Vitamin D, vitamin A, maternal-perinatal considerations: old concepts, new insights, new questions

Growth and micronutrient status parameters of Nigerian preterm infants consuming preterm formula or breastmilk

BACKGROUND

Moderate-to-late preterm infants (32-34 weeks GA) have increased risk of neonatal morbidities compared to term infants, however dedicated nutritional guidelines are lacking.

METHODS

Moderate-to-late preterm infants received a preterm formula (n = 17) or breastmilk (n = 24) from age 2-10 weeks in a non-randomized, open-label observational study. Anthropometric measurements were assessed bi-weekly. Blood concentrations of hemoglobin, ferritin, serum retinol, and 25-hydroxy-vitamin D (25OHD) were analyzed at age 2 and 10 weeks.

RESULT

Average growth per day was 14.7 g/kg BW/day in formula-fed and 12.8 g/kg BW/day in breastmilk-fed infants but not different from each other. Length and head circumference in both groups were in line with the median reference values of the Fenton growth chart. At 10 weeks of age, hemoglobin tended to be higher in the formula-fed group (10.2 g/dL vs. 9.6 g/dL, p = 0.053). 25OHD increased in formula- and breastmilk-fed infants from 73.8 to 180.9 nmol/L and from 70.7 to 97.6 nmol/L, respectively. Serum retinol only increased in the formula-fed group (0.63 to 1.02 µmol/L, p < 0.001).

CONCLUSION

Breastfeeding resulted in adequate growth in moderate-late preterm infants but was limiting in some micronutrients. The preterm formula provided adequate micronutrients, but weight gain velocity was higher than the Fenton reference value.

IMPACT STATEMENT

Unfortified breastmilk resulted in adequate growth in weight, length and head circumference in Nigerian moderate to late preterm infants during an study period of 8 weeks, but status of vitamin D, vitamin A and iron needs to be monitored. The high-energy formula, developed for very preterm infants, resulted in higher growth in body weight in moderate to late preterm infants than the median of the Fenton preterm growth chart. This study supports the necessity of dedicated nutritional guidelines, and regular monitoring of growth and nutritional status of moderate to late preterm infants.

[Relationship of plasma vitamin A levels between neonates and pregnant women in third trimester]

OBJECTIVE

To study the correlation of plasma vitamin A (VitA) levels between neonates and pregnant women in third trimester.

METHODS

A total of 688 pregnant women were recruited in Yuanshi and Laoting counties of Hebei Province, from May to June 2009. Venous blood samples of women before delivery and cord blood samples of newborns were collected and measured for retinol (retinol concentration was used to reflect VitA level) using high performance liquid chromatography assay. According to venous blood plasma retinol concentration, maternal VitA nutritional status was divided into deficiency (<0.70 μmol/L), marginal deficiency (0.70-<1.05 μmol/L), and sufficiency (≥1.05 μmol/L). According to cord blood plasma retinol concentration, neonatal VitA nutritional status was divided into deficiency (<0.35 μmol/L), marginal deficiency (0.35-<0.70 μmol/L), and sufficiency (≥0.70 μmol/L); neonatal VitA relative deficiency was further defined as cord blood plasma retinol concentration lower than the 10th percentile. VitA placental transport ratio was defined as retinol concentration in the neonates divided by that in pregnant women. Multivariable fractional polynomials (MFP) model and Pearson correlation were used to study the dose-response relationship between maternal and neonatal plasma VitA levels, Logistic regression model to estimate the effect of maternal VitA nutritional status on neonatal VitA deficiency, and MFP model and Spearman correlation to describe the relationship between maternal VitA level and VitA placental transport ratio.

RESULTS

The average retinol concentration of the pregnant women was (1.15±0.30) μmol/L, and the prevalence of VitA deficiency and marginal deficiency were 4.5% and 37.8%, respectively. Average retinol concentration of the neonates was (0.78±0.13) μmol/L, and no neonates were VitA deficiency, 28.2% of the neonates were marginal deficiency. After multivariable adjustment, the VitA level of the neonates was positively and linearly related to maternal VitA level (p^m=1, P<0.05), with the corresponding Pearson correlation coefficient of 0.13 (P<0.01). As compared with the women with sufficient VitA, those with VitA deficiency (crude OR=2.20, 95%CI:1.04-4.66) and marginal deficiency (crude OR=1.43, 95%CI:1.01-2.02) had higher risks to deliver neonates with VitA marginal deficiency; while the risks turned to be non-significant after multivariable adjustment. The pregnant women with VitA deficiency had higher risk to deliver neonates with relative VitA deficiency before and after multivariable adjustment (crude OR=3.02, 95%CI:1.21-7.50; adjusted OR=2.76, 95%CI:1.05-7.22). The maternal VitA level was negatively and non-linearly correlated with placental transport ratio (p^m= -0.5, P<0.05), with corresponding adjusted Spearman correlation coefficient of -0.82 (P<0.001).

CONCLUSION

There was a positive linear dose-response relationship between VitA levels of newborns and pregnant women in third trimester, indicating that neonatal VitA storing levels at birth was affected by maternal VitA nutritional status.