The Relationship of Low Back Pain to Postural ChangesDuring Pregnancy

To determine the nature of the posturalchanges in women during pregnancy, the de­grees of lordosis, kyphosis and pelvic inclina­tion ln34 pregnant women were measured pro­gressively. The incidence of low back pain ateach of the three occasions was also monitored.Analys~s revealed that significant increase'soc­curredin the lumbar and thoracic curvaturesand that 82 percent of the women experiencedback pain at some stage during their pregnancy.However, no significant relationship was re­vealed between posture and back pain and thestudy did not support the frequently made as­sertions that back pain in pregnancy lsdue toan increase in lordosis.

JOANNEE.BULLOCK

Joanne Bullock, B.PhtY4Hons. 1),isa graduate of theUniversity of Queensland and combines research ac..tivitieswith clinical practice. Miss Bullock won theBoots ,Award for Research in 1986, with a paper onthe topic of this article.

GWENDOLEN A. JULL

Gwendolen Jull, M.Phty.,Grad.Dip.Manip.Ther., is aSenior Lecturer in the Department of Physiotherapy,University of Queensland.

MARGARET I. BULLOCK

Margaret Bullock, Ph.D.,B.Sc.App., is Professor ofPhysiotherapy and Head of the Department of Physio..therapy, University of Queensland.

Pregnancy is a time of rapid bioIog...ieal change and all bodily organs andsystems are affected by the process(Danforth 1967)a The period of ges­tation involves profound physiologicalchanges which, together with the phys­icaladjustments brought about by thepregnancy itself, can have considerableimplications for the comfort of thewoman during the pregnancy.

The growth of the foetus brings withit alterations in body mass, a subse­quent change in the .centre of gravityand stretching and· possible weaknessof the abdominal musculature. Thesecould lead to compensatory posturalchanges which, in Danforth's (1967)view could be responsible for backachein the pregnant womana

There are few who would argue thatback painis a common occurrence dUf'"ing pregnancy. Unfortunately, little re­search has been undertaken to studythe postures assumed during pregnancyor their possible relationship to backpain. For this reason, a study was un­dertaken in the Department of Physio­therapy, University of Queensland. Itaimed to measure the degree of spinalcurvature and pelvic tilt in the sagittal

plane in women during pregnancy, todetermine the nature of·any posturalchanges occurring and to determinewhether there was any significant re­lationship between posture and backpain during pregnancy.

The StudyFor this study, progressive changes

in the degrees of thoracic kyphosis,lumbar lordosis and pelvic tilt in thesagittal plane were calculated frommeasures· of spinal and pelvic inclina­tions, taken three times on women dur­ing their pregnancies. At each assess­ment, women were surveyed about1?ack pain onset.

SubjectsThe subject group consisted of 34

women attending the antenatal clinicof one large Brisbane women's hospi­tal. Women were included if they hadnot experienced back pain before preg­nancy and were willing to participate.At the time of initial assessment,women were between 14 and 22 weeksgestation (mean = 18 ± 2.96 weeks).

It had been decided to monitor pos'"tura! curves three times at eight weeklyintervals before the 38th week of preg­nancy. This demanded that the lateststage for initial assessment be 22 weeks.The minimum of 14 weeks was consid­ered appropriate as the increase in uter­ine size usually just becomes evident atthis stage and this was thought to markthe beginning· of the increase in ab­dominal size and body weight.

Subjects were excluded from thestudy if they suffered anymusculo­skeletal disorder of the spine, predis­posing them to an abnormality of pos,...ture, or they had suffered any backpain before their pregnancy.

The subjects included were aged be­tween 15 and 35 years, 20 being pri­magravida and 14 multigravida. Table1 shows the distribution of age andgravida in the subject group.

MeasurementsData.collected included measures of

postural curves in the sagittal plane,pelvic inclination, height, weight andthe incidence and location of any backpain experienced.

In order to provide quantitative

10 The Australian Journal of Physiotherapy. Vol. 33t No. 1,1987

Low Back Pain and Pregnancy

erence to the formula shown in Figure2. This was similar to the approachtaken by Cobb (1960), in his measure­ment of the degree of curvature in sco­liotic subjects.

