Pregnancy health centre

Understanding preterm labour and birth - the basics

What is preterm labour and premature birth?

A normal pregnancy lasts about 40 weeks, measured from the first day of the last period (38 weeks after fertilisation). Contractions and dilation, which is the opening of the cervix, before the 37th week of pregnancy is called preterm (or premature) labour. Babies born before the 37th week of pregnancy are called premature babies.

In the UK, about 10% of all pregnancies result in premature birth. The more premature a child is when born, the greater the risk of problems. However, the longer the duration of pregnancy  - that is, the less premature a baby is - the lesser the chance of problems and the greater the chance that a child will survive.

The problem with preterm labour is that a baby will be born prematurely and his or her bodily  organ systems will not be fully developed.  In turn, this means a child may not be able to function and sustain life without medical support. Fortunately nowadays with the availablility of neonatal intensive care units (NICU), where babies can be cared for whilst their organ systems mature,  most babies born prematurely  survive and do very well.

Depending on how premature a child is when they are born problems experienced by the baby may include:

• Problems breathing due to immature lungs
• Difficulty maintaining body temperature
• Problems feeding due to difficulty sucking or coordinating breathing and swallowing
• Jaundice
• Increased risk of infection

Premature babies are at higher risk of long-term complications, which may include visual impairment or blindness, hearing impairment, cerebral palsy and chronic lung problems. The earlier the baby is born, the more likely that he or she will have these problems.

Who has preterm labour?

About one in three preterm babies are delivered for medical reasons, either for your safety or your baby’s. You should know that you are more likely to experience preterm labour or preterm birth if:

• you've had preterm labour or delivered a premature infant in the past.
• you're carrying more than one baby (multiple pregnancy).
• your mother used the medication diethylstilboestrol (DES) while she was pregnant with you.
• you have an abnormally shaped uterus or an abnormal cervix.
• you've had a cone biopsy of your cervix.
• you're younger than 17 or older than 35.
• you got pregnant while using an IUD, and the IUD was left in place during pregnancy.
• you were seriously underweight when you became pregnant.
• you smoke or use illegal drugs.
• you've had second-trimester miscarriages during previous pregnancies, or you've had three or more elective abortions.
• you have pre- eclampsia, kidney disease, heart disease, diabetes, an infection or other medical condition. 
• you're not receiving antenatal care from a qualified healthcare provider.
• you have a cervical infection, such as group B streptococci, gonorrhoea, chlamydia, syphilis, trichomoniasis or gardnerella.
• your job involves extremely strenuous, physical work.

Overview of preterm labour

Although there have been many advances in caring for premature babies, there has been little improvement in solving the problem of preterm labour. Medical science doesn't completely understand why some women go into labour or break their waters too early. There's no completely accurate way to predict which women will do so or prevent these women from giving birth prematurely. However, there have been some advancements in helping to prevent preterm labour and great advances in taking care of preterm babies.