A sweep is when a midwife or doctor finds the cervix with their two fingers at the top of your vagina, then, if the cervix can be found, it is examined, and if possible, one or to fingers are inserted into the opening of your cervix to stretch it a little bit (this opening is sometimes called the os). This then enables them to 'sweep' a small part of the lower part of the bag of water that surrounds your baby, and will cause the bag of membranes to separate slightly from the cervix. This causes a release of a natural hormone called prostaglandins, which send signals to your brain to stimulate labour. However, this only works if the cervix can be found by the person doing the examination, and if the cervix if soft and stretchy already, which can happen up to two weeks before your baby can be born, although it can happen much quicker than this. Therefore, if your cervix was very far back at the time of your examination, it probably means that your baby is not quite ready yet! The success of any form of induction, whether it be through natural methods or medical intervention depends upon the body's readiness to start labour.
not a particularly pleasant procedure...