The angle of pelvic inclination in thesagittal plane was defined as the anglewith the horizontal subtended by theline joining the posterior superior iliacspine (PSIS) and the anterior superioriliac spine (ASIS). This definition wasconsistent with that used by both Flint(1963) and Sanders and Stavrakas(1981) in their measurements of pelvicinclination. In this study, the pelvicangle was measured by the use of anelectrogoniometer (with associatedvoltmeter) attached centrally betweenthe two arms of adjustable curved an­thropometric calipers (Figure 3). Anelectrogoniometer is designed to givedirect angular readings electronicallyvia a potentiometer connected across a9 volt battery. The instrument is similarin principle to the clinometer, and givesa measure of the angle turned by the

- degree of Lumbar lordosis

- a-{3

a" angle Io'llh the horl,:ontalof langen/ 01 T12-L 1

{3 • angle "",fh the hor,zon/alof langenf of L5·S1

if - (90 + aJ + (90 . {}I

Nole The same formula IS used forIhe measwes 01 T1· T2 and T12-L 1.

designated intervertebral levels (T1-T2,TI2-LI, and L5-S1).

Measurement of the degrees of ky­phosis and lordosis was made by ref-

Figure 2: Formula used for meas..urement of spinal curvature

measures of thoracic and lumbar curvesover time, a clinometer was used. Aclinometer is an extremely accurate in­strument used as a 'standard' for meas­urement in a Metrology laboratory andit measures the angle of inclination withthe horizontal of the surface on whichit is placed. For the purposes of thisproject, the clinometer was mountedon a supporting base with two feetspaced 2cm apart and equidistant fromthe centre of its rotation. These feetallowed exact placement of the clino-meter along the spine (Figure I) at three Figure 3: Measurement of pelvic inclination

Figure 1: The clinometer in use

Table 1:Distribution of age and gravida in women measured for postural curvature

Gravida Number of Age (years)subjects 15..20 21 ..25 26-30 30..36 X SO

Primi 20 6 5 7 2 23 5.1Multi 14 0 9 3 2 28 5.5

The Australian Journal of Physiotherapy. Vol. 33, No.1, 1987 11

Low Back Pain and Pregnancy

Table 2:Results of ANOVA and Random Effects Model (I)To determine: a) repeatability of researcher technique;

b) repeatability of postural alignment in normal subjectson one day.

searcher's repeatability in measuringtechnique.

A second repeatability trial, usingwomen in early pregnancy as subjects,was carried out because it was thoughtthat the pregnant state and the possibleincidence of back pain or general dis"'"comfort might affect the pregnantwoman's ability to maintain a consist­ent alignment in standing for a periodof time. Thirty-four pregnant womenwere included in this trial, which fol­lowed exactly the same procedure asthat for normal subjects. TheF..;valuesand percentages of inter-subject vari­ation were calculated. These are sum­marized in Table 3. Examination ofthese values demonstrated that themeasurements of spinal curvature andpelvic inclination in pregnant womendid not vary significantly between trials.It could be assumed therefore that atthe stage of pregnancy when there waslittle increase in abdominal size, themeasurements recorded were repre­sentative of the woman's posture.

To ascertain whether postural align­ment varied from day to day, spinaland pelvic inclinations in normal sub­jects were measured on three separatedays. For this trial, 25 young womenaged between 18 and 28 ·weremeas­ured, as before. To control for theeffect of 'time of day' and environ­mental conditions on posture, eachsubject was measured at the same timeof day in a quiet, airconditioneden"'"

For the first trial, 25 normal youngwomen aged between 18 and 28 wereincluded. The series of four measureswas completed three times. and the de­grees of kyphosis, lordosis and pelvictilt calculated.

For each of the two spinal inclina­tionsanQpelvic inclination, an Anal­ysis of Variance (ANOVA) was con­ducted to determine whether there wasany significant aifference in themeas­urements for each subject at each ofthe three trials. The results revealedthat ·there was no significant differencebetween the three sets of measures (Ta­ble 2). In addition, a Random EffectsStatistical model was used to assess theextent of random error in themeas­urements.For each of the three vari­ables, the amount of variation attrib­utable to inter-subject variation wascalculated and expressed as a ratio ofsubject estimated variance to total var­iance over the 25 measurements.

