Placenta: functions, development and possible complications

The placenta is a vital organ for the life of the fetus. It is attached to the lining of the uterus and supplies it with the oxygen and nutrients it needs.

The placenta and its functions

The placenta is an organ that develops during pregnancy, responsible for regulating all the processes that give rise to the exchange of energy and nutrients between the maternal organism and the fetus.

It is attached to the wall of the uterus, usually on the top or side, and is connected to the fetus by the umbilical cord. Through this cord, maternal blood passes from the mother to the placenta which filters the oxygen, glucose, and other nutrients necessary for the life of the fetus that are present there.

During pregnancy, the placenta serves in particular,

  • to let the baby breathe: he is supplied with oxygen from the maternal blood to which he then transfers carbon dioxide,
  • to filter out those substances that could be harmful to the fetus;
  • to remove all waste substances from the blood of the fetus;
  • the production of numerous hormones – including prolactin , estriol and  progesterone – which are necessary for the good course of pregnancy and for preparation for childbirth;
  • to keep the mother’s blood separate from that of the fetus in order to protect the baby from infection;
  • to provide the fetus with all the nutrients (vitamins, proteins, sugars, etc.) it needs to grow;
  • to transmit – towards the end of pregnancy – to the future child the antibodies which will then protect him after birth.

Warning : alcohol, nicotine and some medicines can cross the placenta and therefore harm the baby.

Development and positions of the placenta during a pregnancy

In the stage of its development. The placenta develops in the lower uterus: it derives from the attachment of the basal decidua (growth and proliferation of
cells) and the leafy chorion (the outermost membrane of the fertilized egg).

During pregnancy. Then, during pregnancy as the uterus lengthens it moves sideways or upwards. The exact location of the placenta is usually established with an ultrasound .

On the occasion of childbirth.  About 15 minutes after delivery, the placenta emerges from the uterus and vagina.

  • In the case of a natural birth, the umbilical cord is gently pulled to facilitate delivery of the placenta.
  • In the case of a  cesarean delivery,  however, it is the doctor who removes it.
  • It is important that after delivery, the entire placenta comes out.

After childbirth.  If fragments of the placenta remain within the placenta after delivery, they will need to be surgically removed to prevent bleeding and infection.

Possible complications related to the placenta

Some problems with the placenta can be potentially dangerous for both mother and baby. There are three main complications concerning the placenta:

1. to placenta accreta

We speak of placenta accreta when it does not remain properly attached to the uterus. This can lead to massive blood loss during or after delivery, and can be fatal.

2. placental abruption

This is a condition where the placenta begins to detach from the uterus before delivery. It can come off a little or a lot. The more marked her detachment, the more dangerous this condition is for mother and child.

3. placenta previa

Placenta previa occurs   when it attaches too low in the uterus, on or next to the cervix. This condition is most common in early pregnancy, and often resolves with its natural movement. A caesarean section will be necessary if the placenta still covers the cervix near the birth.

When to contact your doctor

During pregnancy it is important that the woman visits regularly to check – also – if there are any problems with the placenta. In any case, you should inform your doctor or midwife if you have any questions, or if you:

  • have severe abdominal or back pain;
  • have vaginal bleeding;
  • have contractions.

It is also advisable that you inform your doctor in the event of any trauma to the abdomen due to a fall or a car accident (for example).

Katherine Johnson, M.D., is a board-certified obstetrician-gynecologist with clinical expertise in general obstetrics and gynecology, family planning, women’s health, and gynecology.

She is affiliated with the Obstetrics and Gynecology division at an undisclosed healthcare institution and the online platform,

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