Management of severe odontogenic infections in pregnancy


Professor Alastair Goss
Oral and Maxillofacial Surgery Unit
The University of Adelaide
Adelaide SA 5005


Background:  The objective of this study was to review the management of patients presenting with severe odontogenic infections and who are also pregnant.

Methods:  A retrospective clinical audit was conducted of all female patients admitted to the Royal Adelaide Hospital by the Oral and Maxillofacial Surgery Unit from 1999 to 2009 with severe odontogenic infections. Pregnant patients were identified and their age, medical history, previous obstetric and gynaecological history, stage of current pregnancy, presenting infection, diagnosis and management were recorded, as well as the outcome of the pregnancy.

Results:  A total of 346 female patients were admitted to the Royal Adelaide Hospital under the care of the Oral and Maxillofacial Surgery Unit with an admission diagnosis of severe odontogenic infection and five were pregnant. Besides surgical and anaesthetic assessment, mother and foetus were assessed by the Obstetric and Gynaecology Unit. In all, five with severe infection were successfully resolved and four proceeded to a normal delivery with a healthy child. The remaining patient had an already planned therapeutic abortion.

Conclusions:  Pregnant patients with severe odontogenic infections require urgent referral to a tertiary hospital with full surgical, anaesthetic and obstetric services. This allows appropriate management of the complex requirements of mother and foetus.

Abbreviations and acronyms:



deep venous thrombosis


obstetric and gynaecological service


oral and maxillofacial unit


Ideally routine dental treatment is best avoided in pregnancy, and preferentially dental fitness should be instituted prior to pregnancy. Minor routine dental treatment can be completed in the second trimester with the first and third trimesters best being avoided. Emergency treatment for pulpal, periodontal, pericoronal or early infection should not be avoided. Delay or avoidance by either the patient or clinician may result in severe spreading odontogenic infection. It is essential that dentists have an understanding of pregnancy and how pregnant females are physiologically and psychologically different to non-pregnant females.

It is estimated that up to 50% of all fertilized eggs are spontaneously aborted before the woman knows she is pregnant, and of those women who know they are pregnant, it is estimated that 15–20% have a spontaneous abortion.1 In 2002, there were 250 988 registered births in Australia2 and 52 000 therapeutic abortions.3 Pregnancy results in profound physiologic changes in otherwise medically fit females. Cardiovascular changes include an increase in blood volume and cardiac output, and a decrease in blood pressure. Blood volume can increase by up to 50% by the 32 week of gestation, mainly due to an increase in plasma volume.4,5 Cardiac output increases mainly due to an increased stroke volume or later in pregnancy, due to an increased heart rate.4,5 Early in pregnancy there is a decrease in systemic resistance and blood pressure. Blood pressure returns to normal by the end of the second trimester. In late pregnancy the foetus may compress the inferior vena cava and consequently signs and symptoms of supine hypotension syndrome, with bradycardia, hypotension and syncope on standing may occur.6 There are corresponding respiratory alterations including an increase in the anterior/posterior diameter of the chest due to the superior shift of the diaphragm. There is an increase in the respiratory drive with an increase in tidal volume, respiratory and minute ventilation. This leads to a mild respiratory alkalosis and dyspnoea is quite common. Simultaneously there is an increase in oxygen consumption and a decrease in oxygen reserves. With the alimentary system there is a predisposition towards gastric reflux and heartburn. This is due to increased pressure by the foetus on the stomach with relaxation of the lower oesophageal sphincter tone and decreased gastric motility. Vomiting and constipation are increased.7 Hepatic function changes with the decrease in total protein and albumen levels with an increase in serum alkaline phosphatase, bilirubin, cholesterol, triglyceride and aminotransferase. The decreased albumin levels may lead to peripheral oedema.4 There is an increased risk of urinary tract infections and alteration in kidney output. Haematologically, there is an increase in erythrocyte and leukocyte counts. However, the relatively greater increase in plasma volume leads to a physiologic anaemia.7 Pregnancy also leads to hypocoagulable states due to an increase in the various coagulant factors and a drop in anticoagulant factors.8 Gestational diabetes is common. All of these physiologic changes need to be understood for pregnant patients requiring unavoidable medications, anaesthesia or surgery (Table 1).