When the ANOVA and Random Ef­fects Model are used in combination,an insignificant F-value combined witha high percentage of intersubject var­iation indicates that a high degree ofrepeatability of measures maybe as­sumed. The results of these analysesfor this repeatability trial indicated that

~ there was no significant variation inmeasurement between each of threese­Ties..This demonstrated both the sub­ject's consistency of postural alignmentin standing on one day and the re-

revolving instrument in reference to itsvertically hanging mass. During thisstudY,when the two points of the cal­ipers were placed on the PSIS and ASISrespectively, the voltmeter provided areading from which the angle of slopeof t1l,e line joining them could be cal­culatect

Additional measurements recordedprogressively during this study were theheight and weight of the pregnantwomen. A standard anthropometer wasused for measuring height and a set ofAvery .Jockey scales was ·used for re­cording weight.

Details relating to onset of back painduring pregnancy were collectedthrough subjective assessments of thewomen at each assessment.

ProcedureTo measure the spinal and pelvic

inclinations, the subject was asked tostand comfortably erect on a sheet ofpaper placed 'on the floor, so that atracing of both feet could be made foruse during subsequent measurementsof that subject. After the woman hadremoved her outer clothing, skin mark­ingswere made at left PSIS, left ASIS,and the intervertebral levels atL5-S1,T12-Ll and TI-T2. The accuracy ofthese .spinal markings 'was confirmedwith the subject in side lying by pal­pating the relevant interspaces whileflexing and extending ·ber spine. Thewoman was then asked to stand com­fortablyereet with the feet on the footprints and to look directly ahead. Threesets of measurements of pelvic andspinal inclinations at the three spinallevels were then taken, using the elec­trogoniometer and clinometer (see Fig­ures land 3).

A series of reliability tests were un­dertaken to establish whether the re­searcher could read the measuring in­strumentsconsistently and to determinea subject's ability to maintain a con­sistent postural alignment during thetime required for measurements.

Measurement

KyphosisLordosisPelvic Inclination

F..Value(2,48)

0.66940.23960.3946

F crit= 19.46

Percentage of Total Variationdue to Populalion of group

97.698.693.2

(Pagano 1981)

12 The Australian Journal of Physiotherapy. Vol. 33, No.1, 1987

Low Back Pain and Pregnancy

Table 3:Results of ANOVA and Random Effects Model (II)To determine repeatability of postural alignment in pregnant women on

one day"

forms by the researcher until the com­pletion of the three. series of measure­mentsofall pregnant women.

Table 4:Results of Random Effects Model for normal subjects on three separatedays

To determine repeatability of postural alignment from day to day.

vironment on each occasion. Table 4provides a summary of the F valuesand percentages of inter...subject vari­ations calculated from the values ofkyphosis, lordosis and pelvic inclina­tion. In each case, the F value was notsignificant and there was a high degreeof inter-subject variation. These figuresshow that when asked to stand in acomfortable erect position, individualnormal subjects assume the same pos­tural alignment as they have adaptedon previous occasions, even when aconsiderable period of time has elapsedbetween those occasions.

The results of these repeatability testsindicated that in this study,any majorchanges in postures measured in thewomen throughout pregnancy could beattributed to some external factor (forexample, the pregnancy) and not to·an

Measurement

Kypho~,is

LordosfsPelvic Inclination

Measurement

KyphosisLordosisPelvic Inclination

F..Value(2,48)

2.42302.48081,,9834

Fcrit= 19.46

F-ValiJe(2,48)

0.58891.06741.8704

F crit = 19.46

Percentage of Total Variationdue to Population of Group

96.997.490.5

(Pagano 1981)

Percentage of Total Variationdue to Population of Group

0.9230.9000.840

(Pagano 1981)

innate inability to adopt a repeatablepostural alignment on separate occa­sions.

During the principal study, womenwho satisfied the inclusion criteria werewithdrawn from the waiting room ofthe ante-natal clinic, for the prelimi­nary examination. After checking theexclusion criteria the name, age andgravida of those subjects retained inthe study were recorded. Measure­m.ents were then taken as described pre­viously, an assistant recording the val­uescaUed by the researcher.

Each subject was re-measured duringroutine visits to the ante-natal cliniceight and sixteen weeks after the firstassessment. To avoid expectancy biason the part of the researcher at sub­sequent measurement sessions, no ref­erence was made to the subjects' record

ResultsPreliminary calculations and anal­

yses were conducted to determine thedistributions of the recorded variablesof age, gravida, the mean height andweight, the incidence of pain at eachassessment and the degrees of ky­phosis, lordosis and pelvic inclination.

The distribution of .age and gravidaof women was shown in Table 1..Itwould,be unusual to find equal distri­butions of primigravida and multi­gravida women in a small sample ofpregnant women.Nevertheless,primi­gravida and multigravida women werewell represented in each age group ex­cept the youngest.

