根 據文獻的統計，一個未懷孕的婦女，其兩片恥骨間的正常距離為4～5mm，一旦懷孕，荷爾蒙會使兩者間的距離至少增加2～3mm，因此若恥骨間寬度在9mm 以下，在妊娠的情況下是屬於正常的範圍，通常沒有症狀，即便有疼痛也較為不明顯；一旦兩者之間的距離超過4～5mm以上，則屬於恥骨聯合過度分離，就會引 起較厲害的疼痛。
懷孕中，分娩時或生產 後都有可能會發生恥骨聯合的過度分離，其機率的報導從1/300到1/30,000均有，與病人的體型無關。診斷方面主要是依據臨床症狀而來，而一些影像 學的檢查，例如骨盆腔的X光攝影（生產後），超音波檢查（懷孕中），或核磁共振的掃描，可以做為輔助性的診斷工具。
一 般而言，此類病人的預後均非常的良好，但有少數人其恥骨聯合分離的原因，是因為骨盆排列的錯誤，而非單純因對荷爾蒙的敏感的，則此疼痛可能會持續。大部分 的婦女在下一胎懷孕時，恥骨聯合分離的現象會再發生，但通常都不會比第一胎厲害，哺餵母乳所產生的荷爾蒙變化，亦不會造成產後的恥骨疼痛，孕婦不必過度擔 心。
Pelvic Girdle Pain
Pelvic pain in pregnancy affects up to one in five women. Pelvic pain is also known as Pelvic Girdle Pain (PGP).
It is also is known as:
- Symphysis Pubis Dysfunction (SPD)
- pelvic joint pain
- twisted hips
- pelvic relaxation
- pelvic arthropathy
- osteitis pubis
Pelvic joint pain explained
Although it appears to be a firmly fixed circle of bone, the pelvis is actually four separate bones jointed together - the sacrum and coccyx at the back and at the sides the two hip bones which curve around to meet at the front. These are joined at the front by the symphysis pubis.
"In pregnancy the hormone relaxin is released to soften the joints in preparation for the birth of your baby, but in around one in 35 women the hormone causes the ligaments to soften and stretch too much and become painful," says Ann Johnson, superintendent physiotherapist in women's health at Leeds General Infirmary.
It is normal for there to be a gap of 4-5mm between the two pubic points at the symphysis pubis joint and during any pregnancy this widens by another 2-3mm. If this gap widens more than this pain may occur and in some cases a severe form of the condition called diastasis symphysis pubis is diagnosed.
The job of the symphysis pubis joint is to hold the pelvis steady when we're using our legs, and if the ligaments have softened or stretched too much it won't work properly and strain is put on the other pelvic joints, causing pain.
How to recognise SPD
The main symptoms are pain in your pubic area, groin, the inside of your thighs and sometimes in your lower back and hips. "The pain is worse when you walk or move and climbing stairs is especially painful. Getting in and out of the car or turning in bed is also painful," says Ann Johnson. You might hear a clicking sound when you walk and feel as though the bones are grinding together. Opening your legs is difficult and painful.
If you are experiencing these symptoms, don't let your doctor or midwife dismiss them as 'part of being pregnant'. The condition is now more widely recognised than it was a few years ago, says Ann Johnson. It can be diagnosed by examining your pelvic joints and watching how you move. If it occurs after giving birth, as it does in a few cases, a pelvic X-ray or scan can be done. "You'll normally have a urine sample taken too to exclude any other causes of pain such as a urine infection," says Ann Johnson.
SPD normally happens from the second trimester of pregnancy onwards, but can occur at any stage in any pregnancy, even if you've never suffered before.
- The best person to treat SPD is an obstetric physiotherapist, and usually your GP or midwife can refer you.
- The physiotherapist can give you a pelvic support garment to wear such as a belt or Tubigrip bandage, and crutches if walking is difficult. You'll also be given gentle exercises to help strengthen the muscles supporting the joint and general advice about posture and activities to avoid. S/he will also discuss delivery options and positions with you. If necessary, you can also be referred to an occupational therapist for other aids to make your daily life easier.
- Your doctor can prescribe safe painkillers to take in pregnancy, usually paracetamol.
- The most effective alternative therapies, according to the British SPD Support Group, include chiropractic and osteopathy which help to relieve joint pain.
- In most cases you'll be fully recovered in six months after giving birth, but if the pain continues, surgery to fix the joints together may be considered.
- Rest as much as you can - it really does help.
- Avoid movements that place extra strain on the symphysis pubis. When you get out of bed, roll out with both legs together. When climbing stairs, go one step at a time. Avoid breast stroke when swimming.
How will it affect my labor?
- Make sure anyone attending you is aware that you have SPD. Your midwife should measure how far you can comfortably widen your legs at the onset of labour and ensure that you don't exceed this.
- "If you have an epidural or spinal block injection, it's particularly important to ensure you don't exceed the comfortable gap as you won't be able to feel any damage you do," says Ann Johnson.
- In very severe cases, an elective caesarean may be considered.
- Make sure you're in a comfortable position before any internal examinations are performed.
- Experiment with different positions for giving birth - kneeling on all fours may be more comfortable for you.
Can I avoid it happening again?
Unfortunately, there's no way of predicting whether you'll suffer in subsequent pregnancies, and if you do whether it'll be more or less severe than your first experience of SPD. However, if you have experienced it in one pregnancy, be aware of any signs of pain from the start of a subsequent pregnancy and see your midwife. Being referred to a physiotherapist early on and receiving treatment can help to reduce the pain as much as possible. "However, it's best to avoid a subsequent pregnancy until your baby is walking independently, as lifting your child will be especially difficult if you suffer SPD again," says Ann Johnson.
Nichola tells her story: 'The pain began suddenly and severely at 26 weeks...'
Nichola Morse, 32, from Leeds - full-time mum to Matthew 10, Jacob three and Annie four weeks, and moderator for SPD forum at babyworld tell us how she copes with SPD
"The pain began when I was pregnant with my second son Jacob, although it was my sixth pregnancy as I'd had miscarriages. The pain began suddenly and severely at 26 weeks. I could feel my pelvic bones grinding together when I moved, and walking was very painful. I rang the hospital and they referred me to a specialist and told me not to move until I'd seen him.
"I saw a physiotherapist at the hospital and was given a Tubigrip support, a brace and crutches. I was advised to be careful with any movement that involved separating the legs.
"I drove everywhere and we lived off microwave meals for rest of the pregnancy. In labour the gap between my legs was measured and I had an epidural. The pain slowly improved, but three weeks after giving birth I picked up Jacob in his carrycot and the bones all separated again and I was in pain for the next two years. I was on strong prescription painkillers, I had a wheelchair and crutches. I also had lots of physiotherapy and was given two spinal block injections. At one stage I had a 14mm gap between the pubic joints.
"I've just had my third child, Annie, now four weeks old. I had a much better pregnancy this time as I was better prepared and very careful. The pain is easing, though I can't walk far yet."
- The Pelvic Partnership was founded by women who have experienced SPD and their website offers information and support -www.pelvicpartnership.org.uk/
- Scottish Charity for Symphysis Pubis Dysfunction - PINS (Pelvic Instability Network Scotland) website www.pelvicinstability.org.uk
by Sarah Purcell
(resource from Baby World)