Table 1.   Summary of the changes seen in pregnant females and the actions required
SystemsPotential changesActions
Cardiovascular changesDecrease in blood pressure (1st trimester)Monitor
Increase in blood volume, heart rate and cardiac outputMonitor
Hypercoagulable state due to increase in clotting factorsDVT precautions
Supine hypotension syndromeDue to compression of inferior vena cava – leads to bradycardia, hypotension and syncopePosition patient in left lateral position
Can disrupt uteroplacental blood flow 
Respiratory changesIncrease in tidal volume, respiratory and minute ventilation 
Mild respiratory alkalosis and dyspnoeaCan affect induction and maintenance of intravenous sedation and general anaesthesia
Predisposition to rhinitis, epistaxis and upper respiratory tract infections due to changes to upper airway mucosaAvoid nasal intubation
Gastro-intestinal changesPredisposition to gastric reflux due to relaxation of lower oesophageal sphincter tone and increased gastric pressureRisk of aspiration with anaesthesia
Nausea, vomiting and constipation commonConsider when prescribing medication
Renal changesIncrease renal blood flow and glomerular filtration rate 
Increased renal clearance of creatinine, urea, uric acid and renally cleared medicationsConsider when prescribing renally cleared medications
Increased risk of urinary tract infectionsUse urinary catheter with caution
AnalgesicsAspirin – delivery complications and post-partum haemorrhageContraindicated in pregnancy, especially 3rd trimester
NSAIDs – can inhibit induction of labour and also cause constriction of the ductus arteriosus leading to pulmonary hypertension in the infantContraindicated in 3rd trimester, use with caution in 1st and 2nd trimester
Narcotics – can lead to neonatal respiratory depression, associated with congenital defects– Contraindicated in 3rd trimester (e.g. codeine, propoxyphene)
– Morphine appears to be safe when administered for short periods of time
AntibioticsMetronidazole – potentially teratogenicShould be avoided where possible, especially in 1st trimester
Tetracyclines – cause tooth discolouration and can inhibit bone developmentContraindicated during pregnancy
Gentamicin – potential ototoxicityContraindicated during pregnancy
Sedatives/anxiolyticsCross-placental barrier and inhibit neuronal function and associated with oral cleft developmentContraindicated during pregnancy
Local anaestheticBupivacaine hydrochloride and mepivacaine FDA category C due to lack of data available in studiesContraindicated during pregnancy
Anaesthesia3rd trimester – increased risk of regurgitation and aspirationAvoid intravenous sedation and general anaesthesia where possible in pregnancy patients
RadiographyTotal radiation exposure less than 6–10 centi-Grays (cGy) has no association with increased congenital defects or growth retardation– Full mouth series of intraoral radiographs and panoramic radiograph are within safe dose
– CT scan has radiation exposure of 3–7 cGy – only indicated for spreading odontogenic infections

There are marked oral changes with 70% of pregnant females having pregnancy gingivitis and an increase in periodontal disease including gingival bleeding, hyperplasia and pregnancy epulis.9 There is a threefold increase in periodontal disease if there is concurrent gestational diabetes.9 However, avoiding dental treatment, either in the lead up to pregnancy or during pregnancy, may sometimes result in spreading odontogenic infections. Management of spreading odontogenic infections is at best complicated, particularly when swelling in the neck occurs with the risk of airway obstruction. The detailed issues relating to management of severe odontogenic infections in non-pregnant patients have been previously published.10

In this paper we review the management of severe odontogenic infections in pregnancy, illustrate it with a consecutive cohort of cases and make recommendations on how to minimize the risk for the mother and foetus.


A retrospective audit was conducted for all female patients admitted to the Royal Adelaide Hospital by the Oral and Maxillofacial Unit (OMS) from 1999 to 2009 with spreading odontogenic infection to determine those concurrently pregnant. For this group their age, medical history, previous obstetric and gynaecological history, stage of current pregnancy, presenting infection, diagnosis and management were recorded.

The management of these patients with severe odontogenic infections followed the standard unit guidelines by the OMS and Anaesthetic (A) Units.10 The Obstetric and Gynaecological Service (O & G) reviewed the state of the pregnancy and determined foetal health with foetal monitoring and ultrasound being performed as required.

Management of the infection followed the standard OMS and A protocols, namely, removal of the cause which is the tooth, incision and drainage of the abscess, supportive treatment to both the mother and foetus and high dose intravenous antibiotics.10

The patients were contacted by phone in 2011 by their admitting consultant to determine if there were any subsequent complications to the pregnancy and the health of the child.


