Preterm Labor: Signs, Symptoms, Causes, Risks and Treatment

Quick Answer

Preterm labor is labor that begins before 37 completed weeks of pregnancy. The warning signs include regular contractions or tightenings, period-type cramps, low backache, pelvic pressure, and a gush or trickle of fluid from the vagina. If you are less than 37 weeks pregnant and notice any of these, contact your maternity unit immediately, because prompt care, including steroid injections for the baby's lungs, can make a real difference. Preterm birth is common, affecting more than 1 in 10 babies worldwide, and southern Asia, including India, carries a large share.

Key Takeaways

• Preterm labor is labor before 37 weeks of pregnancy. About 8 in 100 babies are born prematurely (NHS).

• Know the urgent signs: regular contractions, period-type pains, unusual backache, and any fluid leaking from the vagina before 37 weeks. Call your maternity unit at once.

• Many cases have no clear cause, but risk factors include a previous preterm birth, twins or more, infections, a short cervix, high blood pressure and diabetes.

• Prompt treatment helps. Doctors may use medicines to slow labor, steroid injections to mature the baby's lungs, and magnesium sulphate to protect the baby's brain.

• Some preterm births can be prevented in high-risk women with progesterone or a cervical stitch, and good antenatal care matters for everyone.

What Is Preterm Labor?

Preterm labor is when labor starts before the end of the 37th week of pregnancy. If it leads to birth, the baby is born preterm (premature). A full-term pregnancy is 37 to 42 weeks, so a baby born before 37 weeks has had less time to develop, which is why preterm birth needs careful medical attention.

The World Health Organization divides preterm birth into categories based on how early the baby arrives (WHO):

The earlier a baby is born, the more support they usually need, but medical care for premature babies has improved enormously, and many go on to do well.

How Common Is Preterm Birth?

Preterm birth is common and a major global health issue. An estimated 13.4 million babies were born preterm in 2020, more than 1 in 10 births worldwide (WHO). Sadly, complications of preterm birth are the leading cause of death in children under 5, though the WHO notes that around three-quarters of these deaths could be prevented with existing, cost-effective care.

This matters especially for India. The WHO states that the majority of preterm births occur in southern Asia and sub-Saharan Africa, and India carries one of the largest numbers of preterm births in the world. This is exactly why recognising the signs early and attending all antenatal visits is so important here.

What Are the Signs and Symptoms of Preterm Labor?

This is the most important section, because acting quickly can change the outcome. If you are less than 37 weeks pregnant, watch for these signs (NHS):

• Regular contractions or tightenings of the tummy, especially if they keep coming

• Period-type pains or cramps

• Low backache that is not usual for you

• A gush or trickle of fluid from the vagina, which could be your waters breaking

• Pelvic pressure, a feeling that the baby is pushing down

• A change in vaginal discharge, such as it becoming watery, mucus-like or bloody

Some of these can be hard to tell apart from normal pregnancy aches, and that is fine. You do not need to be certain. If in doubt, call. It is always better to be checked and reassured than to wait.

When To Call Your Doctor or Maternity Unit Immediately

Contact your midwife or maternity unit straight away if you are under 37 weeks and have (NHS):

• Regular contractions or tightenings

• Period-type pains

• A gush or trickle of fluid from the vagina (possible waters breaking)

• Backache that is unusual for you

• Any bleeding from the vagina

• A noticeable change or reduction in your baby's movements

If your waters have broken, also seek help urgently if you develop a raised temperature, feel hot or shivery, notice greenish or smelly fluid, bleed, or have tummy or back pain. These can be signs of infection.

Do not wait to see if symptoms settle. Early assessment allows treatments that protect your baby.

What Causes Preterm Labor?

Often, no single cause is found. Most preterm births happen spontaneously, and the exact reason is not always clear (WHO). But several factors raise the risk, and knowing them helps you and your doctor watch more closely.

Having a risk factor does not mean you will have a preterm birth, and many women with none still deliver early. This is why the signs above matter for everyone.

Spontaneous vs Planned (Medically Indicated) Preterm Birth

Not all preterm births are the same (WHO; NHS):

• Spontaneous preterm labor starts on its own, which is what most of this article is about.

