At 21 weeks your baby is about 26.5 cm and 360 grams — roughly a large carrot — and has crossed a real developmental line: movement is starting to become deliberate rather than purely reflexive.
The short answer: the brain has developed enough to begin coordinating intentional movement rather than pure reflex, and taste buds are now fully developed, picking up flavours transmitted through the amniotic fluid. For you, varicose veins often start appearing as the uterus presses on pelvic veins and progesterone relaxes vessel walls, and itchy stretched skin on the belly is common and usually harmless.
Your baby this week
Movement is shifting from reflex to something closer to control. Earlier kicks and jerks were largely automatic; now the brain is developed enough to begin coordinating deliberate movement — reaching out, grasping the umbilical cord, or pressing a hand or foot against the uterine wall in response to being touched from outside.
Taste buds are fully developed, and the fetus is genuinely tasting the amniotic fluid, which carries flavours from your own diet. The digestive system is becoming more sophisticated too: fluid that is swallowed has its water absorbed and passes through the intestines, a rehearsal for digestion after birth.
Your body this week
Varicose veins or spider veins often become noticeable around now. The growing uterus presses on the veins carrying blood back from the legs, and progesterone relaxes vein walls generally, letting them stretch and bulge under the extra pressure. They are more of a nuisance than a danger for most women, though compression stockings and elevating your legs when resting both genuinely help, and most improve after birth.
Skin on the belly may start to feel tight and itchy as it stretches to accommodate the growing uterus. Regular moisturising eases the itch, even though it does not prevent stretch marks themselves — that is largely determined by genetics.
Tests and appointments
Nothing routine falls exactly at 21 weeks. If the anatomy scan is still outstanding, this is close to the edge of its usual window and worth confirming.
✅ Worth doing this week
- Elevate your legs when sitting to ease pressure on developing varicose veins
- Try compression stockings if veins are becoming uncomfortable, not just visible
- Moisturise the belly, thighs and breasts regularly for the itching
- Alternate hot and cold in the shower on your legs — a simple habit some women find helps circulation
- Report palm or sole itching specifically rather than assuming it is the same as belly itching
When to call your doctor
Call the same day if: you have bleeding, severe or one-sided abdominal pain, a severe headache with visual disturbance or sudden swelling of the face and hands, fainting, a temperature above 38°C, or intense itching on the palms and soles, especially worse at night. A hot, red, swollen or tender vein — different from an ordinary bulging varicose vein — needs same-day assessment for a clot.
FAQ — 21 weeks pregnant
Why do varicose veins appear during pregnancy?
Two things combine: the growing uterus presses on the pelvic veins, slowing blood return from the legs, and progesterone relaxes vein walls generally, letting them stretch and bulge. They typically appear on the legs, though vulval varicose veins are also common and rarely discussed. Compression stockings, elevating the legs, and avoiding long periods of standing all help. Most improve substantially after birth.
How big is the baby at 21 weeks?
About 26.5 cm and 360 grams — roughly the size of a large carrot. Weight is now climbing faster than it has at any earlier point in the pregnancy.
What does it mean that movements are "no longer just reflexive"?
Earlier fetal movement was largely automatic — spinal reflexes rather than intentional motion. By 21 weeks the brain has developed enough to begin coordinating deliberate movement: reaching, grasping the umbilical cord, or pressing against the uterine wall in response to touch from outside. It is an early form of motor control, not conscious decision-making in any adult sense.
Is itchy skin on the belly normal at 21 weeks?
Yes, and it is usually just mechanical — skin stretching quickly over the growing bump becomes dry and itchy, and moisturising helps. Itching confined to the belly, arms and legs with no rash is rarely a concern. Itching on the palms and soles, especially if it is intense and worse at night, is different and should always be reported — it can signal a liver condition specific to pregnancy.
Week 21 at a glance
At 21 weeks your baby is about 26.5 cm and 360 grams, with movement shifting from reflex toward genuine coordination, fully developed taste buds picking up flavours in the amniotic fluid, and a maturing digestive system. For you, varicose veins often appear now as the uterus presses on pelvic veins and progesterone relaxes vessel walls, and itchy stretched skin on the belly is common. Itching on the palms and soles is a different signal worth reporting rather than treating as ordinary belly itch.
Inside Baby Novum: log new skin and vein changes alongside your weight and other symptoms, so if something like palm itching does appear later, you have a timeline rather than a guess at when it started.