What causes the pregnancy enlargement of gingivae?

Pregnancy enlargement of the gingivae, also known as pregnancy gingivitis or pregnancy tumor, is primarily caused by hormonal disturbances that occur during pregnancy. These hormonal changes, particularly the increase in estrogen and progesterone levels, lead to alterations in the gingival tissues. The elevated hormone levels can affect the way blood flows to the gums, increase the permeability of the blood vessels, and modify the response of the immune system to bacterial plaque.

As a result, the gums may become more sensitive, inflamed, and prone to swelling in response to plaque accumulation, leading to the characteristic enlargement observed. This condition is more likely to occur in individuals who may already have some level of gingivitis prior to becoming pregnant, as the hormonal fluctuations can exacerbate pre-existing inflammation.

While nutritional deficiencies, bacterial infections, and genetic predispositions can affect oral health and influence the severity of gingival disease under normal circumstances, they are not the primary causes of the distinct phenomenon seen during pregnancy. Hormonal disturbances specifically tie to the physiological changes brought about by pregnancy, making it the correct choice for this question.