Carbon dioxide is a pure substance. A pure substance can be an element or a compound. Carbon dioxide is a pure compound, consisting of two kinds of atoms that are bonded together. An element consists of merely one kind of atom. For example, oxygen is an element.
For Downâs syndrome, a blood test called the quadruple test is available from weeks 14-20 of pregnancy. For Patauâs and Edwardsâ syndromes, you will be offered a mid-pregnancy scan that checks for physical abnormalities.
If your symptoms are disturbing your sleep then you'll feel even more tired and irritable. Try to get as much rest as you can, because fatigue can make nausea and vomiting much worse (PRODIGY 2008) . You may find that your pregnancy sickness eases at about 14 weeks to 16 weeks of your pregnancy (PRODIGY 2008) .t's completely normal to feel tired when you're pregnant. When you're pregnant, huge changes take place in virtually every system in your body, which can make you feel extremely tired (Murray and Hassall 2009, PRODIGY 2009) .