Week by Week Pregnancy: 18 Week Pregnant

At 18 weeks pregnant, your baby is around 14.2 cm long from head to bottom and is roughly the size of a sweet pepper. You are well into your second trimester, and your baby's movements, senses and reflexes are continuing to develop.

You may start to notice your baby's first movements around this stage. At first, they may feel more like fluttering, bubbling or gentle swirling than obvious kicks. However, it is also completely possible not to feel anything yet. Most people first feel their baby move between 16 and 24 weeks, and if this is your first pregnancy it may happen after 20 weeks.

Your body is changing too. Your growing bump may become increasingly noticeable, your breasts may continue to grow, and changes in your circulation can sometimes make you feel dizzy when you stand up quickly. You may also notice a darker vertical line developing down the middle of your abdomen, known as the linea nigra.

Not sure how many weeks pregnant you are?
Use our Pregnancy Week Calculator to estimate your pregnancy week, or our Due Date Calculator to estimate when your baby may be due.

Contents

• What Does 18 Weeks Pregnant Mean?
• Your Baby's Development at 18 Weeks
• Can Your Baby Hear at 18 Weeks?
• Are Your Baby's Swallowing and Sucking Reflexes Developing?
• Can You Feel Your Baby Move at 18 Weeks?
• What's Happening in Your Body at 18 Weeks?
• What Can You See on an Ultrasound at 18 Weeks?
• 18 Weeks Pregnant Symptoms
• When Is the 20-Week Screening Scan?
• Frequently Asked Questions

18 Weeks Pregnant at a Glance

A key development at 18 weeks:
Your baby is now around 14.2 cm long from head to bottom. They are moving inside the womb while their hearing, senses and reflexes continue to develop. You are also approaching, or may already have entered, the window for your 20-week screening scan.

What Does 18 Weeks Pregnant Mean?

At 18 weeks pregnant, you are in your second trimester and your baby is continuing to grow and develop rapidly. Your baby measures around 14.2 cm from head to bottom.

Your baby has been moving for some time, even if you have not been able to feel those movements. Around this stage, the movements may become strong enough for some people to notice for the first time.

Week 18 is also significant because you may now be entering the period when the NHS 20-week screening scan is offered. Despite its name, the scan does not have to take place during your 20th week.

Your Baby's Development at 18 Weeks

At 18 weeks, your baby is around 14.2 cm long from head to bottom and is roughly the size of a sweet pepper. As your baby grows, their nervous system, senses and reflexes continue to develop.

Your baby is active inside the womb and can move their arms and legs and change position. Their hearing and sense of touch continue to develop, alongside skills such as swallowing and sucking.

For a broader look at how these changes progress throughout pregnancy, see our Baby Development in the Womb guide.

Can Your Baby Hear at 18 Weeks?

Your baby's hearing system is continuing to develop at 18 weeks. As pregnancy progresses, your baby becomes increasingly able to respond to sounds.

Hearing does not suddenly become fully developed during a particular week. The structures involved in hearing continue to mature throughout pregnancy.

Are Your Baby's Swallowing and Sucking Reflexes Developing?

Yes. Your baby's swallowing and sucking reflexes continue to develop at 18 weeks. These abilities form part of the continuing development of the nervous system and muscle coordination.

Your baby will continue practising and developing these skills throughout pregnancy in preparation for life after birth.

Can You Feel Your Baby Move at 18 Weeks?

Week 18 is around the time when some people begin to notice their baby's first movements. These early movements are not necessarily obvious kicks. They may feel like gentle fluttering, bubbling, swirling or small movements inside your abdomen.

It is also normal not to feel your baby move at 18 weeks. Most people first notice movements between 16 and 24 weeks. If this is your first pregnancy, you may not feel your baby move until after 20 weeks.

At this stage, you do not need to count a particular number of movements each day. As your pregnancy progresses, you will gradually become familiar with your baby's usual pattern of movement.

Haven't felt your baby move yet?
At 18 weeks, this does not necessarily mean that anything is wrong. If you have not felt your baby move at all by 24 weeks, contact your midwife or maternity service.

What's Happening in Your Body at 18 Weeks?

As your bump grows, your centre of gravity begins to change. You may therefore feel slightly less balanced or more awkward than usual at times.

