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The Placenta part I - A vital organ

Newsletter

Posted on 16/04/2021

The placenta is an incredible organ, which protects and houses the growing and developing foetus over the pregnancy term. The health and efficiency of this organ is vital to your baby’s wellbeing.

The word “placenta” originates from the Greek word ‘plakous’ meaning flat cake, which gives an idea of what a placenta looks like.

The placenta attaches to the lining of the uterine wall (the womb) in the early weeks of pregnancy from the very early trophoblastic layer and grows alongside the developing foetus. The placenta is fully formed and functioning from 10 weeks gestation. At this point and up to 20 weeks gestation the placenta weighs more than the growing fetus as it is supporting early life and growth.

Fully formed, the placenta is a round disc shape, about 20cm in diameter and 2.5 cm thick at the centre. It weighs approx. 700gms. The placenta has two sides, one which attaches to the mothers uterine wall. This side is dark red in colour and is made up of many lobes, called cotyledons. These lobes adhere to the uterus and connect with a mothers’ circulation. The other side of the placenta, the fetal side, is shiny in appearance and is where the baby is connected by the umbilical cord to the placenta, within the placental sac.

The Fetal Sac & Umbilical Cord

The fetal sac is made up of a sturdy double membrane which holds the baby and the amniotic fluid. The amniotic fluid maintains temperature, equalizes pressure and protects the fetus from injury.

The umbilical cord connects the fetus to the placenta. The cord is approximately 50 centimeters in length, and contains two arteries and one vein, which are protected and enclosed by Wharton’s Jelly. The jelly allows the cord to remain soft and flexible. The umbilical vein delivers oxygen and nutrient rich blood to the fetus while the artery returns blood back to the mothers’ blood stream. The umbilical cord plays a vital role in managing respiration, nutrition, storage, excretion and protection of the fetus whilst in utero. The placenta can also excrete hormones, one being Human Chorionic Gonadotrophin ( hCG ) which is found in large supply in early pregnancy and is often tested via a blood test or urine to confirm a pregnancy. This is also the hormone which gives us many of the early pregnancy symptoms.

To help the fetus develop and grow the placenta, with all of its parts, works hard to carry out functions that the fetus is unable to do for itself over the pregnancy period.

Pregnancy ultrasound examinations include checking the placenta for its efficiency and function, to make sure your baby is growing well. The location of the placenta within the uterus, is one purpose of the 18-20 week scan.

If you have any questions relating to this information, please don’t hesitate to contact us, or discuss it at your next appointment.

Next months newsletter will continue with the Placenta particularly focusing on the third stage of labour (which is the delivery of the placenta) delayed cord clamping, cord blood banking, taking your placenta home and placental encapsulation.

By Penny Stanbury
Midwife at Dr Morris | Sydney Mother & Baby

Categories: General Health, Pregnancy Tags: placenta

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What is the placenta

It connects two organisms - the mother and the fetus, providing it with the necessary nutrients.

Where is the placenta located and what does it look like?

In a normal pregnancy, the placenta is located in the body of the uterus along its posterior (more often) or anterior wall. It is fully formed by the 15-16th week of pregnancy, after the 20th week, active exchange begins through the placental vessels. From the 22nd to the 36th week of pregnancy, an increase in the mass of the placenta occurs, and by the 36th week it reaches full functional maturity.

In appearance, the placenta looks like a round flat disk. By the time of delivery, the weight of the placenta is 500-600 g, the diameter is 15-18 cm and the thickness is 2-3 cm.

Functions of the placenta

• First, gas exchange occurs through the placenta: oxygen penetrates from the mother's blood to the fetus, and carbon dioxide is transported in the opposite direction.
• Secondly, the fetus receives through the placenta the nutrients necessary for its growth and development. It must be remembered that many substances (alcohol, nicotine, drugs, many drugs, viruses) easily penetrate through it and can have a damaging effect on the fetus. In addition, with its help, the fetus gets rid of the products of its vital activity.
• Thirdly, the placenta provides immunological protection for the fetus, delaying the cells of the mother's immune system, which, having penetrated to the fetus and recognized a foreign object in it, could trigger its rejection reactions. At the same time, the placenta passes maternal antibodies that protect the fetus from infections.
• Fourthly, the placenta plays the role of an endocrine gland and synthesizes hormones (human chorionic gonadotropin (hCG), placental lactogen, prolactin, etc.) necessary to maintain pregnancy, growth and development of the fetus.

