What is cervical dilation?
The cervix is the lower, narrow part of the womb, which stays long and closed during pregnancy. In labour, contractions first shorten and thin it, which is called effacement, and then open it. Dilation is measured in centimetres. According to pacjent.gov.pl, the Polish Ministry of Health patient portal, full dilation is 10 cm, and the NHS explains that the cervix needs to open this far for the baby to pass through.
The Polish standard of perinatal care defines the first stage of labour by dilation: it runs from the first regular contractions that efface and dilate the cervix until it is fully dilated. The same document says that the onset of labour is recognised from contractions that make labour progress, meaning they shorten and open the cervix. So in practice the question "is this labour yet?" is answered by examining the cervix, not by the pain alone.
The number of centimetres is only one piece of information. The UK's NICE recommends also assessing effacement, how low the baby's head is and which way it faces, and whether the membranes are intact. Two women with the same dilation can therefore be at different points in labour.
What are the stages of labour and at how many centimetres do they start?
The Polish standard divides labour into four stages. The first and longest is further divided into a latent and an active phase. Where one ends and the other begins depends on the source: the WHO puts it at 5 cm, NICE and the NHS at about 4 cm.
| Stage | Dilation | What happens |
|---|---|---|
| First stage, latent phase | Up to 5 cm according to the WHO, up to 4 cm according to NICE | Contractions are painful but do not have to be regular. The cervix softens, shortens and slowly opens. |
| First stage, active phase | From 5 cm (WHO) or about 4 cm (NICE, NHS) to 10 cm | Contractions are regular and stronger, and the cervix opens noticeably faster. |
| Second stage, pushing | Fully dilated, 10 cm | The baby's head moves down, you feel the urge to push, and the stage ends with the birth of the baby. |
| Third stage, the placenta | Not applicable | From the birth of the baby until the placenta and membranes separate and come out. |
| Fourth stage | Not applicable | Under the Polish standard, 2 hours after the placenta is delivered: checking bleeding and how the womb contracts, repairing any tear, the first breastfeed. |
NICE describes the latent phase as a period that is not necessarily continuous: contractions can come, fade and come back. The WHO stresses that labour may not naturally speed up until about 5 cm, so it does not recommend speeding it up with medication or a caesarean before that point, as long as mother and baby are well.
How long do the latent and active phases of labour last?
There is no standard length for the latent phase. The WHO says it varies widely from one woman to another, and the NHS that it can take many hours, or even days, before you are in active labour. The WHO explains the lack of a standard partly by how hard it is to pin down when labour really started.
For the active phase the sources do give figures, but they count from different starting points, so they cannot be compared directly:
| Source | Counted from | First labour | Later labours |
|---|---|---|---|
| WHO | 5 cm | Median 4 hours, usually no more than 12 hours | Median 3 hours, usually no more than 10 hours |
| NICE | 4 cm | 8 hours on average, unlikely to last over 18 hours | 5 hours on average, unlikely to last over 12 hours |
| NHS | About 4 cm | Usually 8-18 hours | Often quicker, around 5-12 hours |
The WHO notes that the upper limits are values that cover about 95% of the labours described in the studies, and that a decision to intervene must not be based on duration alone. The Polish standard does not give the length of the first stage in hours. It does, however, define when lack of progress is diagnosed, which we cover below.
9 cm dilated: how long until the baby comes?
The honest answer is that it cannot be predicted to the hour. But there is data. In its 2018 recommendations the WHO pooled studies of almost 100,000 low-risk women whose labour started on its own and ended without perinatal complications. The table shows the median time it took to reach the next centimetre.
| Dilation | First labour, median | Later labours, median | Slowest 5% of labours without complications, first labour |
|---|---|---|---|
| From 4 to 5 cm | about 1 h 30 min | about 1 h 10 min | 4-15.7 h |
| From 5 to 6 cm | about 55 min | about 40 min | 2.5-10.7 h |
| From 6 to 7 cm | about 40 min | about 25 min | 1.8-9.3 h |
| From 7 to 8 cm | about 35 min | about 20 min | 1.4-6.8 h |
| From 8 to 9 cm | about 30 min | about 17 min | 1.3-4.4 h |
| From 9 to 10 cm | about 30 min | about 16 min | 1-2.6 h |
The last column is the range of 95th percentiles from individual studies of first labours: this is how long it took to gain one centimetre for the slowest 5% of women, who still reached full dilation without complications. The WHO says plainly that it was not uncommon for a woman to need at least an hour to get from 9 to 10 cm. The table also shows that the further dilated you are, the faster the next centimetres usually come.
Once you are fully dilated, the second stage, pushing, begins. According to the WHO, in a first labour the baby is usually born within 3 hours, and in later labours within 2 hours. The Polish standard sets different limits, as described below. So at 9 cm you need to add both the last centimetre and the pushing.
On the WHO labour chart (the Labour Care Guide), staff get an alert to reassess when dilation stays the same for longer than a set time: 6 hours at 5 cm, 5 hours at 6 cm, 3 hours at 7 cm, 2.5 hours at 8 cm and 2 hours at 9 cm. This is not a due time for the birth, only the point at which the midwife or doctor checks that everything is going well.
Who checks dilation and how?
