What is pelvic girdle pain in pregnancy?

You may have heard of the relaxin theory to explain pregnancy-related PGP. The theory is that pain is driven by instability. Relaxin is the hormone that steadily increases through pregnancy to loosen the pelvic joints to prepare for labour. Now the theory goes that this increased movement in the pelvic joints causes uneven movement, making you more unstable, causing pain. It’s a logical theory, but it doesn't hold up when examined in the context of scientific research. When we study the 50% who experience pain in pregnancy versus the 50% who don’t, pelvic joint changes and postural changes do not have an impact.

The biggest factor that increases your risk of being one of the unlucky ones is a history of experiencing pain in the lower back or pelvis. Other factors found are higher BMI, smoking, depression, anxiety, occupational heavy loads, those who are dissatisfied with work, and a belief that pain will not improve^3,4. So why would these things cause PGP?

Enter the neuroendocrine theory – all these factors point towards a stress response from our nervous and hormonal systems. Pain is a sensitivity alarm, not a damage alarm meaning, pain is simply the brain’s opinion of danger. It forms that opinion from our previous experiences, current situation and emotional state.

Pregnancy is a melting pot of changes to our nervous and hormonal system, which means pain can be triggered much more easily. Essentially, our sensitivity alarm is far more sensitive^5,6,7,8. Think about showering with sunburn. When the mildly warm water from the shower hits your sunburnt skin, it feels like the area is being scorched. It isn’t, and no further damage to the skin is occurring, but the temperature receptors in your skin have been become hypersensitive.

Now, let’s take the trigger of getting out of the car, which can cause groin pain in pregnancy. We have stretch receptors in our groin that provide our brain with feedback on the amount of stretch the area is undergoing.If I was to try and do the splits (please note I have never been capable of doing the splits!), then I would absolutely want my stretch receptors to tell my brain to give me pain signal, because if I keep going, I am going to tear a muscle. This is a useful pain signal which keeps me safe..

However, if the pain system has become hypersensitive, then its perception of the perceived danger will also be altered. Now, as I lift my leg to get out of the car, widening my legs, my groin stretch receptors perceive this as a threat. I get the same pain, but there was no actual threat of damage.

Pregnancy-related PGP is a sensitivity issue, a faulty alarm system. So, can we recalibrate the sensitivity alarm during pregnancy? Absolutely, we can!

There are four key areas that can impact our pain centre’s sensitivity: gut health, movement, rest, and stress. You need to address your hypersensitivity drivers to improve your pain, which is why a thorough assessment by a Pelvic Health Physiotherapist is key.

Let’s delve into these four key areas in more detail and some general advice of how to get started…

Many women with pregnancy-related PGP have a vaginal birth and the pain does not impact their experience. This makes sense when we understand that the driver of PGP is sensitivity and not instability. Essentially, the neuroendocrine system is far too preoccupied with labour to also produce PGP as well. In fact, in a study of over 10,000 women, C-section increased the risk of severe PGP continuing at 6 months postpartum⁹.

However, it is important to flag these symptoms to your birthing team, as you can then discuss positions that may be more comfortable for you during labour. It’s a good idea to practice labour positions before the big day to test them out. Many women find water soothing and so if a warm bath or a walk about the swimming pool helps your PGP then you may want to consider a water birth. You can discuss this with your midwife as to the suitability and availability of this in your area.

The key to helping PGP is in the detail, not blanket rules. I’d really encourage you to seek help, especially if your PGP is becoming severe enough to limit your mobility or affect daily activities. Speak to your Midwife, Obstetrician or Pelvic Health Physiotherapist for support.

It’s also worth noting that being in chronic pain is likely to affect your mental health and so support for pregnancy related PGP needs to consider your emotional well being also. If you need support with this if the pain becomes overwhelming, then speak to your healthcare provider.

Suffering with PGP through pregnancy is not a foregone conclusion, it can improve and even resolve during a pregnancy, so seek help and guidance early.