Vitamin D deficiency in pregnant women and newborns in Lagos, Nigeria

Abstract

We aimed to determine the prevalence of Vitamin D deficiency among pregnant women and their newborns in order to make recommendations for Vitamin D supplementation, if necessary. It was a cross-sectional study carried out over a period of 12 months. Information such as use of Vitamin D supplements, number of daytime hours spent outdoors and dressing style was obtained from 166 pregnant women in Lagos, Nigeria; maternal and cord blood 25(OH)D concentration was determined using ELISA. The prevalence of Vitamin D deficiency (<20 ng/mL) in the mothers and newborns was 4.8% and 29.5%, respectively, while insufficiency (21-29 ng/mL) was 28.3% and 46.1%, respectively. Vitamin D supplement use during pregnancy, daytime outdoor exposure and mothers' dressing style were significantly associated with maternal serum 25(OH)D concentration (p < .05). Our study showed that despite a sunny environment like ours, inadequate serum 25(OH)D concentration is still considerable among pregnant women and their newborns and suggests a need for Vitamin D supplementation in pregnant women. Impact Statement What is already known on this subject? Vitamin D is an essential vitamin that plays a major role in maintaining pregnancy and ensuring adequate skeletal formation in the foetus. Studies have shown that there is high Vitamin D deficiency in pregnant women in the temperate regions of the world and thus Vitamin D supplements are being offered to these pregnant women. Studies have also shown that the foetal/neonatal serum Vitamin D level is a reflection of the maternal level. What the results of this study add? The results of this study adds that there may be some factors preventing adequate delivery of Vitamin D from the maternal circulation to the foetal circulation, because despite a low prevalence of Vitamin D deficiency in the mothers, their neonates had a high deficiency rate. What the implications are of these findings for clinical practice and/or further research? The implications of these findings are; further research is warranted in order to find what could be causing a reduced delivery of Vitamin D from the mothers to their foetuses, so as to prevent it if possible. Second, these findings suggest that our pregnant women should still receive a form of Vitamin D supplements, so as to raise their serum Vitamin D to a level which would guarantee optimal foetal concentration.

The prevalence and determinants of vitamin D deficiency in Indonesian infants at birth and six months of age

“…High prevalence of vitamin D deficiency at birth has been previously documented with no clear pattern associated with latitude or ethnicity [22][23][24]. In Poland, New Zealand and the USA, the reported prevalence of vitamin D deficiency (<50 nmol/L) in cord blood was between 29% and 57%, particularly in low UV ambience seasons and dark-skinned people, while in Nigeria, the prevalence was 30% with an indoor lifestyle and maternal veils as the common risk factors [25][26][27][28]. We are not aware of previous studies that have evaluated vitamin D status in Indonesian newborns, though Yani et al reported that of 168 Indonesian children aged less than five years old, one-third were vitamin D deficient [29].…”

Maternal and neonatal umbilical cord serum levels of 25-hydroxy vitamin D among Sudanese women with normal pregnancy: a cross-sectional study

“…In a sample of 100 mothers in Poland, the mean maternal 25-(OH)D level was 22.2 ng/mL, whereas the mean umbilical cord of 25-(OH)D level was 1.3 ng/mL [13]. Interestingly, the prevalence of vitamin D de ciency (< 20 ng/mL) in mothers and newborns was reported to be 4.8% and 29.5%, respectively, upon considering 166 pregnant women in Lagos, Nigeria [14]. In contrast, low prevalence rates of vitamin D de ciency in both mothers and newborns were reported in Iran (1.1% and 2.5%, respectively) [11].…”

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“…Little is known about vitamin D status of apparently healthy Nigerian children. A study done over twenty years ago by Pfitzner, et al [29] reported that there was no vitamin D deficiency in young Nigerian children (aged 6-35 months); whereas three other studies done later which involved Newborns [30] older children [31] and adolescents [32] reported subnormal 25-hydroxyvitamin D levels.…”