Prenatal and birth-related risk factors for hypomineralised second primary molars: a prospective cohort study

Hypomineralised second primary molar (HSPM) is a developmental enamel defect whose aetiology remains incompletely understood. This study aimed to identify prenatal and birth-related risk factors associated with HSPM in children from a prospective cohort.

This study was nested within the Araraquara Cohort. Of the 1,089 children considered potentially eligible for the dental assessment, 303 underwent clinical examination (27.8%). These children were followed from pregnancy through the eruption of the second primary molars. HSPM was diagnosed by a calibrated examiner using the MIH/HSPM Index. Prenatal and birth-related data were obtained from the cohort database. Associations between exposures and HSPM were analysed using generalised linear models to estimate crude and adjusted risk ratios (RR).

The median age of the children was 3.6 years (IQR: 3.1-4.2), and 53.5% were male. The incidence of HSPM was 9.6%. The most frequent findings were white-creamy demarcated opacities and lesions affecting less than one-third of the tooth surface. In the adjusted multivariable analysis, HSPM was associated with alcohol consumption during the third trimester of pregnancy (RR = 2.56; 95% CI = 1.05-6.27), maternal illness during the first trimester of pregnancy (RR = 2.01; 95% CI = 1.02-3.99), and higher household income in the study sample (RR = 1.07; 95% CI = 1.01-1.13).

These findings highlight pregnancy, particularly in the first and third trimesters, as critical periods for the development of HSPM, reinforcing the relevance of prenatal care and early identification of children at risk of developing this defect.