Modifiable vs Non-Modifiable Pelvic Floor Risk Factors

Some of what shapes your pelvic floor risk was settled before you were born. Some of it was settled in a delivery room, possibly years ago, by people making fast decisions for sound reasons. And some of it is on today’s list, sitting quietly alongside the shopping and the school run.

NICE does something unusually useful with this. Its 2021 guideline on pelvic floor dysfunction, NG210, does not simply list risk factors. It formally separates the ones a woman can change from the ones she cannot, and adds a third group specific to pregnancy and labour. That split is the most practical thing in the guideline, because it sorts a frightening subject by leverage rather than by fear. Here is the list in full, what the evidence behind each entry actually shows, and the caveat that has to travel with all of it.

The list, in full

NICE lists a further set specific to pregnancy and labour, which sits outside both columns because none of it is a lifestyle choice.

Why the split matters more than the entries

The two columns are not a ranking of importance. Increasing age and family history sit in the non-modifiable column and are among the most consistent signals in the field. The split is about leverage, not severity, and each column asks a different question. The modifiable one asks what you might change. The non-modifiable one asks something quieter: how attentive to be, and when to start.

The five you can work on

Weight. A systematic review of 22 studies covering more than 95,000 participants found that women with a BMI between 25 and 30 had risk ratios for pelvic organ prolapse of 1.36 to 1.40 compared with women of normal weight, rising to between 1.47 and 1.61 at a BMI of 30 or above. UK Biobank data on 251,143 women found central weight around the abdomen associated with a 48 percent increase in the risk of developing prolapse, independent of BMI altogether. NICE advises that weight loss can help urinary incontinence, overactive bladder and prolapse in women with a BMI over 30. That is a claim about helping, in women above that particular threshold, and it is worth reading precisely rather than generously.

Smoking. This is the entry where the evidence is weakest, and saying so is more useful than tidying it up. One study found smoking an independent risk factor for prolapse at stage II or above, with an odds ratio of 2.37. Other cohorts have found no significant association, and some have found what looks like a protective one. NICE includes smoking on the modifiable list regardless and recommends cessation support. The mechanism usually proposed is chronic cough, which appears on the other side of the table in its own right.

Constipation. Straining is the mechanism and the number is real: a meta-analysis found constipation associated with an odds ratio of 1.77 for prolapse. This is the entry with the clearest everyday translation, and NICE’s prevention advice covers adequate fibre and fluid intake alongside physical activity and weight management.

Lack of exercise. NICE recommendation 1.3.1 states plainly that women should be advised that physical activity and a healthy diet can help prevent pelvic floor dysfunction, pointing at the UK Chief Medical Officer’s physical activity guidelines. Alongside general activity, NICE recommends that all women do pelvic floor muscle training throughout life.

Diabetes. Diabetes appears on the modifiable list, and here it is better to admit the limit than to fill the gap: the guideline names it, and the research behind it attaches no effect size. Treat it as a reason to keep an existing diagnosis well managed and to mention pelvic floor symptoms to whoever manages it, rather than as a risk you can look up.

The column you cannot change, and what it still tells you

Look at the two tables side by side and one oddity stands out. Chronic cough sits in the non-modifiable column while constipation sits in the modifiable one, even though both do much the same thing to the pelvic floor: repeated rises in abdominal pressure against tissue that has to absorb them. The effect sizes are comparable, with a meta-analysis putting persistent cough at an odds ratio of 1.52 and constipation at 1.77. NICE is sorting by whether the cause can be changed, not by whether the mechanism can. Chronic coughing and heavy lifting are both cited contributing factors, and neither is reliably within a woman’s control.

The rest of that column is essentially a list of histories: increasing age, a family history of urinary or faecal incontinence or of overactive bladder, gynaecological cancer or its treatment, gynaecological surgery such as a hysterectomy, and fibromyalgia. What they share is that the factor itself cannot be acted on. What can be acted on is the response to it: pelvic floor muscle training, which NICE recommends for every woman throughout life, and a lower threshold for raising symptoms with a GP instead of waiting to see whether they settle.

Nothing in the non-modifiable column describes something you did. It describes something that happened, or something you inherited, or simply the number of years you have been alive.

Pregnancy and labour: the list nobody is handed at the time

The six pregnancy and labour factors deserve their own reading, because almost none of them is a decision.

An assisted vaginal birth is on the list for a documented mechanical reason. Levator ani avulsion, where the muscle partially or completely detaches from the pubic bone, occurs in 7.8 percent of spontaneous vaginal deliveries and 51.1 percent of forceps deliveries. A second stage lasting more than an hour is on the list for a different reason: pudendal nerve denervation has been found in the levator ani of 80 percent of women after vaginal delivery, and both a longer second stage and a higher birth weight make that nerve damage worse. Caesarean was protective only when it was performed before labour had started, which says a good deal about how much of the strain sits in labour itself.

None of these were choices you made. Forceps are reached for when a birth has to be completed quickly, often to prevent something considerably worse. An occipito-posterior position is not a decision anyone takes, and a long second stage is not a lack of effort. If you are totting up how many apply to you, the useful conclusion is that assessment is worth asking for, not that something was done wrong.

There is one genuinely prospective item here. NICE recommends that a supervised three-month pelvic floor muscle training programme from week 20 of pregnancy be considered for women with specific risk factors. If several of these apply to you and you are pregnant, that is a specific thing to ask for by name. A Cochrane review of four trials covering 2,497 women also found that antenatal perineal massage from around 35 weeks reduced perineal trauma requiring suturing (risk ratio 0.91) and episiotomy (risk ratio 0.84), with the clearest benefit for first-time vaginal births.

What the list is actually for

The strongest preventive evidence attaches to pelvic floor muscle training, and it comes with edges worth knowing. Cochrane found that training reduces urinary incontinence in late pregnancy and in the early postpartum period, with a risk ratio of 0.38 at both points, on high-certainty evidence. Beyond 6 to 12 months no clear benefit has been demonstrated, and there is no evidence that it prevents faecal incontinence at any timepoint. That is a real result with a real boundary, and both halves of it are worth carrying.

It is also worth knowing what NICE does not advise. Its dietary guidance is general: fibre, fluids, weight management and smoking cessation support. There is no evidence cited for collagen supplementation as a preventive measure, which matters given how confidently that is sold.

The gap at the end of the list

The honest close is RCOG’s, not ours. RCOG notes that the 2021 NICE evidence review identified these risk factors, but that there remains no national guidance on which women are at greatest risk, or which specific interventions reduce that risk, and it is calling on policymakers to close that gap. So the list you have just read is a description of populations. It is not a calculator, and it cannot tell you what will happen to you.

That gap sits on top of a much larger silence. RCOG-commissioned polling found that 88 percent of UK women know what the pelvic floor is, yet 24 percent have never done a pelvic floor exercise, rising to 29 percent among 18 to 34-year-olds, and 69 percent have never had an NHS professional talk to them about it. A list of risk factors is only useful if somebody puts it in front of you, and for most women nobody has.

Before acting on any of this, rule things out. Unexplained bleeding, unusual or foul-smelling discharge, pelvic pain, a sensation of heaviness or dragging, persistent incontinence or an overdue cervical screening all warrant a GP or gynaecologist first. Those symptoms need diagnosis, not management. If you have been through that and what remains is a set of risk factors and a question about what to do next, a consultation at our private clinic is a reasonable step for an honest assessment. Bring the whole list, including the column you cannot change. It is context, not a sentence.