Back Pain During Pregnancy

Peripartum Pelvic Pain
Pain in the pelvic region, for which a clear-cut diagnosis has not been made, is termed peripartum pelvic pain. This pain may start during pregnancy, or within three weeks of delivery.

Anatomically, pain presents itself most commonly in the following areas:

• sacroiliac joints at the posterior superior iliac spine (42%)
• the groin areas (53%)
• coccyx (33%)
• pubic symphysis anteriorly (77%)
• and occasionally other areas of the pelvic and upper legs.

Rarely does pain occur below the knee. Pain tends to be influenced by posture and is associated with a waddling gait.

In approximately 80% of pregnancies, back pain is usually localized, but the site may vary. Although long-term pain is very rare, short-term pain tends to be dominant. Usually during the third trimester, 50% of pregnant patients will experience back pain. The prevalence of postpartum period pain falls to approximately 9% in decreasing order as follows: sacral, lumbosacral, lumbar, cervicothoracic, and remaining areas.

Disc Herniation
The prevalence of pain during the first nine months is thought to be 90% versus non-pregnant controls. For the same period of time, the non-pregnant controls had a 20% prevalence of pain. Although the pain may be severe, disc herniation, which is exceedingly rare during pregnancy, is not to be blamed. Disc herniation presents at the same rate as non-pregnant women—or at approximately 1:10,000 (one in 10,000).

Pain Indices
With respect to age and smoking, there has been no demonstrated difference in pain indices. However, a slight increase in peripartum pain has been demonstrated with higher body mass, more pregnancies, and a previous history of pain during pregnancy. Also, younger women tend to have more intense pain when compared to older women. A third of women describe their pain as disabling, restricting their activity, and a costly handicap. Approximately 10% of women describe their pain as extremely disabling.

Etiology of Pain
The etiology of pain is probably related to a combination of mechanical, metabolic, circulatory, and psychosocial contributing factors. One-third of the patients who experience pain starting during the first trimester when mechanical forces are not a significant force are highly indicative that the most probably cause is due to a change in hormonal influence.

It is believed that hormones cause change at the insertion point of ligaments to the bone. A higher concentration of ligaments in the lower spine may suggest the cause for a higher incidence of back pain in the multiparous mother who has had more exposure to hormonal influences.

Furthermore, an increase in premenstrual pain has occurred in a large majority of women whose pain has been suggestively influenced by hormonal changes. There has also been found to be higher serum relaxin levels in women with peripartum pelvic pain. There is some evidence to suggest that a different set of receptors is sensitized in the lower spine during pregnancy by hormones. Therefore, it is believed that most of the pain is secondary to hormonal changes rather than actual chemical stresses.

Lumbar Lordosis
It has been thought that lumbar lordosis is increased during pregnancy. However, in reality with x-ray studies, it has been demonstrated that lordosis decreases during pregnancy. Therefore, overall pain may be due to the muscles and ligaments combined with some alteration in blood flow to the pelvic musculature and ligaments.

Treatment
The treatment recommendations for pelvic pain in most obstetrical and gynecological textbooks are poor. Patients are instructed to avoid excessive weight gain, exercise to strengthen the back muscles, maintain correct posture, and to wear sensible shoes (not high heels).

Some activities do cause or aggravate pain. The most common are: 30 minutes of standing or walking, carrying a full bag of groceries, standing on one leg, climbing stairs, turning over in bed, intercourse, bending forward, stepping in or out of bed, and driving for 30 minutes.

Many treatment options are available, including a pelvic belt (by prescription), exercise, appropriate rest, medication, massage, and standard back exercises. It is interesting to note the percentage of women who found relief using these treatments.

• The pelvic belt helped approximately 50% of women during pregnancy and 66% after pregnancy.

• Bed rest and exercise appeared to be the best treatments resulting in the rapid recovery of 65%.

• Bed rest alone: only 40% got better

• Exercise alone: only 35% improved -- 20% of the patients worsened without appropriate bed rest included

• Manual Therapy: 20% of the patients indicated their pain was worse

• Medication and Massage: 70% of experienced only temporary relief

Good News
The good news is that the median time for back pain to resolve was within six months. Approximately 35% of patients continued to describe intermittent back pain lasting 1-1/2 months after partum. At the first postpartum visit, only 15% of patients continued to have low back pain regardless when the symptoms started during pregnancy. Therefore, in most cases, pain does improve after the postpartum period.