The placenta is an organ that develops in the mother’s womb during pregnancy and performs a number of important functions related to nutrition and maintaining the development of the fetus. The placenta is a disc-shaped organ attached to the inner wall of the uterus and connected to the fetus through the umbilical cord.
What are the functions of the placenta?
The placenta is the main organ that provides the fetus with nutrients and oxygen. It filters the mother’s blood and extracts nutrients from it, which are passed on to the fetus through the umbilical cord. This includes glucose (the main source of energy), amino acids, vitamins and minerals. Other functions of the placenta:
- removal of waste and carbon dioxide. During the metabolic process, the fetus produces waste and carbon dioxide. The placenta has the function of removing these wastes from the fetal blood and transporting them into the mother’s blood so that they can be eliminated from the mother’s body through her kidneys and lungs;
- fetal protection. The placenta serves as a barrier that protects the fetus from many infections and toxins. It filters the mother’s blood to prevent harmful substances from entering the fetus’ blood. However, not all infections and toxins are blocked, and some may sneak in;
- hormonal function. The placenta produces various hormones that regulate and support pregnancy. These hormones include estrogens, progesterone, gonadotropin and others. They play a key role in maintaining pregnancy, uterine growth, breast development, preparation for breastfeeding and other aspects;
- support of the fetal immune system. The placenta helps support the fetus’ immune system by providing it with antibodies from the mother. This helps protect the fetus from certain infections during pregnancy and the first months of life after birth.
The placenta provides the fetus not only with nutrients, but also with growth factors necessary for its normal development. It regulates cell growth and differentiation, as well as the functioning of organs and systems. The placenta plays an important role in maintaining pregnancy and ensuring the health of the fetus. Its functions include not only nutrition and protection, but also the regulation of biological processes that are necessary for the normal development of the unborn child.
How is the placenta formed?
The placenta is a vital organ that develops during pregnancy to provide oxygen and nutrients to the growing fetus and remove waste products. It forms through a complex process known as placentation. Here’s a brief overview of how the placenta is formed:
- Implantation. After fertilization, the fertilized egg, or zygote, undergoes several cell divisions as it travels down the fallopian tube towards the uterus. By the time it reaches the uterus, it has developed into a hollow ball of cells called a blastocyst. The blastocyst then implants itself into the lining of the uterus, a process known as implantation.
- Formation of the chorionic villi. After implantation, the outer layer of cells of the blastocyst forms finger-like projections called chorionic villi. These chorionic villi extend into the lining of the uterus and play a crucial role in the exchange of nutrients, oxygen, and waste products between the maternal and fetal circulatory systems.
- Development of the placenta. As the chorionic villi burrow deeper into the uterine lining, they come into close contact with maternal blood vessels. Over time, these villi develop into the placenta, while the maternal blood spaces around them become interconnected to form the maternal side of the placenta.
- Maternal-fetal circulation/ Blood vessels from the embryo/fetus develop within the chorionic villi. These blood vessels carry fetal blood and come into close proximity to maternal blood vessels within the placenta. This arrangement allows for the exchange of gases (oxygen and carbon dioxide), nutrients, and waste products between the maternal and fetal circulatory systems without direct mixing of blood.
- Placental function. Once fully formed, the placenta acts as a barrier between the maternal and fetal circulatory systems while facilitating the exchange of substances necessary for fetal growth and development. It also produces hormones, such as human chorionic gonadotropin (hCG), progesterone, and estrogen, which are essential for maintaining pregnancy.
Overall, the formation of the placenta is a dynamic process that involves intricate interactions between maternal and fetal tissues, ensuring the proper growth and development of the fetus throughout pregnancy.
What pathologies of the placenta can develop?
There are several placenta-related conditions and complications that can develop during pregnancy. These pathologies can have serious consequences for pregnancy and the health of both mother and fetus. The most common pathologies of the placenta:
- placental insufficiency. This is a condition in which the placenta does not perform its functions effectively, resulting in insufficient oxygen and nutrients to the fetus. This may cause fetal growth restriction and other complications;
- placental ablation. This is the separation of the placenta from the wall of the uterus before the baby is born. The complication can lead to bleeding, which is extremely dangerous for the mother and fetus;
- placental dysfunction. The pathology is associated with disruption of the normal functioning of the placenta, which can lead to changes in the blood circulation and nutrition of the fetus;
- placental infection. Infections can affect the placenta and cause inflammation. This can affect the functionality of the placenta and lead to complications;
- inserted placenta (rectangular placenta). The placenta is closer to the cervix, which can lead to bleeding during labor or complicate the birth process.
Polyhydramnios may be associated with pathology of the placenta. In this case, the placenta may not effectively control the amount of fluid surrounding the fetus.
What happens to the placenta during childbirth?
During labor, the placenta goes through a series of changes and events to ensure the safe completion of the pregnancy and the birth of the fetus. Here’s what happens to the placenta during birth:
- Separation of the placenta. After the baby is born, the uterus begins to contract to separate the placenta from the uterine wall. Contractions of the uterus lead to compression of the blood vessels in the placenta and stop the flow of blood to it.
- Release of the placenta. When the placenta is completely separated from the uterus, it becomes free in the uterine cavity. It then begins to be released through the cervix and vagina.
- Study and evaluation of the placenta. The doctor or midwife will usually carefully examine the released placenta to ensure that it is intact and does not contain additional lobes (this is important to rule out placental pathologies).
- Final removal. In some cases, slight force may be required to permanently remove the placenta. The doctor or midwife may apply gentle pressure to the mother’s abdomen or perform a gentle manual procedure to remove any remaining placenta.
- Counting the parts of the placenta. The placenta usually consists of several lobes. It is important to ensure that all parts are successfully removed to prevent complications.
- Study of the placenta. In some cases, the placenta is examined to identify pathologies or abnormalities that might be important to the health of the mother or fetus.
After the placenta is delivered, the uterus continues to contract to stop bleeding and return to its normal size. The timing of their removal may vary depending on individual circumstances and clinical practice. The main goal is to ensure the safety and health of both mother and newborn.