A baby in the womb goes through several developmental stages. It all begins with a fertilized egg that develops into an embryo and then turns into a fetus with placenta. Every mother wants her baby to grow well in her body, and wants to know what happens during different developmental stages, during the first week, the second week, the 8th and then 36th week. Among these processes, one question that every pregnant woman wants to know is, "When does the placenta form?"
When Does the Placenta Form?
The follicle in the ovary collapses around week 3 of pregnancy and produces the hormone progesterone. It also provides the embryo with the nourishment it needs during the first trimester of pregnancy. The earliest form of an embryo develops and implants itself into the wall of the womb in week 4 of pregnancy. The embryo here is in the form of a mass of cells, out of which some cells split away and go deep into the uterine wall. These cells don't form toes, fingers or other body parts, but they turn into a disc-shaped organ called the placenta during the second trimester – the placenta is chock-full of blood vessels.
In case you have fraternal twins, each baby in your womb will have its own placenta. In case of identical twins, you may have one or two placentas depending on when the egg splits after fertilization. If there's only one placenta, the twins will have separate umbilical cords connecting the babies to the shared placenta.
The placenta, which begins to form in week 4 of pregnancy, will continue to develop over the next couple of months, with smaller capillaries turning into blood vessels and delivering nutrients and oxygen to your growing baby. Your placenta will develop enough by week 12 of pregnancy to work in place of the corpus luteum through the rest of your pregnancy. It will grow as your baby grows. Your placenta will weigh about a pound by the time you are 40 weeks pregnant.
You can also watch the video below to know more about the placenta.
Why Is the Placenta So Important?
Now that you have already known the answer to your question, "When does the placenta form?” You may wonder what makes the placenta so important. It's mainly due to the following reasons.
1. Exchange the Gas
The fetal lungs supplies oxygen and remove carbon dioxide after birth, but the placenta carries out this task while the baby is still in the womb. The process involves microscopic structures called villi that has numerous fetal blood vessels and is always in touch with the mother's blood. The tissue separating maternal blood and fetus becomes thin as the baby grows, and the placenta helps oxygen in the blood of the mother to move into the fetal vessels and then diffuses carbon dioxide from the fetal blood into the mother's blood system. Without the placenta, the exchange of gasses isn't possible.
2. Provide Nutrition
The placenta supplies the fetus with nutrients it needs to grow before birth. The placenta itself makes some nutrients during the early stages of pregnancy – this includes fats and carbohydrates. When the fetus starts growing, the placenta takes the nutrients from the mother's blood that passes through it. It absorbs water, blood sugar, and protein from the mother's blood and transfers it to the fetal blood.
3. Produce Important Hormones
The placenta produces a number of important hormones, including progesterone, estrogen, placenta lactogen, and placental growth hormone. Most of these hormones regulate the mother's response to pregnancy. For instance, it produces a hormoneto help the uterine lining to become thick for holding the embryo.
4. Protect from Infections
Along with providing the fetus with nutrients and sufficient oxygen, the placenta also builds a defense system to protect the fetus from different types of infections. The process involves transferring antibodies from maternal blood to the fetal circulation. Some antibodies like gamma globulins quickly move into the fetal blood, while others take time to transfer completely from the mother's blood into the fetal blood. The process gives the fetus passive immunity that provides effective protection from specific infections.
Will There Be Some Problems with the Placenta During Pregnancy?
After knowing, "When does the placenta form?" and "What role does it play during pregnancy?" it is important to know more about certain complications that may arise to the placenta during pregnancy. Here are some of the most common problems that you may encounter.
- Placental abruption: In this condition, the placenta peels away from the inner wall of the womb before delivery. It may lead to pain, cramping, and excessive vaginal bleeding.
- Placenta previa: Sometimes, the placenta partially or completely covers the cervix. The condition is called placenta Previa, which usually affects women early in pregnancy. The issue may resolve on its own as the uterus grows, but it may cause severe vaginal bleed during delivery.
- Placenta accreta: In this condition, the blood vessels of the placenta grow deeply into the uterine wall, which in turn causes bleeding and results in blood loss after delivery. A C-section delivery is usually required in this case followed by a hysterectomy.
- Retained placenta: In this condition, the placenta isn't delivered within half an hour to an hour after childbirth. This usually happens when the placenta gets trapped behind the cervix, and sometimes it remains attached to the uterine wall. A retained placenta may result in infection or life-threatening blood loss.
As you have known, the placenta is very important to the fetus, it is highly recommended to visit your healthcare provider regularly to avoid facing serious problems during pregnancy and on delivery.
What Happens to the Placenta After the Birth of Baby?
After the baby is born and your midwife cuts the umbilical cord, it is important that you deliver the placenta as well because you no longer need it in your body. A new placenta will develop with a new pregnancy.