The placenta is an amazing organ - it has the sole responsibility of keeping a baby alive for the first 8-9 months of their life. Everyone who has ever taken a breath has done so because of a placenta. It is the only organ I can think of that has such an important function, yet has a limited life span (yes, organs such the tonsils or appendix may be removable with little side effects, but they do not play such an important role maintaining life). I also believe that it is a very misunderstood organ.
Lets look at what we do know about it
This organ originates from the same cells that make the baby, so technically it belongs to your baby.
It acts as the lungs, digestive system, and liver of your baby while in the uterus. The baby in the uterus lives in fluid, there is no air to breath, so the placenta provides oxygen to the baby and removes carbon dioxide from the baby. The baby will also not be taking in any food/milk and so must get nutrients from the mother, which is provided via the placenta. The liver usually filters out any toxins or waste from the blood (the kidneys also do this to a degree, but they will start working and produce urine during pregnancy - fun fact, the baby wees while inside the womb and then swallows the amniotic fluid, which in turn becomes urine), but the liver does not really reach its full potential until after birth, so the placenta does this for the baby.
The placenta also transfers antibodies and hormones to the baby. It releases a hormone called progesterone which will prevent you from making milk during pregnancy - if you have a placenta inside you, there must be a baby in the womb, ergo there is no need to produce milk.
When I became a midwife I obviously came up close and personal with many placentas, and I developed a healthy respect from them. Many of my NICU colleagues tease me for how in awe I am of the placenta. But think about it for a moment - this somewhat unattractive organ literally provides life to your baby.
They may not be terribly attractive, but they provide life!
Myths about the placenta
However, I am saddened to see many negative myths about the placenta being spread, especially by some of my midwifery and NICU nurse colleagues. These include the age old 'the placenta will stop working if you stay pregnant for too long' and 'your placenta was unhealthy'.
Please can someone tell me which other organ in an otherwise healthy human body just suddenly stops working? Now before you say 'oh but your kidneys or liver can stop working' - yes, they can but there is usually an underlying cause for this.