Your blood pressure can be lower during pregnancy, which may make you feel dizzy, particularly if you stand up suddenly after sitting or lying down. Getting up slowly can help.

Your breasts may also continue to increase in size as your body prepares for feeding your baby after birth.

You may notice a darker vertical line developing down the centre of your abdomen. This is called the linea nigra. It is a normal pigmentation change during pregnancy and usually fades gradually after your baby is born.

Your 20-week screening scan is approaching.
In England, the NHS 20-week screening scan is usually offered between 18 weeks and 20 weeks + 6 days of pregnancy. The scan looks in detail at your baby's physical development.

In Part 2:
We'll look at what you may see on an ultrasound at 18 weeks, your baby's size, the 20-week screening scan, common pregnancy symptoms, vaginal discharge, abdominal and back pain, nutrition and exercise.

What Can You See on an Ultrasound at 18 Weeks?

At 18 weeks pregnant, an ultrasound can show your baby's head, body, arms and legs in considerable detail. You may see your baby wriggling, moving their limbs or changing position during the scan.

At this stage, your baby is around 14.2 cm long from head to bottom. As pregnancy progresses, ultrasound can provide increasingly detailed views of your baby's physical development.

If your baby's position allows, the sonographer may also be able to see the external genitalia. However, it is not always possible to determine your baby's sex from the scan, and local hospital policies can vary.

How Big Is Your Baby at 18 Weeks Pregnant?

At 18 weeks, your baby is around 14.2 cm long from head to bottom and is approximately the size of a sweet pepper.

This is an approximate measurement rather than a target that every baby must match exactly. Individual babies develop at slightly different rates, and measurements taken during an ultrasound are interpreted alongside your gestational age and other clinical information.

When Is the 20-Week Screening Scan?

In England, the NHS 20-week screening scan is usually carried out between 18 and 21 weeks of pregnancy. Within the NHS fetal anomaly screening programme, the screening window is generally from 18 weeks to 20 weeks + 6 days.

Despite being commonly called the 20-week scan, it does not have to take place during your 20th week. You may therefore have your appointment while you are 18 weeks pregnant.

The scan, which is also known as the anomaly scan or mid-pregnancy scan, looks in detail at your baby's physical development and checks for signs of 11 physical conditions. Your baby's growth is also assessed.

The sonographer examines areas including your baby's brain, face, heart, spine, kidneys, abdomen and bones. Your placenta and blood flow in your uterus are also checked.

The 20-week scan is a screening test, not a guarantee that your baby has no health conditions.
Some conditions are easier to see on ultrasound than others, and the scan cannot identify everything. If something unexpected is seen, you may be offered further scans, tests or specialist assessment.

What Happens During the 20-Week Screening Scan?

The sonographer uses an ultrasound probe over your abdomen to examine your baby's physical development. You will usually be able to see your baby on a screen while the examination is taking place.

Your baby's position can sometimes make it difficult for the sonographer to obtain all the views needed. If the examination cannot be completed, you may be offered another appointment to obtain the remaining images.

Screening is a choice. You do not have to have the 20-week screening scan if you do not want it. Your midwife can discuss the purpose, possible results and limitations of screening with you.

18 Weeks Pregnant Symptoms

At 18 weeks, you may notice a mixture of continuing pregnancy symptoms and changes associated with your growing womb. Everyone experiences pregnancy differently, so you may have several symptoms, only a few, or very mild symptoms.

Common symptoms and changes around this stage can include round ligament pain at the sides of your abdomen, headaches, nosebleeds, bloating, constipation, indigestion, heartburn, sore breasts, leg cramps, feeling hot, dizziness and swelling in your hands or feet.

Urinary or vaginal infections can also occur during pregnancy. Skin changes may include darker patches on your face, greasier or spot-prone skin and linea nigra. Your hair may also appear thicker or shinier.

Is Dizziness Normal at 18 Weeks Pregnant?

Feeling dizzy can occur during pregnancy. Your blood pressure may be lower than it was before pregnancy, and standing up suddenly after sitting or lying down can make you feel light-headed.

Try getting up gradually rather than making sudden changes in position. If you feel faint, sit or lie down somewhere safe.

Seek medical advice if dizziness is severe, keeps happening or is accompanied by fainting or other symptoms that concern you.

Is Linea Nigra Normal at 18 Weeks Pregnant?

