Scroll, and watch your baby grow. What is being built at each stage, what your body is doing, and which scan or check belongs to that point — without the panic-inducing forums.
Illustration is stylised and not to scale between weeks.
For general understanding only. These are drawings, including the ultrasound view — they are built from typical measurements to explain the idea, and are not real scan images or a picture of your own baby.
For general understanding only. Lengths, weights and size comparisons are typical averages — your baby may be bigger or smaller and still be perfectly healthy. Only your own scan can tell you where yours is.
Pregnancy is dated from the first day of your last period, so the first fortnight happens before conception — a genuinely confusing point that trips almost everyone up. By week four the cells have burrowed into the lining of the uterus and split in two: one half becomes your baby, the other becomes the placenta.
The heart starts beating near the end of week five and is usually visible on a scan by six to seven weeks, at roughly 110–160 beats a minute. The embryo is curled in a C shape with a large head, dark eye spots and small buds where the arms and legs will be.
Fingers and toes have separated, the tail has gone, and all the major organs are formed even though none of them are finished. This is when the first-trimester scan happens, and when the risk of miscarriage drops considerably.
Energy usually returns. The baby can move every joint, is growing hair and eyebrows, and is starting to hear. Most people begin to look pregnant somewhere in here, though first pregnancies often show later.
The anomaly scan checks the brain, heart, spine, kidneys, face and limbs in detail, and looks at where the placenta is sitting. From this week, length is measured head to heel rather than head to bottom — which is why the numbers appear to jump.
The eyes open, the lungs begin producing surfactant, and a baby born at the end of this stretch has a real, though difficult, chance of survival with intensive care. You will start being asked to notice a pattern in the movements.
Mostly weight now — the baby roughly doubles between 28 and 36 weeks, laying down the fat that will regulate temperature after birth. Bones harden, though the skull stays deliberately soft for the journey out. Visits become more frequent.
Most babies settle head-down by 36 weeks; if yours has not, there are options and they are worth discussing early. From 37 weeks the pregnancy is term. Your due date is an estimate — only a small minority of babies arrive exactly on it.
A big lemon
Pick the first day of your last period and we will work out the week and your due date.
Reflexes are appearing — the fingers can curl and the toes flex. The kidneys begin to produce urine into the amniotic fluid.
The uterus is rising out of the pelvis and can be felt just above the pubic bone. Many women feel noticeably more human this week.
A milestone many people wait for: the chance of miscarriage falls considerably after twelve weeks. Many couples choose to share the news now.
For general understanding only. Lengths, weights and size comparisons are typical averages — your baby may be bigger or smaller and still be perfectly healthy. Only your own scan can tell you where yours is.
Everything is being built. You may feel dreadful, or nothing at all — both are normal.
Read this trimester Weeks 14–27Second trimesterUsually the kindest stretch. Sickness settles, energy returns, and you start to feel movement.
Read this trimester Weeks 28–40Third trimesterGrowth and preparation — for the baby's lungs, and for you.
Read this trimesterThis page is general information, not medical advice. Nothing here can diagnose you or replace an assessment of your own history, examination and results. If something here matches what you are experiencing, the next step is a consultation — not a conclusion. If you are in severe pain, bleeding heavily, or feel unwell, seek urgent care rather than waiting for an appointment. Awaiting final clinical review before publication.
Send the clinic a line and the team will tell you what's possible at the moment.