Treatment of Low Back Pain in Pregnancy – Special Considerations

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CHAPTER 124 Treatment of Low Back Pain in Pregnancy – Special Considerations

Adriana S. Prawak, Brinda S. Kantha, Larry H. Chou

INTRODUCTION

The occurrence of back pain in pregnancy ranges from 42% to 81%.¹^–⁷ In retrospective studies among young and middle-aged women with chronic low back pain, 10–25% reported the first episode of back pain during pregnancy.^8,⁹ It is therefore important that effective treatment be pursued.

Back pain during pregnancy is variable but can be classified into low back pain (LBP) or posterior pelvic pain (PPP). Differentiating between these two may be difficult. Low back pain is pain in the lumbar region with or without radiation to the legs whereas posterior pelvic pain is in the sacroiliac (SI) region with or without radiation into the thighs.¹⁰ Treatments for both types of pain include patient education, exercise, modalities, orthoses, medications, alternative treatments such as acupuncture, manipulation, massage, injections, and lastly, surgery. Close monitoring by, or contact with, the obstetrician is essential for appropriate medical management.

No longer should bed rest be prescribed since it has been shown to make no difference in decreasing pain, but increases sick leave and disability in low back pain patients.¹¹ Exercise as well as activity in patients with low back pain, in contrast, has been shown to decrease pain and improve function.¹⁰

EDUCATION

Patients who are provided with individual back care education that reviews anatomy and prognosis of back pain have a reduction in symptoms and sick leave time ^4,^12,¹³ Several authors have also recommended additional guidance, including orthoses (such as a customized lumbar corset), use of a lumbar roll while sitting and Ozzlo pillow while lying, maintenance of proper upright posture, frequent rests when symptoms increase, changing of positions frequently, use of stress management techniques, training in work and home ergonomics, and a self-directed home exercise program. These recommendations have generally been found to reduce back pain and improve activities of daily living.^4,^12,^14,¹⁵

Activities that should be avoided are also part of the education. These activities include high-impact, weight-bearing movements that asymmetrically load the body (such as twisting and lifting, single-leg stance postures, climbing stairs) and frequent motions at the end-range of low back and hip motions.

EXERCISE

General principles

Pregnant females should always consult with their physicians before making any decisions regarding participating in an exercise program. Although this disclaimer is frequently stated, many spine physicians are not well versed in the pregnancy and exercise literature. Women who regularly exercised before pregnancy were found to have a decreased risk of pregnancy-related back pain.⁴ Exercise during pregnancy can have a protective effect and does not appear to be detrimental to the unborn child.¹⁶ Those females who exercise do not have shorter or easier labors but it may enable them to tolerate it better. Exercise may help prevent as well as treat gestational diabetes since the utilization of large muscle groups improves insulin sensitivity.¹⁷

A major concern with exercise is fetal injury, which may potentially occur during the second and third trimester. It is therefore recommended that sports with a high risk of collision and contact sports be avoided. Fetal heart rate may increase during maternal exercise between 10 and 30 beats per minute; however, the clinical significance is unknown. Tachycardia may be due to hypoxia; however, blood flow to the uterus during exercise is maximal at its attachment to the placenta, thereby minimizing any potential hypoxic effects.¹⁸ There is a small decrease in the average birth weight of babies born to women who exercised intensively during pregnancy, yet there are no reported cases of adverse outcome in pregnancy. No cases of premature labor due to maternal exercise have been reported. Hyperthermia is also a concern since it has been shown to possibly cause neural tube defects in animals, though not in humans. Since the neural tube closes approximately 25 days after conception, hyperthermia should be avoided in pregnant females during the first few weeks of pregnancy. Since only minimal increases in core temperatures occur with moderate levels of exercise under normal environmental conditions, this level of activity should be safe in the pregnant female.¹⁹

Risks to the pregnant woman include an increase in musculoskeletal injuries such as low back pain and hypotension, which can occur as a result of lying in the supine position or with prolonged standing. Contraindications for exercise in pregnant females are as listed in Table 124.1.

