Cramps during pregnancy: what is ordinary, what is not, and when to ring
Cramping is one of the commonest things people notice in pregnancy, and most of it is not a sign that anything is wrong. This article is about cramping felt in the abdomen and pelvis. Calf or foot cramp at night is a different problem of later pregnancy and is not covered here, though calf pain that is constant, or that comes with swelling, redness or warmth in one leg, should be reported the same day rather than treated as cramp. The uterus grows from roughly the size of a small pear to an organ that fills the abdomen, and the muscle itself, the ligaments that hold it in place and the gut sitting around it are all stretched and pushed aside while that happens. That work is felt. Mild cramping that comes and goes, lasts a short time and settles when you stop belongs to ordinary pregnancy, and it can appear in any of the three trimesters.
What this article does is separate that ordinary cramping from the smaller group of causes that need looking at, because the two can feel similar at the start. It explains round ligament pain properly, since it accounts for a large share of the pain people describe, then works through the first, second and third trimesters in turn, covers the non-obstetric causes that are most often missed, and it sets out at the start, in a section of its own, the findings that need emergency care and those that mean you should contact your maternity unit the same day rather than waiting for the next appointment.
Why mild cramping is so common in pregnancy
Three things happen at once. The uterine muscle itself enlarges and is a muscle, so it can tighten and ache. The ligaments that anchor the uterus to the pelvis and the groin have to lengthen and thicken to keep up with it, and stretched ligaments hurt. And the hormonal changes of pregnancy relax smooth muscle throughout the body, which slows the bowel and traps wind. Any of the three can produce cramping that feels gynaecological when it is not, and all three can be happening in the same week.
Ordinary cramping tends to share a pattern. It sits low down, centrally or to one side, feels dull and period-like or like a short sharp pull, lasts seconds to a few minutes, and eases when you rest or change position. Nothing else goes with it: no bleeding, no fever, no change in the baby's movements, no symptoms when you pass urine. It is the pattern over a few hours rather than any single twinge that tells you most.
None of this replaces being examined. Your own midwife or obstetrician knows your history, your scans, how your placenta is lying and what happened in any previous pregnancy, and all of that changes how a given pain should be read. Use what follows to decide how quickly to speak to someone, not to reach a diagnosis on your own.
Cramping that needs urgent assessment
Two levels of urgency, and the first one cannot wait for a phone call. Go straight to an emergency department, or call an ambulance, if you have sudden severe abdominal pain with feeling faint, dizzy or sick, if you look or feel very pale, if you collapse, if bleeding is heavy, or if your abdomen is hard, tender and will not soften. In early pregnancy that combination can mean a fallopian tube has ruptured; later on it can mean the placenta is separating. Both are treatable, and both are treated by how quickly you are seen.
Everything below needs you to contact your maternity unit, your midwife or your obstetrician on the same day, and straight away rather than at the end of it. Do not hold it until your next scheduled appointment, do not wait to see whether it improves overnight, and do not be put off because you were seen recently or because you feel you are making a fuss.
- Regular tightenings that are getting closer together before 37 weeks, at whatever interval
- Any single tightening that lasts longer than two minutes
- Six or more tightenings in ten minutes
- Bad or persistent pain high in the abdomen or just under the ribs, particularly on the right, after 20 weeks, whether or not it comes with a severe headache, visual disturbance or sudden swelling of the face, hands or feet
- Any bleeding from the vagina, at any stage, however light and whatever the colour
- A gush or a steady trickle of fluid, or underwear that keeps becoming wet
- Fever, shivering, or feeling generally unwell alongside the pain
- Pain that is severe, or that sits on one side and stays there
- Pain at the tip of the shoulder, particularly in early pregnancy
- Pain that does not ease at all when you stop and rest, or that keeps building
- Fewer movements than usual, or a change in the pattern of movements, once you have begun to feel them
- Cramping with burning on passing urine, much greater frequency, loin or flank pain, or urine that is cloudy or bloodstained
Who to ring depends on the stage. In the first weeks it is usually an early pregnancy assessment service, your own doctor, or an emergency department if you feel faint or the pain is severe. From the second trimester onwards it is the maternity unit looking after you, which is staffed around the clock for exactly this. If you cannot get through, go in. Being assessed and sent home reassured is a good outcome, and no clinician will think the call was unnecessary.
