Labour is considered 'full-term' if it occurs between 37 and 42 weeks of pregnancy. Labour which occurs before 37 weeks of pregnancy is known as premature (or preterm) labour.
What is premature labour?
In premature labour, you start having regular contractions, and the neck of your womb (your cervix) starts to shorten and open, before 37 weeks of pregnancy. Most premature labour occurs between 34 and 37 weeks, but sometimes premature labour occurs well before this. Premature labour can sometimes be stopped after it has begun.
How common is premature labour?
Premature labour (labour before 37 weeks of pregnancy) is fairly common, occurring in 7 in 100 of single baby pregnancies in the UK. However, the average delivery date is around 37 weeks for twins and 33 weeks for triplets. Most premature labours will be at 34-37 weeks. Very premature birth is much less common, with fewer than 1 in 100 babies being born at between 22 and 28 weeks of pregnancy.
About 1 in 4 babies born prematurely are delivered early due to concerns about the health of the mother and/or baby. This leads to labour being artificially triggered (induced) or to the mother having a caesarean section.
Three out of four premature births occur because labour spontaneously began sooner than it should. In about a third of these, the waters break before labour begins.
Does premature labour mean my baby will be born early?
Fewer than 1 in 5 cases of suspected premature labour actually result in the baby being born. In 4 out of 5 cases, either the symptoms turn out to be something else, or the contractions stop of their own accord and the baby is born later.
Who is at risk of premature labour?
Most often, the cause of premature labour is unknown, and in most cases doctors cannot predict which women will go into labour early. Certain factors are known to increase the risk of premature labour, and a combination of several of these factors can be involved. The list of things which can make premature labour more likely includes some which make it much more likely (such as multiple pregnancies and pre-eclampsia) and others which make it a little more likely (such as stress or smoking).
Factors about this pregnancy
- Waters breaking early, called preterm prelabour rupture of membranes (P-PROM).
- Vaginal bleeding after 14 weeks in this pregnancy.
- Abnormality of your womb (uterus) or the neck of your womb (cervix).
- Carrying twins, triplets or more (about half of twin pregnancies end before 37 weeks).
- Excess fluid around your baby (polyhydramnios).
- Known cervical insufficiency, or a short cervix diagnosed on ultrasound scan.
- Placenta praevia.
- Fertility treatment in this pregnancy.
- Less than six months between pregnancies.
- Certain (rare) abnormalities in the baby.
Factors about previous pregnancies
- Premature birth in a previous pregnancy.
- Premature rupture of membranes in a previous pregnancy.
- Previous late miscarriage (after 14 weeks of pregnancy).
- Previous cervical insufficiency.
Factors about your health
- Having a current urine infection.
- Vaginal infection, including group B streptococci, gonorrhoea, chlamydia, syphilis, trichomoniasis or bacterial vaginosis.
- High blood pressure (gestational hypertension).
- Pre-eclampsia, eclampsia or HELLP syndrome.
- Being markedly underweight or overweight before your pregnancy began.
- Diabetes and gestational diabetes.
- Blood clotting problems.
- Being under 18 or over 35 years old at the time of delivery.
- Lack of healthcare in pregnancy, or lack of social support.
- Alcohol or illegal drug use in pregnancy.
- Severe stress.
- Long working hours with long periods of standing.
- Experiencing domestic violence or emotional abuse.
What should I do if I think I am in premature labour?
If you're in any doubt, you should phone your hospital or midwife straightaway. If you are less than 37 weeks pregnant they will almost certainly want you to be seen in hospital.
What are the warning signs of premature labour?
Being aware of the possible signs and symptoms of preterm labour means that you may have an opportunity to stop the labour and stay pregnant for longer. In addition, if you do deliver your baby you are more likely to get to hospital for your baby's birth. This means that your baby's birth will be as smooth as possible.
Babies who are born prematurely are likely to need medical support to begin with (and, in some cases, may need help with breathing and feeding). Your baby's best chance of doing well is to be born in a hospital with a paediatric specialist on hand. You should not plan to deliver your baby at home if labour is premature. The possible signs of premature labour are:
- Your waters may break. Sometimes you may feel a soft, popping sensation. There may be a slow trickle or a gush of clear or pinkish fluid from your vagina or just an increase in vaginal discharge. If your waters break prematurely contractions might begin, but often this does not happen.
