Ineffectiveness of antenatal guidance intervention for vitamin D insufficiency and deficiency in pregnant women in Kyoto, Japan.

Aim: The aim of this study was to investigate the vitamin D status among healthy pregnant women in Japan, and to evaluate the effectiveness of the antenatal health guidance intervention for the pregnant women who were informed about their low vitamin D levels.

Methods: We measured the level of 25-hydroxyvitamin D (25[OH]D) using chemiluminescent immunoassay among the singleton pregnant women who received at antenatal routine check-up (8-24 weeks of gestation) with written consent during September 2017-September 2018. The measurement values were informed by the concerned physician and health guidance intervention was given to the pregnant women with inadequate Vitamin D status (25[OH]D < 30 ng/mL).