Last updated: 9 October 2026
Pregnancy is often viewed as a time of excitement and anticipation. However, for some expectant mothers, complications can arise, leading to premature labour. The main reasons for premature labour are infections of the uterus, urine or vagina, carrying twins or more, a previous preterm birth, high blood pressure or diabetes, and problems with the cervix, uterus or placenta. In many women, though, no single cause is found. This guide covers the causes, warning signs and types of premature birth, and how to care for a premature baby.
Key Takeaways
- Premature labour is labour that starts before 37 weeks of pregnancy.
- The most common causes are infections, twins or more, a previous preterm birth, high blood pressure, diabetes and problems with the cervix or uterus. Often no single cause is found.
- Know the warning signs: regular tightenings, lower back pain, pelvic pressure, and watery or bloody discharge before 37 weeks need an urgent call to your doctor.
- Regular antenatal check-ups lower the risk, because infections, high blood pressure and a short cervix can be found and treated early.
- If your waters break or you bleed heavily, call 108 for an ambulance. Early hospital care gives your baby the best start.
What is Premature Birth?
Premature birth, or preterm birth, is when a baby is born before the 37th week of pregnancy. A full-term pregnancy typically lasts around 40 weeks, so a premature birth can occur anytime from 20 weeks to 36 weeks. While some premature babies may be relatively healthy, others may face serious complications due to their early arrival. Understanding the reasons for premature labour can help in identifying risk factors and taking preventive measures.
What are the Reasons for Premature Labour?
There are several reasons for premature labour, and they can vary from physical to emotional factors. Some common reasons include:
- Multiple pregnancies: Women carrying twins, triplets, or more are at a higher risk of premature labour.
- Infections: Infections in the mother’s uterus or urinary tract can trigger contractions and lead to early delivery.
- Chronic health issues: Conditions like diabetes, hypertension, and autoimmune diseases can increase the likelihood of premature birth.
- Previous preterm births: If a mother has had a preterm birth before, she is more likely to have another.
- Poor nutrition: A lack of essential nutrients during pregnancy can affect the baby’s development and increase the risk of premature birth.
- Stress: High levels of stress, anxiety, and depression can contribute to premature labour.
- Problems with the cervix: A short or weak cervix can open too early, often without pain.
- Problems with the uterus or placenta: An unusually shaped uterus, large fibroids, a low-lying placenta (placenta previa) or a placenta that separates early (placental abruption) can bring on early labour or bleeding.
- Pre-eclampsia: High blood pressure that starts in pregnancy is one of the most common reasons doctors need to deliver a baby early.
- Anaemia: Severe anaemia in pregnancy, which is common in India, is linked to a higher risk of premature birth. Iron and folic acid tablets and regular blood tests help.
Why Doctors Sometimes Deliver a Baby Early
Not every premature birth starts with labour on its own. According to the World Health Organization, most preterm births happen spontaneously, but some are planned for medical reasons, by inducing labour or by caesarean section. Doctors may advise an early delivery when continuing the pregnancy is riskier than an early birth, for example with severe pre-eclampsia, heavy bleeding from the placenta, an infection in the womb, or a baby who has stopped growing well. When there is time, the mother is usually given steroid injections first to help the baby’s lungs.
Types of Premature Birth
Premature births, often caused by various reasons for premature labour, are classified by how early the baby is born.
- Late Preterm: Babies born between 34 and 36 weeks of pregnancy. They often have fewer complications than those born earlier but can still face challenges.
- Moderately Preterm: Babies born at 32 or 33 weeks. They may need some medical assistance but generally have better outcomes compared to those born very early.
- Very Preterm: Babies born from 28 to 31 weeks. They are at a higher risk for complications, requiring significant medical intervention.
- Extremely Preterm: Babies born before 28 weeks. They face the greatest risks, including severe complications and long-term health issues.
How Common is Premature Birth?
According to the World Health Organization, an estimated 13.4 million babies were born prematurely in 2020, which is about 1 in 10 births worldwide. Complications of preterm birth are the leading cause of death in children under five. In India, the rate of preterm birth was about 13% in 2020, according to a 2023 global analysis in The Lancet. Knowing the reasons for premature labour helps parents and doctors lower these risks.