• Planned (medically indicated) preterm birth is when doctors deliberately deliver the baby early, by induction or caesarean, because it is safer than continuing the pregnancy. This happens for reasons such as pre-eclampsia, poor baby growth, or other complications. In these cases, your doctor weighs the risks of the baby being born early against the risks of staying in the womb, and discusses the plan with you.

What Happens If Your Waters Break Early?

If your waters break before 37 weeks without labor starting, this is called preterm pre-labour rupture of membranes (P-PROM). It raises the risk of infection for you and your baby, so you will usually be offered (NHS):

• Antibiotics to reduce the risk of infection

• Tests for infection and monitoring

• Sometimes a short hospital stay for observation

P-PROM does not always mean labor is starting immediately, but you will be watched closely, and you should report any fever, smelly or greenish fluid, bleeding, pain, contractions or reduced baby movements at once.

How Is Preterm Labor Diagnosed?

If you come in with possible preterm labor, your team will check you and your baby to work out what is happening (NHS):

• Questions about your contractions, pain and any fluid loss, and your baby's recent movements

• A vaginal examination to check your cervix

• Blood and urine tests, partly to look for infection

• Cardiotocography (CTG), which records your contractions and your baby's heartbeat

• Checks of your pulse, blood pressure and temperature

These help decide whether you are truly in labor and what care you need.

How Is Preterm Labor Treated?

Treatment depends on how many weeks pregnant you are, whether there is infection or bleeding, and your baby's wellbeing. Options your doctor may use include (NHS):

• Medicine to slow or stop labor (tocolytics). This can buy time, for example to give steroids to work or to move you to a hospital with newborn intensive care. Slowing labor is not always appropriate, such as when it is safer for the baby to be born.

• Steroid injections (corticosteroids). Given to help your baby's lungs mature and get ready to breathe. These are a key, well-proven treatment, usually offered before 36 weeks.

• Magnesium sulphate, given through a drip if you are around 24 to 29 weeks (and sometimes 30 to 33 weeks). It helps protect your baby's brain and nervous system, reducing the risk of problems such as cerebral palsy.

• Antibiotics, especially if your waters have broken or there is infection.

Your team will also consider whether your baby would be safer born now, the local newborn care facilities, and your own wishes. Mylo's guide on Betnesol (betamethasone) injection explains the steroid treatment further, and you can read about contractions and their types to understand what you may feel.

Can Preterm Labor Be Prevented?

Not always, but the risk can be reduced, and some high-risk women can be offered specific preventive treatment.

For women at higher risk (for example, a previous birth before 34 weeks, a previous late miscarriage from 16 weeks, previous waters breaking early, or a cervix injured by past surgery), doctors may (NHS):

• Offer a vaginal ultrasound between 16 and 24 weeks to measure the cervix, since a cervix shorter than 25 mm is linked to a higher risk of early birth.

• Offer vaginal progesterone, a hormone treatment that can lower the risk in some women.

• Offer a cervical stitch (cerclage), a procedure to help keep the cervix closed.

For all pregnancies, the WHO emphasises that preventing preterm birth starts with a healthy pregnancy and good antenatal care (WHO):

• Attend all your antenatal appointments (the WHO recommends at least 8 contacts through pregnancy, starting before 12 weeks) so risks can be found and managed early.

• Treat infections promptly, including urinary and vaginal infections.

• Avoid smoking, alcohol and substance use.

• Eat well and stay at a healthy weight, and manage conditions like diabetes and high blood pressure with your doctor.

• Space pregnancies with an adequate gap where possible.

What Are the Complications of Preterm Birth for the Baby?

Because premature babies have had less time to develop, they may face challenges, more so the earlier they are born (WHO):

• Breathing difficulties, as the lungs are among the last organs to mature (which is why steroid injections help)

• Feeding difficulties and trouble maintaining body temperature

• Higher risk of infections

• Longer-term issues in some babies, such as learning, vision or hearing problems

The encouraging reality is that outcomes have improved greatly with modern newborn care, and many premature babies grow up healthy. Care such as warmth, kangaroo (skin-to-skin) care, breastfeeding support and treatment of infections saves many lives.

