Pregnancy Education Companion: weeks 20-21

Throughout your pregnancy, you’ll hear a lot about different parts of your body. Some words may be new to you. Here are some you’ll hear often:
Amniotic fluid - this is often called your waters. It’s contained in the bag (amniotic sac) that surrounds your baby during pregnancy. The amount of fluid varies throughout your pregnancy.

The fluid has several important functions.
1.    It maintains a consistent temperature in the uterus (womb) for your baby.
2.    It provides protection from minor bumps.
3.    It flows in and out of your baby’s lungs. At around 36 weeks, the placenta produces a hormone that helps your baby’s lungs mature so they can breathe oxygen after birth.
4.    Your baby swallows the fluid which helps develop their taste buds. The swallowed fluid can pass through their kidneys and contribute to fresh amniotic fluid. Or it may be stored in the baby’s bowels and later passed as meconium, a sticky, thick, dark green poo after birth. 
5.    In a healthy pregnancy, the fluid is constantly replaced by the baby’s urine and the placenta.

Usually, the amniotic sac breaks shortly before or during labour. Occasionally, it may break weeks before your due date.

Contact the hospital immediately if you think your waters have broken. Ring (03) 8345 3635.

Antenatal - refers to the time during pregnancy up until birth.

Cervix - the neck or entrance to your uterus. It’s a long, thick tube that is usually closed. As you get closer to your due date and during contractions, your cervix becomes softer, shorter, and starts to open.
During pregnancy, a thick mucous develops in the cervix. This mucous is very sticky and contains lots of antibodies. It forms a mucous plug that blocks the cervix, helping prevent infections from entering your uterus. It comes out of your vagina as the cervix starts to open, sometimes before labour begins or during early labour. This is called a show.  

Conception - (or fertilisation) happens when a sperm joins with an egg, starting a pregnancy.

Endometrium - the lining of the uterus. After your baby and placenta have been birthed, the endometrium will also come out of your body. This lining, along with bleeding from the placenta site, will cause bleeding from your vagina for about 7 to 14 days, sometimes longer.

Fundus – this is the upper edge of the uterus. As your baby grows, the uterus gets bigger, and the fundus rises. During a clinic visit, your doctor or midwife will measure the distance between your pubic bone (symphysis pubis) and the fundus.

Gestation - the time when a baby grows inside your uterus before birth. 

Perinatal - this is the time during pregnancy and the first year after birth.  

Placenta – also called the afterbirth. It forms soon after conception and attaches to the wall of the uterus and connects to your baby via the umbilical cord. It’s responsible for the growth of your baby. It’s well established by the 10th day of pregnancy, with good blood flow through the umbilical cord by the 10th week of pregnancy.
The placenta supplies your baby with nutrients and oxygen, removes waste, and acts as a barrier against some substances. However, harmful substances like alcohol, nicotine, and other drugs can travel through your blood, into the placenta, and then to your baby.
The placenta also produces hormones to help support your pregnancy. 
After your baby is born, you will birth the placenta. This is why it’s often called the afterbirth.
The placenta’s position depends on where its cells attach to the uterus wall. Usually, it attaches higher up in the uterus. But sometimes it attaches lower down, near or over the cervix. This is called placenta praevia. This can cause complications, including bleeding. In these cases, a caesarean birth may be necessary.
However, when the placenta is low early in pregnancy, it will usually grow upwards, away from the cervix as the uterus gets bigger.

Postnatal - refers to the time after birth, usually lasting for 6 to 8 weeks.

Uterus - commonly called the womb (pronounced woom), the uterus is a muscular organ, shaped like an upside-down pear.

Learn more
For more pregnancy and labour definitions, visit the Pregnancy, Birth and Baby website glossary.  
 

When you have a blood test, it will show your blood type. These tests also tell us if you have Rh positive or Rh negative blood. Most people are Rh positive.

If you are Rh negative and your baby is Rh positive, it may cause health problems during pregnancy. These can be treated with Anti-D injections at 28 and 34 weeks. 

You’ll learn more about Anti-D in week 27.
 

You can find your test results through Health Hub, or you’ll receive them at an appointment where you can discuss them.  

