During pregnancy, there are certain changes in a woman´s body that can affect or alter oral health. Likewise, in this period some changes in factors such as pH and salivary flow can contribute to an increased risk of caries in pregnant women; therefore, this research was conducted on 85 women from the city of Montemorelos who attended Montemorelos General Hospital, of whom 53 were pregnant and 32 were not, using these as a control group. Salivary flow, pH, the decayed, missing and filled teeth (DMFT) index, and the Caries Risk Assessment Tool were used to assess caries risk. Of the pregnant women, 67.9% had a low salivary flow compared to non-pregnant women; of these, 50.6% showed a decreased salivary flow. The mean salivary pH of the pregnant women was 6.5 compared to the control group, which was 6.9. The mean DMFT index in pregnant women was 10.92 compared to the control group, which was 8.0. According to the caries risk evaluation, of the 53 pregnant women, 1.9% had low caries risk, 24.5% moderate risk, and 73.6% high caries risk.