Introduction Dental caries is a major chronic disease in children justifying investigate the effect of oral health of the mother during pregnancy on oral health status of the child. Thus, surveillance of oral health of the mother during pregnancy is essential for the promotion of child health.

Objectives To characterise the oral health of the mother during pregnancy and its effect on oral health status of the children.

Methods Observational and cross study conducted on a random sample of 653 mothers and their respective descendants living in the central region of Portugal.

Material Data collection was conducted through a questionnaire on Oral Health in Pregnancy. It is further preceded to the evaluation index of Decayed, Missing and Filled Teeth (DMFT), through the observation of the oral cavity of the children.

Results Most mothers held health monitoring during pregnancy (84.1%), while only 72.8% had six or more appointments, considering that way with a monitored pregnancy The most frequent problems during pregnancy were oral pathology in 18.5% of mothers, 15.9% of these showed decayed teeth, 2.4% gingivitis and 0.3% periodontitis.

The DMFT of the children varied between 0 and 17 (mean = 2.23; SD = 2.484). The children whose mothers had decayed teeth during pregnancy had a higher DMFT index when compared with those whose mothers had no oral problems (OM = 354.54 vs OM = 300.40), (U = 20965.5; Z = –2.828; p = 0.005).

Conclusion The results suggest that on the maternal health consultation and monitoring of pregnancy, health professionals should monitor the oral problems of the pregnant.