Vitamin D Levels May Affect Pregnancy Outcomes in Lupus

TOPLINE:

Both low and high levels of maternal 25-hydroxy [25(OH)] vitamin D are linked to an increased risk for adverse pregnancy outcomes in women with systemic lupus erythematosus (SLE), with levels of 40-59 ng/mL being associated with the lowest risk.

METHODOLOGY:

• Researchers analyzed 260 pregnancies in the Hopkins Lupus Cohort to examine the association between 25(OH) vitamin D levels and adverse pregnancy outcomes in women with SLE.
• The participants were required to have serum vitamin D levels measured during pregnancy and pregnancy-related outcomes data.
• The 25(OH) vitamin D levels were measured at visits every 6 weeks, and the participants were divided into six subgroups on the basis of the mean 25(OH) vitamin D levels:
• The adverse pregnancy outcomes included miscarriage, preterm delivery, and restricted intrauterine growth of the fetus.
• This study used a time-to-event analysis to assess the association between time-varying 25(OH) vitamin D levels and adverse pregnancy outcomes.

TAKEAWAY:

• Adverse pregnancy outcomes were observed in 45.3% of pregnancies; the risks for miscarriage and preterm delivery were significantly different across the six subgroups with varying vitamin D levels (P = .0045 and P = .0007, respectively).
• A U-shaped curve association was observed between vitamin D levels and adverse pregnancy outcomes, with the highest risk seen in patients with the lowest or highest levels of vitamin D during pregnancy, while the lowest risk was seen in those with vitamin D levels between 40 and 59 ng/mL.
• Low 25(OH) vitamin D levels during the second trimester resulted in premature delivery in 9 out of 10 pregnancies; however, a relationship between vitamin D levels in the first trimester and pregnancy outcomes was not observed.
• The time-to-event analysis showed that that U-shaped association between vitamin D levels and adverse pregnancy outcomes was still observed even after accounting for lupus disease activity; however, the elevated risk seen in individuals with the highest levels of vitamin D was no longer statistically significant.

IN PRACTICE:

“We recommend monitoring of maternal serum 25(OH) vitamin D levels throughout SLE pregnancies and supplementing patients with vitamin D insufficiency or deficiency, aiming for 25(OH) vitamin D range of 40-59 ng/mL. Over supplementation should be avoided,” the authors wrote.

SOURCE:

The study was led by Nima Madanchi, MD, Johns Hopkins University, Baltimore, and was published online on September 23, 2024, in Arthritis Care & Research.

LIMITATIONS:

This study could not prove a cause-and-effect relationship between vitamin D levels and adverse pregnancy outcomes. This study included only clinically identified pregnancies, potentially missing very early miscarriages. It also could not adjust for parity due to the unknown parity of the index pregnancy.

DISCLOSURES:

This Hopkins Lupus Cohort was supported by grants from the National Institutes of Health. The authors declared no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.