Some of the most complicated systems in your baby's body are continuing to develop, such as the tiny air tubes that line the lungs. A substance called surfactant is starting to be produced, which coats these tiny tubes and stops their sides sticking together
Depending on the antenatal care arrangements in your area, you'll have a number of appointments with your GP or midwife as your pregnancy progresses. Appointments will probably become more frequent as you get closer to your due date. You may have your blood pressure and weight measured, and may need to give urine or blood samples. Antenatal appointments are good opportunities to get dads involved so try to attend them together if possible.
Some women become diabetic during pregnancy. This means you have unusually high levels of sugar in your blood. Pregnancy-related diabetes usually disappears after you've given birth. It will be picked up in the routine blood and urine tests you have during pregnancy. To treat it you may need to cut down on sugary foods in your diet, and some women have to take insulin to regulate their blood sugar.