What is the second trimester?
Trimesters are a helpful way to think about pregnancy. The changes that happen to you and your baby fall into 3 broad categories of early, middle and late pregnancy, known as the first, second and third trimesters.
The second trimester represents the middle part of your pregnancy, from weeks 13 to 26. During this trimester your nausea might begin to settle, and you may feel that you have more energy.
What happens to my body in the second trimester?
Your body goes through some major changes during the second trimester. Your uterus grows, and you may feel some discomfort or aches as uterine ligaments stretch. The skin over your belly and breasts will stretch, which may cause mild itching. You may also notice stretch marks in these areas, which tend to fade over time.
Although your baby still weighs less than 1kg, your blood volume increases significantly to meet the demands of your babys growth. This contributes to some additional weight gain.
What happens to my emotions in the second trimester?
Pregnancy can be a wonderful and exciting time, but its also normal to occasionally experience anxiety or low mood.
Sometimes, one or both parents experience difficult emotions during pregnancy, such as being worried about the birth or about coping as a parent.
Feelings of anxiety are not uncommon, but if they persist or begin to affect your wellbeing, they can be signs of antenatal depression or anxiety.
If you are worried about feelings of anxiety, low mood or depression, you should:
- talk to your doctor, obstetrician, child health nurse or midwife
- phone Pregnancy, Birth and Baby on 1800 882 436
- call PANDA - Perinatal Anxiety Depression Australia on 1300 726 306
What happens to my baby in the second trimester?
During the second trimester, your baby will grow from being around 7.5cm, and weighing 30 grams in week 13, to around 23cm and 820 grams at week 26. These measurements are not the same for everyone, and your baby might grow at a different rate.
Your baby will be able to move freely within the amniotic sac in your uterus. By about week 19 (or sooner if this isnt your first pregnancy), you may feel this movement. It is often described as a faint tickling or fluttering.
With time, your partner may also be able to feel your baby kicking and moving about by placing their hand on your tummy. This is a great way for your partner to share the experience of pregnancy with you and to get to know your baby.
During these 3 months, your baby's body organs will continue to develop. Their liver, pancreas and kidneys all start to function. This is also the time when babies might start to suck their thumb.
By week 20, your baby can hear sounds, including the sound of your heartbeat, and they are learning to recognise your voice, although the ears are not yet fully formed.
What can I expect during antenatal visits in the second trimester?
Regular antenatal visits are an important part of staying healthy and making sure your baby is healthy. How often you see your health professional will depend on your personal circumstances. For most people, visits will be every 4 to 6 weeks in the second trimester and may become more frequent towards the end of your pregnancy.
At antenatal visits during your second trimester, your doctor or midwife will check your:
- blood pressure
- hands and feet for swelling
Your doctor or midwife will also discuss any blood tests recommended for you at this stage in your pregnancy. For most people, this includes an oral glucose tolerance test at 24 to 28 weeks to check for gestational diabetes.
Your doctor or midwife will check your abdomen to monitor your baby's growth and will listen to your baby's heartbeat. You will also be offered an ultrasound at around 18 to 20 weeks of pregnancy to check your baby's growth and development, known as a morphology scan.
What are the second trimester genetic screening tests?
Your doctor may suggest doing second trimester genetic screening blood tests if you did not do any screening blood tests in your first trimester.
Maternal serum screen (MSS)
This test is sometimes referred to as the triple test or maternal serum screen (MSS) and checks the amount of 3 different hormones in your blood oesteriol, free beta HCG and alpha fetoprotein.
It screens for conditions such as Down Syndrome or neural tube defects. You can do the test from 14 to 18 weeks of pregnancy.
Non-invasive prenatal testing (NIPT)
Another genetic screening test offered in the second trimester is NIPT (non-invasive prenatal testing). This blood test can be done in either your first or second trimester.
During pregnancy, some of the DNA (genetic material) from the placenta crosses into your blood stream. This DNA carries your babys genetic information. NIPT analyses this DNA to see if your baby is at an increased risk for a genetic condition.
Are any ultrasound scans routinely recommended during the second trimester?
An ultrasound is recommended during all pregnancies at about 18 to 20 weeks of pregnancy. This test is known as a morphology or anatomy scan.
This ultrasound checks for:
- the position of the placenta
- the cervical length
- the amount of amniotic fluid
- your baby's growth and development
- any anatomical (structural) abnormalities in the foetus
How can I stay healthy through the second trimester?
Light to moderate exercise in pregnancy is usually safe. Walking, swimming, yoga and stationary cycling are all good exercises to consider in your second trimester.
High impact exercise and activities, where there is a risk of falling or overheating are not recommended.
Your choice of food during your pregnancy is also important but that doesn't mean eating for two. What you eat during your pregnancy has been shown to affect how your baby grows, as well as your baby's health later in life.
When should I seek medical help?
Contact your doctor, midwife or hospital immediately if you experience any of the following symptoms:
- vaginal bleeding or constant, clear watery vaginal discharge
- severe nausea, vomiting or abdominal pain
- sudden blurry vision or a severe headache
- sudden swelling of the face, fingers or ankles
- regular, painful contractions before 37 weeks of pregnancy
- a change in your baby's movements (if you already feel them regularly)
What else should I consider in the second trimester?
Here are some things you might like to discuss with your partner (if you have one) and then with your employer:
- How will you share the care of your baby with your partner (or other family members)?
- When do you plan to start your leave?
- When you intend to return to work?
- When would you like to share your pregnancy news with your employer?
- Will your role at work change after your baby is born?
- Ask your midwife or doctor about antenatal education available in your area.
- Consider attending classes together with your birthing partner not only will you learn a lot about how to prepare for labour, you'll meet people who will share their experience of becoming parents.
Resources and support
Follow your pregnancy week-by-week to find out how your baby is growing and what is happening to your body.
For more information about the stages of pregnancy and birth, see the following resources:
- The Having a baby book
- The Royal Womens Hospital website.
- What to expect during pregnancy by Queensland Department of Health.
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.
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Last reviewed: May 2022