There are some physical signs that your caregiver will watch for as indicators that the placenta is separating or has separated. These include:
Contractions
Trickle of blood
Cord lengthening
Contractions
After a resting phase of around 10 to 20 minutes, the uterus will usually contract again. The uterus changes from being able to be felt in the abdomen as a large, soft, round lump to becoming smaller and harder and feeling quite firm (like a cricket ball). The caregiver will usually gently rest their hand on the woman's abdomen (without prodding or poking) to feel this contraction. This contraction can be experienced as mild cramping or discomfort for most women, although a few will describe it as strong or 'labour-like'. It normally takes only one contraction to separate and deliver the placenta and membranes.
The uterus will then continue to contract after the placenta has been expelled, to control the bleeding. Most first time mothers will not feel the contractions after the placenta is delivered, but women having their second or subsequent baby will often feel them as strong 'after pains' for a couple of days after the birth. Try using a heat pack on your belly to help ease the pain or you may need to take a mild painkilling tablet.
Trickle of blood
When the placenta separates, the blood vessels that have been supplying blood to the placenta tear and bleed, usually minimally (about 30 to 100 mls) as the uterus contracts down to constrict these blood vessels and control the bleeding. This can be seen as a small trickle of bright blood coming away from the woman's vagina and is a 'sign of separation' for the caregiver to know that the placenta is ready to come.
Cord lengthening
As the placenta separates from the uterine wall it moves down from the upper part the uterus into the lower segment. When this occurs the cord protruding out from the woman's vagina visibly lengthens by about 5 to 10 cm.