Premature labour (also known as pre-term labour) is when a woman begins having real contractions where the cervix dilates, prior to 37 weeks gestation. Women who go into premature labour may then go on to give birth prematurely, although in some cases, they may be able to continue with the pregnancy if medical treatment is able to stop or slow down the labour.
Premature labour poses a risk to the health of a baby because babies who are born too early may not have properly developed all their vital organs, particularly the lungs, and it will be hard for them to breathe on their own. Often referred to as “premmies”, babies born earlier than 37 weeks will usually need to be cared for in a neonatal unit (NICU) in a hospital, and be monitored closely to make sure they are coping and gaining weight.
Occasionally premature labour will need to be deliberately induced for the sake of the expecting mother’s health, or when the risks of premature birth are lower than continuing with the pregnancy, such as when there is an infection or the baby is not developing properly.
What are the risk factors?
There are some general risk factors that are closely associated with premature labour and birth:
- being pregnant with more than one baby
- being underweight or overweight
- having a premature labour or birth in a previous pregnancy
- being pregnant with a baby with health problems such as congenital heart problems or spina bifida
- having family members who have experienced premature labour or birth
- falling pregnant after age 35 or under age 17
- falling pregnant less than 6 months after completing a previous pregnancy
- smoking, drinking and drug use during the pregnancy
- multiple abortions
- having a history of miscarriages
- some types of previous surgery to the cervix or uterus.
Existing health problems or problems that arise specifically during pregnancy can also contribute to premature labour and birth, including:
- uterus or cervix issues
- recurring bladder or kidney infections
- pregnancy complications such as pre-eclampsia/HELLP syndrome, obstetric cholestasis, gestational diabetes or a blood clotting disorder
- placenta issues such as placenta praevia or placental abruption
- too much or too little amniotic fluid
- infections in the pelvis, including bacterial vaginosis, UTIs and some STDs
- stress and mental illness
- rupturing of the membranes or “water” around the baby (which is often due to injury or impact from things such as a fall or a car accident, but which is a serious problem even when it is not related to premature labour as it increases the risk of infection).
Women with one or more of these issues may need to receive special prenatal care and additional ultrasounds to check on the health of their baby.
However, some women go into premature labour even without having any risk factors, so it is worth being aware of the signs so you'll know to act as quickly as possible if it happens to you.
What are the signs?
Signs of premature labour are exactly what you will experience when you go into labour after 37 weeks, so if you experience any of the things listed below, you should contact your doctor immediately and follow their advice about what to do next:
- contractions and cramps in the abdomen and/or back that are ongoing, tight and which increase in frequency and pain
- strong pressure on the pelvic floor muscles
- watery discharge, which could mean the membranes or “water” encasing the baby have ruptured
- vaginal bleeding
- blood in urine or discharge
- reduced movement from the baby
- pain when urinating
- swelling in the hands, feet or face
- blurred or impaired vision.
Doctors can confirm whether a woman has gone into premature labour by doing a vaginal examination, checking the foetal heart rate and speed of the contractions, and ordering further blood or urine tests to check for possible infection.
What's the treatment?
For certain women that are at a high risk for premature labour, doctors can look for progress in premature labour ahead of time, by checking to see if a protein is present in the vagina that indicates that the body is close to triggering labour and take actions such as:
- giving progesterone vaginal pessaries (usually between 20 and 37 weeks), which can help some women stay pregnant longer by making it harder for the uterus to contract and prompt premature labour
- surgically placing cervical stitches in women with cervical problems to prevent the cervix opening too soon and inducing premature labour, by holding the baby in until the 37th week of pregnancy, after which time it can be removed, or alternatively an elective caesarean section can be performed to remove the baby when true labour begins.
When a woman unexpectedly goes into premature labour, treatment will start with trying to stop or delay pre-term birth. There are several ways doctors can do this:
- tocolytic drugs to slow down contractions, which in some women may lead to the contractions tailing off completely.
- antibiotics, if premature labour is due to infection.
- treating any triggering factors (such as dehydration which can stimulate the uterus to contract).
If labour continues and premature birth is inevitable, extra drugs may be given, including:
- more tocolytic drugs to postpone labour for a few days, so that other drugs (such as corticosteroids) can be given time to work or so that a pregnant women can be transferred to a hospital with a neo-natal care unit
- drugs to speed up a baby’s lung development (corticosteroids) so if they are delivered prior to 37 weeks they have a better chance of survival
- drugs to reduce the risk of other health problems in babies born too early, such as magnesium sulphate.
Once premature labour is effectively stopped, bed rest may be recommended for women who are likely to go into premature labour again, who need to try and reach 37 weeks.
Does it affect the baby?
Premature labour, when it leads to premature birth, can lead to babies having developmental delays, disabilities (such as loss of sight or vision) or other health problems, such as cerebral palsy and infections.
Babies could also be fine, once they have had time to grow while being cared for in a neonatal unit. It will depend on how early a baby is born as to how they develop afterwards. Babies born between 34-37 weeks generally grow to be very healthy, but each baby will be different.
Facts verified by Dr Andrew Zuschmann. Dr Andrew Zuschmann is a Miranda-based fertility specialist, obstetrician and gynaecologist.