Signs of Preterm Labor Before 37 Weeks, Braxton Hicks and What to Do

What are the signs of preterm labor?

The signs of preterm labor are regular or frequent contractions or tightenings, which ACOG says are often painless, along with period-like cramps, a constant low and dull backache, pressure in the pelvis or lower belly, and a change in vaginal discharge, including leaking fluid. ACOG says that if you have any of these before 37 weeks, do not wait: call your ob-gyn's office right away or go to the hospital.

NICHD says some contractions through the day are normal, but six or more in one hour are not, and it lists contractions every 10 minutes or more often as a symptom. It also says frequent tightenings may cause the cervix to begin to open.

What counts as preterm labor?

Preterm labor is labor that starts before 37 weeks of pregnancy, according to ACOG, and NICHD describes it as labor from 20 weeks through 36 weeks. ACOG calls a birth before 37 weeks a preterm birth. The CDC says preterm birth affected about 1 in 10 babies born in the US in 2022, and the NHS says about 8 in 100 babies are born prematurely.

ACOG says preterm labor does not automatically lead to a preterm birth and stops on its own for about 3 in 10 women, but that it still needs medical attention right away.

Is it Braxton Hicks or preterm labor?

Braxton Hicks contractions have no pattern and stay weak, while labor contractions come at regular intervals, get closer together and get stronger, according to ACOG. ACOG says Braxton Hicks can start many weeks before labor, can be very painful, may be more noticeable at the end of the day, and may stop when you walk, rest or change position. The NHS describes them as usually painless, short, infrequent and not building up.

ACOG's general labor advice is to time contractions and note whether they continue when you rest and drink water; if rest and fluids make them go away, they are not true labor. Its preterm labor advice is not to wait if you have any of the signs above. ACOG also says that sometimes the only way to tell the difference is a vaginal exam to look for changes in the cervix.

What should you do if you think you are in preterm labor?

If you think you are in preterm labor, call your ob-gyn or midwife right away or go to the hospital. ACOG and NICHD give the same advice. The NHS says to call your midwife or maternity unit, or 111 if you cannot reach them, and not to wait until the next day, even in the middle of the night.

At the hospital, ACOG says preterm labor is diagnosed when your cervix is found to change after contractions start, so you may have pelvic exams over a few hours and your contractions may be monitored. Tests can include an ultrasound, a transvaginal ultrasound to measure the length of your cervix, and a vaginal swab for fetal fibronectin. The NHS lists a vaginal exam, blood and urine tests, and monitoring of contractions and the baby's heartbeat.

If your baby may be born early, ACOG describes three kinds of medicine:

• Corticosteroids can help speed up development of the baby's lungs, brain and digestive organs. ACOG says they may be recommended between 24 and 34 weeks if birth may happen within 7 days, sometimes up to 36 weeks and 6 days, and may be considered from 22 weeks. The most benefit comes 2 days after the first dose, with some benefit in the first 24 hours.
• Magnesium sulfate may reduce the risk of cerebral palsy. ACOG says it may be given before 32 weeks if birth may happen within 24 hours. The NHS says it should be offered from 24 to 29 weeks and may be offered from 30 to 33 weeks.
• Tocolytics can delay delivery, sometimes for up to 48 hours. ACOG says even a few hours can allow time for steroids, magnesium sulfate or a transfer to a hospital with specialized care for preterm babies.

If your group B strep status is not known when labor starts before 37 weeks, ACOG says you may be given antibiotics during labor.

Who is at higher risk of preterm labor?

People who have had a preterm birth before are at higher risk: ACOG says a past preterm birth makes another 2 to 3 times more likely, and the risk rises with each one. ACOG's other risk factors include a short cervix, past procedures on the cervix, carrying more than one baby, vaginal bleeding or infections in pregnancy, low weight before pregnancy, smoking, and being younger than 17 or older than 35. ACOG also says preterm labor can happen to anyone without warning, and many women who give birth early have no known risk factor.

If you are at risk, ACOG says vaginal progesterone may be offered for a short cervix found on ultrasound before 24 weeks, and a stitch in the cervix (cerclage) if you have a short cervix and a past preterm birth. The NHS says people with certain risk factors are usually offered a vaginal ultrasound between 16 and 24 weeks, and that a cervix shorter than 25 mm (about 1 inch) is linked to a higher risk. ACOG says bed rest is not recommended, because it can raise the risk of blood clots, bone weakening and loss of muscle strength.

When should you call your doctor or midwife?

Before 37 weeks, call your doctor or midwife right away, or go to the hospital, if you have:

• regular or frequent contractions or tightenings, such as six or more in an hour, which ACOG says are often painless
• period-like cramps, with or without diarrhea
• a constant, low, dull backache, or backache that is unusual for you
• pressure in your pelvis or lower belly
• a change in vaginal discharge: watery, bloody or with mucus, or more of it than usual
• a gush or trickle of fluid from your vagina, which may be your waters breaking
• bleeding from your vagina

ACOG's general labor advice is to go to the hospital if you are bleeding heavily from the vagina, have constant, severe pain with no relief between contractions, or notice your baby moving less often. The NHS also says to call your midwife or maternity unit urgently if you have vaginal bleeding or your baby is moving less than usual.

If your waters broke early and you have been sent home, the NHS says to call immediately if you have a raised temperature or feel hot, cold or shivery, the fluid turns greenish or smelly, you bleed, you have pain in your belly or back, you have contractions, or your baby's movements change.