Symptoms and Causes
The symptoms of premature labour can feel like ordinary pregnancy aches, so they are easy to miss. Some common signs include:
- Regular contractions: Experiencing contractions every 10 minutes or more frequently can signal premature labour.
- Lower back pain: Persistent lower back pain that does not go away may be a sign.
- Pelvic pressure: A feeling of pressure in the pelvic area can indicate that labour is beginning.
- Changes in vaginal discharge: An increase in discharge, especially if it is bloody or watery, can be a warning sign.
- Ruptured membranes: If the water breaks before 37 weeks, seek medical help immediately.
Risk Factors for Premature Birth
Certain factors can increase the likelihood of premature birth complications. These include:
- Age: Mothers under 17 or over 35 are at a higher risk.
- Low pre-pregnancy weight: Being underweight before pregnancy can lead to complications.
- Inadequate prenatal care: Lack of regular medical check-ups during pregnancy can increase risks.
- Tobacco, alcohol and drug use: Smoking, chewing tobacco, alcohol, and drug use during pregnancy can sharply increase the chances of premature labour.
- Stressful life events: Major stressors, such as loss of a loved one or financial issues, can impact a pregnancy.
Knowing these risk factors helps you and your doctor reduce the risk of premature birth complications.
The US National Institute of Child Health and Human Development lists several other risk factors that doctors look for:
- Twins and IVF pregnancies: more than half of twin births are preterm, compared with about 1 in 10 single births.
- A short cervix, or a cervix that shortens in the second trimester.
- A short gap between pregnancies, of less than 6 months from one birth to the next pregnancy.
- Placenta previa (a low-lying placenta) and vaginal bleeding during pregnancy.
- Being underweight or obese before pregnancy.
- Urinary tract and vaginal infections, such as bacterial vaginosis.
- Long hours of standing work, a lack of support at home, and domestic violence.
Can Premature Labour Be Prevented?
Not always. In many women, labour starts early with no clear cause. However, these steps can lower the risk and help doctors act in time:
- Start antenatal check-ups early, ideally as soon as you know you are pregnant, and attend every visit.
- Get urine and vaginal infections tested and treated, even if you have only mild burning or discharge.
- Keep blood pressure, blood sugar and thyroid levels under control, as advised by your doctor.
- Avoid smoking, alcohol and all tobacco, including gutka, paan masala and second-hand smoke.
- Eat a balanced diet and take the iron and folic acid tablets your doctor prescribes.
- Plan the gap between pregnancies with your doctor, since getting pregnant again within 6 months of a birth raises the risk.
- Ask about extra care if you are at high risk. If you have had a preterm birth before or have a short cervix, your doctor may suggest progesterone treatment or a stitch in the cervix (cervical cerclage).
Weight, Length, and Head Circumference by Gestational Age for Boys
| Gestational Age (Weeks) | Weight (grams) | Length (cm) | Head Circumference (cm) |
|---|---|---|---|
| 24 weeks | 600 to 700 g | 30 to 32 cm | 21 to 22 cm |
| 26 weeks | 760 to 900 g | 32 to 34 cm | 23 to 24 cm |
| 28 weeks | 1,000 to 1,200 g | 35 to 37 cm | 25 to 26 cm |
| 30 weeks | 1,300 to 1,500 g | 37 to 39 cm | 26 to 28 cm |
| 32 weeks | 1,700 to 2,000 g | 40 to 42 cm | 28 to 30 cm |
| 34 weeks | 2,200 to 2,500 g | 43 to 45 cm | 30 to 32 cm |
| 36 weeks | 2,600 to 2,900 g | 45 to 48 cm | 32 to 34 cm |
| 38 weeks | 3,000 to 3,300 g | 48 to 50 cm | 34 to 36 cm |
| 40 weeks | 3,200 to 3,600 g | 50 to 52 cm | 35 to 37 cm |
These figures are approximate averages; healthy babies born in the same week can weigh noticeably more or less. Premature birth complications in boys can lead to growth challenges and developmental delays, so close monitoring matters. Proper neonatal care helps reduce the impact of premature birth complications.
