Iodine deficiency during pregnancy: a national cross-sectional survey in Latvia

Public Health Nutrition
Q2
Mar 2015
Citations:26
Influential Citations:2
Observational Studies (Human)
81
S2 IconPDF Icon

Enhanced Details

Methods
Nationwide cross-sectional twenty-cluster survey of pregnant women in Latvia (spring and autumn 2013); all regions represented; Caucasian; data collected via questionnaire; urinary iodine concentration and thyroid function tests; creatinine-standardized UIC used; TPO-Ab analysis performed only in women without prior thyroid disease (n=496).
Intervention
Iodine-containing dietary supplements; dosage categories observed: <100 µg, 100–149 µg, ≥150 µg iodine per supplement; duration: during pregnancy; taken regularly (trimester-specific usage reported); no standardized regimen.
Results
Median creatinine-standardized UIC: 80.8 µg/g Cr (IQR 46.1–130.6); 69.4 µg/L (IQR 53.9–92.6). 81% had UIC below WHO-recommended 150–250 µg/g Cr. UIC was lowest in the first trimester (56.0 µg/g Cr) and higher in the second (87.5 µg/g Cr) and third (86.9 µg/g Cr) trimesters. Regular iodine-containing supplements (≥150 µg iodine) used by 6.8%; UIC in supplement users 96.2 vs 80.3 µg/g Cr in non-users (P=NS). TPO-Ab did not significantly correlate with UIC (ρ = −0.012, P = 0.78). Multivariate analyses: age, gestational age, milk intake, and seafood intake positively associated with UIC; parity negatively associated. Among women without prior thyroid disease, TPO-Ab >60 U/mL more common in spring (17.3%) than autumn (8.9%); no clear link between iodine supplementation or iodized salt and elevated TPO-Ab. Authors conclude that median UIC indicates iodine deficiency; iodine supplementation of 150 µg daily and regular UIC monitoring should be recommended to reach WHO levels without inducing autoimmunity. Preconception guidance proposes daily 100 µg iodine with folic acid; first-trimester introduction of 150 µg iodine; universal autoimmune thyroid disease screening in the first trimester.
Limitations
Cross-sectional design with single measurements; not repeated across pregnancy; self-reported iodized salt use may be misclassified; incomplete TPO-Ab data (496/665 without prior thyroid disease); limited data on iodine status in nonpregnant women of childbearing age; seasonal differences observed but not consistent; generalizability to Latvia may be limited.

Abstract

Abstract Objective Low iodine intake during pregnancy may cause thyroid dysfunction, which results in inadequate fetal brain development. In the absence of a universal salt iodization programme, we conducted a nationwide survey of iodine deficiency i...