Table 124.1 Contraindications to exercise in pregnant females

ABSOLUTE CONTRAINDICATIONS
MATERNAL RELATED
	Congestive heart failure
	Active myocardial disease
	Rheumatic heart disease
	Active infectious disease
	Thrombophlebitis
	Recent pulmonary embolism
	Restrictive lung disease
	Severe hypertensive disease
PREGNANCY RELATED
	No prenatal care
	Persistent uterine bleeding
	Ruptured membranes
	Placenta previa after 26 weeks of gestation
	Preeclampsia/pregnancy-related hypertension
	Intrauterine growth retardation
	Suspected fetal distress
	Severe isoimmunization
	Any risk for premature labor
	Incompetent cervix/cerclage
	Multiple gestations
RELATIVE CONTRAINDICATIONS
MATERNAL RELATED
	Severe anemia
	Unevaluated maternal cardiac arrhythmia
	Chronic bronchitis
	Poorly controlled seizure disorder
	Poorly controlled hyperthyroidism
	Poorly controlled hypertension
	Poorly controlled diabetes mellitus
	Heavy smoker
	Essential hypertension
	Thyroid disease
	Blood disorders
	Sedentary lifestyle
	Excessive obesity or underweight
PREGNANCY RELATED
	Breech presentation in last trimester

Adapted from American College of Obstetricians and Gynecologists committee opinion, Exercise During Pregnancy and the Postpartum Period.²⁰

If the pregnant woman was exercising before pregnancy, barring any pregnancy-related abnormalities or complications, she can safely continue without increasing complication risks to the unborn fetus. There is, however, a tendency for the mother to gain less weight and deliver smaller babies than sedentary women.²¹ She should be prepared to modify the intensity and duration of her regimen if she experiences severe discomfort and as the pregnancy progresses, usually around the sixth month. Sedentary pregnant women should not initiate high-intensity exercise programs, yet moderate exercise should be encouraged. As pregnancy progresses into the third trimester the adverse effects of supine exercises need to be taken into consideration.²² The Sports Medicine Australia position statement indicates that moderate exercise for pregnant females is safe. It also indicates that studies have shown that it may be possible for trained athletes to exercise at a higher level than is recommended by the American College of Obstetricians and Gynecologist. No adverse effects have been seen with resistance training with moderate weights and submaximal isometric contractions in pregnant women.²³

There are general guidelines published by the American College of Obstetricians and Gynecologists and the American College of Sports Medicine for exercise in pregnancy.^20,²⁴ Some highlights are listed below:

1. Thirty or more minutes of moderate exercise a day most days of the week, if not all, is safe unless contraindicated or advised by the physician.

2. Sports that include direct contact, trauma, or risk of falling are to be avoided, such as most court sports and downhill skiing.

3. Scuba diving should be avoided for the duration of the pregnancy due to the risk to the fetus of decompression sickness, since the fetal pulmonary circulation is unable to filter bubble formation.²⁵

4. Exertion at altitudes below 6000 feet appears to be safe; however, above 10 000 feet the risks significantly increase.²⁶

5. Supine activities are to be avoided after the third or fourth month of gestation, as well as prolonged motionless standing, due to potential venous return obstruction and subsequent decreased cardiac output.^20,²⁷

Prevention of back pain

Patients who regularly exercised before pregnancy are less likely to develop low back pain during pregnancy.¹⁶ In a study by Mantle et al.,³ there was no evidence linking backache during pregnancy with height, weight, obesity index, weight gain, or the baby’s weight. There were differences, however, between LBP in pregnancy and ‘mechanical’ LBP in the nonpregnant patient. This finding is consistent with Kristiansson.²⁸ Pregnant patients attending antenatal physical therapy had slightly less LBP reported, but no clear evidence of a protective effect was established. Smoking, however, has been shown not only to be detrimental to fetal growth, but in the nonpregnant population it has been correlated with disc herniation and the severity of low back pain.²⁹ Weight and weight gain were not associated with LBP in pregnancy. Focusing on weight loss or minimizing weight gain is not likely to be beneficial at preventing or treating back pain.^3,³⁰ A prospective study has shown that the functional pattern of back extensors is related and can predict future back pain, including in pregnancy. Dysfunction in the relaxation of the lumbar extensors was directly related to current and future pain levels, and back muscle activity level was inversely related to disability.³⁰

Strength and resistance training

According to the American College of Sports Medicine’s guidelines, an exercise program for pregnant females is somewhat unique in that stretching is recommended only to relieve muscle soreness and not to lengthen muscle because of concern with overstretching connective tissue.²⁴ Relaxin is a polypeptide hormone secreted by the corpora lutea of mammalian species during pregnancy. It is thought to facilitate the birth process by remodeling pelvic connective tissue via softening and lengthening of the pubic symphysis and cervix during pregnancy. Kristiannson et al. noted that there was an increase in serum relaxin levels that occurred, with peak value at the twelfth week followed by decline until the seventeenth week. Thereafter, it remained stable around 50% of peak value. By 3 months postpartum, serum relaxin was no longer detectable. They noted that there was a strong correlation between mean serum relaxin levels during pregnancy and symphyseal or low back pain during late pregnancy by medical history or pain provocation tests. Although this information is very interesting, it is currently not only impossible to determine the exact role of relaxin, but it is currently unalterable.³¹

