Premature labour: the facts

Most pregnancies end with a bouncing baby at the end of a normal full term pregnancy, but there is a small percentage of women who have their babies early. And like most things related to pregnancy and birth, when it comes to premature labour, old wives tales and misinformation abound.

It’s important that every pregnant woman is aware of the facts surrounding an early labour and birth, even if you don’t believe you are at risk. Premature labour can be scary, but if you are armed with accurate information it will help you process and understand what’s happening and how things may unfold.

Most pregnancies are around 40 weeks long, and a full term baby is one that arrives between 37 and 42 weeks. A baby born between 20 weeks and 37 weeks (and is over 400gm in weight) is considered premature, while a baby born prior to 20 weeks is considered a miscarriage.

Around one in 10 babies in Australia arrive before 37 weeks, and the World Health Organization has three categories for premature babies:

• extremely preterm: less than 28 weeks
• very preterm: 28 to less than 32 weeks
• moderate to late preterm: 32 weeks to less than 37 weeks.

Causes of premature labour

There are some known causes for premature labour, but often babies just arrive early and no reason can be found. This can be difficult for parents of premature babies, as understanding why it happened that way can help process any trauma attached to the birth.

But research shows that some lifestyle choices can increase the risk of premature birth. Major stress and overwork, smoking, poor weight management (including both weight loss and weight gain) or drug and alcohol abuse can increase the risk of premature labour. Poor antenatal care can also be a contributing factor.

However, many mothers who are looking after themselves, not engaging in risky behaviour such as smoking and drinking, eating well and generally being as healthy as possible still experience preterm labour.

Some other known causes of premature labour are:

• an ‘incompetent cervix’, where the cervix is not strong enough to hold the pregnancy once the baby reaches a certain weight
• hormonal imbalance
• anatomical problems, such as with the structure of the uterus
• infection
• placental problems such as placenta previa or placental abruption
• age of mother – women under 19 or over 35 are statistically more prone to premature birth
• certain chronic illnesses
• a multiple birth (twins or more)
• a previous preterm birth, where labour started naturally or waters broke without medical intervention – with each preterm birth, the risk increases for the next pregnancy
• pregnancy resulting from assisted reproduction (the rate of premature birth is around 15 per cent for assisted reproduction, compared with around 10 per cent for babies conceived naturally)
• pregnancy complications such as too much amniotic fluid.

Regardless of what the ‘old wives tales’ tell you, the following things will not cause premature labour:

• working
• exercise
• travelling
• bed rest
• sex
• past terminations of pregnancy.

Signs of premature labour

Premature labour can be difficult to diagnose, as in the last couple of months of pregnancy the uterus can be particularly active with Braxton Hicks contractions (and indeed, many women experience Braxton Hicks as early as 15 weeks).

The key difference between a Braxton Hicks contraction and a real contraction is that Braxton Hicks don’t hurt the way a contraction hurts. While Braxton Hicks can be intense, the feeling is not the same as a real contraction – Braxton Hicks will usually stop if you change position, and they are much more irregular, stopping and starting at random intervals.

Premature labour is much the same as regular labour, but it is earlier than expected. Signs of labour include:

• back ache that doesn’t ease with pain medication, heat packs etc.
• period-like cramping, sometimes accompanied by diarrhoea
• strong pressure on your pelvic floor muscles
• contractions that come regularly, increasing in volume, length and intensity
• evidence of a ‘slow leak’. This is when you are leaking amniotic fluid from your uterus and it feels like your underwear is a little bit wet. If you feel this, change your underwear and monitor the level of wetness. If your underwear continues to be wet after changing you should contact your care giver
• a ‘show’, where the plug of mucus that seals the uterus comes away
• sudden breaking of waters or watery discharge
• bleeding from the vagina.

If you experience any of these symptoms prior to 37 weeks it is important to contact your care giver.

The important thing for pregnant women to remember is that while rates of premature labour in Australia are quite low, they can still experience premature labour even if they have none of the risk factors. Being in tune with your body and reporting any symptoms that seem unusual or too early is essential.

Early intervention in premature labour and birth increases the chances of a positive outcome for both mother and baby. Knowing how to recognise premature labour, and being proactive by reporting your symptoms, will help improve your birthing experience.

 

Treatments for women in premature labour

In some instances doctors can intervene and keep labour at bay, depending on the circumstances. If this is the case, doctors may give the expectant mother certain drugs designed to slow down contractions. These can be very effective, and in some cases the contractions will stop.

Doctors may stitch the cervix closed if weak muscles in the cervix are the cause, or may give antibiotics if the mother has an infection. They can also treat any triggers, such as severe dehydration.

If the treatments are successful bed rest is often recommended until the baby is due.

Despite these interventions, some labours continue. In these cases, depending on how far along the pregnancy is, doctors may give drugs to reduce the risk of health problems once the baby is born. Drugs such as corticosteroids can help increase the strength of the baby’s lungs, increasing their chances of positive health outcomes.

Most babies who arrive early require specialist care, so they will be admitted to the hospital’s neonatal intensive care unit (known as NICU).

Survival rates of premature babies depend on how early they arrive, and the closer to 37 weeks gestation, the better their chance of survival. But babies born at 24 weeks still have 45-50 per cent chance of survival, and a baby born at 31 weeks has a 95 per cent chance of survival. So while premature labour and birth can be a frightening experience for parents, you chances of taking home a baby are still very high.