The menstrual cycle and contraception
The differences in mucous production and consistency
during the menstrual cycle may either protect against,
or make women susceptible to, PID. During the first
phase of the menstrual cycle, where oestrogen is the
dominant hormone, the mucous is thinner to allow
sperm to easily travel to the upper genital tract.
During this phase, however, it may also be easier for
bacteria to ascend, potentially causing inflammation.
Conversely, when progesterone is dominant, the
mucous is thicker creating an obstruction to the upper
genital tract, reducing the likelihood of bacteria being
able to ascend. Holmes et al (2008) identified that PID
symptoms tended to occur around menses, suggesting
bacteria find it easier to ascend to the fallopian tubes
during this phase. They also suggest that during
this period small uterine contractions can facilitate
bacteria to move upwards towards the fallopian tubes
(Holmes et al, 2008).