Free family guide · Warning signs and common problems

Signs of preterm labor

MedlinePlus says labor that starts before 37 completed weeks is preterm labor.[1]

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Sources on this page: MedlinePlus; ACOG; NHS; CDC

This page shares what health organizations say. It is not medical advice. It is general information. Talk to your doctor, midwife or pediatrician about your own situation.

In an emergency, call 911.

Signs

MedlinePlus lists these signs of preterm labor:[1]

  • contractions every 10 minutes or more often;[1]
  • leaking fluid or bleeding;[1]
  • pressure in the pelvis;[1]
  • a dull backache;[1]
  • cramps like a period, or belly cramps with or without diarrhea.[1]

Sources differ

Sources describe the contraction pattern in different ways:[1][2]

  • MedlinePlus lists contractions every 10 minutes or more often.[1]
  • ACOG lists regular contractions, 4 times every 20 minutes or 8 times an hour, for more than 1 hour.[2]

The NHS says to contact your midwife or doctor if tightenings are painful or come at regular intervals, because this could be early labor.[3]

Risk factors CDC lists

CDC lists risk factors that include:[4]

  • a past preterm birth;[4]
  • carrying twins or more;[4]
  • infection or high blood pressure;[4]
  • tobacco or drug use;[4]
  • pregnancy through IVF.[4]

Full term and viability

The NHS says a baby is full term at 37 weeks, and a birth then would not be considered early.[5] It says a baby is considered viable from 24 weeks, with a chance of survival with support from a neonatal unit.[6]

Questions families ask

What counts as preterm labor?

MedlinePlus says labor that starts before 37 completed weeks.[1]

How can I tell Braxton Hicks from preterm labor?

The NHS says Braxton Hicks tightenings last 20 to 30 seconds and should not hurt, and to call if they are painful or regular.[3]

Free from UpOnly Learning. Written for families of every faith. No outside ads and no affiliate links. Every fact on this page comes from the sources listed below. How we source and review these pages

Updated 2026-10-24: first published.

Sources

All sources were opened and checked on the date shown.

  1. MedlinePlus (National Library of Medicine). Preterm Labor. Checked October 24, 2026.
  2. American College of Obstetricians and Gynecologists. Bleeding During Pregnancy. Checked October 24, 2026.
  3. NHS (United Kingdom). 31 weeks pregnant guide. Checked October 24, 2026.
  4. Centers for Disease Control and Prevention. Preterm Birth. Checked October 24, 2026.
  5. NHS (United Kingdom). 37 weeks pregnant guide. Checked October 24, 2026.
  6. NHS (United Kingdom). 24 weeks pregnant guide. Checked October 24, 2026.