The means and standard deviationsof the women's heights and weightsindicated that while there was littlechange in the ·women'sheight duringthe assessment period, (164.7 ± 6.2;164.7 ± 6.'6; 164.3 ± 5.6cm),majorchanges occurred in weight during thelatter half of pregnancy, (59.6 ± 7.9;64.5 ± 8.6; 68.3 ±9.7 kg). To avoida high correlation with height in thestatistical analysis of Multiple Regres­sion, the ratio of weight over heightwas calculated for each assessment.

It was found that of the 34 women,30 (88.2 percent) suffered pain at somestage during their pregnancy. .At thefirst assessment, twenty-one (62 per­cent) had already experienced back painand by the second and third assess­ments, a further four and five womenrespectively, had experienced backpain. Two subjects who had pain atinitial assessment had a period of reliefat Assessment 2, but regained their painby Assessment 3. Another two had lostpain by Assessment 2 and reported nofurther problem in this regard duringpregnancy. The percentage incidenceof pain at Assessments 1, 2 and 3 were62, 62 and 76 respectively. At the be­ginning of the study, it had been an­ticipated that pain would have started

The Australian Joumalof Physiotherapy. Vol. 33, No.1, 1987 13

Low Back Pain and Pregnancy

Table 5:Means and standard deviations for lordosis, kyphosis and pelvicinclination at each assessment

Table 6:The results of the ANOVAs for lordosis, kyphosis and pelvic inclinationat each assessment

Source SS OF MS F P

LORDOSISAssessment 906.5054 2 453.2527 21.976 0.000*Error 1361.2416 66 20.6249

KYPHOSISAssessment 744.2950 2 327.1475 21.819 0.000*Error 1125.7049 66 17.0561

~ PELVIC INCLINATIONAssessment 28.7631 2 14.3816 2.995 0.057Error 316.8902 66 4.8014

N = 34* P < 0.05

between the 4th and 9th months ofpregnancy there was a significantchange in the magnitude of lordosisand kyphosis. For pelvic inclination theANOVA revealed no significant dif­ference in the overall·assessment.

The relationships between lordosis,kyphosis and pelvic inclination andgravida, pain, age and weight/heightwere examined using the Pearson Prod­uctMoment Correlation and fromthose data, a further examination .was

after the commencement of abdominalenlargement in more cases than it did.However,as outlined above, over halfof the women already had pain at As­sessment 1, and only a small propor­tion (11 of the 34) gained or regainedpain during the major growth period.

\

FroI1\ the values for spinal and pelvicinclinatipn,measures of the degrees oflordosis, kyphosis and pelvic inclina­tion were calculated for each assess­ment. The means and standard devia­tionsof these curves are shown in Table5. Examination of the values in Table5 reveals that the mean degrees of 10r­dosisand kyphosis increased by 7.2and 6.6 degrees respectively over the

. 16 week assessment period. The meanpelvic inclination decreased by 1.3 de­grees between Assessments 1 and 2 andincreased minimally by 0.6 degrees be...tween Assessments 2 and 3. 1

Statistical analyses of results wereundertaken to determine whether therewas a significant difference in spinalcurvature and pelvic inclination be­tween each pair of assessments, 1­2; 2 - 3; 1 - 3; to determine theinter-relationship between the threepostural parameters and gravida, pain,age and weight/height; and to deter­mine whether there was a significantdifference in the postural curves ofwomen who had pain or who had nopain" The level of significance chosenfor this study was five percent (p <0,,05), which indicates that the differ­encebetween the means was not likelyto occur by chance (Thorndike 1978).

To determine whether there was asignificant change in each of thepos­tural parameters measured throughoutpregnancy, three one-way Analyses ofVariance (ANOVA) were conducted..The ANOVA revealed that the meanvalues for both lordosis and kyphosisincreased significantly over all assess­ments (see Table 6).. Post hoc analysis(Newmans-Keuls test) showed thatthere was a significant difference in themeans between Assessments 1 - 2, 2- 3, and 1 - 3(p < 0..05 for bothspinal curvatures). This indicated that

Measure

Lordosis

Kyphosi.;)

