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.
You can even choose to work right up to the date the baby is born. You should note that the start of your maternity leave might be triggered automatically if: 1  you have a pregnancy-related illness or absence in the last four weeks of your pregnancy.2  your baby is born before the day on which you were planning to start your leave.ou should note that the start of your maternity leave might be triggered automatically if: 1  you have a pregnancy-related illness or absence in the last four weeks of your pregnancy. 2  your baby is born before the day on which you were planning to start your leave.