Symphysis Pubis Pain aka “Lightning Crotch” or Pelvic Pain During Pregnancy: Part 1

Part 1 - What is pubic symphysis dysfunction and what causes it?

Symphysis pubis pain is unaffectionately known as lightning crotch. It's that feeling that 20% of pregnant women know all too well—the sharp and sudden pain deep in their pelvis. The feeling of their pelvis shearing, pain that can stop a mama mid-step or leave her gasping for air trying to roll over in bed. Affecting 1/5 of all pregnancies, it's important to know what it is and what to do if you are one of the mamas affected.

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What is the pubic symphysis?

The pubic symphysis is a cartilagenous joint that connects the left and right pubic rami. The pubic symphysis helps transfer weight during normal activities like walking but also helps to stabilize the pelvis.

During Pregnancy, the pubic symphysis opens and expands in order to make more space for the baby to descend. With the help of hormones, the average pubic symphysis widens 3mm (30-40% of normal) during pregnancy and up to 20mm during labor. This widening is extremely beneficial to allow the baby to rotate, the pelvis to open and the baby to descend. 

What are the signs and symptoms of symphysis pubis dysfunction (SPD)?

SPD can present in many ways from a mild twinge of pain to a debilitating pain. Here are a list of ways pubic symphysis pain can show up:

  • Sharp pain at front of pelvis

  • Pelvic/pubic radiating to upper thigh/groin

  • Throbbing or deep achy pain around hips, low back, lower abdomen or perineum (between vagina and anus)

  • Pain with transferring weight from one leg to another - pain with walking, standing on one leg, climbing stairs, getting in/ out of the car or bed and rolling over in your sleep

  • Clicking or popping sound of pelvis accompanied with pain or discomfort

  • “Pregnancy waddle” to avoid pain

What causes pelvic pain during pregnancy?

Like most of women’s health care especially around pregnancy and postpartum, we do not know the cause of SPD. Realistically, there is not one cause but instead SPD is related to a variety of factors and it’s important to find the root cause for yourself. However, here are some theories as to the links/causes of pelvic pain during pregnancy and postpartum:

1. Prior pelvic trauma 

2. Hypermobility

Whether you have a connective tissue disorder like Ehlers-Danlos Syndrome or are just generally bendy, excessive mobility in the pelvis can lead to increased instability.

3. Pelvic joints not moving properly (unequal muscle pull), bony misalignment 

As we naturally progress throughout pregnancy we alter our general posture including the angle of our pelvis. Changes in biomechanics along with added weight and gravity can lead to increased pressure in the pubic region

4. Baby positioning 

Those kiddos can be an adventure before they even make it Earth-side. If a baby is posterior, asynclitic or transverse, it may lead to increased pressure or pain on the pubic bone.

5. Repetitive motion

If your occupation, hobbies or past fitness routines were one-sided, this may be shown in muscular imbalances that can lead to uneven force transfer and mobility/stability. 

6. Hormones

During the 1st trimester there is an increase relaxin and progesterone. This helps increase joint laxity to allow for the opening of the pelvis. The studies are inconclusive but this increase in relaxin may be related to SPD.


Stay tuned for Part 2- Managing pelvic pain through exercise and mindset