fetuses, increases in hepatic LDL receptor activity were positively correlated with gestational age and were negatively correlated with LDL cholesterol concentration.[17] This may be the possible explanation of low LDL-c concentration in these LBW and preterm.

 Conclusion



Mean birth weight does not differ among the neonates of LBW categories (LBW, VLBW, and ELBW) with maternal postpartum BMI categories, but LDL is more in the neonates of the obese mother than that of the overweight mothers, but it does not differ among the neonates of the normal and overweight mothers. There was no difference in LDL concentration among LBW, VLBW, and ELBW neonates.

Acknowledgment

The authors would like to thank Professor Mohammod Shahidullah, Chairman Department of Neonatology, Bangabandhu Sheikh Mujib Medical University, for his kind support to conduct this study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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