During pregnancy, changes in hormone levels during pregnancy can cause gingival hypertrophy and other conditions that predispose to gingivitis and result in bleeding gums, especially after brushing, a common symptom during late pregnancy. Gingivitis is also a common cause of gingival hypertrophy. Gingivitis is an inflammation of the gums, often accompanied by grinding teeth and bleeding gums. The causes of gingivitis are divided into local factors and systemic factors, and we can ask for examination by the above causes. 1, whether there is a partial chewing habit: it can make the waste side of the tooth surface to accumulate a large amount of plaque, calculus, thus triggering gingivitis. At the same time, the teeth on the habitual side can be severely worn out, resulting in dental congestion and triggering or aggravating gingivitis. 2, whether there are partial food habits: it can cause protein and vitamin A, C, D deficiency, leading to or aggravate gingivitis. 3, whether there are night grinding, clenching teeth habits: it can cause serious wear and tear on the teeth, increasing the burden on the gum tissue, can cause food embedment, or aggravate the original gingivitis. 4, whether there are lip biting, pen biting, nail biting, open mouth breathing and other habits: these can increase the load on the gum tissue, but also the front teeth can be displaced, the emergence of congestion and other symptoms, or aggravate the original lesions of the gum tissue. 5, whether smoking habits: smoking has an impact on the whole body bone, can aggravate the absorption of bone, smoking nicotine, tar and other toxic substances attached to the gums, can cause gingivitis.