By this stage your baby's urinary system is working. As well as taking in fluids through the umbilical cord, which connects mother and baby, your baby will also be drinking in some of the amniotic fluid in which he or she is floating. The waste products go back into the amniotic fluid as urine.
Your breasts will be getting bigger as your pregnancy at 17 weeks progresses and your nipples may also become darker. As your body prepares for motherhood and gets ready to make milk for your baby, you may notice a creamy white discharge from your nipples. You're likely to need larger bra sizes during pregnancy - look for soft yet supportive cotton styles.
Your immune system, which fights illnesses, is under more pressure during pregnancy. Try to avoid people who have colds or flu. If you do catch a cough or cold, it's best to avoid taking any unnecessary medicines. Drink plenty of fluids and eat fresh fruit and vegetables containing vitamin C. Paracetamol is one of the safer options for pain relief, but check with your pharmacist before taking any over-the-counter remedies.