Most pregnancies last about 40 weeks. By definition, a premature birth takes place more than three weeks before the due date.

What is it?

Most pregnancies last about 40 weeks. By definition, a premature birth takes place more than three weeks before the due date.

A premature birth gives a baby less time to develop and mature in the womb. The result is an increased risk of various medical and developmental problems, including trouble breathing and bleeding in the brain. If you go into labor too early, your doctor may try to delay your baby's birth. Even if premature birth is inevitable, a few extra days in the womb can promote significant development.

Although the rate of premature birth seems to be on the rise, there's good news. A healthy lifestyle can go a long way toward preventing preterm labor and premature birth.


Prompt recognition of preterm labor may help you prevent premature birth. Even months before your due date, be on the lookout for:

  • Contractions that occur more than eight times each hour — you'll feel a tightening sensation in your abdomen, often reminiscent of menstrual cramps
  • Low, dull backache
  • Pelvic pressure or pain
  • Diarrhoea
  • Vaginal spotting or bleeding
  • Watery vaginal discharge — this may be amniotic fluid, which surrounds your baby in the uterus

Risk factors

Often, the specific cause of preterm labour or premature birth isn't clear. Many factors may increase the risk of early labor and premature birth, however, including:

  • Having a previous preterm labour or premature birth
  • Pregnancy with twins, triplets or other multiples
  • An interval of less than six months between pregnancies
  • Conceiving through in vitro fertilisation
  • Problems with the uterus, cervix or placenta
  • Smoking cigarettes, drinking alcohol or using illicit drugs
  • Poor nutrition
  • Some infections, particularly of the amniotic fluid and lower genital tract
  • Some chronic conditions, such as high blood pressure and diabetes
  • Being underweight or overweight before pregnancy
  • Stressful life events, such as the death of a loved one or domestic violence
  • Multiple miscarriages or abortions
  • Physical injury or trauma

For unknown reasons, black women are more likely to experience preterm labor and premature birth than are women of other races. But preterm labor and premature birth can happen to anyone. In fact, many women who have a premature birth have no known risk factors.


Preterm labor and premature birth may have various complications.

For mothers

Aside from starting too early, preterm labour typically resembles normal labour. Unfortunately, treatments used to delay delivery have only limited success and may carry risks. Medications that halt uterine contractions may cause fluid to collect in your lungs, which can make it difficult to breathe. Other side effects depend on the medication used to stop labour. Some medications can lead to fatigue and muscle weakness. Others may cause a rapid heartbeat, blood sugar abnormalities, headaches, dizziness or nausea.

On a more positive note, your doctor can give you medications that will increase the rate your baby matures in the uterus. These can have a beneficial impact in as little as 48 hours.

Your health care provider will weigh the potential risks from medications used to stop labor against the risks for your baby if he or she is born too soon.

For babies

The risks of premature birth vary depending on how soon a baby is born. Although survival is possible for babies born as early as 23 to 26 weeks, the risks are greatest for the youngest babies.

Complications of premature birth may include:

  • Difficulty breathing
  • Episodes of stopped breathing (apnea)
  • Bleeding in the brain (intracranial haemorrhage)
  • Fluid accumulation in the brain (hydrocephalus)
  • Cerebral palsy and other neurological problems
  • Vision problems
  • Intestinal problems
  • Developmental delays
  • Learning disabilities
  • Hearing problems

Less serious complications may include:

  • Yellowing of the skin and whites of the eyes (jaundice)
  • Decreased number of red blood cells (anaemia)
  • Low blood pressure

For some premature babies, difficulties may not appear until later in childhood or even adulthood. Not performing well in school is often a prime concern. Some studies suggest that premature babies may face an increased risk of type 2 diabetes and cardiovascular disease in adulthood.

But not all preemies have medical or developmental problems. By 28 to 30 weeks, the risk of serious complications is much lower. And for babies born between 32 and 36 weeks, most medical problems related to premature birth are short term.


If preterm labour seems likely, your health care provider will check to see if your cervix has begun to dilate and whether the fetal membranes have ruptured. The duration and spacing of your contractions may be closely monitored. In some cases, your health care provider may use ultrasound to monitor the length of your cervix. A swab from the cervical canal may be tested for the presence of fetal fibronectin, a glue-like tissue that's discharged during labour.

If you're in preterm labour, you and your health care provider will discuss the risks and benefits of trying to stop your labour.