Prior pregnancies deplete maternal folate status and increase risks of neural tube defects in Addis Ababa, Ethiopia.

BACKGROUND: Folate is essential for foetal neural development, and maternal deficiency during early pregnancy increases the risk of neural tube defects (NTDs). Ethiopia has among the highest NTD rates globally, yet data on folate status determinants among pregnant women are scarce. OBJECTIVE: To identify the role of dietary and demographic factors in determining maternal folate status and to interpret these findings in the context of NTD prevention. METHODS: We conducted a cross-sectional study among pregnant women (n = 404) attending their first antenatal care visit at three public health centres in Addis Ababa, Ethiopia. Serum folate was measured using electrochemiluminescence immunoassay. Increased risk of NTD was defined by serum folate <24.3 nmol/L. Sociodemographic, dietary, and clinical data were collected by questionnaire. We examined factors associated with serum folate concentrations using linear regression models. RESULTS: 61% of women had concentrations below levels estimated to be protective against NTDs. Supplement use was rare (<3%). After adjustment for wealth, residency, dietary intake, BMI, inflammation and trimester, serum folate was lower among women with two (β = -2·2 nmol/L; p = 0·04), three (β = -6·2 nmol/L; p < 0·001), four (β = -11·2 nmol/L; p < 0·001), and five (β = -13·7 nmol/L; p < 0·001) prior pregnancies compared with primigravidae. Serum folate was higher in the second than first trimester (β = 3·90 nmol/L; p = 0·003). CONCLUSION: Higher gravidity is strongly associated with lower folate status, consistent with maternal depletion. Multiparous women may be at increased risk of NTD-affected pregnancies. Interventions to improve folate status before conception, including supplementation, food fortification, and strategies to lengthen interpregnancy intervals, should be prioritised in Ethiopia.