Round ligament pain, one of the commonest explanations
A pair of round ligaments runs from the upper part of the uterus on each side, forward and down through the groin, to the soft tissue of the labia. They are cords of fibrous tissue with a little muscle in them, and their job is to hold the uterus forward over the bladder. As the uterus enlarges, these cords are pulled long and thin, like a rubber band being stretched. A sudden movement loads a ligament that is already at full stretch, and it protests.
The pain is characteristic once you recognise it. Most people describe a sharp, stabbing or pulling sensation low in the abdomen or deep in the groin, sometimes running down towards the pubic area. It arrives suddenly, peaks almost immediately and is gone within seconds to a couple of minutes, often leaving a dull ache for a while afterwards. It is felt more often on the right, because the uterus commonly tilts and rotates slightly to the right as it grows, but it can be on the left or on both sides on different days. It is most common from the middle of pregnancy onwards, and most noticeable in the second trimester, though it can carry on to the end.
- Standing up quickly from sitting or lying down
- Rolling over or turning in bed
- Coughing, sneezing or laughing
- Getting in or out of a car
- A long walk, a flight of stairs, or a day spent on your feet
- Reaching or stretching upwards
The defining feature is that it is tied to movement and relieved by stopping. Sitting or lying down, bringing the knees up towards the chest, or lying on the side so the ligament is slackened will usually settle it within a few minutes. Round ligament pain does not cause bleeding, does not cause a fever, does not come in a regular rhythm and does not stay while you are lying still. Pain that behaves in any of those ways is something else and needs assessing.
First trimester: a growing uterus, implantation and the gut
Some people notice mild cramping in the second half of the luteal phase, roughly six to twelve days after ovulation and most often around days eight to ten, occasionally with light spotting. The cramping is produced by progesterone, by ordinary uterine activity and by the bowel rather than by the attachment itself. It is worth saying plainly that this cannot be distinguished from premenstrual cramping by how it feels, and its absence means nothing either, so it is not a test for pregnancy. If you are trying to read early symptoms, implantation cramping and the earliest signs of pregnancy are covered separately.
Through the first twelve weeks the uterus roughly doubles and doubles again in size while still sitting inside the pelvis. That expansion is often felt as period-like cramping low in the abdomen, which is exactly why the weeks after a positive test are so unsettling: the sensation is the one you associate with a period starting. Ordinary expansion cramping is mild, comes and goes over hours or days, has no rhythm to it, and is not accompanied by bleeding.
The gut accounts for a good deal of first trimester cramping and gets too little credit for it. Progesterone slows transit through the bowel, so stool sits longer and dries out, wind is trapped more easily, and iron supplements make both worse. Cramping from this source tends to wander around the abdomen, feels colicky and gripping, often comes in waves, and eases after opening the bowels or passing wind. Changes in diet, fluids and gentle activity usually improve it.
First trimester: ectopic pregnancy and miscarriage have to be excluded
An ectopic pregnancy, where the pregnancy implants outside the uterine cavity and usually in a fallopian tube, most often declares itself between about the fourth and twelfth weeks. The pain is typically on one side, persistent rather than coming and going, and it builds rather than fades. It may come with vaginal bleeding that is darker or more watery than a period, pain on opening the bowels, pain at the tip of the shoulder, dizziness or fainting. This is an emergency. Pain of this character in early pregnancy needs assessment that day, not an appointment next week, and if the pain is sudden and severe, or comes with faintness, dizziness, feeling sick or looking pale, go to an emergency department or call an ambulance rather than ringing for an appointment.
Miscarriage more typically brings cramping together with bleeding, and the cramping is usually stronger and more rhythmic than stretching pain, because the uterus is contracting. Cramping on its own, with no bleeding at all, is a common experience in early pregnancy and is far more often explained by the uterus growing or by the bowel. That is a genuine reassurance, but not a reason to sit on pain that is persistent, one sided or worsening.
How this is sorted out is straightforward: an early pregnancy assessment service will examine you, take a urine sample, perform an ultrasound scan, usually through the vagina at this stage, and often measure the pregnancy hormone in blood and repeat it after a couple of days to see which way it is moving. How those hormone measurements are interpreted is explained in more detail in the article on hCG levels in early pregnancy.
