What is the second trimester?

Trimesters are a helpful way to think about pregnancy because the changes that happen to you and your baby fall into 3 broad categories of early, middle and late pregnancy, as reflected in the first, second and third trimesters.

The second trimester represents the middle part of your pregnancy, from weeks 13 to 26. For many women, one of the best things about this trimester is that nausea might begin to settle.

What happens to your body?

Your body will undergo some major changes during the second trimester. Your uterus will grow, and you may feel some discomfort or aches as uterine ligaments stretch. You will start to feel your skin stretch around your belly and your breasts, which may cause mild itching. Some women get stretch marks in these areas, which tend to fade over time.

Although your baby weighs less than a kilo, your blood volume will increase to meet the demands of all the growth happening inside you, which will mean you will gain some additional weight.

What happens to the baby?

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.

Your baby will be able to move freely within the amniotic sac in your uterus. By about week 19 (or sooner if this isn’t your first pregnancy), you may feel this movement – as a faint tickling or fluttering. During these 3 months, your baby’s organs will continue to develop and the 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.