The honest answer to "when will I start showing" is an anatomy answer. Until about 12 weeks the uterus is still inside the bony pelvis, where nothing it does is visible from outside. Around 12 weeks its top edge, the fundus, rises level with the pubic bone; by about 20 weeks it has reached the navel. The bump other people notice is the space in between, which is why a first pregnancy usually shows somewhere in the early second trimester and a second pregnancy often shows sooner.
This guide follows the bump week by week, explains why yours may come earlier or later than a friend's, and separates a bump from the bloating that impersonates it in the first trimester. It also covers fundal height — the tape measurement from 24 weeks — because "is my bump too small" is the same question asked at the next appointment, and that one has a proper answer.
The short answer. The uterus clears the pelvis at around 12 weeks and reaches the navel at about 20, so most first-time mothers see a definite bump a few weeks after 12 and other people see it nearer 20. Second and later pregnancies usually show earlier. A first pregnancy, strong abdominal muscles, a long torso or a higher starting weight all push it later, and none of them says anything about how the baby is growing. That is measured from 24 weeks with a tape and, if needed, a scan.
What the Bump Actually Is
It is the uterus, not the baby. At 12 weeks the baby is about 5.4 cm long — the NHS compares it to a plum — and at 20 weeks about 25.6 cm, a banana. The uterus grows ahead of the baby, with the placenta and fluid, and it is the uterus lifting out of the pelvis that changes your shape. Before 12 weeks any "bump" is a mix of bloating — progesterone slows the gut — and abdominal muscles that the same hormone has relaxed. Our page on bloating in pregnancy explains why it is worst by evening.
Your Bump Week by Week
| Weeks | Where the uterus is | What you see |
|---|---|---|
| 8–11 | Still inside the pelvis | Bloating, a waistband that is tighter by evening. Nothing anyone else can see. |
| 12–13 | Fundus level with the pubic bone | The lower belly starts to round, especially late in the day. You notice; most others do not. See week 12. |
| 14–16 | Rising above the pubic bone | The typical first "showing" in a first pregnancy; often earlier in a second. Twinges at the sides as the round ligaments stretch. |
| 18–20 | At the navel | Obvious to other people. First movements are felt around now. See week 20. |
| 24–28 | Above the navel, measured from 24 weeks | Fundal height in centimetres runs close to the week number. The bump rounds and lifts; stretch marks may start. |
| 32–36 | Highest point, under the ribs | Breathlessness and rib ache as the uterus presses upwards — see shortness of breath. |
| 37–40 | May drop as the baby's head engages | The bump sits lower and the tape measurement can fall slightly. Breathing eases; the bladder does not. |
Why You Might Show Earlier
- A previous pregnancy. Muscles and skin that have been stretched once give way sooner. This is the biggest single factor.
- Twins or more. A bigger uterus, sooner.
- A shorter torso. Less room for the uterus to grow upwards before it grows outwards.
- Weaker abdominal muscles, including a separation left by an earlier pregnancy.
- Fibroids, which add to the size of the uterus.
- Bloating, which is not a bump but looks like one and arrives first.
Why You Might Show Later
- A first pregnancy. An abdominal wall that has never been stretched holds the uterus in longer.
- Strong abdominal muscles. Same mechanism; athletes often show late.
- A longer torso, which gives the uterus room to rise before it pushes forward.
- A higher pre-pregnancy weight, which makes the outline less distinct rather than the uterus smaller.
One myth to retire: an anterior placenta — one on the front wall of the uterus — delays when you feel movements, because it cushions the kicks. It does not delay showing. The NHS week 12 guide puts the honest list of what decides bump size as hormones, pre-pregnancy weight, previous pregnancies and muscle strength, and none of those is the baby.
Not showing is not a sign the baby is small. Growth is checked with a tape measure from 24 weeks and with scans when the tape raises a question. How your jeans fit at 16 weeks measures your abdominal wall, not your baby.
Fundal Height: The Measurement That Actually Counts
From 24 weeks, NICE guidance is that the symphysis-fundal height — the distance from the top of the pubic bone to the top of the uterus — is measured with a tape at every antenatal appointment, no more often than every two weeks, and plotted on a growth chart. Between about 20 and 36 weeks the number of centimetres runs close to the number of weeks, give or take two: at 30 weeks, 28 to 32 cm is unremarkable.
What happens when it is off is proportionate. A measurement that is small for dates leads to a growth scan being offered, urgently if it comes with reduced movements or raised blood pressure. A measurement that is large for dates leads to a scan being considered. Most of the time the scan shows an ordinary reason: your body size, a full bladder, fibroids, twins, more or less fluid than average, or the baby lying sideways or having already dropped. Our guide to fetal growth percentiles explains what the scan measures instead, and the appointment schedule shows where the tape measure fits in.