Second trimester: ligaments, the first tightenings and urinary infection
The second trimester is when round ligament pain is at its most noticeable, because this is the stage at which the uterus rises out of the pelvis and the ligaments are being loaded hardest. If you have reached the middle of pregnancy and started getting sharp catches in the groin when you stand up or turn over, that is the usual explanation, and for many people it eases somewhat later on as the uterus settles into position, although it can continue into the final weeks.
Braxton Hicks tightenings also begin somewhere around the middle of pregnancy for many people, although plenty do not notice them until much later. They feel like the bump going firm and then softening again, often more of a tightening than a pain, and usually short, commonly under a minute though sometimes longer. The thing that makes them recognisable is that they have no pattern: they come at random, stay far apart, and usually settle if you rest, change position or have a drink.
Urinary infection deserves naming here rather than being left to the end, because it is easy to miss and simple to check. Mid pregnancy cramping that fits neither of the patterns above is worth a urine sample even when nothing else points that way. It can be quieter in pregnancy than outside it, so the classic burning may be mild or absent and low abdominal discomfort is the main complaint. A urine sample is the way to settle it, and it is a reasonable thing to ask for.
Third trimester: Braxton Hicks or true labour contractions
In the final weeks this becomes the question that matters, and the honest position is that a single tightening cannot be classified. What distinguishes practice tightenings from established labour is how they behave over an hour or two: whether they organise themselves into a rhythm, whether that rhythm tightens up, and whether rest makes any difference. Timing them for a short while, writing down when each one starts and how long it lasts, gives you far more information than trying to judge how strong each one feels.
| Feature | Braxton Hicks tightenings | True labour contractions |
|---|---|---|
| Rhythm | Irregular and unpredictable, with no pattern you can time | Regular, and the pattern becomes easier to time as it goes on |
| Spacing over an hour or two | Stay far apart, or stop altogether | Come closer together |
| Length of each one | Short and variable | Lengthen as labour establishes |
| Intensity | Stays much the same, often a tightening rather than a pain | Builds, so each one is harder to talk through than the last |
| Effect of rest, a change of position, a drink or a warm bath | Usually settle | Carry on regardless |
| Where it is felt | Usually across the front of the bump | Often in the lower back and thighs as well as the front |
| What else is happening | Nothing else changes | A show, waters breaking, loose bowels, or heavy pressure low down |
Two cautions about using that table. Regular tightenings that are getting closer together before your pregnancy is due are not reassuring and should be reported straight away, whatever the interval. And guidance on exactly when to come in differs between maternity services and between national bodies: the NHS asks you to ring once tightenings are coming every five minutes or more often, while other services use a different interval, and units vary further for a second or later baby. Follow the instruction your own unit has given you rather than anything you have read, and ring sooner if you are unsure.
Pelvic girdle pain in later pregnancy
Pelvic girdle pain is often mistaken for cramping because it is felt in the same region. It comes from the joints of the pelvis, which loosen in pregnancy, and is typically felt over the pubic bone at the front, across one or both sides of the lower back, between the legs, or spreading down into the thighs. Some people hear or feel a clicking or grinding as they move. It is usually worse walking, climbing stairs, standing on one leg while dressing, turning in bed, or parting the legs.
What separates it from ligament pain is that it is provoked reliably by particular movements rather than coming out of nowhere, and it tends to persist rather than vanish in seconds. The Royal College of Obstetricians and Gynaecologists advises that it should be assessed and that referral to a physiotherapist experienced in obstetric pelvic problems should be offered, with advice on movement, pacing and sometimes a support belt. It is not something to be told to put up with, so raise it if it is limiting you.
Urinary infection and constipation, the causes most often missed
Urinary infection in pregnancy can show itself as low abdominal cramping with little else, or with burning on passing urine, needing to go far more often, urgency, cloudy or strong smelling urine, or blood in the urine. If it reaches the kidney it adds pain in the loin or flank, fever, shivering and vomiting, and that combination needs assessing the same day. Infection is diagnosed on a urine sample and treated with antibiotics chosen as suitable in pregnancy. That treatment has to be prescribed by a clinician who has your sample and your history; it is not something to source yourself.
