Determinants of changes in vitamin D status postpartum in Swedish women

Abstract

Low vitamin D status has been associated with unfavourable health outcomes. Postpartum, it is speculated that maternal vitamin D status decreases due to transfer of vitamin D from mother to child through breast milk. A few studies have investigated changes in maternal vitamin D postpartum and possible determinants. Thus, the aims of the present study were to determine changes in serum concentrations of 25-hydroxyvitamin D (25(OH)D) between 2 weeks and 12 months postpartum in Swedish women and to evaluate lactation and other determinants for changes in 25(OH)D concentration postpartum. In total, seventy-eight women were studied at 2 weeks, 4 months and 12 months postpartum. Data collection included measurements of weight and height as well as information about lactation, sun exposure, use of oestrogen contraceptives and physical activity level. Blood samples were collected and serum 25(OH)D levels were analysed using liquid chromatography-tandem MS.

Breastfeeding woman are at higher risk of vitamin D deficiency than non-breastfeeding women - insights from the German VitaMinFemin study

“…Recent studies of breastfeeding women in other countries have also shown a high prevalence of inadequate vitamin D status [18, 20, 21]; however, the prevalence was often lower than those rates found in our study [17, 22]. For example, in Sweden, the prevalence of 25(OH)D concentrations < 50 nmol/L in women, who were breastfeeding for 12 months, was 22% in the winter months (November to April) and 15% in the summer months [17].…”

“…In our study, the 25(OH)D level was independent of the duration of breastfeeding, and inconsistent results have been reported in previous studies [17, 32, 40]. The duration of breastfeeding may impact vitamin D status in circumstances of an extended breastfeeding duration (>9 months) [40] and in combination with exclusive breastfeeding [32].…”

“…In a global study of China, the USA and Mexico, 43% of breastfeeding women at 4 weeks postpartum showed vitamin D insufficiency (<50.0 nmol/L) [22]. In contrast to our non-supplementation study sample, in both previous studies, 18% [17] and 22–94% [22] of the women were supplemented with vitamin D. However, in the study sample described by Seth et al, none of the participants supplemented vitamin D, and 93.8% had vitamin D insufficiency [21]. …”

“…For example, in Sweden, the prevalence of 25(OH)D concentrations < 50 nmol/L in women, who were breastfeeding for 12 months, was 22% in the winter months (November to April) and 15% in the summer months [17]. In a global study of China, the USA and Mexico, 43% of breastfeeding women at 4 weeks postpartum showed vitamin D insufficiency (<50.0 nmol/L) [22].…”

Vitamin D levels were significantly higher during and after lifestyle intervention in pregnancy: A randomized controlled trial

“…Vitamin D deficiency was observed in 30% at baseline, which is comparable to results from recent Danish studies . Vitamin D levels increased during pregnancy, as shown by others . The physiological increase in vitamin D may be due to increased bioavailability and metabolic adaptations, as well as adherence to intake of supplements, during normal pregnancy.…”