Final answer:
The pH of vaginal secretions is normally below 4.5 due to the presence of Lactobacillus but may alter during pregnancy due to hormonal changes, potentially affecting susceptibility to infections.
Step-by-step explanation:
The pH of vaginal secretions tends to be more acidic, maintaining a pH below 4.5, primarily because of the activity of bacteria from the genus Lactobacillus. These bacteria produce lactic acid, which lowers the pH and provides protection against infections. During pregnancy, hormonal changes can alter the microbiota composition of the vagina, which might lead to different vaginal pH levels and increased susceptibility to infections such as candidiasis or vaginosis. Typically, these infections can be successfully treated with topical medications, with a high success rate. However, persistent or recurrent infections may require long-term or intermittent treatment.