Yes. A darker vertical line developing down your abdomen can be a normal pregnancy-related skin change. It is known as the linea nigra.

It may run from your tummy button towards your pubic area and can sometimes extend above your tummy button. How noticeable it becomes varies between individuals and different skin tones.

Linea nigra does not normally require treatment and usually fades gradually during the months after your baby is born.

Is Vaginal Discharge Normal at 18 Weeks Pregnant?

Having more vaginal discharge during pregnancy is common. Healthy pregnancy discharge is usually thin, clear or milky white and should not have an unpleasant smell.

Speak to your midwife or GP if your discharge smells unpleasant, is green or yellow, you feel itchy or sore around your vagina, or you have pain when you pass urine. These changes can be signs of an infection.

White discharge that looks similar to cottage cheese, particularly when accompanied by itching or irritation, can be associated with thrush. Ask a healthcare professional about pregnancy-appropriate treatment rather than treating it yourself without advice.

Think you may be leaking fluid?
If you notice a persistent watery loss or a sudden gush of fluid from your vagina, contact your maternity service for advice rather than assuming it is normal pregnancy discharge.

Is Abdominal Pain Normal at 18 Weeks Pregnant?

Mild abdominal discomfort can be common as your womb grows. The ligaments supporting your womb stretch as pregnancy progresses, which can cause sharp or pulling pains around the sides of your lower abdomen. Constipation and trapped wind can also cause abdominal discomfort.

Mild pain that improves when you change position, rest, open your bowels or pass wind is often less concerning.

Seek medical advice if abdominal pain is severe, persistent or getting worse, particularly if it occurs with vaginal bleeding, regular cramping, lower back pain, unusual discharge, fluid loss, fever or pain when passing urine.

Can You Have Back Pain at 18 Weeks Pregnant?

Back pain is common during pregnancy and can occur during the second trimester. Pregnancy affects the ligaments in your body, while your growing womb and changing posture can place additional strain on your lower back and pelvis.

Paying attention to your posture, avoiding unnecessary heavy lifting and bending your knees rather than your back when lifting can help reduce strain. Try not to remain in the same position for long periods.

Speak to your midwife or GP if your back pain is very painful, worsening or accompanied by symptoms such as fever, vaginal bleeding or pain when passing urine.

What Should You Eat at 18 Weeks Pregnant?

A varied, balanced diet remains important throughout your second trimester. Aim to include fruit and vegetables, higher-fibre starchy foods, pregnancy-safe sources of protein and dairy foods or suitable alternatives.

You do not need to “eat for two”. Rather than doubling your portions, focus on nutritional variety and balanced meals.

If constipation is troubling you, fibre-rich foods and adequate fluids may help. Continue following pregnancy food-safety guidance and avoid foods that are not recommended during pregnancy.

Can You Exercise at 18 Weeks Pregnant?

If your pregnancy is progressing normally and your healthcare professional has not advised otherwise, staying physically active is generally encouraged. Walking, swimming and other pregnancy-appropriate activities can be good options.

If you were not active before pregnancy, avoid suddenly starting strenuous exercise. Build up gradually and listen to your body.

A useful guide to intensity is whether you can still hold a conversation while exercising. If you become breathless while talking, you may be exercising too intensely.

Stop exercising and seek appropriate medical advice if you experience symptoms such as vaginal bleeding, severe or persistent abdominal or pelvic pain, significant dizziness, fainting or feeling unwell.

In Part 3:
We'll cover what may be considered normal at 18 weeks, when to contact your midwife or maternity service, bleeding, abdominal pain, vaginal discharge, your baby's movements, common myths, your week 18 checklist, FAQs and related pregnancy guides.

What Is Considered Normal at 18 Weeks Pregnant?

At 18 weeks, a growing bump, mild stretching discomfort, digestive changes and the first sensations of your baby moving can all be part of a normal pregnancy. The timing and intensity of pregnancy symptoms vary considerably from person to person.

You may experience headaches, dizziness, nosebleeds, constipation, bloating, heartburn, leg cramps, backache or an increase in vaginal discharge. You may also notice pigmentation changes such as a darker line down the centre of your abdomen, known as the linea nigra.

It can also be completely normal not to have felt your baby move yet. Most people first notice movements between 16 and 24 weeks of pregnancy.

How Can You Support a Healthy Pregnancy at 18 Weeks?

