It is important for your caregiver to position the ventouse accurately, and to have you in a 'stable' position, so your body weight can counteract the traction needed to deliver your baby. It is for this reason that your caregiver will require you to be on your back, often with your legs up in stirrups (although it is possible not to need stirrups, if the baby's head is low). You may be able to prop yourself up a little with a couple of pillows, to be able to see better and have some eye contact with your caregiver, if you prefer.
Image 6-76 show a woman positioned in stirrups.
An internal vaginal examination is carried out to estimate the
engagement of the baby's head, the dilation of the cervix and determine which way the baby's head is lying, so that the crown of the baby's head can be found. The aim is to position the ventouse cup on the crown of the baby's head, so that the crown will lead the way down the birth canal. This makes the baby's head the smallest possible diameter. It is also important that your caregiver avoids the 'soft spot' (or anterior fontanelle) on the top of the baby's head (at least 3 cms away) and for the cup not to touch your cervix, if it is not fully dilated.
If the cup is metal, it will be placed sideways into the woman's vagina and then placed on the crown of the baby's head. If it is a soft cup, the cup can be compressed with the caregiver's fingers to fit into the vagina, and then allowed to open out, once inside to be applied to the baby's head.
Image 6-57 shows the position of the ventouse on the baby's head.