Other symptoms of premature labour may include the following (many of which are also common when you are not in premature labour):
- Cramps like strong period pains (usually more painful than Braxton-Hicks 'practice' contractions, although these can also be painful in late pregnancy).
- Frequent need to urinate.
- Feeling of pressure in your pelvis.
- Feeling sick (nausea), being sick (vomiting) or having diarrhoea.
- A 'show' when the mucus plug in the cervix comes away.
If you have any of these symptoms you should seek advice straightaway, particularly if you also feel unwell or have a temperature.
How will the healthcare team know I am in premature labour?
The healthcare team will check whether you are in labour or, if not, what is causing your symptoms. They will do a number of checks on you and the baby, to see what - if any - immediate medical care you need. This may include:
- A general examination and a check of your temperature, pulse and blood pressure.
- An examination of your tummy (abdomen).
- A check of your baby's heartbeat - you will be put on a monitor to watch the pattern of your baby's heart rate, which can show whether your baby looks tired or stressed.
- A blood sample to check for signs of infection.
- A urine sample for testing for infection and protein (which could be due to pre-eclampsia).
- An ultrasound scan to check your baby's well-being and which way he/she is lying.
- A vaginal examination to assess whether the neck of your womb (your cervix) has started to shorten and open.
- A vaginal speculum examination to look at whether there is fluid leaking through the cervix.
- A vaginal swab to check for infection.
- If you are less than 34 weeks pregnant, a type of swab called fetal fibronectin may be taken from the top of the vagina. Fibronectin is found in amniotic fluid and vaginal secretions, and also in the vaginas of women over 35 weeks pregnant or whose bodies are about to go into labour:
- 1 in every 5 women with a positive fibronectin swab go into labour within 10 days.
- Less than 1 in 100 women with a negative test will go into labour within two weeks.
If labour is not confirmed or if you have a negative fetal fibronectin swab, you should be able to go home, assuming you are well and there are no other concerns for you or your baby.
What are the options if I go into labour early?
This will depend on how pregnant you are, on what has happened so far, on the health of you and your baby and on why you are in labour. It is usually not advisable to stop labour if you or your baby are unwell, if your baby is showing signs of fetal distress, or if you have a multiple pregnancy.
The options available to the team may include:
- Speeding your delivery up with medication, induction or caesarean section. This is more likely if you or your baby are unwell.
- Delaying your delivery for 48 hours or so to buy time to give you treatments to help your baby whilst still in the womb (uterus). If your labour is very early this also allows the chance to transfer you to a specialist unit.
- Delaying your delivery for as long as possible, sometimes several weeks.
- Letting labour continue naturally.
If you are 34 weeks pregnant or more
If you are more than 34 weeks pregnant then your baby will already be very mature, and the obstetric team will usually be happy to let the labour continue. It is best that this happens in hospital where there is equipment on hand if your baby has unexpected problems, or needs support.
If you are less than 34 weeks pregnant
If you are less than 34 weeks pregnant (and sometimes up to 35 weeks) then, depending on the particular circumstances, doctors may consider delaying your delivery at least until they have been able to give you steroids to mature your baby's lungs (see below) and transferred you to a unit with special care facilities. It may be possible to stop your labour and prevent it restarting until much nearer to your due date. They will not usually recommend this if they feel it is safer for your baby to be born straightaway.
Why are steroids used in premature labour?
Corticosteroids help your baby's lungs (and brains) mature. They are given by injection (two injections are given, 12-24 hours apart), and work within about 48 hours. If you have been given corticosteroids your baby is far less likely to develop respiratory distress syndrome (and some other complications). These medicines have no known side-effects, for either you or the baby. If you are at risk of having your baby prematurely, you are likely to be offered corticosteroids.
Why is magnesium sulfate used in premature labour?
Magnesium sulfate, given as a single infusion into your vein, seems to protect your baby's brain and reduces their risk of having problems such as cerebral palsy, if born too early. It has some side-effects, particularly flushing, feeling warm or 'fluey', headache, dry mouth, feeling sick (nausea) and having blurred vision. It is recommended if you are in labour at 30 weeks or less.
