Know your symptoms. Know when to go. Evidence-based guidance for warning signs before 37 weeks.
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If you have heavy vaginal bleeding, severe abdominal pain, or feel the baby is coming — call 911 or go to Labor & Delivery immediately. Do not use this tool.
This tool is for assessing early or uncertain symptoms. It does not replace emergency care.
Evidence Base
ACOG Practice Bulletin No. 234. Prediction and Prevention of Spontaneous Preterm Birth. Obstet Gynecol. 2021;138(2):e65-e90. Defines preterm birth, risk factors, and evidence for prevention.
Iams JD, et al. The Preterm Prediction Study: recurrence risk of spontaneous preterm birth. NICHD MFMU Network. Am J Obstet Gynecol. 1998;178(5):1035-1040. Symptom sensitivity/specificity data for preterm labor diagnosis.
Romero R, et al. Preterm labor: one syndrome, many causes. Science. 2014;345(6198):760-765. Pathophysiology framework and clinical presentation of preterm labor.
Goldenberg RL, et al. Epidemiology and causes of preterm birth. Lancet. 2008;371(9606):75-84. Preterm birth epidemiology — 10% of births, leading cause of neonatal mortality.
What is Preterm Labor?
Preterm labor is defined as regular uterine contractions with cervical change before 37 weeks of gestation. It is the leading cause of neonatal morbidity and mortality worldwide. Symptoms are often subtle and easily confused with normal pregnancy discomfort.
10%
of births are preterm
<37 wks
definition of preterm
#1
cause neonatal death
📅 How far along are you?
If 37 weeks or beyond, labor is no longer preterm — contact your provider if you think you are in labor.
🩺 Check all symptoms you are experiencing right now
Symptoms selected:0
⚠ High-Urgency Symptoms — Go to L&D Now
Call Your Doctor or Midwife Today
If None of the Above Apply
📋 Symptoms You Reported
⚠ Are You at Higher Risk?
These factors increase your risk of preterm labor — tell your provider if any apply:
Prior preterm birth (strongest risk factor — recurrence risk 15–50% depending on history) ·
Short cervix (<25mm on transvaginal ultrasound) ·
Multiple gestation ·
Uterine anomalies ·
Infections (UTI, BV, STI) ·
Substance use ·
BMI <19 or >35 ·
African American race (2x higher risk — structural racism, not biology)
Source: ACOG PB 234, 2021; Romero et al. Science 2014.
⏱ How to Time Contractions
Start timing from the beginning of one contraction to the beginning of the next. Concerning pattern: 4 or more contractions in 20 minutes, or 8 or more in 1 hour — even if mild. Try hydrating (drink 2–3 glasses of water) and lying on your left side for 30–60 minutes. If contractions persist or increase — call your provider or go to L&D.
Note: Braxton-Hicks contractions are common and irregular. True preterm labor contractions become regular, more frequent, and often more intense over time.
