Your baby at 13 weeks
Your baby weighs around 25g.
Your baby's ovaries or testes are fully developed inside their body, and the genitals are forming outside their body.
Where there was a swelling between the legs, there will now be a penis or clitoris growing, although you will not usually be able to find out the sex of your baby at an ultrasound scan at this stage.
You at 13 weeks
If you've been feeling sick and tired with morning sickness, you'll probably start to feel better when you're around 13 or 14 weeks pregnant.
You may start to experience an increased sex drive around this time, possibly as a result of pregnancy hormones or increased blood flow to the pelvic area. It is perfectly normal if you do not.
Read more about sex in pregnancy.
You'll notice a small bump developing as your womb grows and moves upwards. If you've been feeling the urge to pee more often over the last few months, it's because your womb was pressing on your bladder. This should ease off now.
See your doctor if you notice any pain when you pee. Urinary tract infections (UTIs) can happen in pregnancy, and it's important to treat them quickly to reduce the risk of kidney infection.
Your baby at 14 weeks
At 14 weeks, the baby is about 85mm long from head to bottom.
Around now, the baby begins to swallow little bits of amniotic fluid, which pass into the stomach. The kidneys start to work and the swallowed fluid passes back into the amniotic fluid as urine.
You at 14 weeks
How much weight you put on in pregnancy depends on your weight before you get pregnant. You're likely to gain between 10kg and 12.5kg. But gaining too much or too little may cause health problems for you or your baby.
Smoking in pregnancy harms your baby and quitting will benefit you both.
Your baby at 15 weeks
Around this time, your baby will start to hear – they may hear muted sounds from the outside world and any noises your digestive system makes, as well as the sound of your voice and heart.
The eyes also start to become sensitive to light. Even though your baby's eyes are closed, they may register a bright light outside your tummy.
You at 15 weeks
It's normal to have more vaginal discharge in pregnancy. It's usually thin, clear or milky white and should not smell unpleasant.
If it's smelly, you feel itchy or sore, or have pain when you pee, contact your midwife as these could be signs of an infection.
You may have backache in pregnancy as your womb gets heavier and pregnancy hormones affect the ligaments in your body, which can put a strain on your lower back.
Your baby at 16 weeks
The muscles of the baby's face can now move and the beginnings of facial expressions appear. Your baby cannot control these yet.
The nervous system continues to develop, allowing the muscles in your baby's limbs to flex. Around this time, your baby's hands can reach each other – they can form a fist and hold each other when they touch.
The information on this page has been adapted by NHS Wales from original content supplied by