Vaginal secretions: Composition and Function
In forensic investigations, vaginal secretions play a pivotal role, particularly in cases of sexual assault. The vaginal swabs collected as evidence in sexual assault cases may contain sperm or semen along with vaginal secretions. DNA profiling from these samples allows forensic experts to identify the perpetrator. Additionally, the presence of foreign substances (such as drugs) in vaginal secretions may indicate drug-facilitated sexual assault.
COMPOSITION OF VAGINAL SECRETIONS
Vaginal secretions, also known as vaginal discharge, is a clear or milky white fluid that consists of a complex mixture of substances produced by various glands of the female reproductive system.
The main components found in vaginal secretions are as follows:
Water
On average, vaginal secretions contain approximately 90-95% water. This water content contributes to the overall fluidity and moisture of the vaginal environment, playing a crucial role in maintaining the health and functionality of the female reproductive system.
Mucus
The cervix, which is the lower part of the uterus, contains mucus-secreting glands. These glands play a crucial role in producing mucus that contributes to the lubrication and provides a protective barrier in the vagina. The amount and consistency of mucus can vary during different phases of the menstrual cycle.
Glycogen
The glycogen present in vaginal secretions is primarily produced by the epithelial cells lining the vaginal wall. The glycogen serves as a substrate for the production of lactic acid (pH buffer).
Bacteria
Beneficial bacteria, particularly Lactobacillus species, are essential for maintaining the acidic pH of the vagina. The breakdown of glycogen by these bacteria produces lactic acid, helping to maintain the slightly acidic pH of the vagina.
pH Buffers
A normal and healthy vaginal pH is slightly acidic, ranging between 3.8 and 4.5. Several substances such as lactic acid, bicarbonate ions, and phosphates act as pH buffers in the vagina, helping to maintain the acidic environment. This slightly acidic pH is crucial for maintaining the balance of the vaginal microbiota, preventing the overgrowth of harmful bacteria and yeast.
Proteins
Various proteins are present in vaginal secretions, including enzymes and immune system components. These proteins contribute to the defense against infections and support the overall health of the vaginal environment.
Lipids
Lipids (including fatty acids) present in vaginal secretions contribute to the maintenance of the skin barrier and protect against external irritants.
Cells
Shed epithelial cells from the vaginal lining are a normal component of vaginal secretions. The shedding of these cells is a natural process that helps renew the vaginal epithelium.
The composition of vaginal secretions can be influenced by factors such as the menstrual cycle, hormonal changes, age, sexual arousal, pregnancy, certain medications, and underlying health conditions.