Weekly Guide to Pregnancy: Week 18

Week 18
Week 18 

Your Baby

How big is my baby?

This week your baby measures approximately 12.5-14cm (5-5.6 inches) in length and weighs about 150 grams (5.25 ounces).

Your baby is looking more and more human as time goes by. Your baby can now make facial expressions, including frowning and squinting. Eyes are still closed, but are sensitive to bright light outside your abdomen. Eyelashes and eyebrows have started to grow.

Limbs become longer, start to gain proportion and begin to move as the connections between nerves and muscles are established. The nerves are now being coated in myelin (a fatty layer), enabling them to pass messages to and from the brain. Your baby's hands can now form fists and if they meet, will clasp together.

The lungs are developing, but until birth the placenta will provide your baby's oxygen.

Your Pregnancy

What pregnancy symptoms will I be experiencing?

This trimester you will probably have more energy and will probably be feeling better if you have been feeling sick.

You may not have gained much weight, but your uterus has been pushed forward into your abdomen and can be felt. Normal weight gain at this point is between 2.3-5.8kg (5-13 pounds). If you have gained more than this, you should talk to your health care practitioner. You shouldn't diet during pregnancy, but you do need to make sure you eat a healthy balanced diet. Visit the Essential Baby Diet During Pregnancy pages for more information.

It has become almost routine for you to have at least one ultrasound scan during pregnancy. Ultrasound is used to check your dates and to check for any obvious abnormalities in your baby. A routine scan is usually performed during week 18 or 19. At this stage of development the baby is a good size for viewing by ultrasound, as it is fully formed. Most babies are around the same size at this age. In order to get a good picture of the baby it is necessary to have a full bladder (which can be uncomfortable). You will be asked to drink a few glasses of water and to refrain from urinating an hour or so before the scan. The position of the baby and the placenta is visible, and twins can also be detected. Later in pregnancy scans can be performed to check a baby's growth or to investigate vaginal bleeding.

You may experience nosebleeds or a blocked nose during pregnancy (a bit like sinus or hay fever). This may be due to changes in your circulation. Don't use nasal sprays, decongestants or other over the counter medication before seeking the advice of your doctor.

Your nipples are probably darker in colour and may feel tingly or sore. You will also be able to see the veins in your breasts more clearly. A dark line (linea nigra) may be visible down the middle of your abdomen.

Learn more about your pregnancy

Read more information on Pregnancy and Birth on Essential Baby.

Discuss Pregnancy in the Essential Baby Forums.

The First Trimester

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The Second Trimester

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The Third Trimester

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