Chan et al. found that soft tissue laxity may be more important as a cause of low back pain than disc prolapse or bulge in pregnancy.³² Before the hazards of radiation to the unborn fetus were known, earlier anatomical studies showed an increase in amount of articular fluid within the sacroiliac joint. This was thought to decrease friction and increase stability of the SI joints.³³^–³⁵ In 2001, Damen et al. found that SI joint laxity was not associated with pregnancy-related pelvic pain since laxity was found in all pregnant women. The patients who experienced symptoms of PPP had an asymmetric laxity of the SI joints.³⁶ Treatment recommendations including a nonelastic sacroiliac joint belt,^4,³⁷ as well as strengthening the muscles that stabilize the SI joint,³⁸ are discussed in more detail below.

Kristiansson et al. found that a provocative examination may be more useful than history and range of motion testing in identifying back pain in pregnancy. Since low back pain in pregnancy seems to have several pain generators because of the involvement of numerous ligaments forming a functional unit, this may have therapeutic implications.²⁸ Mens et al. showed less LBP and pelvic pain following cesarean section. Other risks with a positive correlation for LBP and PPP include: twin pregnancy, first pregnancy, higher maternal age, and larger weight of the baby, forceps or vacuum extraction, and fundus expression, prolapse, and flexed position of woman during childbirth. They hypothesized that peripartum pelvic pain is caused by strain of ligaments in the pelvis and lower lumbar spine due to combination of new or previous ligamentous injury, hormonal effects, muscle weakness, and weight of the fetus. Of all the predisposing factors, only muscle weakness and parturition position can be adequately addressed.³⁹

Franklin and Conner-Kerr took measurements in 12 pregnant females in the first and third trimesters and showed that there was a significant increase in low back pain and hyperlordotic posture; however, there was no correlation between magnitude of change in posture and low back pain. There was no conclusive evidence that postural changes leads to increased LBP. It may call into question the appropriateness for posture-correcting exercises in pregnancy.⁴⁰ In a study by Foti et al., a gait analysis was done on 15 pregnant women whose gait remained relatively unchanged throughout pregnancy, with no evidence of the ‘waddling gait.’ The maximum anterior pelvic tilt increased a mean of 4 degrees during gait, but there was a wide variability noted in test subjects. Significant increases in hip and ankle gait parameters resulted in increased demands placed on hip abductors, hip extensor, and ankle plantarflexor muscles during pregnancy. Perhaps strengthening these muscle groups should be emphasized. It should be emphasized that this study was not done on pregnant females with low back pain.⁴¹ As well, Ostgaard et al. concluded that biomechanical factors, such as abdominal sagittal diameter, transverse diameter, and depth of lumbar lordosis, could not alone explain back pain in pregnancy.⁴²

When the sacroiliac joint is thought to be the cause of back pain in pregnancy, using an SI joint belt (see below) and addressing the surrounding musculature may be helpful. The strengthening of muscles that create a force that is perpendicular to the SI joint and surrounding muscles, such as the internal and external abdominal obliques, the latissimus dorsi, multifidus (part of the erector spinae) and the gluteus maximus, could stabilize the SI joint via force closure.⁴³^–⁴⁵ Mens et al. studied persistent pelvic pain after delivery. Although 63.6% of patients noted improvement after 8 weeks of treatment, they found no difference in outcomes between the experimental group and both control groups. Participants in all three groups received an information video describing causes of peripartum pelvic pain, prognosis, and treatments in addition to recommendations on activity modifications and instructions on the use of a pelvic belt. The treatment group received additional nonindividualized training of the external and internal abdominal oblique and gluteus maximus muscles, while one control group was taught strengthening exercises for the rectus abdominus, the longitudinal components of the erector spinae, and the quadratus lumborum. The other control group did no exercises. Twenty-five percent of the treatment group developed increased fatigue and pain when strengthening the hip extensors and had to cease training. The development of pain and the training cessation may have offset any benefit that they might have otherwise appreciated.³⁸

The goal of exercise is not always to strengthen the surrounding musculature around the sacroiliac joint. Mooney et al. found symptomatic patients with SI joint pain had electromyographic evidence of hyperactivity in the ipsilateral gluteus maximus and contralateral latissimus dorsi. When those patients underwent a rotary strengthening exercise program, there was not only improvement in strength and myoelectric activity but also a decrease in pain.⁴³ Vleeming and colleagues reported tension not only in the gluteus maximus but also in the hamstring muscles further decreases the mobility of the SI joint.³⁷