What happens if my waters have broken but I am not in labour?
It is possible for your waters to break before 37 weeks and without contractions - this happens in about 3 out of every 100 pregnancies. This is called preterm prelabour rupture of the membranes (P-PROM). You may notice a soft popping sensation, or feel either a gush, or a slow trickle of watery fluid, which is often pinkish or clear. Some women with P-PROM go into labour, and about one third of premature babies are born following P-PROM.
- If you have P-PROM but are not in labour, and you and the baby are otherwise healthy, you will usually be given antibiotics for up to 10 days to prevent infection, plus a dose of steroids to increase the maturity of your baby's lungs. Leaks from the waters around the baby can sometimes stop, but there is an increased risk of infection, so you and your baby will be carefully monitored. Doctors will hope you will continue the pregnancy to at least 34 weeks and sometimes up to 37 weeks, after which you will usually be induced.
- If you have P-PROM but are not in labour you will usuaklly not have a manual vaginal examination in case this introduces infection, but may be examined using a sterile speculum.
- If you develop an infection (called chorioamnionitis) in the womb (uterus) then your baby will need to be delivered as soon as possible. Chorioamnionitis usually gives you a raised temperature and gives your baby a rapid heartbeat. This infection is dangerous to both you and your baby. Chorioamnionitis is more likely if your waters have been broken for a long time, but antibiotics reduce the risk.
What happens if I am in labour?
If you are 34 weeks or over, the team will usually let the labour and birth go ahead.
Delaying labour with tocolytics
If you are in labour with only one baby and are less than 34 weeks pregnant, and you and your baby are well, the obstetric team may try to stop the contractions with medicines called tocolytics. These may be taken as tablets, or given through a drip:
- To buy time while you are having your course of corticosteroids for the baby's lungs.
- To buy time if you need to be transferred to a hospital where there is a neonatal intensive care unit (NICU), particularly if you are less than 32 weeks pregnant.
In women whose waters have broken and who are in premature labour
- Tocolytics are not always recommended. If they are used, it tends to be just for 48 hours to buy time for a course of corticosteroids to mature your baby's lungs. It is not absolutely proven whether this is helpful to your baby.
In women having twins (or more babies)
- Tocolytics are not routinely recommended for women having twins or triplets because it is not clear that they are beneficial for the babies in that situation.
You may also be given intravenous antibiotics, especially if you have a temperature, if your waters have broken early, or if you are in premature labour and known to carry a bug (bacterium) such as group B streptococcus in your vagina.
What happens if my labour doesn't stop or can't be stopped?
Sometimes tocolytics do not stop labour and sometimes they are not the best choice for you and your baby. If labour is going ahead prematurely then a paediatrician and special care midwife will be on hand for your baby's birth, which may be a vaginal birth or a caesarean birth, depending on the particular circumstances.
- If you are less than 30 weeks pregnant, and likely to give birth within 24 hours, you will usually be given treatment with magnesium sulfate, through a drip in your arm. Some women who are 30-34 weeks pregnant and in active labour are also offered this treatment. If you are advised to have it, your doctor will discuss it fully with you.
- If you are 27 weeks pregnant or less you may be moved to a specialist unit before your baby is born. It is usually safer to transfer the baby while he/she is still protected inside you. However, if you are at high risk of giving birth on the way to the unit, or if your condition is unstable, you will stay where you are. The team may transfer the baby to a specialist unit in an incubator after he/she is born.
- If you have an intrauterine infection (chorioamnionitis) or severe pre-eclampsia, or if there are problems with the health of your baby or with the afterbirth (placenta) then the obstetric team will usually need to deliver your baby as quickly as possible, and a caesarean section is likely.
What is premature labour like?
Premature labour is often shorter than full-term labour, but it can otherwise be very similar. There are regular contractions which may need pain relief, and a period of pushing before delivery. The pain relief options available to you will include most of those available to women in labour at the expected time. However, doctors may be keen to avoid painkillers which may suppress your baby's breathing at delivery.
