The effect of vitamin D supplementation on fetal cerebroplacental ratio in pregnant women with systemic lupus erythematosus: a quasi-experimental study

Pregnancy in women with systemic lupus erythematosus (SLE) is associated with increased maternal and fetal risk. Vitamin D is involved in placental vascular function and fetal circulation. The cerebroplacental ratio (CPR) reflects fetal adaptation to hypoxia. A quasi-experimental pretest–posttest study was conducted at Dr. Hasan Sadikin General Hospital, Bandung (May–October 2024). Thirteen pregnant women were screened. Two were excluded before the intervention because of moderate-to-severe SLE activity. Eleven participants received vitamin D supplementation, of whom one discontinued follow-up after experiencing vaginal bleeding and intrauterine fetal death. Therefore, 10 participants were included in the final analysis ( n = 10). Serum vitamin D levels and CPR were measured monthly. Mean vitamin D increased from 21.92 ± 4.85 to 35.85 ± 5.68 ng/mL ( p = 0.005). CPR improved from 1.30 ± 0.16 to 1.61 ± 0.24 ( p = 0.007). The correlation between vitamin D levels and CPR was positive but not statistically significant. As conclusions, Vitamin D supplementation significantly increased serum vitamin D levels, while CPR increased during follow-up. However, causal interpretation is limited due to study design and sample size.