This is the middle third of pregnancy and it is now considered 'safe' to share your news with everyone that you're pregnant. When you reach this stage the risk of miscarriage is much less likely than in the first three months.
By week 13 your baby is fully formed and throughout the remainder of the pregnancy he will grow and his vital organs will mature to make him capable of independent life. By week14 your midwife should be able to hear your baby's heartbeat using a sonicaid, though some midwives and doctors prefer to wait another few weeks to avoid disappointment and panic if it is too difficult to find, your baby is still only about 10cm long and is moving around quite a bit. During week 16 fine hair begins to grow all over the baby's body, this is called lanugo, the eyebrows and eyelashes also start to grow. Your baby's movements are vigorous and you may start to feel them although most women don't for another few weeks in a first pregnancy. As his eyes and ears continue to develop your baby is now aware of sound and light.
By week 20 your baby is about 25cm long and weighs about 12oz. His teeth are forming in his gums and hair is beginning to grow on his head. As his muscles develop his movements increase and become more vigorous, so much so that you should now be able to feel them.
Your baby is continuing to grow and mature at a rapid pace. By week 24 he is about 33cm long and is now considered legally viable - meaning that if he was born now he is capable of sustaining independent life with special care. Although he has the proportions of a newborn he is still very thin and hasn't yet laid down fat stores.
By week 28 your baby's chance of survival, if born early, has increased to 80%. He is beginning to accumulate fat stores and his lungs are becoming more mature. His body is covered in vernix, a thick greasy substance that helps protect the skin from becoming soggy while immersed in the amniotic fluid. He now weighs about 2lbs and is about 35cm long.

As you enter the second trimester you should begin to feel much better. Nausea should start to wear off and you should start to regain a closer to normal level of energy. The uterus should have moved up and released the pressure on your bladder so that you may have to urinate less often. However you might discover new problems when you reach this stage. Constipation and heartburn might become an issue. Try to have plenty of fibre in your diet and drink as much water as possible. I found that drinking milk helped combat heartburn but it should be safe to take some over the counter indigestion remedies. Check with your doctor if you're not sure and always read the label.
By week 16 you may find that your clothes are getting tighter and that a bump is starting to appear. This is a very exciting time and I remember being very frustrated when no one else seemed to be able to see my 'huge' bump except me! You may also find that your breasts are getting larger and the veins become more prominent, this is common and is a result of your body preparing to feed your baby when he is born. Another common symptom of pregnancy is gum disease and if you find that your gums are bleeding it's a good idea to make an appointment with your dentist to have them checked. You might as well make the most of the free dental care while you are pregnant and for the first year of your baby's life!
Somewhere between weeks 16 and 22 you should start to feel your baby move. To begin with it feel s bit like when your stomach rumbles when you are hungry, almost like lots of tiny bubbles bursting. Though these movements become very noticeable to you it will be several weeks before the real kicks begin and anyone else can share your excitement.
Some women experience a heavy vaginal discharge during their second trimester this is called leukorrhoea and is perfectly normal; if you are one of them remember use a panty liner or sanitary pad, not a tampon. Your centre of gravity will start to shift as your bump gets bigger you may find that you lose your balance and you need to be especially careful when going up stairs.