Three hundred and forty-six female patients were admitted to the Royal Adelaide Hospital under the care of the OMS Unit with an admission diagnosis of severe odontogenic infection. Of these, five were pregnant. The details of these patients are presented in Table 2.

Table 2.   Summary of the management of consecutive pregnant cases treated
PatientAgePregnancyHistoryDiagnosisManagementICU stayInspect siteOutcome
13333 weeks• Iron deficient
• 5 previous miscarriages
L submandibular abscess
Trismus 20 mm
IV ab
LA & IV sedation
extraction 36
I & D
1 day4 daysNormal delivery
Live birth
22235 weeks• Smoker
• 3 previous C-sections
R submandibular abscess
IV ab
D/C via socket
declined anaesthesia
0D/C from OMS back to OG
ab contained
Live birth
332 8 weeks (previous planned termination)• Fit and well
• Breastfeeds 8/12  son
L buccal abscess
IV ab
LA extraction
I & D
01 dayTermination as planned
42910 weeks• Asthma
• Allergic to penicillin
Bilateral submandibular abscess
Trismus 15 mm
extraction 37, 38, 5 days prior
fibre optic
IV ab
I & D
3 days6 daysNormal term delivery
Live birth
52630 weeks• Fit and wellR submasseteric and buccal abscessIV ab
I & D
04 daysNormal delivery
Live birth


This paper shows that the pregnant patients with severe odontogenic infections were successfully managed and four of the pregnancies proceeded to successful delivery of a live baby without congenital defects and in one case the patient had already booked for termination of pregnancy.

Anaesthetic and surgical management requires modification to that of non-pregnant patients.10 The principles of surgical and anaesthetic management need to be well understood by the initial dentist managing the case, otherwise there is a risk that the patient will be undermanaged. This occurred with two patients in our series who preferentially should have been referred earlier. From the anaesthetic point of view, the altered cardiovascular state of mother and foetus needs to be monitored. Postural hypotension is a risk and the patient is best nursed in the left lateral position to minimize compression of the inferior vena cava by the placenta. The altered respiratory drive predisposes both the mother and the foetus to hypoxia, particularly in the induction stage of the anaesthetic. The upper airway mucosa, particularly of the nose, is more friable and thus increased bleeding may occur during intubation. The increased risk of gastric reflux needs to be carefully evaluated to minimize the risk of aspiration and aspiration pneumonia postoperatively.4,5

Pharmacologically, altered hepatic and renal excretion capabilities need to be carefully considered. In the first trimester of pregnancy older drugs with a known low teratogenic rate need to be used. Non-steroidal anti-inflammatory drugs are best avoided in general but particularly so in the third trimester due to the effect on the foetus’ ductus arteriosus. Narcotic analgesics similarly are best avoided as they cross the placental barrier and may result in neonatal respiratory depression. Hence, the analgesic drugs of choice in pregnancy are paracetamol and short courses of morphine. Similarly, antibiotic use needs to be carefully considered although in a spreading odontogenic infection this is an important adjunct to surgical management. Metronidazole may be teratogenic in the first trimester although recent studies have shown no definitive teratogenic effect. Gentamicin should be avoided as it is associated with potential toxicity in the developing foetus. Tetracyclines are best avoided as they are ineffective for odontogenic infections and they may stain the developing teeth.

Most sedatives such as the benzodiazepines cross the placental barrier and thus are best avoided. Local anaesthesia generally is safe although there is uncertainty through lack of data on the use of bupivicaine and mepivicaine. Although it is commonly stated that prilocaine and octopressin should be avoided in pregnancy the tiny amounts involved have no effect on inducing labour.11

Intravenous sedation has less physiological effect than general anaesthesia on the pregnant patient and the developing foetus, and can be used for short, simpler procedures such as extraction. Care needs to be taken to protect the airway against regurgitation. With severe spreading infections in the neck, then it is mandatory that the patient is intubated. If they have trismus, this means a fibre optic intubation. Although theoretically there is a risk of teratogenesis and spontaneous abortion, large studies which have compared the outcome of pregnancy where the patient did have a general anaesthetic versus where they didn’t, shows no change in risk.12,13

