Gases that contribute to the greenhouse effect include: 1  Water vapor. 2  Carbon dioxide (CO 2). 3  Methane. 4  Nitrous oxide. 5  Chlorofluorocarbons (CFCs).
You can start maternity leave any time from 11 weeks before the beginning of the week your baby's due. You can bring the date forward if you need to take time off work for pregnancy-related reasons within four weeks of the expected birth date. Your employer may make you start your leave from then.
If you are unemployed, Maternity Allowance will start 11 weeks before your baby is due. If you are working, you can start claiming 11 weeks before your baby is due, but you can delay claiming up until the day following the birth. It is paid for up to 39 weeks.