Bump Shapes, and What They Do Not Predict
High, low, wide, pointed, "B-shaped" with a crease across the middle — bump shape is decided by your abdominal muscles, your torso, how the baby is lying and how much fluid there is. It does not predict the baby's sex; the reliable answers there are a blood test from 10 weeks and the scan from 18, which our guide to finding out the sex covers. And it only loosely tracks the baby's size, which is exactly why size is measured on a scan rather than eyeballed.
Looking After a Growing Bump
What helps as it grows
- Moisturise if it itches, but know that creams do not prevent stretch marks — the honest evidence is in our stretch marks guide. Itching without a rash, worse on palms and soles, is a different question: see itching in pregnancy.
- Sleep on your side from 28 weeks, with a pillow under the bump — see sleep positions.
- A support band for the second half if your back or pelvis complains.
- Keep moving. Our safe exercise guide covers what changes by trimester.
- Weigh the bump, not the comparison. The weight gain guide gives the ranges that actually apply to you.
When to Call Your Doctor
Call the same day if: your bump has measured small and your baby's movements have changed or reduced; the bump suddenly feels much bigger, tight and painful, or you become breathless lying down; you have constant, severe abdominal pain; or you have any bleeding. Mention at your next appointment, or call if it worries you, if the bump seems to have stopped growing over several weeks.
At a Glance
The uterus clears the pelvis at around 12 weeks and reaches the navel at about 20, and the visible bump is the space between: a first pregnancy usually shows in the early second trimester, a second pregnancy sooner. A first pregnancy, strong abdominal muscles, a long torso or a higher starting weight push it later and say nothing about the baby. Before 12 weeks, what you see is bloating. From 24 weeks the tape measurement in centimetres runs close to the week number, and a reading that is small or large leads to a scan, which usually finds an ordinary reason. Bump shape predicts nothing about sex and little about size.
Inside Baby Novum. The belly photo timeline reminds you once a week to take a bump photo, lines any two weeks up side by side, and plays the whole pregnancy as a slideshow. The belly measurement tracker records your own tape-measure readings and, with Premium, draws them as a curve — so you are comparing yourself with yourself, not with the internet.
Next: Second Trimester Guide → · Stretch Marks → · Weight Gain Guide →
Frequently Asked Questions
When do most women start showing?
The top of the uterus rises above the pubic bone at around 12 weeks and reaches the navel at about 20, and the visible bump is the space between. In a first pregnancy most women notice a real bump a few weeks after 12, and other people notice it closer to 20. In a second or later pregnancy it is usually earlier, because the abdominal muscles have been stretched before.
Why am I showing earlier in my second pregnancy?
Because your abdominal wall has done this before. Muscles and skin that were stretched by a previous pregnancy give way sooner, so the same-sized uterus pushes forward earlier. Bloating also tends to arrive earlier the second time. It does not mean the baby is bigger or that anything is different inside.
Why am I not showing at 16 weeks?
A first pregnancy, strong abdominal muscles, a longer torso that gives the uterus room to grow upwards before it grows outwards, and a higher pre-pregnancy weight that makes the outline less distinct are the usual reasons. Not showing is not a sign the baby is small. Growth is checked with a tape measure from 24 weeks and with scans, not by how your clothes fit.
Is it a bump or just bloating?
Bloating changes through the day: flatter in the morning, bigger after meals and by evening, and it comes and goes. A bump is firm, sits low between the hip bones, and is still there when you wake up. Before 12 weeks almost everything you can see is bloating and relaxed muscle, because the uterus is still inside the pelvis.
What is fundal height and when is it measured?
The distance in centimetres from the top of the pubic bone to the top of the uterus, measured with a tape. NICE guidance is to measure it at every antenatal appointment after 24 weeks, no more often than every two weeks, and plot it on a growth chart. Between about 20 and 36 weeks the centimetres run close to the number of weeks, give or take two.
What if my bump measures small or large for dates?
A measurement that is small for dates leads to a growth scan being offered — urgently if there are also reduced movements or raised blood pressure. A large measurement leads to a scan being considered. Most of the time the explanation is ordinary: body size, a full bladder, fibroids, twins, the amount of fluid, or the baby's position, including having dropped into the pelvis near the end.
Does bump size or shape tell you the baby's size or sex?
Not the sex — there is no evidence bump shape predicts it, and the reliable answers are a blood test from 10 weeks and the scan from 18. Only roughly the size: the bump is the uterus, fluid and your own body as much as the baby, which is why size is measured on a scan rather than judged from outside.