Normally, the placenta together with the membranes (afterbirth) is born 10-15 minutes after the birth of the fetus. She is carefully examined and sent for a morphological study. First, it is very important to make sure that the whole placenta was born (that is, there are no damages on its surface and there is no reason to believe that pieces of the placenta remained in the uterine cavity). Secondly, according to the state of the placenta, one can judge the course of pregnancy (whether there was an abruption, infectious processes, etc.).

What do doctors want to know about the placenta?

During pregnancy, it is important to look for signs of placental dysfunction - placental insufficiency. To do this, during an ultrasound study, the structure of the placenta, its location in the uterine cavity, thickness, and the correspondence of the size of the fetus to the gestational age are studied. In addition, the blood flow in the placental vessels is studied.

Degree of maturity

This parameter, as doctors say, is "ultrasonic", that is, it depends on the density of the structures of the placenta determined by ultrasound.

There are four degrees of placental maturity:

• Normally, zero degree of placental maturity should be determined before 30 weeks of pregnancy.
• The first degree is considered valid from 27 to 34 weeks.
• Second - from 34 to 39.
• Starting from 37 weeks, the third degree of placental maturity can be determined.

At the end of pregnancy, the so-called physiological aging of the placenta occurs, accompanied by a decrease in the area of ​​its exchange surface, the appearance of areas of salt deposition.

Place of attachment

Determined by ultrasound. As mentioned above, during a normal pregnancy, the placenta is located in the body of the uterus. Sometimes, during an ultrasound examination in the first half of pregnancy, it is found that the placenta is located in the lower parts of the uterus, reaching or even overlapping the area of ​​​​the internal os of the cervix. In the future, as pregnancy progresses, the placenta most often shifts from the lower sections of the uterus to the top. However, if after 32 weeks the placenta still overlaps the area of ​​the internal os, this condition is called *placenta previa**, which is a serious complication of pregnancy.

Placenta previa can lead to bleeding, which can occur during the second or third trimester of pregnancy or during childbirth.

Thickness

Also determined by ultrasound - placentometry: after establishing the site of attachment of the placenta, the area where it has the largest size is found, which is determined. The thickness of the placenta, as already mentioned, continuously increases until 36-37 weeks of pregnancy (by this time it ranges from 20 to 40 mm). Then its growth stops, and in the future the thickness of the placenta either decreases or remains at the same level.

Deviation from the norm of at least one of these indicators may indicate trouble during pregnancy.

