References
Vitamin D status was measured in three different ways: baseline vitamin D level (serum 25-hydroxyvitamin D 25(OH)D (ng/mL) measured in a blood sample at enrollment), treatment assignment (treatment or placebo vitamin D supplementation), and vitamin D level change over the trial period (high change or an increase of at least 10 ng/mL between the enrollment and third trimester and low change or a difference of less than 10 ng/mL). (The baseline vitamin D is associated with the microbiome composition but not with its richness; the microbiome is robust for vitamin D supplementation. (The sulfate−reducing bacteria Summary of the participants’ characteristics with respect to their measurement of the serum 25−hydroxyvitamin D 25(OH)D level at enrollment (baseline vitamin D level).Summary of the participants’ characteristics with respect to the treatment group that they were assigned.