Weight, Length, and Head Circumference by Gestational Age for Girls
| Gestational Age (Weeks) | Weight (grams) | Length (cm) | Head Circumference (cm) |
|---|---|---|---|
| 24 weeks | 560 to 680 g | 29 to 31 cm | 20 to 21 cm |
| 26 weeks | 730 to 870 g | 31 to 33 cm | 22 to 23 cm |
| 28 weeks | 950 to 1,150 g | 34 to 36 cm | 24 to 25 cm |
| 30 weeks | 1,200 to 1,400 g | 36 to 38 cm | 25 to 27 cm |
| 32 weeks | 1,600 to 1,900 g | 39 to 41 cm | 27 to 29 cm |
| 34 weeks | 2,000 to 2,400 g | 42 to 44 cm | 29 to 31 cm |
| 36 weeks | 2,500 to 2,800 g | 44 to 47 cm | 31 to 33 cm |
| 38 weeks | 2,900 to 3,200 g | 47 to 49 cm | 33 to 35 cm |
| 40 weeks | 3,100 to 3,500 g | 49 to 51 cm | 34 to 36 cm |
Girls born prematurely are also at risk of premature birth complications, including low birth weight and delayed growth. Early medical intervention can help manage premature birth complications and support healthy development.
When to See a Doctor
If you experience any signs of premature labour, contact your healthcare provider immediately. Early treatment can make a real difference to outcomes for both the mother and baby. Here are factors associated with preterm birth that warrant an immediate call to your doctor:
- If you notice regular contractions before 37 weeks.
- If you experience severe abdominal pain.
- If there are changes in vaginal discharge, especially if it’s bloody.
- If you feel increased pelvic pressure.
What to Do If You Think Premature Labour Has Started
- Stop what you are doing and rest. Note the time of each tightening for the next hour.
- Call your doctor or maternity unit straight away. Do not wait until morning or until the next check-up.
- Call 108 for an ambulance if your waters break, you bleed heavily, you have severe pain, or your baby is moving less than usual.
- Take your antenatal records and scan reports with you to the hospital.
What doctors may do: they will check your cervix, your baby’s heartbeat and signs of infection. If birth is likely, they may give medicines to slow contractions for a short time, steroid injections to help the baby’s lungs mature, and antibiotics if there is an infection. Where possible, a baby expected to arrive early should be born in a hospital with a neonatal intensive care unit (NICU).
How Doctors Confirm Premature Labour
Doctors confirm premature labour by checking whether the cervix is starting to open or shorten while contractions are regular. The usual tests are:
- Contraction and heartbeat monitoring (CTG) to see how often the womb is tightening and how the baby is coping.
- An internal examination to check if the cervix has started to open.
- A transvaginal ultrasound to measure the length of the cervix. A short cervix means birth is more likely soon.
- A fetal fibronectin swab, in hospitals that offer it. A negative result means birth within the next week or two is unlikely.
- Urine and vaginal swab tests to look for an infection that may be triggering labour.
Taking Care of a Premature Baby
Caring for a premature baby can feel overwhelming at first, but with the right support and knowledge, parents can provide the best care. Here are some practical tips:
- Follow medical advice: Work closely with your healthcare team to understand the specific needs of your baby.
- Skin-to-skin contact: This can help regulate the baby’s temperature and promote bonding.
- Breastfeeding: Breast milk protects a preterm baby against infection and supports growth. If your baby cannot feed directly yet, expressing milk gives them the same benefits.
- Keep the environment calm: Minimize loud noises and bright lights to create a soothing atmosphere for your baby.
- Regular check-ups: Follow up with pediatric hospitals for the appointments to monitor your baby’s growth and development.
Preterm Birth Survival
Survival rates for premature babies have improved a great deal thanks to better neonatal intensive care. The cause of the early labour can also affect outcomes. Survival depends a great deal on where a baby is born. The WHO notes that in low-income settings half of babies born at or below 32 weeks die, while in high-income countries almost all of these babies survive. Babies born before 28 weeks face the most challenges, including long-term health issues.
The following factors influence preterm birth survival:
- Gestational age: The earlier a baby is born, the higher the risk for complications.
- Birth weight: Babies with a higher birth weight generally have better survival rates.
- Access to medical care: Prompt and specialized care in neonatal units can greatly improve outcomes.
Conclusion
Knowing the reasons for premature labour helps expectant parents spot the warning signs early and get care in time. With knowledge of the symptoms, risks, and care techniques, families can handle the challenges of premature birth with more confidence. If you have any concerns about your pregnancy or need guidance, don’t hesitate to reach out for professional help.