Test results can’t be given over the phone.

If your midwife or doctor has any concerns about your results, they’ll contact you by letter or phone.
 

At your first hospital visit, your midwife or doctor will help you work out your baby’s estimated due date.

The average length of pregnancy (or gestation) is counted as 40 weeks. The start of a pregnancy is counted from the first day of your last period, not the date of conception, which usually occurs 2 weeks later.  

So, a baby is considered:
•    early term if it’s born between 37 weeks and 38 weeks, 6 days
•    full term if it's born between 39 weeks and 40 weeks, 6 days
•    late term if it’s born between 41 weeks and 41 weeks, 6 days.  

We estimate your baby’s birth date by looking at: 
•    the date of your last normal menstrual period (LNMP) 
•    the pattern of your menstrual cycles, including how long they usually last, and how often they occur
•    any contraception used before you got pregnant.   

We also use a dating ultrasound or a dating scan to estimate your baby’s due date. This scan happens between 8 and 14 weeks, usually before 12 weeks.  

If you have a regular menstrual cycle, an early ultrasound usually gives a similar estimate of your baby’s age and due date as your last normal period. When the dates are close (within a few days of each other), either can be used for the due date. But if they’re more the 5 days apart, the ultrasound due date is more reliable, and your due date may be changed at your first hospital visit.   
 

During pregnancy, ultrasound scans are done to create a picture of your baby, your uterus, your cervix, and your pelvis. You may have an ultrasound several times during pregnancy to check how your baby is developing, if needed.   

The ultrasound uses sound waves. This is safe for both you and your baby. It is different to an x-ray. 

Your 18 to 20-week ultrasound scan is also known as the morphology scan or fetal anomaly scan. It looks for abnormalities in your baby's structural development and growth. It also checks the position of the placenta and the length of your cervix. This scan gives you the chance to see your baby, often for the first time.

A morphology scan is a routine antenatal test and is very important because it checks:   
•    how many babies there are
•    where the placenta and the umbilical cord are positioned 
•    the amount of fluid around your baby  
•    that your cervix is closed  
•    your baby’s growth, including the head, belly, and long bones of the arms and legs 
•    any structural abnormalities or problems in the baby’s spine, brain, heart, stomach or lungs.   
 

You can have the scan over your belly (transabdominal) or through your vagina (transvaginal). The preferred method is transvaginal as it allows the person doing the scan (sonographer) to accurately assess the length of your cervix and get better pictures.

During the ultrasound, a thin probe is inserted into your vagina. It’s a safe procedure that most people don’t find uncomfortable.   

Weight gain varies between women and may depend on your pre-pregnant weight. Weight gain averages from 11.5 to 16 kilograms. If you were under-weight at the start of your pregnancy you might gain a little more than average. If you were overweight you may aim to gain less.

However, strict dieting is not recommended.

Talk with your health professional about food, diet, nutrition, supplements and weight during pregnancy. Dietitians have specialist knowledge about nutrition during pregnancy and can give you expert advice about any problems with your diet. You can ask to see a dietitian at any time during your pregnancy.

More information on Food and nutrition in pregnancy

Contaminated food can cause toxoplasmosis and listeria. These infections are extremely rare, but they can harm your developing baby.

Toxoplasmosis is caused by a tiny parasite found in raw meat and in cat faeces. Anyone can be infected with the parasite, but it is most serious if you are pregnant as you may pass the infection on to your baby. We recommend you avoid contact with cats faeces, as toxoplasmosis increases the risk of birth defects if parasites cross the placenta.

To reduce the risk of toxoplasmosis:

• wash your hands well after handling pets or gardening
• wash salad vegetables thoroughly
• cook meat thoroughly
• avoid contact with cat faeces and wear gloves to dispose of cat litter.

More information is available by visiting the Better Health Channel website or the We are Family website.  

Listeria is a bacterium that can contaminate food and cause infection. Although uncommon, listeria infection is very dangerous for you and your baby as it can cause miscarriage, stillbirth or premature birth.

Newborn babies infected with listeria from their mother can become seriously ill with meningitis, blood poisoning or other infections.

