Difficult vaginal deliveries cause injuries to pelvic nerves. Once nerves are cut or torn then they start to re-grow to restore the job they were doing previously. Instead of just one nerve re-growing; many nerve-lets start to regrow from the injured stump. After several years there is a mass of abnormal nerves that cause pain in repsonse to light touch. Women present with chronic pelvic pain, painful sex, painful vulva, irritable bladder and bowel symptoms. Typically in the UK, women present in their early thirties with CPP and menstrual problems when there first child is seven, and the second child is five years of age – though clearly there is some variation.
When you think about it – what else would cause such common gynaecological problems ? There are some other causes of injuries to pelvic nerves including straining during defaecation and one or two rare causes. Obstetricians, notably Professor Sir Dugald Baird, wrote about it extensively in the 1950′s though the precise mechanisms were unclear at the time. Subsequent generations have not inquired into injuries to pelvic nerves.
Abnormal Uterus. There are masses of abnormal nerves running in all directions in this section.
Injuries usually occur in the first labour. They result from any serious difficulties during vaginal delivery. Studies of 2240 nulliparous women, followed up for five years, confirm that:
induction of labour,
prolonged labour (> 12 hours),
prolonged pushing (> 2 hours),
increased birthweight (> 4 kgs),
forceps delivery, etc
all contribute to these injuries and subsequent gynaecological presentations with pelvic pain, painful sex, painful, heavy periods and urinary symptoms including frequency and urgency.
Injuries affect the nerves supplying the uterus and those to the bladder and bowel. So you can have wide-ranging symptoms that present alone, or in combination with others affecting adjacent organs. Many women also become prone to infections with thrush, bacterial vaginosis and other organisms.
Does Caesarean section prevent these problems ? Not completely – as there are circumstances where, particularly in repeat CS, there are other injuries to the nerve supply of the uterus that result in adenomyosis (see Adenomyosis) and painful menstrual symptoms.
For a library of images depicting the effects of childbirth on the lower genital tract, click here.