PelvicInclination

AssessmentDegrees

Mean Standard Deviation

1 26.7 8.82 29.4 9.83 33.9 10.9

1 44.3 7.22 47.8 8.13 50.9 8.4

1 5.8 3.32 4.5 3.53 5.1 3.1

done using a Multiple Regression Anal­ysis. Pearson Product Moment Co­efficients were calculated for the aboveparameters at each .assessment. Thevariable to be predicted is commonlycalled the criterion and thesetofvar­iablesused to predict the criterion areknown as predictors (Thorndike 1978).The·results revealed that weight/heightcorrelated with lordosis at each·assess­ment (r=0.4409, 0.4217 and 0.3782,respectively, where r crit= 0.3494),

14 The Australian Journal of Physiotherapy. Vol. 33, No.1, 1987

Low Back Pain and Pregnancy

suggesting that increased weight/heightvalues are associated with an increasedlordosis.

In Assessment 1, none of the otherpredictors correlated with any of thecriterion parameters, but a correlationbetween kyphosis and pain appearedin Assessment 2, .suggesting that withincreasirl~ kyphosis there is an increasein pain (r' = 0.3813). Kyphosis and ageshowed a negative correlation indicat­ing that for pregnant women, as ageincreases kyphosis decreases (r=0.3782). At Assessment 2 there ap­peared to be a relationship betweenweight/height and pain, suggesting thatthese two predictors may increase to­gether in some form of relationship (r= 0.3588).

Due to the large number of variablesin this .study, Multiple Regression wasthe most appropriate statistical profe­dure to determine the inter-relation­ships between gravida, pain, age,weight/height and lordosis, kyphosisand pelvic inclination. The contribu­tion of each variable in the model wastested for significance using the statis­tical computer programme REGRAN(Veldman 1967).

Using lordosis as the criterion andthe other four variables as thepredic­tors, lordosis was not found to be sig­nificantlyrelated to any of the predic­tors in Assessments 1 or 2,F(4,29) =2.284 andF(4,29)= 1..718 respectively.However, weight/heightwas found tobe significantly related to lordosis atAssessment 3 (F value, (4,29)= 3.508,p = 0.0185).

With kyphosis as the criterion, nosignificant relationships were found inany of the full models of ·regressionfor any of the assessments.

Using pelvic inclination as thecri­terion, no significant relationships werefound at Assessments land 3. At As­sessment 2, 32.50070 (1-= 0.3250) ofthe total variance was explained by thepredictorgroup,F(4,29)= 3.490, p=0.0189. This demonstrates a significantrelationship between pelvic inclinationand gravida, pain, age and weight/height. In the reduced model, the two

predictors, pain and weight/height ,were found to be significantly relatedto pelvic inclination p == 0.0042 and p= 0.0257 respectively.

To determine if .there was any sig­nificant difference in posture at anyassessment between women with andwithout pain during pregnancy, one­way ANO·VA's were done using therelevant means and standard devia­tions. The only Significant differencein the means of those with pain andthose without occurred for kyphosis inthe second assessment (p == 0.045).Those people with pain had a highermean thoracic kyphosis than thosewithout.

DiscussionDespite the prevalence of back pain

in women during pregnancy, surpris­ingly little research appears to havebeen undertaken to determine thecause, or to ascertain how it might berelated to any of the particular featuresof the gestation process or the preg­nancy. Authors .such as Wickstrom,Haslam and Huchinson (1955), Sands(1958) andSpankus (1958) suggest thatan aching back is a 'normal state' fora pregnant woman and that little moretherapy is required than 'a certainamount of patience in listening to thepatient describe the severity of herpain'. It is perhaps because of this at­titude that so little research has beendirected at this important topic..

While it is commonly acknowledgedthat pain is.a frequent occurrence dur­ing pregnancy (Wickstromet of 1955,Epstein 1959, Hagen J974), the patho­physiological mechanism of this painproduction has not beenclearlyenun­ciated.A number of authors have dis­cussed the cause or accentuation ofback pain as arising from the preg­nancy. For example, Rhodes (1958) hassuggested that nearly all the backachesof childbearing are postural in origin.In the view of Danforth (1967), Epstein(1959) and Spankus (1965), thepos­tura! adjustment is one of increasedlumbar lordosis, occurring by the

eighth month of pregnancy to preventthe woman's loss of balance.. Spankus(1965) .has suggested that a forwardpelvic rotation develops in pregnancyand that the rapidity of this 'physio­logic' postural change causes unusuallysevere stress on ligaments and muscularattachments,with resultant back pain.Unfortunately, the absence of quanti­tative data has prevented thesubstan­tiation of any of these views and indeedhas prevented the implementation ofscientifically based therapeutic meas­ures.

