Day 105 of 280 · 15 weeks
Hearing begins
Last reviewed · 3 min read · 6 sources · Plain-text version
Fifteen weeks. Your baby is about the size of an apple and begins hearing around now: your voice, your heartbeat, your digestion. Today you both say something out loud.
- Size this week
- about the size of an apple
- Length this week
- around 10.1 cm from head to bottom

Fifteen weeks exactly. Something changes this week that isn't visible on any scan: the baby begins to hear. Today is a two-minute conversation, for both of you.
Your baby

Around 10.1cm long from head to bottom, about the size of an apple (NHS). The baby begins hearing around now and may hear your voice, your heartbeat and your digestive sounds (NHS). It's a start, not a finished sense: the NHS's week 21 page is where it says the baby is able to hear sounds and voices outside the womb (NHS). For now, the inside of you is the whole soundscape.
Your body
The NHS's new symptom for this week is balance: it may become less stable as the bump grows (NHS). In the second trimester the abdomen expands (OWH), and your centre of gravity moves with it. Take stairs with a hand on the rail this week, and we'll come back to shoes in a few days.
The other change is below the bump. The NHS says to expect increased vaginal discharge from the extra blood flow in the pelvis, and to seek advice if the colour, smell or texture changes, or if there's pain when peeing, itching or soreness (NHS).
Try today
The first conversation
Time: 2 minutes, both of you
Sit somewhere quiet. Say one sentence to the baby, out loud, in your normal voice. The NHS says the baby begins hearing around now and may hear your voice (NHS).
Partner: your turn. Get close and say your sentence too.
Don't reach for anything profound. Your names work. So does what's for dinner.
Write down what each of you said. In a month you won't remember, and you'll want to.
Make it work:The page says "may hear". There's no test to pass and nothing here claims what the baby makes of it. It's a habit you're starting, not a result you're checking.
Watch for
Normal
more vaginal discharge, from the extra blood flow in the pelvis (NHS).
Call your provider
if the colour, smell or texture changes, or you have pain when peeing, itching or soreness (NHS); vaginal infections matter in pregnancy because they may cause preterm labor (MedlinePlus).
Normal
feeling a little less steady on your feet (NHS).
Call your provider
if you fall; the NHS says to stay calm but tell your midwife as soon as possible (NHS).
Normal
the gurgling the baby may be listening to; your digestive sounds are on the list (NHS).
Call 911
for trouble breathing, or chest pain or a fast-beating heart; both are on the CDC's list of urgent warning signs (CDC).
For you
Your heartbeat is on the list of what the baby may hear (NHS). Before a single word, the sound of you is the sound of the world. You don't have to do anything with that. It's just true, and it's a good thing to know on a tired day.
One practical note, since you're being heard now at home too: the NHS puts telling your employer on this week's list, and in the UK that's when maternity rights and paid time for antenatal appointments begin (NHS). In the US, MedlinePlus's starting point is that most pregnant women can keep working, some until delivery (MedlinePlus). When you tell work is still your call.
If you're the partner: talk, don't perform. The baby isn't grading you, and neither is she.
Sources
- NHS. "Week 15." Week-by-week guide to pregnancy, Best Start in Life. https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-15/
- NHS. "Week 21." Week-by-week guide to pregnancy, Best Start in Life. https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-21/
- Office on Women's Health. "Stages of pregnancy." U.S. Department of Health and Human Services. https://womenshealth.gov/pregnancy/youre-pregnant-now-what/stages-pregnancy
- MedlinePlus. "Common symptoms during pregnancy." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000583.htm
- MedlinePlus. "Pregnancy and work." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000609.htm
- Centers for Disease Control and Prevention. "Urgent Maternal Warning Signs and Symptoms." HEAR HER campaign, 2024. https://www.cdc.gov/hearher/maternal-warning-signs/index.html
This guide is general education that summarizes published research and guidance from groups like the American Academy of Pediatrics, the CDC, and the WHO. It isn’t medical advice, and every child develops on their own timeline. Your pediatrician knows your child; if something feels wrong, call them. In an emergency, call 911.
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