Common Myths About Preterm Labor

Many worries about triggering early labor are unfounded, so here is honest reassurance on the questions parents search for most.

If you have a high-risk pregnancy, always follow your own doctor's guidance, which may differ from these general points.

Preterm Labor: Frequently Asked Questions

"What is considered preterm labor?"
Preterm labor is labor that starts before 37 completed weeks of pregnancy. If it leads to birth, the baby is premature. A baby born at or after 37 weeks is considered full or term.

"What are the first signs of preterm labor?"
Regular contractions or tightenings, period-type cramps, unusual low backache, pelvic pressure, a change in vaginal discharge, and a gush or trickle of fluid from the vagina. If you have any of these before 37 weeks, contact your maternity unit immediately.

"What causes preterm labor?"
Often no clear cause is found. Known risk factors include a previous preterm birth, carrying twins or more, infections, a short cervix, high blood pressure, diabetes, smoking, and a short gap between pregnancies.

"Can preterm labor be stopped?"
Sometimes. Doctors may use medicine to slow or stop labor, which can buy time for steroid injections to help the baby's lungs, or to transfer you to a hospital with newborn intensive care. Whether to slow labor depends on your situation, and it is not always the safest option.

"How many weeks is safe to deliver?"
Full term is 37 to 42 weeks, which is the ideal window. Babies born from 37 weeks are usually well developed, though your doctor guides the safest timing for your pregnancy.

"Can I prevent preterm labor?"
Not always, but you can lower your risk with good antenatal care, treating infections, avoiding smoking and alcohol, and managing conditions like diabetes and high blood pressure. High-risk women may be offered progesterone or a cervical stitch.

"Does stress cause preterm labor?"
High stress is associated with a modestly higher risk, so looking after your mental wellbeing matters. But stress alone is rarely the sole cause, and you should not blame yourself if you experience preterm labor.

"Will my premature baby be okay?"
Many premature babies do very well, especially with modern newborn care, though the earlier the birth, the more support they may need. Your neonatal team will explain your baby's specific situation and care.

When To Seek Help

Contact your maternity unit or doctor immediately, at any time, if you are under 37 weeks and have:

• Regular contractions or tightenings

• Period-type pains or unusual backache

• A gush or trickle of fluid from the vagina

• Any vaginal bleeding

• Reduced or changed baby movements

• A fever or feeling unwell, especially if your waters have broken

There is no such thing as bothering your maternity unit over this. Early assessment is exactly what protects you and your baby.

This article is for information only and does not replace urgent medical assessment. If you think you may be in preterm labor, seek care now rather than waiting.

Bottom Line

Preterm labor is labor before 37 weeks, and it is common, affecting more than 1 in 10 babies worldwide, with India carrying a significant share. The single most important thing you can do is recognise the warning signs, regular contractions, period-type pains, unusual backache, and any fluid leaking from the vagina, and contact your maternity unit immediately if you notice them before 37 weeks. Prompt care, including steroid injections for the baby's lungs and magnesium sulphate to protect the brain, genuinely improves outcomes. Many causes cannot be prevented, but good antenatal care, treating infections, avoiding smoking and alcohol, and specific treatments for high-risk women all help. When in doubt, always get checked, because acting early is what makes the difference.

References

All links verified live on 17 September 2026.

1. Preterm birth — World Health Organization. Source for the definition and categories of preterm birth, the global figures (13.4 million in 2020, more than 1 in 10, leading cause of under-5 deaths), the concentration in southern Asia and sub-Saharan Africa, causes, and prevention through antenatal care.

2. Premature labour and birth — NHS, UK. Source for the signs and urgent-advice list, the 8 in 100 figure, diagnosis (vaginal exam, blood/urine tests, CTG), P-PROM management, treatments (tocolytics, steroid injections, magnesium sulphate 24 to 33 weeks), and prevention (cervical scan, progesterone, cervical stitch).

3. Guidelines for diagnostic imaging and antenatal care in pregnancy — American College of Obstetricians and Gynecologists (ACOG). Supporting source on preterm labor signs and management.

4. Mylo internal guides: pre-eclampsia, contractions and their types, and the stages of labour.

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