Need to talk? Call 1800 882 436.
It's a free call with a maternal child health nurse. *call charges may apply from your mobile

Is it an emergency? Dial 000
If you need urgent medical help, call triple zero immediately.

beginning of content

Pregnancy at week 18

4-minute read

Your baby

Your baby weighs about 200g and has grown to about 14cm – about the length of a $20 note. They have eyebrows, hair and fingernails.

The baby can yawn and hiccup. Their nervous system is developing and a layer of myelin is growing to cover their nerve cells. Their bowel is filling with meconium, which will become their first poos.

Your baby is moving around a lot by now. You might notice this as little 'bubbles' or 'flutters' in your stomach, and it's known as the ‘quickening’. The baby will probably rest at times when you are active, so you’re more likely to feel them when you’re lying still at night.

If you can’t feel your baby’s movements yet, don’t worry – you might not feel anything for another couple of weeks.

Your baby at 18 weeks

Length:14cm
Weight:200g

Your body

By 18 weeks, many women are starting to feel light-headed and dizzy. This is because the growing uterus can push against an artery when you’re sitting or lying down. When you stand up, there’s a rush of blood which makes your head spin.

Your body is making more blood to nourish your baby, so you’ll need to drink plenty of fluids to support the process.

You may notice that you’re starting to gain weight now. If you were in the healthy weight range before you fell pregnant, you should aim to gain about 1.5 to 2 kg each month from now until you give birth. You don’t need to eat a lot more food, but do make sure you have a healthy diet so that you and your baby get the nutrition you need.

Things to remember

Between 18 and 20 weeks, you will have an ultrasound to check your baby’s development. This is called a fetal anomaly or morphology scan. It checks the size of the baby and measures physical features including the heart, brain, spine and kidneys.

At this scan you may be able to find out (if you want to) whether you’re having a boy or a girl. If the scan shows there might be problems with the baby’s development, you may be referred to an obstetrician or genetic counsellor for more tests.

Read next


Pregnancy at week 19

Your pregnancy at 19 weeks

Learn about your pregnancy journey and what is happening to you and your baby.

Speak to a maternal child health nurse

Call Pregnancy, Birth and Baby to speak to a maternal child health nurse on 1800 882 436 or video call. Available 7am to midnight (AET), 7 days a week.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: April 2022


Back To Top

Need more information?

Folate and pregnancy

Taking the vitamin folate before and during pregnancy reduces the risk of your baby having a neural tube defect

Read more on WA Health website

Second trimester: pregnancy week by week | Raising Children Network

Pregnant? In our pregnancy week by week guide, you can find out what to expect and follow your baby's development during the second trimester.

Read more on raisingchildren.net.au website

Pregnancy at week 17

By week 17, you may want to start thinking about antenatal classes to help you and your partner prepare for the birth and beyond.

Read more on Pregnancy, Birth & Baby website

Pregnancy tests - ultrasound - Better Health Channel

Ultrasound is used during pregnancy to check the baby's development and to help pick up any abnormalities.

Read more on Better Health Channel website

Radiation exposure during pregnancy

Large doses of radiation could be harmful during pregnancy. Learn how you can be exposed to radiation and how radiation could affect your baby.

Read more on Pregnancy, Birth & Baby website

Morning sickness

Morning sickness is the nausea and vomiting experienced by many women during pregnancy. It affects between 70 to 85 per cent of pregnant women.

Read more on WA Health website

How big is your baby?

Are you pregnant and curious about the size of your baby? Comparing your baby’s size to various foods can be a fun way to grasp their size each week.

Read more on Pregnancy, Birth & Baby website

About the placenta

The placenta develops inside the uterus (womb) during pregnancy. It gives your baby nutrients and oxygen. Find out more about the placenta here.

Read more on Pregnancy, Birth & Baby website

Second trimester

During the second trimester, your baby’s organs will develop and they will start to hear sounds. Any morning sickness will likely ease off around this time.

Read more on Pregnancy, Birth & Baby website

Nuchal Translucency Scan - InsideRadiology

InsideRadiology provides free and easily accessible, accurate, up to date and credible information about medical imaging tests and procedures.

Read more on InsideRadiology website

Call us and speak to a Maternal Child Health Nurse for personal advice and guidance.

Need further advice or guidance from our maternal child health nurses?

Healthdirect Australia acknowledges the Traditional Owners of Country throughout Australia and their continuing connection to land, sea and community. We pay our respects to the Traditional Owners and to Elders both past and present.

This information is for your general information and use only and is not intended to be used as medical advice and should not be used to diagnose, treat, cure or prevent any medical condition, nor should it be used for therapeutic purposes.

The information is not a substitute for independent professional advice and should not be used as an alternative to professional health care. If you have a particular medical problem, please consult a healthcare professional.

Except as permitted under the Copyright Act 1968, this publication or any part of it may not be reproduced, altered, adapted, stored and/or distributed in any form or by any means without the prior written permission of Healthdirect Australia.