Continue focusing on a varied diet, regular fluids, pregnancy-appropriate physical activity and your scheduled antenatal care.

• Eat a varied and balanced diet.
• Drink regularly throughout the day.
• Continue following pregnancy food-safety advice.
• Avoid alcohol and smoking.
• Do not stop prescribed medicines without speaking to a healthcare professional.
• Check before taking medicines, supplements or herbal remedies during pregnancy.
• Stay physically active if it is appropriate for your pregnancy.
• Include pelvic floor exercises in your daily routine.
• Continue looking after your teeth and gums.
• Attend your antenatal appointments and any screening you choose to have.

When Should You Seek Medical Advice at 18 Weeks Pregnant?

Many new symptoms can occur during pregnancy, but some changes should be discussed with your midwife, GP or maternity service.

Seek medical advice if you experience:

• vaginal bleeding or spotting;
• severe, persistent or worsening abdominal or pelvic pain;
• abdominal pain that does not settle with rest;
• regular cramping or tightening;
• possible fluid leaking from your vagina;
• unpleasant-smelling, green or yellow vaginal discharge;
• vaginal itching or soreness;
• pain or burning when passing urine;
• a high temperature;
• severe or repeated dizziness or fainting;
• vomiting that prevents you from keeping food or fluids down;
• pain, swelling, tenderness or warmth affecting one leg.

Some symptoms require urgent assessment.
Seek urgent medical help if you have severe abdominal pain, heavy vaginal bleeding, shoulder-tip pain, severe dizziness, fainting or loss of consciousness.

Is Bleeding Normal at 18 Weeks Pregnant?

Bleeding during pregnancy does not always mean there is a serious problem, but it should be assessed. The amount, colour and duration of the bleeding, as well as whether you have pain or other symptoms, can help healthcare professionals determine what may be happening.

If you have vaginal bleeding or spotting at 18 weeks, contact your maternity service for advice. Seek urgent medical help if the bleeding is heavy or occurs with severe abdominal pain, shoulder-tip pain, significant dizziness or fainting.

When Should You Be Concerned About Abdominal Pain at 18 Weeks?

Mild, short-lived abdominal discomfort can occur as your womb grows and the supporting ligaments stretch. Constipation and trapped wind can also cause abdominal pain during pregnancy.

Mild discomfort that improves when you change position, rest, open your bowels or pass wind is often less concerning.

Contact your maternity service if the pain is severe, persistent or worsening, particularly if it occurs with vaginal bleeding, regular cramping, lower back pain, unusual discharge, fluid loss, fever or pain when passing urine.

When Should Vaginal Discharge Be Checked?

An increase in thin, clear or milky white vaginal discharge without an unpleasant smell is common during pregnancy.

Speak to your midwife or GP if the discharge smells unpleasant, becomes green or yellow, or is accompanied by itching, soreness or pain when passing urine, as these can be signs of infection.

White, cottage cheese-like discharge accompanied by itching or irritation may be associated with thrush. Ask a healthcare professional about suitable treatment during pregnancy.

If you think you may be leaking watery fluid rather than having normal vaginal discharge, contact your maternity service for advice.

Is It Normal Not to Feel Your Baby Move at 18 Weeks?

Yes. It can be completely normal not to have felt your baby move at 18 weeks. Most people first notice movements between 16 and 24 weeks. If this is your first pregnancy, you may not feel movement until after 20 weeks.

The first movements may feel like gentle fluttering, swirling, bubbling or small movements rather than obvious kicks.

If you have not felt your baby move at all by 24 weeks, contact your midwife. They can check your baby's heartbeat and movements and arrange further assessment if necessary.

Once you regularly feel your baby moving, become familiar with their usual pattern.
If your baby is moving less than usual, you cannot feel them moving any more, or their usual pattern of movement changes, contact your midwife or maternity unit immediately. Do not wait until the next day.

What Should You Know About the 20-Week Screening Scan?

At 18 weeks, you may now be entering the window for your NHS 20-week screening scan. In England, the scan is usually offered between 18 and 21 weeks, with the NHS fetal anomaly screening programme using a screening window of 18 weeks to 20 weeks + 6 days.

The scan looks carefully at your baby's physical development and screens for 11 physical conditions. The sonographer also takes measurements and checks your baby's growth.