To prevent listeria infection:

• wash your hands, cooking utensils and chopping boards thoroughly
• wash raw vegetables and fruit thoroughly
• avoid high-risk foods. These include soft cheeses (such as ricotta, camembert, brie, blue cheese and feta), cold cooked chicken, cold sliced meats, pâté, uncooked or smoked seafood, pre-prepared salads, and soft-serve ice-cream
• refrigerate leftover food as soon as it has stopped producing steam. When you reheat food make sure it is piping hot, as heat kills listeria.

More information is available on the Food Standards Australia New Zealand website.

Tea, coffee, cola drinks and energy drinks all contain caffeine. There are mixed research results about the effects of large amounts of caffeine on a developing baby. However, moderate amounts appear safe. This means up to three cups of coffee or five cups of tea a day.

Guarana, a caffeine substance, is used in some energy drinks such as V, Mother and Red Bull. These drinks are not recommended during pregnancy.

It is recommended that you stop smoking or significantly reduce your cigarette intake during pregnancy. Your baby will immediately feel the benefits. It is never too late in pregnancy to stop.

Smoking increases the risk of miscarriage, premature birth or having a low-birth-weight baby. The baby is also more at risk of infections and longer-term health problems. Smoking in pregnancy and after the birth increases the risk of SIDS (Sudden Infant Death Syndrome) commonly known as cot death. It is recommended that there be no smoking in your baby’s environment, including in or near the house or in the car.

As soon as you think you may be pregnant, ask for advice and support for you and/or your partner to stop smoking. You can get free information, advice and support from a trained Quitline counsellor, or talk to your midwife and doctor.

For more information go to: Quitline – Tel: 137 848

Not all medicines are safe during pregnancy and breastfeeding. This can include medicines that are prescribed, natural medicine or supplements, or over-the-counter medicines from the pharmacy or supermarket.

Remember to tell your:

• doctor, nurse or midwife about all the medicines you are taking. Include over-the-counter medicines from your pharmacy, supermarket or health food store
• doctor that you are pregnant or breastfeeding before they prescribe medicines for any conditions
• chemist (pharmacist) that you are pregnant or breastfeeding before you buy medicines.

For more information, call the Women’s Medicines Information Service on (03) 8345 3190 (9am-4pm Monday to Friday except public holidays) or email drug.information@thewomens.org.au.

Complementary and alternative medicines

The use of complementary medicines and alternative medicines (CAM) in pregnancy has increased. These include a wide range of treatments such as acupuncture, chiropractic care, naturopathy, herbal preparations, homeopathic remedies and nutritional supplements. 

Unfortunately, very few CAM are known to be safe during pregnancy, and some herbal remedies can be harmful to your baby. If you are considering using a complementary therapy, please talk to your health provider (such as your doctor, nurse, midwife or pharmacist) for more information. 

You can also call the Women’s Medicines Information Service on (03) 8345 3190 (9am-4pm Monday to Friday except public holidays).

More information about Medicines in pregnancy,  Medicines in breastfeeding and Herbal Medicines in pregnancy and breastfeeding.

Alcohol in pregnancy

We don’t know how much alcohol is safe in pregnancy or when you are breastfeeding. Excessive use of alcohol can make your baby very sick. The safest approach is to not drink alcohol.

Tell us about your drug and alcohol use

If you are pregnant and using alcohol or other drugs, early pregnancy care is important for your baby’s development.

Your midwife or doctor can support you to reduce and stop using in a way that is safe. The Women’s Alcohol and Drug Service gives confidential information, advice, pregnancy care and counselling to women with alcohol and drug issues.

More information on Drug and Alcohol use in Pregnancy

Although it may not seem like a common occurrence, unplanned pregnancies are common.

Everyone’s situation is different when they learn of their pregnancy. It is normal to feel both scared and excited at this news. Having access to good support and information can assist with any decisions you may wish to make if your pregnancy was unexpected.

Several services are available to support and provide accurate information. These include:

• The Women’s Abortion and Contraception Service
• 1800 My Options     
• Women's Life Centre
• Pregnancy Counselling Australia