CASE REPORTOpen Access
Low back pain during pregnancy caused by a
sacral stress fracture: a case report
Miguel Pishnamaz*, Richard Sellei, Roman Pfeifer, Philipp Lichte, Hans C Pape and Philipp Kobbe
Introduction: Sacral stress fractures are a rare but well known cause of low back pain. This type of fracture has
also been observed as a postpartum complication. To date, no cases of intrapartum sacral stress fractures have
been described in the literature.
Case presentation: We report the case of a 26-year-old Caucasian European primigravid patient (30 weeks and
two days of gestation) who presented to our outpatient clinic with severe low back pain that had started after a
downhill walk 14 days previously. She had no history of trauma. A magnetic resonance imaging scan revealed a
non-displaced stress fracture of the right lateral mass of her sacrum. Following her decision to opt for non-
operative treatment, our patient received an epidural catheter for pain control. The remaining course of her
pregnancy was uneventful and our patient gave birth to a healthy child by normal vaginal delivery.
Conclusions: We conclude that a sacral stress fracture must be considered as a possible cause of low back pain
Although sacral stress fractures are uncommon, they are a
well-known cause of low back pain, especially in athletes
[1-5]. The underlying pathology of stress fractures is either
a weakened bone or an unusually high load that normal
bone is unable to withstand . The latter has been cited
by several authors as the cause of postpartum sacral frac-
tures occurring during the course of childbirth [7-10].
Usually, the fracture is diagnosed by magnetic resonance
imaging (MRI), which shows a vertical fracture line with
surrounding osseous edema. This fracture is particularly
challenging during pregnancy since adequate analgesic
control is complicated by drug interactions with the fetus,
as well as the continued load imposing stress on the
sacrum over the course of the pregnancy. To the best of
our knowledge, this case is the first report of an intrapar-
tum sacral stress fracture and outlines the difficulties and
limitations of pain control in these patients.
A 26-year-old Caucasian European primigravid patient
(30 weeks plus two days of gestation) was transferred
from a local area hospital with severe low back pain.
She first experienced slight discomfort over her bilateral
iliosacral joints while walking downhill 14 days pre-
viously. She reported that water exercises gave her com-
plete pain relief. Three days after the initial discomfort,
she exacerbated the condition and experienced severe
pain while exiting the passenger seat of her car. The
pain was described as radiating from the right side of
her lower back to the back side of her knee, and being
electric in character. At that point, she was unable to
walk independently and was admitted to the hospital for
pain management with oral paracetamol.
On admission to our hospital, a clinical examination
revealed a healthy young woman with a height of 162 cm
and a weight of 56 kg. She had gained 6 kg during her
pregnancy. She had previously run one hour daily until
approximately 12 months before her pregnancy. She
denied any drug, alcohol or nicotine consumption. She
had thus far had an uncomplicated pregnancy.
Upon admission, a fetal weight of 1,400 g was estimated.
Our patient had a temperature of 38.5°C and elevated
inflammation parameters, with a C-reactive protein level
of 95 mg/L (reference range, < 5 mg/L) and a white blood
cell count of 13.6 G/l (reference range 4.3 to 10 G/l).
Thrombosis was ruled out by color-coded Doppler
* Correspondence: firstname.lastname@example.org
Department of Orthopedic and Trauma Surgery, University of Aachen
Medical Center, 30 Pauwels Street, 52074 Aachen, Germany
Pishnamaz et al. Journal of Medical Case Reports 2012, 6:98
JOURNAL OF MEDICAL
© 2012 Pishnmaz et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative
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reproduction in any medium, provided the original work is properly cited.
ultrasonography. An MRI of her spine and pelvis was
obtained. It did not show an ischemic or inflammatory
process but did reveal a non-displaced fracture of the right
lateral mass of her sacrum with surrounding osseous
edema (Figure 1).
Our patient continued to have persistent severe pain
despite oral analgesics and immobilization. A Patrick’s
test was positive and our patient complained of a mas-
sive pain in her lower back which increased on direct
pressure to the iliosacral joint. She was therefore given
epidural anesthesia. She was started on a regimen of
ropivacaine 0.2% and sufentanil 0.5 μg/mL. On the sec-
ond day, the sufentanil was discontinued and she con-
tinued to receive ropivacaine only. Thereafter, she
experienced significant pain relief. Under regular fetal
cardiotocographic monitoring, our patient was then able
to mobilize under physiotherapeutic guidance. The
remaining course of her pregnancy was uneventful. A
qualitative bone density measurement (osteosonometry)
performed by her gynecologist one week after delivery
showed no signs of pregnancy-related osteoporosis.
At the end of her pregnancy, our patient was comple-
tely free from pain. She did not opt for a Cesarean sec-
tion, as per our recommendation, and delivered a
healthy girl weighing 2,950 g by normal spontaneous
vaginal delivery at term. In the postpartum period, she
could walk with oral analgesics and experienced a clini-
cally uneventful healing of the sacral stress fracture.