Surgically, the patient needs to be carefully examined and worked up. There is no contraindication to the sparing use of radiology. It has been shown that doses of less than 5 to 10 centigrays (cGy) have no association with increased development of congenital defects or intra-uterine growth retardation.14 Thus generally for a patient with a spreading odontogenic infection, a single OPG will provide sufficient information at an acceptable radiation exposure.14 With advanced spreading odontogenic infections into the neck, generally this is best demonstrated by a CT scan. A single CT scan has less than the normal safe level of irradiation (e.g. 5–10 cGy) but is greater than for an OPG.15 Thus, CT scanning is best avoided in pregnant patients and only used if strongly clinically indicated, such as to define a pus collection in patients not responding to surgical management.13 Ultrasound has a place in defining moderate to large pus collections in the neck and it should be considered over and above a CT scan.

Surgically, the standard means of management of spreading odontogenic infections need to be followed. In advanced pregnancy, the risk of hypercoagulation needs to be considered and the use of thrombolic stockings to minimize deep venous thrombosis (DVT) formation. The patient should also be mobilized early. All patients in this study had management which followed the recommended guidelines (Table 3). However, there were some important variations. Three patients had initially presented to peripheral hospitals without OMS staff. One was in the country, some hours drive from Adelaide, and two were in the outer urban areas. All three were initially medically stabilized and transferred to the central tertiary hospital where the full range of services were available.

Table 3.   Protocol for management of pregnant patients with severe odontogenic infections
Emergency referral by LDO or LMO to hospital
Medical assessment including maternal airway and foetal health
On referral to a tertiary hospital with full specialist teams
- Oral and Maxillofacial Surgery (OMS)
- Obstetrics and Gynaecology (O & G)
- Anaesthesia and intensive care (A)
Admit under the care of the OMS team
Control airway (A)
Full maternal and foetal monitoring (O & G)
Infection assessment
Airway monitoring
Commence intravenous antibiotics
Full specialist assessment by teams
Develop plan and informed consent
- Surgical management
- Extraction
- Incision and drainage
Admit to ICU if airway issues (A)
Ongoing maternal and foetal monitoring (O&G)
General ward until stable
Discharge on oral antibiotics
Outpatient review by obstetrician and OMS

The O & G Service reviewed all of the patients prior to treatment commencing. In particular, they reviewed the patients’ previous obstetric history and assessed foetal health by ultrasound and foetal monitoring. All the patients had this assessment repeated post-procedure. Of the five patients, two were considered high risk of miscarriage by the O & G Service. One patient had had five previous miscarriages and at 33 weeks this was the longest that she had held a child toward term. However, she did have a severe infection with trismus and limited jaw opening. Hence, she had the extraction and drainage performed under local anaesthesia and IV sedation. She was maintained in ICU for observation for one day and then had a further four days in the ward. She had a normal term delivery with a live birth. The second patient was at 35 weeks and her previous deliveries had been by caesarean section. She was due to have a caesarean section close to the time when she developed the severe infection with trismus. She had a tooth extraction three to four days previously, prior to admission. It was recommended that she have a further anaesthetic for incision and drainage, but following informed consent discussions with her obstetrician, anaesthetist and surgeons, she declined. Accordingly, she was maintained on high level antibiotics and proceeded to a further caesarean section with a normal live birth. The infection resolved with spontaneous drainage via the previous extraction socket.

The remaining three patients were stable from the obstetric point of view. One had already decided to have a termination. It was possible to manage her infection with local anaesthesia and she was observed in hospital for one day. After the infection was controlled she proceeded with the planned abortion. With the fourth patient she had a severe infection and was allergic to penicillin. Accordingly, she was given clindamycin and metronidazole. She required a fibre optic intubation for incision and drainage. She was maintained in intensive care for three days and then six days, until the infection had resolved. She had a normal delivery and a live birth. The final patient was surgically treated uneventfully.


Severe spreading odontogenic infection can be difficult to manage and there is a small but real risk of death from either airway obstruction or overwhelming systemic infection. Pregnancy and its physiological changes make management of such patients challenging. The treating clinician must consider the anaesthetic and surgical effects on the foetal and maternal health while following well established clinical guidelines in managing odontogenic infection. This retrospective study demonstrated that successful clinical outcomes can be achieved by emergency referral to a tertiary centre with full surgical, anaesthetic and obstetric services available.