This study demonstrated that sig­nificant increases in curvature occurredin both the thoracicand lumbar regionsduring successive assessment intervals(Table 5). It should be .noted that al­though the total mean changes wererelatively small (ie six to eight degrees),some women showed a marked in­crease in curvature during ·the sixteenweek period, the largest change in lor­dosis for one woman being 22..3 de­grees and in kyphosis, 24..6 degrees(Bullock 1985).

There have been some differingviewpoints as to the ways in which awoman adjusts to carrying the weightof the foetus.. Forexample,Rhodes(1958), Epstein (1959), Spankus (1965),Danforth (1967) and Nwuga (1982) re­fer to an increase in lordosis. Thesig...nificant increases in lumbar curvaturefound in this study confirm their sub­jectiveopinions. On the other hand,Cyriax (1965) and Snijders et af (1976)considered that women lost their lor­dosis when adjusting to accommodatefor the growing pregnancy. Althoughsome women in this study showed sucha postural change, they were in theminority.

Sands (1958) and Spankus (1965)considered that forward displacementof the sacrum and pelvic inclinationtook place during pregnancy.. In thisstudy, a significant change in pelvicinclination (in the backward direction)occurred during Assessments 1 and 2and, although a forward tilt took placebetween Assessments 2 and 3, this

The Australian Journal of Physiotherapy. Vol. 331 No. 11 1987 15

Low Back Pain and Pregnancy

change did not reach a significant level.Results of this study therefore, do notconfirm views expressed in the pastregarding pelvic inclination.

No previous references to an increasein kyphosis have been made in the lit...eratu~eandin this study, the changesin thoracic curvature were of equalmagnit~e and significance to those inthe lumbar region.

Previous studies of the incidence ofback pain in pregnant women haveproduced varying results. For example,in England, Mantleet al (1977) foundthat 48 percent of women complainedof backache which was judged to be'at least troublesome' ,one .third ofthese suffering severe pain. On theother hand, in Nigeria, Nwuga (1982)found that 90 percent of surveyedwomen experienced pain. In this studyof women in an Australian Hospital,88 percent of the women experiencedback pain, confirming that this is amajor problem in women during child­bearing.

Significant changes in posture oc...curred during the fifth to ninth monthof pregnancy. During this period, eightof the fourteen women who had noinitial pain gained pain and the pos­sibility that changing posture could ac­count for the pain had to beconsid­ered. However, the results of thePearson Product Moment Correlationand the Multiple Regression Analysisshowed that there was no significantrelationship between back pain andposture in .the thoracic, lumbar andpelvic areas during pregnancy. Therewas no significant relationship betweenpain and gravida, age or weight/height.It is possible that some other factormay be present in pregnancy to accountfor the early onset of pain. Hormonalchanges and their influence on soft tis­sues may be important factors in thisearly pain production and this couldbe an avenue of research forphysiol­ogists in the future.

It had been thought that the postureof women with pain as a group mighthave differed from that of women

without pain. The significant differ­ence revealed was for kyphosis at thesecond assessment, at which time,women experiencing pain had a greaterdegree of kyphosis than those without.In view of the continued increase inkyphosis at Assessment 3 and the in­crease in number of women experienc­ingpain "at this stage of pregnancy, itis surprising that the correlation be­tween kyphosis "and pain was not stillevident at Assessment 3. Althoughky...phosis was not found to be a significantpredictor of pain, the change in thispostural curve is worthy of closer at...tention both in research and therapeu­tically. ·No significant differences werefound for either lordosis or pelvic in­clination in the women with and with­out pain. It should be stated however,that no attempt at quantitative evalu­ation of pain was made in this study.Further research in this field could in­clude attention to assessing such ad­ditional features as the nature and de­gree of severity of pain, duration ofbouts of pain and the functional lim­itations imposed by the pain.

The findings of this study contrastwith the· views expressed by many ofthe authors who have discussed backpain in pregnancy in the past. Theiropinions regarding the effect of lor...

~ dosis on pain appear to have been basedon subjective perceptions of posturalchange, consideration of the effect ofphysiological changes on posture andassumptions that these factors ac­counted for the back pain experienced.The absence of any sustained correIa...tion between posture and pain in thisstudy, together with the relatively highincidence of pain at the earlier stagesof pregnancy suggest that some factorother than posture plays an importantrole in pain -production.

