Sepsis Score in Obstetrics

Because normal pregnancy physiology (raised heart rate, raised white cell count, lower blood pressure baseline) overlaps with sepsis features, general adult sepsis scores (SOFA, qSOFA, SIRS) tend to over-diagnose sepsis in pregnant/postpartum women. This led to development of obstetric-specific modified scores. The three most used are below.

1. Sepsis in Obstetrics Score (SOS)

Proposed in 2014 specifically to predict ICU admission risk in obstetric patients, accounting for pregnancy physiology. Scored across 8 parameters (range from -/+4 each):

Variable	Worst high (score)	Normal (0)	Worst low (score)
Temperature (°C)	>40.9 (+4)	36-38.4	<30 (+4)
Systolic BP (mmHg)	-	>90	<70 (+4)
Heart rate (bpm)	>179 (+4)	≤119	-
Respiratory rate (bpm)	>49 (+4)	12-24	≤5 (+4)
SpO2 (%)	-	≥92%	<85% (+4)
WBC (×10³/mm³)	>39.9 (+4)	5.7-16.9	<1 (+4)
% immature neutrophils	≥10% (+2)	<10%	-
Lactate (mmol/L)	≥4 (+2)	<4	-

A score ≥ 6 is the validated cut-off for higher risk of ICU admission/critical illness (negative predictive value ~98.6% for score <6 excluding ICU need).
In a validation study for sepsis in pregnancy after abortion (PAS), SOS ≥6 predicted severe sepsis with sensitivity ~69%, specificity ~81%, AUC 0.81 - performing better than MEWS for critical care prediction (- Agarwal et al., PMC6560845).

2. Obstetrically Modified SOFA Score (Table 71.3, adapted from SOMANZ guidelines)

System	0	1	2
Respiratory: PaO2/FiO2	>400	300-399	<300
Coagulation: Platelets	>150,000/μL	100-150k	<100k
Hepatic: Bilirubin	<1.2 mg/dL	1.2-1.9	>1.9
Cardiovascular: MAP	>70	<70	Vasopressors required
CNS	Alert	Rousable by voice	Rousable to pain
Renal: Creatinine	<1.0 mg/dL	1.0-1.4	>1.4

Used to identify organ dysfunction meeting the Sepsis-3 definition, adapted for pregnancy's normal physiologic ranges (e.g., pregnancy normally lowers creatinine and platelets slightly).

3. Obstetrically Modified qSOFA (bedside screening tool, Table 71.4)

Parameter	0	1
Systolic BP	>90 mmHg	<90 mmHg
Respiratory rate	<25/min	>25/min
Altered mental status	Alert	Not alert

Quick screen at the bedside (no labs needed); a score ≥2 should prompt formal organ dysfunction assessment (modified SOFA) and sepsis workup.

Other tools worth knowing

Maternal Early Warning Criteria (MEWC) / Maternal Early Warning Triggers (MEWT) - consensus-driven, not sepsis-specific, but trigger bedside evaluation for any of the top causes of maternal morbidity (sepsis, hemorrhage, hypertension, VTE).
MEOWS (Modified Early Obstetric Warning Score) - a UK-derived vital-sign trigger tool, internally validated against ICNARC audit data.

Source: Creasy & Resnik's Maternal-Fetal Medicine: Principles and Practice, Ch. 71 ("Risk Factors for Sepsis in Obstetric Patients," Tables 71.3-71.5), modified from Bowyer L et al. SOMANZ guidelines for investigation and management of sepsis in pregnancy, Aust NZ J Obstet Gynaecol. 2017;57:540-51.

Clinical context

Global incidence and severity of maternal sepsis remains an active research area; a 2025 systematic review/meta-analysis (PMID: 40056980) quantifies global incidence of maternal sepsis and may be worth checking if you need current epidemiologic figures.
A 2024 systematic review/meta-analysis on early warning scores generally (PMID: 38379353) found predictive performance for in-hospital mortality varies significantly by score and population - reinforcing why obstetric-specific scores (SOS, modified SOFA/qSOFA) are preferred over general adult scores in pregnant/postpartum patients.

If you want, I can pull the original 2014 SOS derivation study or the SOMANZ full guideline for management steps (antibiotics, source control, fluid resuscitation) rather than just the scoring tool.

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