Premature labour

What is premature (early) labour and how common is it?

Being in premature (or preterm) labour means that:

• You will start feeling regular, painful contractions before you have completed 37 weeks of pregnancy.

• The contractions will be strong enough to make the neck of your womb (cervix) to dilate.

Premature labour most often happens between 34 and 37 weeks, but sometimes starts well before this. Sometimes it is possible to stop premature labour.

About 8 in every 100 babies are born prematurely.

What does early labour feel 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 (children's) doctors, as well as midwives, present when your baby is born.

Signs and symptoms of early 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. 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):

• Backache.

• 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 mucous 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.

Risk factors for premature birth

Usually the cause of premature labour is unknown. 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 (PPROM).

• 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 (where the placenta is lower in the womb than it should be).

• 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.

• Smoking.

• 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.

Examination at the hospital

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.

National Institute for Health and Care Excellence standard

The National Institute for Health and Care Excellence (NICE) has published new 'quality standards' for doctors about the care they should offer to women who are in possible or premature labour, or who are at risk of going into premature labour. Quality standards are recommendations of treatments and advice which should be offered to all patients, although in practice, implementation varies by area.
The recommendations include:

• If you are at risk of premature labour, your team should advise you about the signs and symptoms of early labour to look out for, as well as what the risks of preterm labour are.

• If you have had a previous premature labour, or have lost a baby after 13 weeks of pregnancy, you should have an assessment between 16 and 24 weeks of labour to check the length of your cervix. If it is at least 25 mm long, you should be offered a choice of cervical suture or progestogen pessaries.

Other recommendations are included in the appropriate sections below.

Early labour options

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 there are signs of infection, if your baby is showing signs of fetal distress, or if you have a multiple pregnancy.

Speed up labour

Speeding your delivery up with medication, induction or caesarean section. This is more likely if you or your baby are unwell.

Delay labour

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.

Delaying your delivery for 48 hours or so to buy time to give you treatments to help your baby whilst still in the womb. If your labour is very early this also allows the chance to transfer you to a specialist unit.

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.

Let labour continue naturally

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.

Prevention

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 progestogen pessaries.

• Advised to have a stitch (suture) put around your cervix to prevent it opening early.

See the separate leaflet called Cervical insufficiency and suture (Incompetence and cerclage).

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.

Frequently Asked Questions

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 open their eyes less than you might expect.

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.

There are three types of unit where a premature baby might be cared for - they are listed here in order from the most to the least amount of support that is given:

• Neonatal intensive care unit (NICU) - this is for the most premature or most unwell babies. A baby born at 27 weeks or less would usually go to a NICU.

• Local neonatal unit (LNU) - a baby who does not need NICU care, but is too unwell to be cared for on a special care baby unit might go to an LNU. Typically babies on an LNU will be born between 28 and 31 weeks.

• Special care baby unit (SCBU) - this is for babies who are not well enough to stay with their mother on the ward, but do not need the care provided on an LNU or NICU. Typically they will be born after 32 weeks of gestation.

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.

See the separate leaflet called Premature babies for more information.

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.

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.

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 seems to protect your baby's brain and reduces their risk of having problems such as cerebral palsy, if they are born too early. It is given as a single infusion into your vein and has some side-effects, particularly flushing, feeling warm or 'fluey', headache, dry mouth, feeling sick (nausea) and having blurred vision. It will be discussed with you if you are in labour between 23 and 34 weeks of gestation.

What if water breaks but no contractions?

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 usually 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 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.

How common is premature labour?

Premature labour (labour before 37 completed weeks of pregnancy) is fairly common, occurring in 8 in 100 of single baby pregnancies in the UK. Of all premature babies, around 84 in 100 are born after 32 weeks, 10 in 100 between 28 and 32 weeks, and 6 in 100 before 28 weeks. Twins and triplets are often born earlier than 37 weeks.

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.

Dr Mary Lowth is an author or the original author of this leaflet.