At birth the umbilical cord is approximately 2.5cm thick and 50cm in length. It contains two arteries and one vein, enclosed and protected by a thick gristle-like substance called Wharton's Jelly. The cord contains no nerves (similar to your hair or fingernails) so when it is cut there is no pain experienced by either mother or baby.
Once the baby is born the cord is clamped and then cut. You may not have any preconceived ideas about when the cord is cut, but for some people there are issues associated with this momentous event, which you may wish to familiarise yourself with. They include:
Cord pulsating
Extra cord blood, does my baby need it?
Too much of a good thing?
Clamping and cutting
Cord pulsating
At some stage after the baby is born the cord is cut to separate the baby from the placenta. When the 3rd stage of the labour is
managed naturally, the cord is not cut immediately. The idea being to allow for a resting phase and to clamp and cut the cord after the cord stops pulsating, indicating the placenta has separated. You can feel the cord pulsating in rhythm with your baby's heart rate soon after birth, you may notice your caregiver feeling the cord to make sure the rate is normal.
The cord continues to pulsate until the placenta detaches from the wall of the uterus. The flow of blood in the cord from the placenta to the baby via the umbilical vein continues (at a greatly reduced rate) for up to 2 to 3 minutes after birth. Minimal oxygen is being supplied at this point to the baby, as the baby's lungs take over.
Blood flow from the baby to the placenta via the 2 umbilical arteries stops at birth (as the blood vessels spasm), preventing the baby from losing blood. By the time the placenta totally separates the blood in the cord has stopped flowing completely, as the cord spasms. The cord is usually cut at this point or some caregivers cut it after the placenta has been fully expelled from the mother.