About half of women who are pregnant experience a condition called pregnancy gingivitis. This condition can be uncomfortable and cause swelling, bleeding, redness or tenderness in the gum tissue. A more advanced oral health condition called periodontal disease may affect the health of your baby. Studies have shown a relationship between periodontal disease and preterm, low birth-weight babies. In fact, pregnant women with periodontal disease are seven times more likely to have a baby that is born too early or too small. The likely culprit is a labor-inducing chemical found in oral bacteria called prostaglandin. Very high levels of prostaglandin are found in women with severe cases of periodontal disease.