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.
You might not experience fatigue every single month, but chances are youâve experienced PMS fatigue before. Fatigue is actually one of the first pregnancy symptoms to show up. It can strike about one week after conception â before youâve even missed a period. This early pregnancy symptom is caused by increased levels of progesterone, a hormone that helps support the pregnancy and baby.