How does placenta work

Spiral arteries in the uterine wall are remodeled to supply blood to the fetus during pregnancy. When there is no pregnancy, the spiral artery spans the tissue of the uterine wall, supplying blood to the lining.

In a normal pregnancy, cytotrophoblast cells from placental villi invade the space around the spiral artery, replacing cells which normally line the vessel. This remodeling makes the vessel larger and optimizes the blood flow to the placenta to support its function. In an abnormal pregnancy, cytotrophoblasts invade the space in and around the spiral artery, but the artery is not completely remodeled and blood flow from the mother to the placenta is not optimized to support proper placental function.

Placental Development: Fertilization to Full Term This timeline compares development of the fetus and the placenta across 40 weeks of pregnancy. To support this process, you need a lifeline to help your baby eat and breathe. The placenta, an organ that develops inside your uterus, provides a connection between you and your baby. This connection via the umbilical cord is what helps to sustain your developing baby throughout pregnancy.

Necessary nutrients, oxygen, and antibodies pass from the placenta through the umbilical cord and to your baby. In addition to being a lifeline to your baby, the placenta also produces and secretes hormones directly into the bloodstream to help support pregnancy and fetal growth. These hormones include:. Pregnancy involves a complex series of events, one of which is the formation of the placenta. In general, once the fertilized egg implants in the uterine wall, the placenta begins forming.

But the ball starts rolling several days before implantation. When you ovulate, an egg leaves the ovary to travel through the fallopian tube in hopes of being fertilized. If successful, the ovulated egg meets up with a spermatozoid to begin formation of the fetus. This ovulated egg is called a zygote. Over the course of a few days, the zygote will complete many cell divisions in the fallopian tube.

When the zygote reaches the uterus, these cell divisions continue, and then the zygote becomes a blastocyst. At this stage, some cells begin to form into the placenta and others begin to form the fetus. The blastocyst embeds in the endometrium aka implantation.

To help support pregnancy, the placenta produces a hormone called human chorionic gonadotropin hCG. Over the course of your pregnancy, the placenta grows from a few cells into an organ that will eventually weigh about 1 pound. By week 12, the placenta is formed and ready to take over nourishment for the baby. However, it continues to grow throughout your pregnancy.

Under normal conditions, the placenta will attach to the wall of your uterus. As pregnancy progresses, it will move with your growing uterus. Although each pregnancy is different, you can expect the placenta to take over around weeks 8 to 12 of pregnancy, with 10 weeks being the average time for most women.

Those who get pregnant via in vitro fertilization or have hormone deficiencies may need progesterone supplementation in the first trimester. These individuals are often able to stop taking this hormone once the placenta begins its own production. Many women look forward to the second trimester — energy levels rise, hormone levels begin to balance out, and morning sickness subsides.

But why does everything seem to get better? As already mentioned, towards the end of the first trimester around week 10 , the placenta takes over the production of progesterone. This helps reduce nausea and vomiting. For many mamas, this means an end to morning sickness. The placenta may play a role in that case, too.

After the baby is born you will continue to have mild contractions. You will have to give one more push to deliver the placenta. Sometimes your abdomen will be massaged or you will be given an injection of oxytocin and the umbilical cord will be gently pulled to help deliver the placenta.

If you have a caesarean section , the doctor will remove the placenta at the same time. It is important that the whole placenta comes out after pregnancy. If any fragments of the placenta stay inside, they will have to be surgically removed to prevent bleeding and infection. It is important to visit your healthcare provider regularly during pregnancy to check for any problems with your placenta. Tell your doctor if you have had problems with the placenta in a previous pregnancy, or if you have had any surgery to your womb.

Always consult your doctor before you take any medicines, including over-the-counter medicines , natural therapies and supplements , while you are pregnant. There is also a rare practice, known as placentophagy, in which women cook and eat the placenta. Some commercial service providers will offer to turn your placenta into capsules for you to swallow. However, these practices should be treated with caution since there is no regulation in Australia either of these products or the providers of placenta pills.

Recent research shows there are no known health benefits from eating the placenta, but there may be a risk of infection from poor production standards. Learn more here about the development and quality assurance of healthdirect content. A retained placenta is when part or all of the placenta is not delivered after the baby is born. It can lead to serious infection or blood loss. Read more on Better Health Channel website. Placenta praevia is a condition where the placenta lies low and may cover the cervix, blocking the baby's exit during birth.

Placenta accreta is a serious but rare pregnancy complication that causes heavy bleeding. If you have it, you will need special care at the birth. The placenta develops inside the uterus during pregnancy and provides your baby with nutrients and oxygen.

If something goes wrong, it can be serious. Placental insufficiency occurs when the placenta does not work properly and your baby doesn't get the oxygen and nutrients they need.

If a woman drinks during pregnancy the alcohol crosses the placenta to the baby. But what about the effect of alcohol on men? Read more on Alcohol and Drug Foundation website. Placental abruption is when some or all of the placenta peels away from the uterus wall before birth.

It can deprive the baby of oxygen and nutrients. Starting approximately two weeks after conception, a hormone called human chorionic gonadatropin hCG hormone is produced by the developing placenta and can be detected in urine and in blood.