The etiology of intrapartum or postpartum sacral stress
fractures has thus far not been determined. To date, 29
cases of sacral stress fractures in athletes have been
described in the literature . To the best of our knowl-
edge, nine cases of postpartum stress fractures have been
described. Of these, only six cases have reported the
patient’s bone density: five presented with normal and
one with decreased bone density [11,12]. The incidence
of pregnancy-related osteoporosis is approximately 0.4
cases per 100,000 women. Sacral stress fractures present
universally with pain localized to the lower back, sacroi-
liac region, buttocks or groin. Radicular pain is common
and described in a number of cases [2,6]. A positive
Patrick’s test or a tender sacroiliac joint is typically found
on clinical examination. There are several other tests to
localize sacroiliac joint pain that are also useful in the
examination of sacral stress fracture (Table 1, ).
Imaging is paramount in securing the diagnosis. Con-
cerns regarding radiation exposure to the developing
fetus limit the imaging options. Plain radiographs expose
the unborn child, and are only utilized for ruling out
other sources of pain. Shah and Stewart  reviewed a
series of 27 sacral stress fractures and found 25 cases
with normal radiographs.
MRI is the modality of choice during pregnancy because
of its lack of radiation emissions. As in our patient, all
cases described in the literature involved a vertical fracture
line with surrounding edema on the MRI scans. If neces-
sary, after delivery, bone scintigraphy or bone scans with
higher sensitivity than MRI can be utilized .
Bone density measurements should be performed to
rule out pregnancy-related osteoporosis.
Because of the high radiation load, the investigation
should occur only after the pregnancy has ended. For
assessment of the bone density during pregnancy, osteo-
sonometry can be considered, but its use is controversial
and not evidence-based.
Pregnancy-related osteoporosis most often occurs in
the third trimester [14,15], and if the bone mineral den-
sity does not normalize within five to ten years of the
delivery, then the osteoporosis is likely to be permanent
. Along with sacral fractures, vertebral compression
fractures as well as osteoporosis of the proximal femur
are associated with pregnancy. Therefore these areas
Figure 1 Coronal and axial short inversion-time inversion-
recovery sequence magnetic resonance imaging of the sacrum
shows the fracture line of the right lateral mass surrounded by
an area of edema.
Table 1 Specific pain tests for the iliosacral-region from
Dreyfuss et al. 
Pressure to sacral sulcus
Pain at iliosacral joint
Pain radiation to the buttock
Pain at posterior iliac spine
Pressure to the center of sacrum
Pain radiation to the knee
Pain in sitting position and lifting up the
Pishnamaz et al. Journal of Medical Case Reports 2012, 6:98
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should be examined for injuries after a bone density
The first step in the pain management of sacral stress
fractures is usually rest and activity modification . This
is difficult in pregnant patients in whom the stress on the
fracture is exerted by the fetus. There is some contro-
versy with those supporting early mobilization because
weight bearing appears to be necessary to stimulate
osteoblastic activity [6,11]. In our case of an intrapartum
sacral fracture, pain control was the greater challenge
because of the limited therapy options. In such cases, we
endorse early immobilization until sufficient pain control
is achieved. Subsequent partial weight bearing is essential
to accelerate bone healing and to reduce other complica-
tions of immobility.
The following points should be considered for the
application of analgesics during pregnancy: effects on the
fetus, stage of the pregnancy, influence on the pregnancy
course, influence on the mother, risk of pre-eclampsia
and analgesia. In principle, especially early in pregnancy,
there should be strict indications, low dosages and a
short duration of drug administration. Oral paracetamol
is the primary analgesic choice during all phases of preg-
nancy. Ibuprofen can also be used under a strict maxi-
mum daily dose of 1,600 mg. In certain situations,
intravenous Perfalgan (paracetamol), morphine or pethi-
dine can be administered. Because of its less systemic
side effects, epidural anesthesia is recommended in cases
of severe pain of the lower extremity and sacrum that is
refractory to other therapies.
The cases currently described in the literature demon-
strate that most patients regain their activities of daily
living within six weeks. Surgical treatment was never
necessary. The heterogeneity of the risk groups (preg-
nant women, endurance athletes or older patients) and
the differences between stress and insufficiency fractures
mean that treatment options must be adapted. Never-
theless, in all cases, a prompt diagnosis and sufficient
pain management must be achieved.
During pregnancy, fractures of the sacrum must be
included in the differential diagnosis of patients with
low back pain. The injury should be diagnosed early,
and treatment should be tailored accordingly. Even in
the complicated setting of pregnancy, insufficient treat-
ment of severe pain should be avoided.
Written informed consent was obtained from the patient
for publication of this manuscript and any accompany-
ing images. A copy of the written consent is available
for review by the Editor-in-Chief of this journal
MP analyzed and interpreted the patient data and wrote a major part of the
manuscript. RS performed the clinical examination, analyzed the blood levels
and partook in the discussion of the manuscript. RP performed the literature
review and organized the radiological picture material. PL performed the
literature review and completed the abstract. HCP controlled the patient’s
treatment and managed orthopedic and interdisciplinary treatment. PK
interpreted and completed the patient data and wrote a part of the case
discussion. All authors read and approved the final manuscript.
The authors declare that they have no competing interests.
Received: 6 July 2011 Accepted: 4 April 2012 Published: 4 April 2012
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Cite this article as: Pishnamaz et al.: Low back pain during pregnancy
caused by a sacral stress fracture: a case report. Journal of Medical Case
Reports 2012 6:98.
Pishnamaz et al. Journal of Medical Case Reports 2012, 6:98
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