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 baby is overdue. Pregnancy normally lasts about 40 weeks (that's around 280 days from the first day of your last period).Most women go into labour a week either side of this date, but some women go overdue.If your labour doesn't start by the time you are 40 weeks pregnant, and this is your first pregnancy, your midwife will offer you a membrane sweep at your 40 and 41 weeks appointments.If you have had a baby before, you will be offered this just at your 41 weeks appointment.f your labour doesn't start by the time you are 40 weeks pregnant, and this is your first pregnancy, your midwife will offer you a membrane sweep at your 40 and 41 weeks appointments.