Changes in salivary flow rate and pH in pregnancy

To evaluate changes in pH and Flow Rate (FR) of the Unstimulated Whole Saliva (UWS) in a sample of pregnant women in different gestational periods.

After collecting demographic data and medical histories, as well as conducting an oral examination, a sample of pregnant women were instructed on how to prepare prior to the sample collection. At a time between 11.00 and 12.00 a.m., they were subjected to salivary collection (spitting method, time 5 minutes); the measurement of FR was carried out using a professionally calibrated precision scale and the pH with a portable pH meter.

The average FR of the women's detected sample (0.40 ± 0.20 ml/min) was lower than that of non-pregnant women (0.48 ± 0.15 ml/min) of the same age (p <0.05). We observed an increase (p <0.001) of FR in the first trimester (0.56 ± 0.20 ml/min) compared to second (0.34 ± 0.14 ml/min) and third (0.31 ± 0.14 ml/min) trimester. The salivary pH of pregnant women was lower than the one detected in the non-pregnant women's sample (p <0.0001).

Our study highlighted an increase in the FR in the first trimester compared to that detected in the second and third trimesters of pregnancy which viceversa was lower than the average FR in non-pregnant women. This data, combined with the decrease in salivary pH, supports the hypothesis that correlates the FR increase with the attempt to counter the decrease in pH due to gastric regurgitation frequent in the first trimester. Further studies are necessary to evaluate salivary FR and pH in pregnant women samples related to the emesis phenomenon.