Week 13-26: your baby

Week by week, the second trimester (weeks 13 to 27) is often the most enjoyable phase. During the latter part of this phase you will feel your baby move for the first time – one of the most exciting moments of your pregnancy.

Eyebrows and a little hair have grown. All of your baby’s organs, limbs, muscles, genitalia and bones have formed and the heartbeat is strong. By the second trimester your baby is now drinking some of the amniotic fluid and receiving nourishment through the placenta and is about 8cm long.

Your baby is now fully formed and is around 16cm long. The rest of the time in the uterus will be spent growing and maturing until baby is able to survive independently. The eyes are still closed in the second trimester. Lanugo, a fine hair, starts to form all over his/her skin to keep the temperature stable in the second trimester.

Your baby now has a firm grip and even has fingerprints. Your baby becomes increasingly energetic at this time; as well as kicking he/she is sucking and will now be about 20cm long. Until now, your baby’s bones had been developing but were still soft. In the second trimester, they begin to harden, or ossify. Some of the first bones to ossify are those in the clavicles and the legs.

Buds for permanent teeth are forming behind those for your baby’s milk teeth, which have already formed, and hair continues to grow on his/her head. A thick, greasy substance, called vernix, will cling to the downy hair on your baby’s skin, forming a protective barrier. Your baby is now about 25cm long and by this stage you could hold him/her in the palm of your hand. Your baby’s sex may be determined in the second trimester.

Your baby is still moving around a great deal and has probably settled into a fairly regular pattern of sleep and activity. Fingernails are now almost fully formed.

Babies have a chance of survival if born prematurely at this stage. However, special care is needed as lungs are not developed fully enough to cope with life outside the womb without help. This is a period of very rapid growth and your baby is now about 32cm long and weighs over 1lb (2.2lbs = 1kg).

Your baby’s eyes now open for the first time. At birth, your baby’s eyes will be blue and if they are going to change colour they will not do so until a few weeks after birth. Their tiny bodies are covered with fine, downy hair and the skin is starting to change. Until now it has been thin and translucent but it will become more opaque.