During pregnancy, the placenta (or afterbirth) feeds and protects the baby from harmful infections while extracting microscopic, blood-soluble waste. Placental problems are rare in the first and second trimester, so most placenta-related obstetric complications occur during the third trimester.
Interesting placenta facts
- Among traditional midwives and birth attendants, the placenta is called the ‘tree of life’.
- In Pedi it’s known as the ‘baby’s blanket’, the ‘baby’s cushion’ or the ‘baby’s cradle’.
- In Peru and India, the placenta is called the ‘baby’s friend’.
- In Indonesia it’s known as ‘the baby’s brother or sister’.
What is the placenta and where does it come from?
At birth, the average placenta is about the size and shape of a side plate and weighs about 500g. It’s the thickness of a medium-sized steak with a smooth surface where the baby grows and a rough side that is attached to the womb.
The placenta develops from specialised cells on the surface of the egg eight to 10 days after fertilisation. These ‘landing cells’ penetrate the lining of the womb, or endometrium, much like the landing of a space module on a foreign outer-space surface. Following this, there is an exchange of hormonal signals, nutrients, waste and gases between the mother and her baby’s blood. This is sifted through a membrane, which means that there’s no direct contact between the mother’s blood and her baby’s.
Why is it called the afterbirth?
It’s named the afterbirth, because the placenta comes away after the baby is born. Without drugs, this can take 30 to 60 minutes. Doctors and midwives can give the mother an oxytocin injection in her thigh as soon as the head emerges. This helps to initiate the separation of the placenta and it comes away about 10 minutes after the birth.
Can the placenta harm my baby?
In the early weeks of pregnancy, symptoms of nausea, exhaustion and emotional meltdowns may be disconcerting, but the good news is that they’re proof that the placenta is functioning and the pregnancy is progressing. The placenta needs to be healthy to function at its best. It consumes two thirds of the oxygen and at least half of the sugar available to it before passing the balance on to the baby.
It can be put under pressure when there are existing medical problems or if the following occur during the pregnancy:
- Blood group incompatibility
- High blood pressure
- Prolonged pregnancy after 40 weeks.
What can you do to have a healthy placenta?
The best thing you can do for your body, baby and placenta is to adopt a healthy lifestyle. Eat a balanced diet of fresh fruit and vegetables, proteins and carbohydrates that are not fried or sugary.
Exercise is important. Walking for at least 20 minutes every day will do the trick.
Stay away from known placental toxins, such as alcohol and nicotine, and viruses like rubella and HIV. Nausea in early pregnancy is often triggered by smells – it’s nature’s way of protecting the developing baby from harmful environmental chemicals such as pesticides, car fumes and even air fresheners. It is advised to avoid crowded places where people are closely confined during your first trimester as this is where unseen harmful viruses can spread.
Other ways to stay healthy during your pregnancy include:
- Avoiding fish that’s high in mercury, such as tuna
- Preventing bacterial infections by staying away from raw fish, shellfish and undercooked meat, poultry and eggs
- Avoiding unpasteurised milk, yoghurt and cheese
- Minimising caffeine intake
- Always washing fruit and vegetables.
What will happen to the placenta if I fall?
Any trauma to the abdomen – for example, from a fall, being physically attacked or a car accident – however minor, should be checked at the emergency room. Although there may not be immediate evidence of imminent complications, these could develop over the next 24 hours and women are usually admitted to hospital for observation.
The biggest danger to both mother and baby is if the placenta separates from the womb, which will cause vaginal bleeding. If this happens and the mother is HIV positive, the baby could become infected with the virus.
My doctor told me that the placenta is low lying. what does this mean?
The inverted, pear-shaped womb is divided into the top and the bottom half with the cervix (mouth of the womb) dipping into the vagina. When the fertilised egg implants into the bottom half, this is called placenta previa (placenta before the baby).
This condition is divided into four categories:
- Low lying – this is usually self correcting. When the womb starts to grow, the placenta grows with it and moves away from the cervix
- Marginal – the edge of the placenta grows close to the cervix
- Partial – when some of the placenta covers the cervix
- Total – when the placenta completely covers the cervix.
Women with partial and total placenta previa will be carefully monitored in the last trimester and will be given a C-section. Any sign of vaginal bleeding warrants prompt admission to hospital.
How does the placenta come away?
Labour is divided into three stages. During the first stage, the womb contracts and the cervix opens. The second stage is the birth of the baby, and the third stage is when the placenta comes away.
The area of the womb covered by the placenta has many blood vessels that need to be ‘tied off’ to prevent haemorrhaging. The womb is made up of three layers of muscles, each one lying in a different direction. As the womb contracts, blood vessels feeding the placenta slowly become strangulated between these layers. Once the baby is born, the womb continues contracting, but the tissue of the placenta cannot change its size or shape so it no longer ‘fits’ and begins to separate.
What happens when there is more than one baby?
There are two types of multiple pregnancies – identical (or monozygotic) from a single fertilised egg and non-identical (fraternal twins) from separate fertilised eggs. Identical twins develop together in one sac and share the placenta while non-identical twins have separate sacs and placentas.
What happens to the placenta after the birth?
After a birth, the placenta is incinerated. In some cultures, the placenta is buried under a newly planted tree to celebrate the birth of the child.
More about the expert:
Sister Burgie Ireland is a qualified and registered nursing sister and midwife.
Read more about Sister Burgie here.
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