Pregnancy, per se, does not cause caries. Saliva is slightly more acid during pregnancy, but the degree of acidity is not sufficient to initiate caries.
Effects of pregnancy, mouth acidity, and age on caries were studied by means of an index based on number of carious surfaces (BOdecker’s Caries Index). Salivary pH was determined colorimetrically. Histories indicated that most carious cavities noted during pregnancy were present before the terms began. The factor of dietary instruction was eliminated, in many cases, by mouth examinations when patients first applied for routine prenatal care. The method of least squares was used to analyze statistical data, with the general negative conclusion indicated in the opening sentence above. A review of literature does not support the belief that calcium is withdrawn from teeth, as from bone, during pregnancy. Other studies—constitutional, statistical, histological, on animals and humans—confirm the foregoing deductions.
References: Am. J. Obst. Gyn., 1926; J. Den. Res. (with Harold Hotelling), 1937.