The abdominal muscles are weakened during pregnancy. Fast and colleagues found that 16.6% of pregnant women had difficulty performing a single sit-up whereas all nonpregnant women could do a single sit-up. Although the abdominal muscles become insufficient during pregnancy, there is no statistically significant correlation with abdominal muscle weakness, specifically sit-up performance, and occurrence of LBP.^46,⁴⁷ In a cross-sectional analysis by Mens et al. performed in patients with posterior pelvic pain after pregnancy (PPPP) it was concluded that hip adduction strength can be used to measure disease severity. The apparent decrease in strength, however, appeared to be caused by the inability to activate the hip muscles rather than by true neurologic weakness.⁴⁸ Therefore, correcting the muscle inhibition would, in theory, decrease PPPP. Another exercise that could potentially decrease back pain is the ‘sitting pelvic tilt exercise.’ In a prospective, randomized, single-blinded study evaluating primigravidas treated during the last trimester, it was found that the ‘sitting pelvic tilt exercise’ could decrease back pain without complications to the mother or unborn child.⁴⁹

Aquatic therapy

Water therapy is used to aid in the treatment of many musculoskeletal disorders. In a prospective, randomized, controlled trial of pregnant women, with 129 patients treated with water gymnastics in the second half of pregnancy and 129 patients in the control group, water gymnastics was found to reduce the intensity of LBP and number of days on sick leave. Back pain invariably increased with pregnancy, but there was no excess risk of LBP, or urinary or vaginal infections in the water gymnastics group, indicating this method of treatment is safe in pregnancy. The water temperature ranged 32–34°C, and the program consisted of exercises recommended by the Swedish Swimming Society performed 17–20 times (once a week during the second half of the pregnancy). The duration of the class was one hour: 30 minutes of physical training and 30 minutes of relaxation.⁵⁰

Self-directed versus formal physical therapy

Should the patient undergo a formal physical therapy treatment program or simply receive instructions and/or perform exercises on an individual basis? Noren et al. compared the effects of an individual-based education and training program to no treatment in pregnant females who had peripartum pelvic pain. They found that the intervention group had a decrease in sick leave in comparison to the no treatment group.¹² In another study, Mantle et al. noted that when back care advice (as used in low back pain schools) was given to primiparous women as early as possible, patients experienced significantly less ‘troublesome and severe backache’ than the control group, who were not advised.⁵¹ In a randomized trial, Ostgaard et al. evaluated 407 pregnant patients.⁴ Sick leave was reduced in patients who had undergone an individualized program that consisted of back school education and training program, whereas the control group participants did not fair as well.

Summary

Stuge et al. performed a systemic review of prospective, controlled clinical trials assessing the effectiveness of physical therapy interventions for the prevention and treatment of pregnancy-related back and pelvic pain. Three high-quality studies were found. Two showed no difference in pain intensity and functional status between the exercise and control groups. The third study found a significant reduction in sick leave in patients participating in water gymnastics compared to the control group. Strong evidence supporting the effectiveness of physical therapy in preventing and treating pregnancy-related back and pelvic pain is lacking.⁵²

MODALITIES

Modalities can provide patients autonomous management of fluctuating painful symptoms. Such modalities normally include the use of hot and cold packs, ultrasound, and transcutaneous electrical nerve stimulations (TENS). The use of these modalities is modified, and sometimes contraindicated, in pregnant women. Although there is no significant literature on the use of heat or ice for analgesia in the pregnant patient, these options are widely available and easily utilized. They may be safe when used appropriately and cautiously in the forms of warm and cold packs placed over the low back. In the nonpregnant patient, therapeutic ultrasound is a common modality used during physical therapy. However, this option is not recommended in a gravid patient over or near the fetus since cavitation in the amniotic fluid could harm the fetus.¹⁰

TENS use during labor seems to be safe ⁵³ but evidence for improvements in pain is weak.⁵⁴ A randomized clinical trial performed by van der Ploeg et al.⁵⁵ reveals that TENS does not appear to decrease the intensity of pain or preclude the use of other forms of analgesia during labor. Similar results were seen in a study by Labrecque et al. of 34 patients during labor with the use of TENS to mitigate intensity of back pain.⁵⁶ Analgesic TENS used over the abdomen during pregnancy is not recommended by the FDA owing to a lack of safety data.¹⁰ In general, the use of modalities in treatment of pain is targeted toward temporary symptomatic relief and should be included as part of a comprehensive treatment regimen.