average 25-hydroxyvitamin D (25(OH)D) concentration rises to a peak within 2 weeks, then gradually declines towards the baseline concentration over a period of about 2 months (Armas et al., 2004;Ilahi et al., 2008). The single dose of 60 000 IU D3 administered by Sahu et al. in the 5th month of gestation would not be expected to have a perceptible effect on 25(OH)D concentrations in most women at delivery, which was the only time at which the biochemical response was assessed. Even the larger doses administered later in pregnancy would have been predicted to have minor effects on the 25(OH)D concentration measured at delivery, despite almost certainly having caused important but undetected elevations in 25(OH)D concentration during the third trimester. Therefore, it is incorrect to conclude from Sahu et al.'s report that the reported supplement regimens had little or no effect on vitamin D status during pregnancy.The interpretation of the data is further complicated by the unspecified variation in the precise length of the interval between D3 dosing and 25 (
Conflict of interestThe author declares no conflict of interest. Vitamin D replacement in pregnant women in rural north India: a pilot study.
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