Final answer:
The bacteria related to pregnancy gingivitis is Prevotella intermedia. Hormonal changes during pregnancy can predispose to an overgrowth of this bacteria in the gums, leading to gingivitis.
Step-by-step explanation:
During pregnancy, hormonal changes can affect the gums and lead to gingivitis, a condition characterized by inflammation of the gums. This allows for the overgrowth of particular types of bacteria, including Prevotella intermedia, which thrives in the gingival space made anaerobic by plaque accumulation. While other bacteria such as Porphyromonas gingivalis, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans are involved in various oral diseases, it is Prevotella intermedia that is often associated specifically with pregnancy gingivitis.