The smaller size of your baby's head may mean that you may not need to push for as long (or as hard) to deliver your baby - but everyone is different. Your baby is usually closely monitored during labour and there will usually be paediatric doctors, as well as midwives, present when your baby is born.
What will premature birth mean for me?
Having a baby born early is usually unexpected, worrying and even frightening. You will be in a situation that is hugely challenging and, for most parents, beyond anything you have ever experienced before. You may at first still be a hospital inpatient yourself.
This is a time in your life that you may have expected to be natural and joyful, and instead is full of worries and questions. On top of this you have to cope with changes in your own body caused by the delivery and the postpartum period, and you may have other children to look after. Don't be surprised or feel guilty if you are upset, disappointed, or feel as though your plans have been ruined. These are natural feelings and are a part of coming to terms with a huge change of plan.
Your doctor and/or midwife will give you any information you want or need and they are there to answer your questions. There will be a lot to take in and you may feel overwhelmed. It can help to keep a list of questions as you think of them, so that you don't forget to ask.
The first few days, weeks or months with a premature baby can be tough. You may feel you cannot meet all of your baby's needs and this can make you feel inadequate. Or, you may feel as if you are not the real parent, but your baby needs you more than anyone else. You will be shown how to handle and interact with your baby from very early on and you will play a vital role in caring for your baby and judging what your baby wants and needs. You will be encouraged to express breast milk, as this is very good for premature babies, and to spend as much time with your baby as you can. You are essential and you will be as much an expert in your baby as you would be if they had been born at term. You need to stay as healthy and as well as possible, so you have the strength and energy to be there.
What will premature birth mean for my baby?
Premature babies are small and have not yet finished developing in the womb (uterus). The earlier your baby arrives, the smaller they will be. Premature babies have less fat under the skin, so their skin can look translucent, and they have fine hair (lanugo) on their backs. They cry softly (very early babies can't yet cry at all), and before 28 weeks your baby will not yet open their eyes.
Premature babies have an increased risk of health problems, particularly with breathing, keeping warm, feeding and infection. The earlier your baby is born, the more likely he or she is to have these problems. Your baby may need to be looked after in a specialist neonatal unit, and very early babies may spend a prolonged period in special care.
- If your baby is born at 27 weeks or less, he/she will need to be transferred to a neonatal intensive care unit (NICU). He or she will need help with breathing.
- Babies born very early (28 weeks to 31 weeks) are usually cared for in a special care baby unit (SCBU) or local neonatal unit (LNU), and help with breathing is often needed. Some need more specialised care at an NICU.
- All babies born at less than 35 weeks are admitted to an LNU.
- Moderately early babies (32 weeks to 33 weeks) may have problems with breathing, feeding and infection, and are likely to need SCBU or LNU.
- Early babies (34 weeks to 36 weeks) may not need any treatment. This will depend on how well your baby is feeding and whether he or she has problems with temperature, blood sugar levels, or infection.
More than 8 out of 10 premature babies born after 28 weeks survive. A small number of these babies will have a long-term disability.
Babies born before 24 weeks of pregnancy sadly have a much lower chance of surviving, as they have missed out on so much developing and maturing time. Babies who do survive after such a premature birth often have serious long-term health disabilities.
Can premature labour be prevented?
In some circumstances, particularly if you have had a baby born prematurely or a late miscarriage in the past, you may be:
- Offered vaginal scans in pregnancy to measure the length of the neck of your womb (your cervix).
- Treated with progesterone pessaries.
- Advised to have a stitch (suture) put around your cervix to prevent it opening early.
What about a future pregnancy?
Having your baby early means that you have an increased risk of having a premature birth in a future pregnancy. However, you are still most likely to have a baby born at more than 37 weeks next time. Your next pregnancy should be under the care of a consultant obstetrician who will discuss with you a plan for your pregnancy, how likely you are to have your baby early again and what extra monitoring you should have.
Did you find this information useful?
- The management of babies born extremely preterm at less than 26 weeks of gestation; British Association of Perinatal Medicine (October 2008)
- Preterm labour and birth; NICE Guidelines (November 2015)
- Preterm labour and birth; NICE Quality Standard, October 2016
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.