The Tree of Life

Absolutely everything you need to know about the placenta. And more.

Trish Stack

Have you ever wondered what the Placenta is and what it does?

If you had a baby before or have attended a birth you might have been aware of a midwife in the corner carefully examining the placenta and membranes. Perhaps your midwife invited you or your partner to examine it with her? 

It may be that you chose not to look then, however, you might be fascinated by what you see.  

What Does the Placenta Look Like? 

The word placenta derives from the Latin for cake and the Greek for “flat or slab-like” and this is how it appears. Placentas vary but they are approximately the size of a dinner plate. Roughly 15 – 20 cm in diameter, 2 – 3 cm in thickness, and 500g in weight.

If you look at it immediately following birth, you will see that it has two surfaces, a fetal surface and a maternal surface. The fetal surface or baby’s surface is smooth, shiny and blue/purple in colour and covered in a double layer of membranes. The umbilical cord is inserted into it (more about the cord and insertion types in a moment). The maternal surface has a cobblestone appearance due to the cotyledons (or lobes of the placenta) and looks like raw liver. It may sound gross, but as a piece of engineering, it is miraculous.

What Does the Placenta Do?

For nine months your baby has been swimming in a pool of amniotic fluid, warm and safe inside your womb. What maintains the pregnancy? How does your baby manage to take in oxygen? Their lungs were not operating yet. How do they manage to receive nutrients and how do they dispose of waste like carbon dioxide? The answer is the temporary organ called the placenta and you and your baby’s co-operation at a cellular level.

How it Works on the Mother’s Side.

The maternal side of the placenta or basal plate which is made of the mother’s tissue allows for maternal blood vessels such as arteries and veins to create a lake of blood rich in oxygen and nutrients. This is easily available to your baby. However, there is no direct contact between maternal and fetal blood vessels due to a semipermeable layer of tissue in the placenta called the placental barrier.  

This barrier acts as a selective membrane to substances passing from maternal to fetal blood. It is a protection mechanism to keep both circulation systems separate. However, certain drugs can cross this barrier and affect your baby which is why morphine injections, for instance, are not given if birth is imminent.

How it Works on the Baby’s Side.

To explain what is happening it is easiest to start with the umbilical cord. The umbilical cord has two veins and one artery within it, all encased in a jelly-like substance called Wharton’s Jelly.  When the cord is cut, all three vessels are visible and it resembles a smile emoticon ☺. The large vein forming the lips at the bottom and the two smaller arteries forming the eyes.  

If you have never seen umbilical cords, I recommend you look at photography sites online showing their intricate spirals and colours (shades of blue and creamy white). One of my favourite births was when a baby girl emerged with her hand holding onto her cord.  She seemed particularly relaxed.  Nowadays it is common practice to allow the cord to stop pulsing before it is cut. Your midwife will ask you if you wish this as part of your Birth Plan. 

The whole placenta looks like a drawing of the Tree of Life on the baby’s side of the surface. If you trace the cord back from your baby’s umbilicus (belly button) you will discover that the three vessels within the umbilical cord eventually branch out and split up inside the chorionic plate (or baby’s placental tissue) creating a tree-like network of branches and roots that protrude into the maternal lake of blood described above. This allows for your baby to receive oxygen and nutrients from you and for your system to take away carbon dioxide on behalf of your baby.  Cool isn’t it?

The Placental Examination or What Your Midwife is checking for?

Firstly, the appearance and size of the placenta which indicates how well the placenta has been functioning. We also check that there is no unusual smell and that it is in good condition. A bad smell may indicate an infection has been present and perhaps that you and or your baby may need antibiotics. 

We check that there are two membranes present. You may see us rubbing the membranes between our gloved fingers or peeling the membranes back and we check that there are no ragged edges on the maternal side of the placenta.  Nor any missing lobes or (cotyledons).  

If the membranes or part of the placenta is left inside, this may lead to infection or make it difficult for the uterus to contract properly and stop the bleeding from your womb. Midwives also check the umbilical cord to ensure the three blood vessels described above are present.

We also note how and where the cord is inserted and if there have been any knots in the cord. The umbilical cord insertion site to the placenta can be described as central, lateral, marginal (battledore) and velamentous insertions (where the cord is inserted into the membranes instead of the placenta). Central and lateral insertions are the most common types.

All the findings are documented and you may see the following written on your discharge paperwork – “placenta and membranes complete” or “placenta and membranes doubtful”. This information is useful for your GP or Community Midwife in helping to assess your risk for excessive postnatal bleeding and or infection.

How long can it take for me to deliver my Placenta?

Delivery times for the placenta vary, but if you are having a natural birth usually you will deliver your placenta within an hour. If your bleeding is heavy or if you have decided to have an oxytocin injection (a drug to help your uterus contract and shear away the placenta) then delivery of the placenta can take 5 or 10 minutes. Your midwife will discuss delivery options with you as part of your birth plan.  

Cutting the Umbilical Cord

Some parents wish to cut the cord themselves, but be warned the cord can feel quite resistant to cut through. Imagine cutting into a thick rubber band with a none too sharp scissors. Parents usually look at me horrified when I describe the sensation of cutting the cord as “being chewy”. I promise no midwife to my knowledge has ever yet bitten into one. 

Occasionally, parents opt for a “Lotus birth” where the umbilical cord is left uncut after childbirth. This means the baby remains attached to the placenta until the cord naturally separates at the belly button. This usually happens within 3–10 to days after delivery. It is often done to honour the shared life between baby and placenta.

Cultural Beliefs and Customs

Many societies give particular significance to the placenta, seeing it as a twin, grandparent or guardian to the newborn. In the Maori tradition, the word “Whenua” is used for both the placenta and land. The placenta is buried on tribal land. It is thought that the placenta creates a bond between the child and tribe. Often a tree, signifying new life, is planted during the ceremony and its burial is viewed as a gift to Mother Earth. In Malay culture following birth, a ritual cleansing of the placenta and the umbilical cord takes place. Both of these are then buried in the doorway of the familial home, alongside books and pencils to encourage the child to be studious.  

Placentophagy (eating part or all of the placenta) became popular in the United States in the 1960s and 1970s. Although there is little clinical support for doing this practice, traditional Chinese medicine believes that ingesting the placenta after birth ensures a quick recovery, improved lactation, and prevents postnatal depression. The first recorded practice of this took place 2000 years ago in China.

Perhaps you feel differently about the placenta now? In any case, you should realise that the placenta belongs to you and that how you choose to dispose of it is entirely up to you.