Illustration of a baby at week 25 inside the womb in cross-section, with the placenta and umbilical cord
Womb in cross-section, enlarged to show detail. Not true size.

Second trimester, week 25

25 weeks pregnant: Responding to your voice

Size of a
Cauliflower
Length
34.6 cm head to heel
Weight
778 g WHO median
Heart rate
110–160 bpm typical range
Due date
105 days away 63% of the way
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Checked against the sources listed on this page. Not reviewed by a clinician. Last updated 5 November 2026. How we check.

At 25 weeks pregnant, your baby is about the size of a cauliflower: roughly 34.6 cm from head to heel, weighing about 778 g. You’re in your second trimester, with about 15 weeks to go until your due date.

Your baby this week

  • The baby may respond to familiar voices with movement or changes in heart rate.
  • The nostrils, which have been plugged, begin to open.
  • Small blood vessels (capillaries) are forming under the skin, making it look pinker.

Your body this week

  • Sleep may become harder because of heartburn, needing to pee, leg cramps or restless legs.
  • Carpal tunnel symptoms (tingling hands) can come from fluid retention.
  • Piles (haemorrhoids) are common. Fibre and fluids help prevent constipation.
Typical weight gain so far
5.4–8.2 kg
Your uterus
Fundal height ≈ 25 cm (±2 cm)

Weight gain range is for a pre-pregnancy BMI of 18.5–24.9 (IOM guideline). Your provider may advise differently.

Scans, tests and checkups

  • This week
    Know your baby’s movements Self-care

    Get to know your baby’s pattern. If movements slow down, change or stop, contact your maternity unit straight away. Don’t wait until the next day.

  • This week
    Glucose test (gestational diabetes) Blood test

    A sugary drink followed by blood sugar checks. The UK offers it based on risk factors. The US screens almost everyone.

  • From week 27
    Whooping cough (Tdap) vaccine Vaccine

    Antibodies pass to the baby and protect them in their first weeks. The US recommends 27–36 weeks. The NHS offers it from 16 weeks, usually around 20, and ideally before 32.

  • From week 28
    Anti-D (if Rh-negative) & repeat bloods Blood test

    If your blood group is Rh-negative, anti-D immunoglobulin is offered around 28 weeks. Blood count and antibodies are often rechecked.

  • From week 28
    RSV vaccine Vaccine

    Protects newborns from RSV, a serious lung infection. The US gives it at 32–36 weeks in RSV season. The UK offers it from 28 weeks. Check local guidance.

See the full scan and test timeline

Real size, next to an adult hand

Adult hand 18.5 cmbaby 23.5 cm curled up

Growth curve

01 kg2 kg3 kgwk 10wk 20wk 30wk 40
Typical weight by week: WHO median from week 20, approximate before that. Healthy babies vary widely.

When to call your midwife or doctor at 25 weeks

Call your midwife, doctor or maternity unit straight away, day or night, if you have any of these:

  • A change in your baby’s usual pattern of movement. Call straight away rather than waiting until the next day.
  • Vaginal bleeding, or a gush or steady trickle of fluid.
  • Severe belly pain that doesn’t go away.
  • A severe headache, vision changes, pain under your ribs, or sudden swelling of your face, hands or feet. These can be signs of pre-eclampsia.
  • Regular tightenings, period-like cramps or lower back pressure that keep coming. This could be early labour.
  • Fever of 38 °C (100.4 °F) or higher, or pain or burning when you pee.
  • Pain or swelling in one leg, chest pain, or sudden shortness of breath. These can be signs of a blood clot.
  • Feeling very low, hopeless or anxious most days. If you feel you might harm yourself, get emergency help.

Based on NHS and ACOG guidance. This list isn’t complete. If something feels wrong, call anyway. In an emergency, call your local emergency number.

Tip for this week

Read or sing to your baby. It isn’t required for bonding, but they are learning the sound and rhythm of your voice.

Common questions at this stage

All common questions

More myths around week 25

Questions people ask about week 25

Can the baby recognise my voice?

Studies show fetal heart rate responses to the mother’s voice in late pregnancy, and newborns prefer their mother’s voice. So yes, familiar voices are learned in the womb.

Why can’t I sleep at 25 weeks?

Common reasons include heartburn, needing to pee, leg cramps, restless legs and finding a comfortable position. Sleeping on your side with pillows for support usually helps.

References

  1. NHS Best Start in Life: 25 weeks pregnant
  2. NHS: Your antenatal appointments
  3. Mayo Clinic: Fetal development, the second trimester
  4. NHS: Your baby’s movements
  5. NHS: Pre-eclampsia
  6. Kiserud T et al. The WHO Fetal Growth Charts. PLoS Medicine, 2017
  7. MedlinePlus (US National Library of Medicine): Fetal development

Advice differs between countries, so follow your own care team’s plan. Weights from week 20 are the WHO median, and earlier weights are approximate. How we check this.

All 40 weeks

First trimester Weeks 1–13

From conception to a fully formed, tiny fetus. The most rapid change of the whole pregnancy.

  1. Prenatal development at week 1 Week 1A new cycle begins
  2. Prenatal development at week 2 Week 2Ovulation — and maybe conception
  3. Prenatal development at week 3 Week 3A ball of cells finds its home
  4. Prenatal development at week 4 Week 4Poppy seed
  5. Prenatal development at week 5 Week 5Sesame seed
  6. Prenatal development at week 6 Week 6Lentil
  7. Prenatal development at week 7 Week 7Blueberry
  8. Prenatal development at week 8 Week 8Raspberry
  9. Prenatal development at week 9 Week 9Cherry
  10. Prenatal development at week 10 Week 10Strawberry
  11. Prenatal development at week 11 Week 11Fig
  12. Prenatal development at week 12 Week 12Lime
  13. Prenatal development at week 13 Week 13Lemon

Second trimester Weeks 14–27

Growth, movement and senses. Often the most comfortable stretch for parents.

  1. Prenatal development at week 14 Week 14Peach
  2. Prenatal development at week 15 Week 15Apple
  3. Prenatal development at week 16 Week 16Avocado
  4. Prenatal development at week 17 Week 17Pear
  5. Prenatal development at week 18 Week 18Bell pepper
  6. Prenatal development at week 19 Week 19Mango
  7. Prenatal development at week 20 Week 20Banana
  8. Prenatal development at week 21 Week 21Carrot
  9. Prenatal development at week 22 Week 22Papaya
  10. Prenatal development at week 23 Week 23Grapefruit
  11. Prenatal development at week 24 Week 24Ear of corn
  12. Prenatal development at week 25 Week 25Cauliflower
  13. Prenatal development at week 26 Week 26Zucchini
  14. Prenatal development at week 27 Week 27Head of lettuce

Third trimester Weeks 28–40

Weight gain, brain and lung maturation, and getting into position for birth.

  1. Prenatal development at week 28 Week 28Eggplant
  2. Prenatal development at week 29 Week 29Butternut squash
  3. Prenatal development at week 30 Week 30Cabbage
  4. Prenatal development at week 31 Week 31Coconut
  5. Prenatal development at week 32 Week 32Napa cabbage
  6. Prenatal development at week 33 Week 33Pineapple
  7. Prenatal development at week 34 Week 34Cantaloupe
  8. Prenatal development at week 35 Week 35Honeydew melon
  9. Prenatal development at week 36 Week 36Papaya (large)
  10. Prenatal development at week 37 Week 37Winter melon
  11. Prenatal development at week 38 Week 38Pumpkin (small)
  12. Prenatal development at week 39 Week 39Mini watermelon
  13. Prenatal development at week 40 Week 40Watermelon