Among infants with spina bifida, the combination of no folic acid supplementation and low dietary folate intake was associated with a modestly elevated risk of preterm birth (RR 1.73, 95% CI: 1.01-2.96), though neither factor alone reached statistical significance.
Key Findings
Results
Among 1199 infants with spina bifida, 18.1% were born preterm.
Total sample consisted of 1199 infants with spina bifida: 1011 from NBDPS (1999-2011) and 188 from BD-STEPS (2014-2019).
217 out of 1199 infants (18.1%) were born preterm, defined as less than 37 weeks gestation.
The study used a retrospective population-based design combining two study datasets.
Results
Lack of folic acid-containing supplement use alone was not statistically significantly associated with preterm birth among infants with spina bifida.
The risk ratio for preterm birth associated with lack of supplementation was RR 1.24 (95% CI: 0.92–1.69).
The confidence interval crossed 1.0, indicating no statistically significant association.
Robust Poisson regression was used to calculate risk ratios and 95% confidence intervals.
Results
Maternal dietary folate intake quartile alone was not statistically significantly associated with preterm birth among infants with spina bifida.
Risk ratios across dietary folate intake quartiles ranged from 1.12 to 1.39.
None of the quartile-based associations were statistically significant, as confidence intervals crossed 1.0.
Dietary folate intake was assessed as a quartile-based variable in the regression models.
Results
The combination of no folic acid supplementation and low dietary folate intake had the strongest association with preterm birth among infants with spina bifida.
The combined variable of no supplementation and low dietary folate intake yielded RR 1.73 (95% CI: 1.01–2.96).
This was compared to women who took supplements and had higher dietary folate intake.
This was the only association that reached statistical significance in the study.
A combined variable accounting for both supplementation and dietary folate status was constructed for this analysis.
Methods
The study used robust Poisson regression to evaluate associations between folate-related exposures and preterm birth in spina bifida-affected pregnancies.
Exposures assessed included maternal use of folic acid-containing supplements, dietary folate intake quartile, and a combined supplementation-plus-dietary-folate variable.
Data came from two population-based studies: NBDPS (1999–2011) and BD-STEPS (2014–2019).
The outcome was preterm birth defined as less than 37 weeks gestation.
The study design was retrospective and population-based.