Dilation is assessed by a midwife or doctor in an internal (vaginal) examination with their fingers. Under the Polish standard, an examination that assesses how far labour has progressed and whether the membranes are intact is done on admission, and the findings are recorded on the labour chart, the partogram. The start of the second stage is also recognised this way.
- How often: for low-risk women the WHO and NICE recommend an examination every 4 hours in the active phase, and more often only when it will add important information, for example if labour seems to have stalled. The WHO stresses that the frequency and total number of examinations should be kept down because of the risk of infection, especially when there are other risk factors, for example if your waters broke a long time ago.
- Consent: NICE recommends explaining why the examination is offered and what it involves, getting your consent and making sure you have privacy. You can decline or ask to stop at any point. The NHS adds that your midwife can then talk you through why she is offering it.
- Timing: according to the WHO manual, the examination should not be started during a contraction.
- Result: ask not only about the centimetres but also how things have changed since the last examination. The standard requires staff to keep you informed about how labour is progressing.
You cannot check dilation at home. The best guide at home is the rhythm of your contractions, which we describe in our article on the signs of labour. If you labour with a private midwife who stays with you at home in early labour, she can assess progress and help you decide when to go to hospital.
What happens if dilation stops progressing?
Slower dilation does not have to mean a problem. The WHO considers the old rule of 1 cm per hour unrealistically fast for some women and says that a slower rate on its own should not be a routine reason to intervene. The sources differ on when labour counts as stalled:
- Polish standard: lack of progress is diagnosed when the cervix does not dilate any further during 4 hours of observation. If a midwife diagnoses lack of progress in the first stage, an obstetrician joins your care.
- NICE: delay is suspected when, in a first labour, dilation has increased by less than 2 cm in 4 hours. In later labours, also when labour clearly slows down. A further examination is offered 2 hours later, and delay is diagnosed if progress has been less than 1 cm.
- WHO: staff look at how long dilation has stayed at a given centimetre, using the labour chart thresholds described above.
According to the NHS, labour most often slows down when contractions are not frequent or strong enough, or when the baby is in an awkward position. NICE recommends first making sure you have support, fluids and effective pain relief, discussing the examination findings with you and deciding together what to do next. Possible steps are:
- Breaking the waters (amniotomy): according to NICE it shortens labour by about an hour, but contractions may become stronger and more painful. A further examination is offered 2 hours later.
- An oxytocin drip: according to NICE it makes contractions more frequent and stronger and brings the birth forward, but it does not change the mode of birth or how the baby is after birth. It requires continuous CTG monitoring.
- Review by a doctor: according to NICE, when delay is confirmed an obstetrician examines your abdomen and does an internal examination, then decides with you what to do next.
How long does pushing, the second stage of labour, last?
This is where Polish rules differ from WHO and NICE guidance. The Polish standard says the second stage should not exceed 2 hours, and in women with regional anaesthesia, such as an epidural, it lasts up to 3 hours. An obstetrician decides on extending it after assessing the risk factors. The WHO and NICE instead distinguish between first and later labours: the baby is usually born within 3 hours in a first labour and within 2 hours in later ones. NICE counts this time from the start of active pushing.
NICE splits the second stage into a passive phase, when you are fully dilated but not yet pushing, and an active phase, when you are pushing or the baby's head is visible. For women with an epidural who do not feel the urge to push, NICE allows pushing to be delayed by up to 2 hours in a first labour and up to 1 hour in later ones. The NHS points out that with an epidural you may not feel any urge to push at all.
The standard requires staff to let you take whatever positions you find most comfortable in the second stage, with particular attention to upright positions, and to follow your urge to push. An episiotomy is done only when there is a medical reason.
How long does delivering the placenta take and what happens after the birth?
The third stage starts when the baby is born and ends when the placenta comes out. Under the Polish standard it should not last longer than an hour. The NHS describes two ways of managing it: with active management you get an oxytocin injection and the placenta usually comes out within 30 minutes, while with physiological management it can take up to an hour for the placenta to separate. NICE diagnoses a prolonged third stage after 30 minutes with active management and after 60 minutes with physiological management.
- Umbilical cord: under the standard it is clamped once it stops pulsing, but not earlier than one minute after birth.
- Skin-to-skin contact: if you and your baby are well enough, it should last uninterrupted for at least 2 hours. You can end it whenever you wish.
- Placenta: the standard says the placenta should be actively delivered after it has separated, and outside of haemorrhage it does not recommend pressing on the top of the womb, massaging the womb or pulling on the cord.
- Fourth stage: for 2 hours after the placenta is delivered, staff monitor your condition, how the womb contracts and the bleeding, repair any tear or episiotomy and help with the first breastfeed. Under the standard, normal blood loss during birth should not exceed 500 ml.
How the perineum heals over the following weeks is covered in our separate article on perineal healing after birth.
When should you go to hospital?
You cannot base the decision on centimetres, because dilation is only known after an examination. The NHS says the latent phase is usually spent at home, and if you get to hospital before labour has got going, staff may suggest you go home again for a while. Which signs mean labour has started, what contraction pattern means it is time to go and when to call 112 are covered in detail in our article on the signs of labour.
The physiology of labour and positions for the first and second stages are part of the antenatal education programme described in the Polish standard, so antenatal classes (szkoła rodzenia) are a good time to practise them before your due date. If you want a midwife with you from the first contractions, on MyMidwife you can find midwives who support part-home births, and the details are on our birth midwife service page.
