The second trimester — weeks 14 through 27 — is widely considered the most comfortable period of pregnancy. Morning sickness typically eases, energy returns, and you'll feel your baby move for the first time. Meanwhile, your baby transforms from a 9 cm foetus into a 35 cm fully formed human with a face, fingers, and dreams.
Key milestones: First kicks (weeks 18–22) · Anatomy scan at week 20 · Measurable REM activity from week 23 · Viability improves week over week from around 23–24
Weeks 14–16: Energy Returns, Baby Moves
Welcome to the second trimester
The placenta is now fully in charge of hormone production — morning sickness often fades. Your baby is about 9–12 cm long and weighing ~100 g. Facial muscles are working; the baby can squint, frown and grimace. Sex organs are fully formed and may be visible on ultrasound. Fine hair called lanugo begins covering the skin. The baby starts making sucking motions and reacting to light through the uterine wall.
Week 15–16: Many providers offer the second-trimester blood screening (quad screen or NIPT) to assess chromosomal risk. This is also a good time to start sleeping on your side — a growing uterus can compress the inferior vena cava when you're on your back.
Weeks 17–20: First Kicks and the Anatomy Scan
Feeling baby move for the first time
Around weeks 18–20 (or as early as 16 for second-time mums), you'll feel the first quickening — subtle flutters, bubbles or pops that are unmistakably baby. Your baby's nerves are undergoing myelination: being coated with myelin to speed up nerve signals, making movements stronger. Ears are fully formed; the baby can hear your heartbeat and voice. At week 18, baby weighs ~205 g and is as long as a bell pepper.
Anatomy scan at week 20: The mid-pregnancy ultrasound checks every chamber of the heart, brain structure, spine, kidneys, limbs and facial features. The uterus is now at the level of the navel. Most parents learn the sex at this scan — our guide to when you can find out your baby's sex covers what the scan can and cannot tell you, and why an earlier one usually cannot. Our guide to when you start showing follows the bump from here.
Halfway! — 25 cm, 300 g
Week 20 is the official midpoint. Your baby weighs ~300 g and measures ~25 cm from crown to heel. The brain is developing dedicated zones for each sense: smell, taste, hearing, sight and touch. Meconium (first stool) begins accumulating in the intestines.
Weeks 21–27: Senses, Sleep Cycles and Improving Viability
Baby can taste what you eat
By week 21, taste buds are so developed that the baby can taste what you eat through the amniotic fluid. Skin begins to be covered in vernix — a white protective coating. Fine lanugo grows over the body. At week 22, distinct brows and lashes appear; the pancreas begins producing hormones. By week 23, brain activity recorded during sleep shows measurable REM patterns — a real marker of neurological development, though it does not mean the baby is dreaming in any way that can be confirmed. Weight: ~500 g.
Viability improves week by week
From around 23–24 weeks, survival with intensive neonatal care becomes possible and improves with each additional week in the womb — a statistical range that gets steadily more favourable, not a single cutoff. The lungs begin producing surfactant — the substance that keeps air sacs open after birth. Brain development accelerates dramatically. Babies born in this window still face significant challenges, and every extra week of pregnancy meaningfully improves the outlook.
Brain grooves form, eyes begin to open
The baby's brain begins developing characteristic folds and grooves (gyri and sulci) that dramatically increase its surface area. Eyes begin to open and close. The baby responds to sounds from outside the womb — music, voices, and even bright light. By week 27, weight is ~900 g and length ~37 cm. The third trimester is just days away.
Common Second Trimester Symptoms
- Round ligament pain — sharp twinges as the uterus stretches (weeks 14–20)
- Heartburn and indigestion — uterus pushing on the stomach
- Back pain as centre of gravity shifts
- Leg cramps (especially at night — often a magnesium signal)
- Skin changes: stretch marks, chloasma (facial pigment spots), itching belly
- Swollen feet and ankles in the evening
- Pregnancy gingivitis — bleeding gums from increased blood flow
- A permanently blocked nose — rhinitis of pregnancy, with no cold behind it
- Vivid, strange dreams from hormonal changes
Second Trimester Checklist
- Schedule the anatomy scan (week 18–22)
- Start sleeping on your left side; use a pregnancy pillow
- Add iron, omega-3, calcium and magnesium to your supplement routine
- Check hemoglobin and ferritin at week 18–20
- Begin noting fetal movements from week 20 onwards
- Apply moisturiser to belly, thighs and breasts daily for stretch marks
- Consider prenatal yoga or swimming for back pain
- Start talking and singing to your baby — they hear you clearly by week 22
Weight gain accelerates through this trimester — roughly 0.4 kg a week from week 14 — and the weight gain guide covers the expected ranges by starting BMI. For a closer look at any single week in this stretch, the week-by-week guide breaks all 40 out individually.
Next: Third Trimester Guide: Weeks 28–40 →
FAQ — Second Trimester
Why is the second trimester called the "golden period"?
Nausea has typically faded by week 14, energy tends to return, and the bump becomes visible without yet being physically limiting. It is also when many people feel the first kicks — a genuinely exciting milestone — and the anatomy scan around week 20 offers real reassurance that development is on track. None of this is guaranteed for everyone, but it is the general pattern that gives the trimester its reputation.
What exactly does the anatomy scan check?
The mid-pregnancy ultrasound, usually between 18 and 22 weeks, examines every chamber of the heart, the brain structure, spine, kidneys, limbs and facial features in detail — confirming that development is on track rather than just checking growth. Most parents also learn the baby's sex at this appointment if they choose to find out.
When should I feel the baby move for the first time?
Most first-time mothers notice the first flutters, sometimes called quickening, between weeks 18 and 22; people who have been pregnant before often notice it a few weeks earlier, since they already know what the sensation feels like. If you have reached week 24 with no movement felt at all, mention it at your next appointment rather than waiting.
Is round ligament pain normal in the second trimester?
Yes — sharp, brief twinges on one or both sides of the lower abdomen as the uterus stretches are common from around week 14 to 20, especially with sudden movement like standing up quickly or coughing. It is a mechanical stretching pain, not a sign of a problem, though pain that is severe, constant, or comes with bleeding or fever needs same-day assessment rather than assumed to be routine.