The scan can provide important information, but it cannot detect every condition. If something unexpected is seen, you may be offered further scans, diagnostic tests or an appointment with a specialist.

Common Myths About Being 18 Weeks Pregnant

Your 18-Week Pregnancy Checklist

• ☐ Check the dates of your upcoming antenatal appointments.
• ☐ Check when your 20-week screening scan is booked.
• ☐ Continue eating a varied, balanced diet.
• ☐ Drink regularly throughout the day.
• ☐ Continue following pregnancy food-safety advice.
• ☐ Check that any medicines or supplements you take are suitable during pregnancy.
• ☐ Stay physically active if appropriate for your pregnancy.
• ☐ Continue your pelvic floor exercises.
• ☐ Remember that not feeling movement yet can still be normal at 18 weeks.
• ☐ Pay attention to unusual changes in vaginal discharge.
• ☐ Seek medical advice for bleeding, severe pain or other concerning symptoms.

Key Takeaway

At 18 weeks pregnant, your baby is around 14.2 cm long from head to bottom and roughly the size of a sweet pepper. Your baby's movements, senses and reflexes continue to develop, and you may begin to feel the first gentle movements. It can still be normal not to feel anything yet. You may also now be entering the window for your NHS 20-week screening scan.

Frequently Asked Questions

How big is a baby at 18 weeks pregnant?

At 18 weeks, your baby is around 14.2 cm long from head to bottom and is roughly the size of a sweet pepper. Individual measurements can vary.

How many months is 18 weeks pregnant?

18 weeks pregnant is often described as being around 4 months pregnant. However, because calendar months vary in length, healthcare professionals use weeks rather than months to date a pregnancy accurately.

Which trimester is 18 weeks pregnant?

At 18 weeks, you are in your second trimester.

Does a baby move at 18 weeks?

Yes. Your baby is actively moving inside the womb and can move their arms and legs and change position.

Can you feel your baby move at 18 weeks?

You may begin to feel your baby's movements at 18 weeks, but it is also normal not to feel them yet. Most people first notice movements between 16 and 24 weeks.

What do baby movements feel like at 18 weeks?

Early movements can feel like gentle fluttering, bubbling, swirling or small movements inside your abdomen rather than obvious kicks.

Can you have the 20-week scan at 18 weeks?

Yes. In England, the NHS 20-week screening scan is usually offered between 18 and 21 weeks, with the fetal anomaly screening programme using a window of 18 weeks to 20 weeks + 6 days.

Can you find out your baby's sex at the 20-week scan?

It may be possible if your baby's position allows a clear view. However, finding out your baby's sex is not the purpose of the screening scan, it may not always be possible, and local hospital policies can vary.

Should you have a bump at 18 weeks pregnant?

Your bump may be clearly visible by 18 weeks, but there is wide variation between pregnancies. The size and shape of your bump alone do not indicate how well your baby is growing.

Is linea nigra normal at 18 weeks pregnant?

Yes. Linea nigra is a normal pigmentation change that can appear as a darker vertical line down the abdomen during pregnancy. It usually fades gradually after birth.

Is dizziness normal at 18 weeks pregnant?

Occasional dizziness can happen during pregnancy, particularly when standing up quickly. Seek medical advice if dizziness is severe, keeps happening or leads to fainting.

What happens at 19 weeks pregnant?

At 19 weeks, your baby continues to grow and develop, movements may become easier to recognise, and you remain within the usual period for the mid-pregnancy screening scan.

Related Guides

• 16 Weeks Pregnant
• 17 Weeks Pregnant
• Pregnancy Week Calculator
• Due Date Calculator
• Baby Development in the Womb

References

• NHS – 18 Weeks Pregnant
• NHS – Week-by-Week Guide to Pregnancy
• NHS – Your Baby's Movements
• NHS – 20-week Screening Scan
• NHS – Vaginal Discharge in Pregnancy
• NHS – Stomach Pain in Pregnancy
• NHS – Vaginal Bleeding in Pregnancy
• NHS – Back Pain in Pregnancy
• NHS – Healthy Diet in Pregnancy
• NHS – Exercise in Pregnancy
• NICE – Antenatal Care

Medical information: This guide provides general information and is not a substitute for personalised medical advice, diagnosis or treatment. If you have concerns about your pregnancy or any symptoms, contact your midwife, GP or maternity service.