Mucus plug: what it is, what it looks like and what losing it means

The mucus plug is a thick mass of mucus that seals the neck of the womb (cervix) during pregnancy and helps to protect your baby from infection. Towards the end of pregnancy, when the cervix starts to soften and open, it comes loose and passes out through the vagina: it is jelly-like, like egg white, clear, whitish, pink or brown, sometimes with streaks of blood, and it can come away all at once or in pieces. Losing your mucus plug does not mean labour has started: labour may still be a few hours or several days away. You don't need to go to hospital just because you have lost it; you do if you bleed as much as a period, your waters break, you have regular contractions or you lose it before 37 weeks.

In this guide, our midwives explain what the mucus plug is, what it looks like, when it comes away, how to tell it apart from discharge or your waters breaking, and when to call or go to hospital.

In short:

• What it is: the mucus that seals the cervix during pregnancy.
• What it looks like: jelly-like and thick; clear, whitish, yellowish, pink or brown, sometimes with streaks of blood.
• When it comes away: at the end of pregnancy, days or hours before labour, or during labour itself. Some women don't notice it.
• Does it mean labour is starting? Not on its own. Labour starts with regular contractions that get stronger and stronger.
• When to go to hospital: bleeding as heavy as a period or heavier, your waters breaking, regular contractions, your baby moving less, a fever, or if it happens before 37 weeks.

What is the mucus plug?

During pregnancy, the cervix produces thick mucus that builds up in its canal and closes it like a plug. It is a natural barrier: it separates the womb from the vagina and helps to stop germs travelling up towards the amniotic sac and your baby.

In the last few weeks, the cervix gets ready for birth: it softens, shortens and starts to open. With these changes, the plug comes loose and comes away. Sometimes small blood vessels in the cervix break too, which is why the mucus can be tinged with blood. This is often called a show (or a “bloody show”).

What does the mucus plug look like? Colour and appearance

• Texture: jelly-like, sticky and stretchy, thicker than your usual discharge. It is often compared to egg white.
• Colour: clear, whitish or yellowish; also pink or brown, or with streaks of red blood. All of these can be normal.
• Amount: it can come away all at once, as a blob of mucus, or little by little, in pieces, over several days. Many women notice it in their underwear or when they wipe.

What is not normal is heavy bleeding with red blood, as much as a period or more: in that case you need to go to hospital (we explain more below).

Mucus plug, discharge, waters breaking or bleeding: the differences

	What it looks like	What to do
Mucus plug	Thick, jelly-like mucus, clear, pink or brown, sometimes with streaks of blood	Nothing urgent if you are full term and there are no other signs
Pregnancy discharge	Thinner and more watery, whitish, with no blood; increases towards the end of pregnancy	Normal; get advice if it itches, stings or smells unpleasant
Waters breaking	Fluid that leaks and makes you wet, in a gush or a trickle, and that you can't hold in; usually clear	Call or go to hospital; urgent if it is green, brown, red or smells unpleasant
Bleeding	Heavy bleeding with red blood, as much as a period or more, with or without pain	Emergency: call 112 (999 in the UK)

When do you lose your mucus plug?

Usually at the end of pregnancy, from 37 weeks onwards, when the cervix starts to get ready. It can come away a few days before labour, a few hours before or during labour itself. Some women lose it without realising, and others never notice a plug at all.

It is also common for it to come away, or for a little blood-stained mucus to appear, after a vaginal examination at an appointment or after sex, because the cervix has a very rich blood supply. It does not mean labour has started.

What if I lose it before 37 weeks?

If you lose your mucus plug, or notice a lot of mucus or blood-stained mucus, before 37 weeks, call your midwife or your maternity unit the same day, especially if you also have contractions, backache or pain low in your tummy, pressure in your pelvis or leaking fluid: these can be signs of premature labour.

Does losing your mucus plug mean labour is starting?

No. It is a sign that your cervix is getting ready and that labour is getting closer, but on its own it does not mean you are in labour or that labour is imminent. Between losing the plug and the start of labour contractions, hours or several days can pass.

Labour really starts when regular contractions appear, closer and closer together, longer and stronger, gradually opening the cervix. Before that, many women go through a phase of irregular contractions, early (latent) labour, which prepares the cervix but is not yet active labour.

How long after losing your mucus plug does labour start?

There is no way of knowing. For some women labour comes within hours, and for others several days go by. What will tell you the time has come is regular contractions or your waters breaking, not the plug.

I've lost my mucus plug: what should I do?

• If you are 37 weeks or more and have no other signs, you don't need to go to hospital. You can carry on as normal, have a shower and rest. Mention it at your next appointment.
• Keep an eye on contractions: if they start, note down how often they come and how long they last.
• Keep track of your baby's movements, as always.
• Use a sanitary pad or panty liner, not a tampon, so you can see clearly the colour of what comes out.

When to go to hospital or call

Go to your hospital or maternity unit straight away, or call 112 (999 in the UK) or your local emergency number if you can't get there, if you have:

• Vaginal bleeding as heavy as a period or heavier, especially if it comes with pain.
• Your waters breaking (fluid leaking from the vagina). If the fluid is green, brown, red or smells unpleasant, go without waiting.
• Regular, painful contractions. Follow your maternity unit's advice on when to come in. As a reference, some public hospitals in Spain advise, for example, one painful contraction every 3–4 minutes for 3 hours if it is your first baby, or every 5 minutes for 2 hours if you have had children before.
• Your baby is moving less than usual or you can't feel them moving.
• A fever above 38 °C.
• You have lost the plug before 37 weeks with contractions, pain or leaking fluid.

If you are unsure, call your midwife or your maternity unit: it is always better to ask. To learn how to recognise labour and when to leave home, also read our labour guide: when to go to hospital.

While you wait: getting ready for your baby's arrival

These last few weeks are a good time to get everything ready for your baby. If you are going to breastfeed and want to have a bottle ready, for mixed feeding, to give your expressed milk or in case you need it in the first few days, our advice as midwives is that the teat should be as similar as possible to your breast. That is why we designed the made-to-measure Happymami bottle, with a teat designed from the shape of your breast, and you can order it before the birth.

Frequently asked questions

How can I tell if it is my mucus plug?

By its texture: it is much thicker and more jelly-like than discharge, and it usually comes away all at once or in pieces, sometimes pink or with streaks of blood. If what comes out is watery and makes you wet, it may be your waters.

What if I lose my mucus plug and have no contractions?

Nothing. It is common: your cervix is getting ready, but labour may take days to start. Carry on as normal and wait for regular contractions to begin.

Should I go to hospital when I lose my mucus plug?

No, if you are full term and there is no heavy bleeding, no sign of your waters breaking, no regular contractions, no fever and your baby is moving as usual.

Does the mucus plug come out all at once?

Not always. It can come away all at once or little by little, and it is normal to keep losing bits of it for several days.

Can you lose your mucus plug without noticing?

Yes. Sometimes it comes away little by little, mixed with discharge, or during labour, and you don't notice it.

Conclusion

Losing your mucus plug is a sign that your body is getting ready for labour, but it is not the starting signal. If you are full term, watch it calmly and pay attention to contractions, your waters and your baby's movements. And if you have any doubts, ask your midwife or your maternity unit. We wish you a beautiful birth.

Sources

• NHS. Signs that labour has begun.
• MSD Manual, consumer version (Spanish edition). Trabajo de parto (Labour).
• Hospital Universitario de Fuenlabrada (Madrid Health Service, Spain). Se acerca mi parto: ¿cuándo acudir a las urgencias del hospital? (My labour is approaching: when should I go to the hospital emergency department?)