Constipation is one of the most under-recognised causes of cramping, and it can occur at any point in pregnancy. The slowed bowel, the pressure of the enlarging uterus on the rectum and iron supplementation combine to make it worse as pregnancy goes on. The pain is colicky, moves around, is often worst on the left lower side, and eases after a bowel movement. Fluid, fibre and movement are the first measures. Anything beyond that, including products sold without prescription, should be checked with your own midwife or doctor first.
There is genuine variation between countries on how widely urine should be cultured in pregnancy when there are no symptoms at all. Some services culture routinely at the booking appointment on the grounds that silent infection can progress; others have narrowed that. The practical consequence is that your antenatal schedule may not match what you read elsewhere, and that is not an error.
Appendicitis in pregnancy, which does not sit where you expect
Appendicitis is among the commonest non-obstetric surgical emergencies in pregnancy, and it is the one most likely to be put down to pregnancy itself. Part of the reason is anatomical. The enlarging uterus can displace the appendix upwards and outwards, so tenderness is not always where it would be outside pregnancy, and pain higher up or further round towards the flank does not rule appendicitis out. How much the appendix actually moves is debated, and in every trimester the commonest site is still low on the right, so pain there should not be written off as stretching either. Pain in the upper right abdomen or just under the ribs in later pregnancy should never be assumed to be stretching. Two things have to be excluded. Appendicitis is one. The other is pre-eclampsia, which usually begins after 20 weeks and can cause bad or persistent pain high up under the ribs, most often on the right, sometimes with a severe headache, visual disturbance such as flashing lights or blurring, or sudden swelling of the face, hands or feet. Either needs assessing the same day.
Several of the usual clues are blunted as well. Nausea and vomiting are so common in pregnancy that they stop being a signal, the white cell count rises normally in pregnancy so a raised count means less, and temperature may be only modestly up. Ultrasound is usually the first test, with cross sectional imaging that avoids radiation used where it is available and the picture is unclear. Because a delay allows the appendix to perforate, pain that is constant, progressive and tender to the touch is a same-day problem, whatever week you are in.
What assessment usually involves
Expect questions first, because the history does most of the work: when the pain started, where it sits, whether it comes and goes or stays, what brings it on, what settles it, whether there has been bleeding or fluid loss, whether the baby is moving as usual, and whether there are urinary or bowel symptoms. Then pulse, blood pressure and temperature, and examination of the abdomen to find where the tenderness is and whether the uterus is soft between tightenings.
After that it depends on the stage. Early in pregnancy a urine test, blood tests including the pregnancy hormone, and a scan through the vagina are usual. Later on a urine culture, blood tests, an abdominal scan to look at the baby, the fluid and the placenta, and a period of monitoring of the baby's heart rate alongside any tightenings are more typical, with an internal examination if labour is a possibility. Most people who are assessed for cramping are reassured and go home.
What often eases ordinary cramping
- Stopping and sitting or lying down when a sharp pain catches you, rather than pushing through it
- Moving slowly between positions, and drawing your knees up towards you when a ligament pain strikes
- Rolling rather than twisting when you turn in bed, and keeping your knees together as you get out of a car
- A warm bath or a warm compress over the area, provided the water is comfortable rather than hot
- Fluids, fibre and gentle regular walking when constipation is part of the picture
- A support belt or a pregnancy pillow, if a clinician who has examined you has suggested one
Deliberately, no medicine is named here. What is safe in pregnancy depends on the stage, on your own health, on anything else you are taking and on what is actually causing the pain, and that is a decision for the clinician looking after you. Nothing bought over the counter, including herbal preparations and supplements, should be started in pregnancy without asking your own midwife or doctor first, however harmless it appears on the packet.
One last practical suggestion. Keep a brief note of your cramping: when it happens, how long it lasts, what you were doing, and whether anything else went with it. A few lines are far more useful at an appointment than trying to remember, and a pattern that looked random to you often becomes obvious to the person reading it. Mention cramping even when it has settled, because how it behaved is part of the picture for the rest of your pregnancy.
Related Reading
- When does morning sickness start? The timeline in early pregnancy
- Implantation cramps: what they feel like and what they cannot tell you
- Recurrent UTIs in women: why they return and what gets checked
- Earliest signs of pregnancy: what the hormone timeline actually allows
- hCG Levels in Early Pregnancy and After IVF: What the Numbers Mean
Sources and references
This article is supported by the following independent, authoritative sources: