Week 15: Baby Can Hear You

A whole new world is opening up for your baby this week! Hearing is beginning to function, and the fetus can now pick up muffled sounds from the outside world. Your heartbeat, your voice, and the sounds of your digestion are your baby's very first sound experiences.

Your baby is now about 10 cm long (crown to rump) and weighs around 70 grams — about the size of an apple. You are well into the second trimester, and many feel better than they have in a long time. Your body has adjusted to the new hormone levels, and energy levels are noticeably better.

This week it is especially important to focus on iron status and dental health. According to WHO and ACOG, iron needs increase significantly in the second trimester, and dental care during pregnancy is important for both your health and your baby's.

Baby's Development

Hearing developing: Your baby can now pick up sounds, although they are muffled through the amniotic fluid. Your voice is one of the clearest sounds
Bones hardening: The ossification process continues, and the skeleton becomes gradually stronger. Bones are still soft and flexible, but calcium is actively being stored
Eyes responding to light: Even with closed eyelids, your baby can sense strong light shining through your abdomen
Movements increasing: Your baby is very active now — kicking, turning, and stretching. You may soon feel the first movements
Taste buds developing: Your baby can now taste the amniotic fluid, which changes flavour based on what you eat
Hair growing: The first head hairs are beginning to grow, and eyebrows are taking shape
Joints functioning: All major joints in the body are now mobile, and your baby can bend and stretch arms and legs
Size: The fetus is about 10 cm long (crown to rump) and weighs around 70 grams

Baby's Hearing in Detail

Hearing is one of the first senses to fully develop. At week 15, the inner ear structures are beginning to function, but hearing itself is still primitive. Your baby picks up vibrations and deep tones best — such as heartbeats and bowel sounds.

Your voice is especially clear because it is transmitted through your body as well as through the air. Research shows that newborns prefer their mother's voice above all others, precisely because they have been listening to it for many months. Deep voices can also be picked up through the abdominal wall, so partners should start talking to the bump now too.

In the coming weeks, hearing will become increasingly refined. By weeks 24–26, your baby will be able to distinguish between different voices and react to sudden sounds.

Your Body

Nasal congestion: Pregnancy rhinitis is common and is caused by swollen nasal mucous membranes. It affects up to 30% of pregnant people. Saline nasal spray can provide relief without medication
Bump rounding: The uterus is now about the size of a small melon, and the baby bump is noticeable for most
Increased blood volume: Your body now has significantly more blood than usual. You may feel warm and sweat more easily
Gums may bleed: Hormonal changes make gums swollen and more vulnerable. Be gentle when brushing
Nosebleeds may occur: Increased blood volume and swollen membranes mean some pregnant people experience nosebleeds more often
Better sleep: Many sleep better now than in the first trimester, as the body has adjusted to hormone levels
Round ligament pain: Brief, stabbing pains in the groin when you move quickly. Caused by the ligaments supporting the uterus being stretched

Round Ligament Pain

Many pregnant people experience round ligament pain for the first time at weeks 14–16. It feels like a sharp, stabbing pain in the groin, often on one side. The pain is typically triggered by quick movements like standing up, coughing, or turning in bed. It is completely harmless and is caused by the ligaments supporting the uterus stretching.

Tips for managing round ligament pain:

Move slowly and support your abdomen with your hands when standing up
Bend gently towards the pain to give the ligament some relief
Use a warm pack on the painful area
Gently stretch the hip flexors
Avoid sudden position changes

Good to Know

Dental health is especially important during pregnancy. Hormonal changes can make gums swollen and prone to bleeding — a condition called pregnancy gingivitis. The NHS and ACOG recommend regular dental check-ups during pregnancy. Contact your dentist to book an appointment, and always tell your dentist you are pregnant so they can adapt your treatment.

Iron needs continue to increase through the second trimester. Many pregnant people develop iron deficiency because blood volume increases rapidly. Symptoms of iron deficiency include fatigue, dizziness, and paleness. Blood tests at prenatal appointments will reveal this. Good iron sources are lean red meat, beans, lentils, and dark leafy vegetables. Take iron with vitamin C for better absorption.

Talk to your bump, read aloud, or play music. Research shows that babies can recognise voices they have heard regularly during pregnancy. Your voice is already a safe and familiar soundscape for your little one.

Remember to eat regularly and spread meals throughout the day. Blood sugar can fluctuate more during pregnancy. Long periods without food can cause dizziness and nausea. ACOG recommends three main meals and two to three snacks daily.

Sound Stimulation and Baby's Development

Now that your baby is beginning to hear, it is a good time to think about sound stimulation. Research shows that babies who have heard certain sounds regularly during pregnancy prefer those sounds after birth.

What Your Baby Hears Best

Your voice: The clearest sound, because it is transmitted through your body in addition to through the air
Heartbeat: The constant rhythm of your heartbeat is your baby's most familiar sound
Digestive sounds: Bowel sounds and gurgling are part of your baby's soundscape
Deep voices: Your partner's voice can be picked up through the abdominal wall
Music: Calm, melodic music can be perceived by your baby

Tips for Sound Stimulation

Talk to your baby regularly — it does not need to be anything special, just everyday conversation
Read aloud from a book you enjoy
Play calm music — classical music or gentle melodies are popular choices
Let your partner speak close to your bump
Sing to your baby — it builds early attachment

What Research Says

Studies show that newborns prefer their mother's voice over other voices, and can recognise melodies and stories they have heard regularly during pregnancy. Babies exposed to music during pregnancy often show a stronger response to those same melodies after birth.

Dental Health in Pregnancy

Why Is Dental Health Important Now?

Hormones make gums more vulnerable to inflammation
Nausea and vomiting in the first trimester may have damaged tooth enamel
Untreated gum disease is associated with increased risk of preterm birth, according to research
Periodontal disease can negatively affect pregnancy outcomes

Tips for Good Dental Health

Brush twice daily with fluoride toothpaste
Floss daily — be gentle with swollen gums
Rinse your mouth with water after vomiting — wait 30 minutes before brushing to protect enamel
Eat less sugary food between meals
Use a soft toothbrush if gums are sore
Tell your dentist you are pregnant so they can adapt treatment

Iron Deficiency and Supplements

Iron deficiency is the most common nutritional deficiency in pregnancy. According to WHO and ACOG, it is important to monitor iron levels throughout pregnancy.

Why Do You Need Extra Iron?

To produce more blood (blood volume increases by up to 50%)
To supply the placenta with oxygen
To build up your baby's own iron stores for the first months of life

Symptoms of Iron Deficiency

Unusual fatigue beyond normal pregnancy tiredness
Dizziness and headache
Paleness in skin and mucous membranes
Breathlessness with light exertion
Heart palpitations and ringing in the ears

Good Iron Sources (per WHO and ACOG)

Lean red meat (best source of haem iron, which the body absorbs easily)
Beans, lentils, and chickpeas
Dark leafy greens (broccoli, kale)
Fortified breads and cereals
Dried fruits (prunes, apricots)

Take iron-rich food with vitamin C (peppers, oranges, strawberries) for better absorption. Avoid coffee, tea, and dairy products with iron-rich meals — they inhibit iron absorption. Wait at least 30 minutes after an iron-rich meal before drinking coffee or tea.

Exercise and Physical Activity

Regular exercise is important for both body and mind during pregnancy:

Walking: 30 minutes daily at moderate pace — good for cardiovascular fitness and fresh air
Swimming: Relieves joints and back, provides excellent full-body exercise in the water. Many pools offer dedicated prenatal classes
Prenatal yoga: Strengthens, stretches, and provides mental calm. Focuses on breathing exercises that are useful during birth
Kegel exercises: Continue daily with pelvic floor exercises to prepare your body for birth and prevent urinary leakage
Adapted strength training: Keep the body strong with exercises tailored for pregnant people

According to ACOG and WHO, pregnant people should be physically active for at least 150 minutes per week at moderate intensity. Moderate intensity means you can hold a conversation while exercising, but become somewhat breathless.

Exercise to Avoid

Contact sports (ice hockey, martial arts, handball)
Activities with high fall risk (horse riding, skiing, climbing)
Exercising while lying flat on your back after week 16 (the growing uterus can compress large blood vessels)
Scuba diving (pressure changes are dangerous for the baby)
Very intense exercise where you cannot hold a conversation

Amniotic Fluid and Its Cycle

Amniotic fluid plays a crucial role in your baby's development and wellbeing. At week 15, there is about 200 ml of amniotic fluid in the uterus, and the amount increases gradually.

Functions of Amniotic Fluid

Protects your baby from bumps and shocks from outside
Gives your baby room to move and exercise muscles and joints
Maintains a consistent temperature around your baby
Helps lung development — your baby "breathes in" amniotic fluid
Enables swallowing reflex and digestion practice

The Amniotic Fluid Cycle

Your baby swallows amniotic fluid, which passes through the digestive system and kidneys, and is released again as urine. This cycle helps regulate the amount of amniotic fluid. The kidneys now produce about 7–14 ml of urine per hour.

Amniotic fluid levels are assessed at the anatomy scan (weeks 17–19). Too little (oligohydramnios) or too much (polyhydramnios) may require extra monitoring, but most people have completely normal levels.

Mental Health at Week 15

Many feel an emotional lift in the second trimester after the demanding first period. But it is still normal to have mixed feelings:

Worry about test results and your baby's health
Excitement about feeling the first movements soon
Uncertainty about the changing body
Thoughts about parenthood and the future
Pride and joy at having come this far

Talk with your partner, friends, or midwife about your feelings. Regular physical activity, good sleep, and social contact are important for mental health. According to the NHS and ACOG, you should contact your midwife or GP if you experience persistent sadness, anxiety, or sleep problems.

Your Relationship During Pregnancy

Pregnancy can put a strain on relationships. Open communication is key:

Talk about expectations, worries, and needs
Plan quality time together while you are still just the two of you
Discuss practical matters like parental leave division and finances
Be patient with each other — pregnancy affects both partners
Consider childbirth preparation classes with partner exercises

Urinary Tract Infections in Pregnancy

Pregnant people have an increased risk of urinary tract infections (UTIs) due to hormonal changes and altered blood flow to the kidneys. It is important to be aware of symptoms:

Symptoms

Burning or pain when urinating
Frequent urge to urinate (beyond what is normal in pregnancy)
Dark, cloudy, or foul-smelling urine
Pain in the lower abdomen or lower back
Fever or chills

Prevention

Drink plenty of water throughout the day
Fully empty the bladder at each visit to the toilet
Wipe from front to back after using the toilet
Do not hold on to urine — go to the toilet when you feel the urge
Urine is checked at all prenatal appointments

According to ACOG and the NHS, untreated UTIs in pregnancy should be taken seriously, as they can cause complications. Contact your doctor if you have symptoms — antibiotics are safe and necessary for a confirmed infection.

For Partners

Talk to the bump! Your baby can now pick up your voice. It builds early attachment between you
Help remember to book a dental appointment. Dental care is important during pregnancy
Be prepared for your partner's body to change rapidly now. Be positive and supportive
Read aloud to the baby together — it is a lovely shared activity that strengthens the bond
Offer to cook meals with a focus on iron-rich ingredients

Tips for Week 15

Book a dental appointment: Schedule a check-up — tell your dentist you are pregnant so they can adapt your care
Try saline nasal spray: If nasal congestion is troublesome, saline spray is safe and has no side effects
Play music for your baby: Calm music or singing can be your baby's first sound experience from outside
Check your iron levels: Ask your midwife about your iron status at your next appointment. Supplements may be needed
Kegel exercises: Continue with daily pelvic floor exercises — they prepare your body for birth
Document your bump: Take weekly photos — they make lovely memories
Plan ahead: Use our due date calculator to keep track of important dates and appointments
Eat iron-rich foods: Combine iron-rich foods with vitamin C for the best absorption

When to Contact Your Doctor

Contact your doctor or midwife if you experience:

Severe itching all over the body, especially on the hands and feet (may indicate intrahepatic cholestasis of pregnancy)
Nosebleeds that are frequent or difficult to stop
Pain or pressure in the lower abdomen that does not go away
Sudden swelling in face, hands, or feet
Groin pain that is persistent or very severe (beyond normal round ligament pain)
Fever above 38°C (100.4°F)
Burning or pain when urinating

Prenatal Appointments in the Second Trimester

In the second trimester, you will typically have prenatal appointments about every 4 weeks. According to ACOG and the NHS, the following is checked at each appointment:

At Each Appointment

Blood pressure: To detect early signs of pre-eclampsia
Urine test: Checks for protein (sign of pre-eclampsia) and sugar (sign of gestational diabetes)
Weight: Follows the weight gain curve
Fundal height: Measurement from pubic bone to the top of the uterus to follow your baby's growth
Listening to heartbeat: Confirms your baby's heart is beating normally

Upcoming Important Checks

Weeks 17–19: Anatomy scan — thorough examination of your baby's organs
Week 24: Routine prenatal appointment
Week 28: Appointment with blood tests, possible glucose tolerance test

Tips for Appointments

Write down questions in advance so you remember to ask them
Bring your maternity notes to every appointment
Your partner is welcome to come
Use our due date calculator to keep track

Did You Know?

Your baby recognises your voice: Research shows that newborns prefer their mother's voice over other voices. This is because your voice is the clearest sound your baby hears through the amniotic fluid, from as early as week 15. Studies have also shown that your baby's heart rate can change in response to your voice
Your heart is pumping 20% more blood: Even now, your heart is working harder than normal. Blood volume has increased significantly, and your heart is pumping about one extra litre of blood per minute to supply the placenta
Your baby has taste buds: There are already around 10,000 taste buds in your baby's mouth — actually more than an adult has! The number gradually decreases throughout life. Your baby prefers sweet flavours and may react to bitter flavours in the amniotic fluid
Your baby is practising facial expressions: The fetus can now grimace, frown, and move its mouth. These facial movements are important for developing the facial muscles and preparing for feeding
Dental care is important in pregnancy: Hormonal changes increase the risk of gum inflammation and dental problems. Schedule a check-up and let your dentist know you are pregnant

Frequently Asked Questions About Week 15

What is pregnancy rhinitis?

Pregnancy rhinitis is nasal congestion caused by swollen mucous membranes due to hormonal changes and increased blood volume. It affects up to 30% of pregnant people and can occur in any trimester. Saline nasal spray is safe and effective, and the condition resolves after birth. Avoid decongestant nasal sprays (like oxymetazoline) without speaking to your doctor first — they can cause dependence and are generally not recommended during pregnancy.

Are nosebleeds dangerous in pregnancy?

No, nosebleeds are common and harmless in pregnancy. They are caused by the mucous membranes in the nose being more engorged and fragile due to the increased blood volume. Lean your head forward and pinch your nostrils together for 10–15 minutes. Use a humidifier at home and apply a little petroleum jelly to the nasal lining to prevent dryness. Contact your doctor if bleeding is very heavy, frequent, or does not stop after 20 minutes.

How do I know if I have iron deficiency?

Common symptoms of iron deficiency are unusual fatigue (beyond normal pregnancy tiredness), dizziness, paleness, headache, and breathlessness with light exertion. Iron levels (haemoglobin and ferritin) are checked at prenatal appointments through blood tests. Your midwife will recommend iron supplements if levels are low. According to ACOG and WHO, many pregnant people need supplements from the second trimester onwards.

Can I travel by plane now?

Yes, the second trimester is considered the safest period for air travel. Most airlines allow pregnant passengers to fly until week 36 (week 32 for twins). Drink plenty of water, move regularly during the flight, and wear compression stockings to reduce the risk of blood clots. Talk to your midwife if you are planning a long trip, and remember to bring your maternity notes.

What is round ligament pain?

Round ligament pain is brief, sharp pain in the groin that occurs when the ligaments supporting the uterus are stretched. It is typically triggered by quick movements, coughing, or sneezing. The pain is harmless and completely normal in the second trimester. Move slowly, support your abdomen with your hands, and use warmth for relief. Contact your doctor if the pain is persistent or very intense.

When will I feel my baby kick?

Most first-time parents feel the first movements between weeks 18 and 22. If you have been pregnant before, you may feel them as early as weeks 15–16. Early movements are often described as bubbles, butterflies, or a gentle tickling sensation in the lower abdomen. Placental position also matters — an anterior placenta (at the front) dampens the sensation and means you may feel kicks later.

Do I need iron supplements during pregnancy?

Not everyone needs iron supplements, but many pregnant people develop iron deficiency in the second and third trimester. Your midwife checks iron levels (haemoglobin and ferritin) at prenatal appointments. According to ACOG, iron supplementation should be considered when levels are low. Take iron tablets on an empty stomach with a glass of orange juice for best absorption, or between meals. Side effects like constipation and stomach cramps are common — talk to your midwife about dosage and type of supplement.

Should I take omega-3 supplements?

According to ACOG and WHO, it is best to get omega-3 through your diet, especially from oily fish 2–3 times per week. If you do not eat fish regularly, an omega-3 supplement with DHA may be appropriate. DHA (a type of omega-3) is especially important for your baby's brain and eye development.

Is it safe to colour my hair during pregnancy?

Research suggests that hair colouring is generally safe after the first trimester. The amount of chemicals absorbed through the scalp is minimal. If you are concerned, choose ammonia-free products, plant-based dyes (like henna), or only colour the lengths without letting the dye touch the scalp. Ensure good ventilation during colouring.

Should I tell my dentist I am pregnant?

Yes, always inform your dentist that you are pregnant. Some dental treatments and X-rays should be avoided or postponed, especially in the first trimester. Your dentist can adapt treatment to your pregnancy. Dental health is important in pregnancy — hormonal changes increase the risk of gum disease. Schedule a check-up and let your dentist know.

Next week: Your baby's movements become more coordinated, and you may feel the very first kicks!