Implications for thePbysiotherapistAs part of their ante-natal care of

pregnant women, physiotherapists areconcerned to encourage the mainte­nanceof'good posture'. Particular at­tention is paid to strengthening thosemuscles concerned with flattening the

lumbar spine and posterior tilting ofthe pelvis. The significant increase inlordosis which has been shown to de­velop during pregnancy justifies thisapproach.

The finding that kyphosis increasesas significantly as lordosis suggests thatphysiotherapists could direct rnore at­tention to this .area in their treatmentprogrammes. It also >emphasizes theimportance of looking at the woman'stotal posture during assessment ratherthan focussing particularly on the lum­bar spine.

Examination of the standard devia­tions for initial posture and the varietyin magnitude and nature of posturalchanges during pregnancy highlight theimportance of the physiotherapist as­sessing each patient posturally early inthe ante-natal programme. It is ob­viously important not only to deter­mine initial postural alignment, but alsoto evaluate it progressively, so that suit­able preventive and therapeutic meas­uresmay be taken. While no posturalcurvature was found to be a significantpredictor of pain, it is nevertheless im­portant for the physiotherapist to en­sure that the woman does not developpoor postural habits during pregnancywhich could continue in later life.

The absence of quantitative data re­vealed during the review of literaturefor this study indicates the need forphysiotherapists to be more active inresearch in this field. Monitoring ofpostural changes, using the simple in­clinometer or clinometer, together withcomprehensive recordings of pain dur­ing the ante-natal period could produceimportant data for further guidance ofthose concerned with the care of thepregnant woman. The physiotherapistcould explore whether the woman's in­itial posture had a significant influenceon the development of particular pos­tural changes during pregnancy, or onthe development of pain. The resultsof the study reported here suggest thatfurther research relating to posture andpain during pregnancy would be jus­tified.

16 The Australian Journal of Physiotherapy. Vol. 33, No.1 J 1987

Low Back Pain and Pregnancy

ConclusionsThe progressive measurement of

spinal curvature and pelvic inclinationin this study allowed a review of thepostural changes in women duringpregnancy. Records of pain onset alsoprovid~d a means of determining anyrelationsllip between pain and the pos­tures asstimed.

A high incidence of pain in pregnantwomen was revealed by this study. Sur-

.prisingly, the largest proportion ofthose women who reported back painwere already experiencing this problembefore their fifth month of pregnancy.Tbis fact, and the lack of a sustainedsignificant relationship between pos-

.tureand pain.during pregnancy leadsto the conclusion that some other fac­tor is responsible for the early onset ofpain. It is possible that hormonalchanges and their subsequent softeningof soft tissues could have an influenceon the production of pain early in preg­nancy.

The significant increases in spinalcurvature found to occur during preg-

nancy suggest that physiotherapistscould focus closer attention on pre­venting the possible development ofboth lordosis and kyphosis in womenreceiving ante-natal advice.

Although further research on thetopic of pain and posture in pregnancyis warranted, it is hoped that the find­ings of this study will enhance the ther­apeutic and preventative approachestaken· by physiotherapists during tbeirante-natal care of pregnant women.

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nancy and its relationship to pain, B.Phty (Hons)thesis, Department of Physiotherapy, Universityof Queensland.

Cobb JR (1960), The .problem of the primarycurve, The Journal 01 Bone and Joint Surgery,42A,1413-1425.

Cyriax J (1965), Textbook 01 Orthopaedic Med­icine"Cassell, London.

Danforth DN (1967), Pregnancy and labor fromthe vantage point of the physical therapist,American Journal oj Physical Medicine, 46(1),653-658.

Epstein JA (1959), Symposium of treatment oflowbackpain and. sciatic syndrome during preg~nancy, New York Journal ofMedicine" 59,1757­1768.

FlintMM (1963), Lumbar. posture: A study ofroentgenographic measurement and the influ­ence of flexibility and strength, Research Quart­erly34(I), 15-20.

MantleMJ,GreenwoodRM and CurreyHLF(1977), Backache in pregnancy, Rheumatologyand Rehabilitation, 16, 95-101.

Nwuga VCB (1982), Pregnancy and back painamong upper class Nigerian women, The Aus­tralian Journal ojPhysiotherapy, 28(4), 8-11.

Pagano R (l981), Understanding Statistics in theBehavioural Sciences, West Publishing Co.

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