References

• Tiwari D., Das CR., Sultana R., Kashyap N., Islam M., Bose PD., Saikia AK., Bose S. Increased homocysteine ​​mediated oxidative stress as key determinant of hepatitis E virus ( HEV) infected pregnancy complication and outcome: A study from Northeast India. // Infect Genet Evol - 2021 - Vol - NNULL - p.104882; PMID:33905889
• Salmanian B., Belfort M.A., Shamshirsaz A.A. The risk of placenta accreta spectrum in women with in vitro fertilization in different populations. // Am J Obstet Gynecol - 2021 - Vol - NNULL - p.; PMID:33905744
• Olmos-Ortiz A., Olivares-Huerta A., García-Quiroz J., Zariñán T., Chavira R., Zaga-Clavellina V., Avila E., Halhali A., Durand M., Larrea F., Díaz L. Placentas associated with female neonates from pregnancies complicated by urinary-tract infections have higher cAMP content and cytokines expression than males. // Am J Reprod Immunol - 2021 - Vol - NNULL - p.e13434; PMID:33905581
• Tandl V. , Hoch D., Bandres-Meriz J., Nikodijevic S., Desoye G., Majali-Martinez A. Different regulation of IRE1α and eIF2α pathways by oxygen and insulin in ACH-3P trophoblast model. // Reproduction - 2021 - Vol - NNULL - p.; PMID:33904834
• Ji S., Gumina D., McPeak K., Moldovan R., Post MD., Su EJ. Human placental villous stromal extracellular matrix regulates fetoplacental angiogenesis in severe fetal growth restriction. // Clin Sci (Lond) - 2021 - Vol - NNULL - p.; PMID:33904582
• Shmeleva EV., Colucci F. Maternal natural killer cells at the intersection between reproduction and mucosal immunity. // Mucosal Immunol - 2021 - Vol - NNULL - p.; PMID:33903735
• Moreno-Sepulveda J., Espinós JJ., Checa MA. Lower risk of adverse perinatal outcomes in natural versus artificial frozen-thawed embryo transfer cycles: a systematic review and meta-analysis. // Reprod Biomed Online - 2021 - Vol - NNULL - p.; PMID:33903031
• Owen M.D., Cassidy A.L., Weeks AD. Why are women still dying from obstetric hemorrhage? A narrative review of perspectives from high and low resource settings. // Int J Obstet Anesth - 2021 - Vol - NNULL - p.102982; PMID:33903002
• Liu CN., Yu FB., Xu YZ., Li JS., Guan ZH., Sun MN., Liu CA., He F., Chen DJ. Prevalence and risk factors of severe postpartum hemorrhage: a retrospective cohort study. // BMC Pregnancy Childbirth - 2021 - Vol21 - N1 - p.332; PMID:33902475
• Munoz JL., Kimura AM., Xenakis E., Jenkins DH., Braverman MA., Ramsey PS., Ireland KE. Whole blood transfusion reduces overall component transfusion in cases of placenta accreta spectrum: a pilot program. // J Matern Fetal Neonatal Med - 2021 - Vol - NNULL - p.1-6; PMID:33902384

10 amazing facts about the placenta

Home "News" 10 amazing facts about the placenta

10.10.2020

Liat Ben -Senior, MBA MSC

of the placenta - this is a rescue circle between mother and her child , the organ in which the connection between them is first established. Scientists consider the placenta the least studied human organ, but one of the most important organs of the body. It affects the health of a woman and her baby during and even after pregnancy. In honor of the incredible properties of the placenta, we list 10 amazing facts about it.

Emma Jean Photography

1. Small but powerful - the parachute-shaped placenta is a highly specialized organ that helps support your baby's development. The middle placenta is 23 cm across, about 3 cm thick and usually weighs 500-600 grams. The blood of mother and baby passes through the placenta but never mixes. At term, about 500 ml of mother's blood passes through the placenta every minute. This alone is amazing (and also explains why pregnancy is so exhausting).


2. One organ, many functions - Your developing baby doesn't eat or breathe and relies solely on its mother for nutrients and oxygen. The placenta acts like a baby's lungs, supplying oxygen and removing carbon dioxide. It also acts like a baby's kidneys, filtering waste products from the bloodstream.


3. The placenta is not a maternal organ - In fact, the placenta develops from a fertilized egg, which means that, like a child, it is genetically half from mom and half from dad. The placenta begins to form as soon as a fertilized egg implants in the uterine wall, about 6-7 days after conception, and continues to grow with your baby to meet her growing needs.


4. The placenta is also a gland - The placenta acts like a gland, releasing hormones during pregnancy that are important in supporting your growing baby and preparing your body for motherhood.


5. The placenta is an immune mediator - The placenta helps the immune systems of mother and child to talk to each other without quarreling. During pregnancy, the placenta prevents the mother's body from perceiving the child as foreign and from attacking it. During the 3rd trimester, the placenta allows mom's antibodies to pass to the baby, giving your baby a booster immune system, and this protection lasts up to 6 months after birth.


6. Identical twins can share a placenta - Fraternal twins develop from two separate fertilized eggs and will always have two placentas. But the number of placentas in identical twins is determined by whether the fertilized egg splits before or after the formation of the placenta.


7. Your baby's stem cells are coming to you - baby's stem cells can pass through the placenta and seem to target areas where the mother has been damaged. Even years later, small amounts of cells from previous pregnancies can be found in the mother's skin, organs, and bone marrow. This phenomenon is called "microchimerism of the fetus and mother."


8. The only disposable organ - the placenta will re-develop with each pregnancy to support your baby's growth. After completing its mission, the placenta comes out after the baby is born, which is why it is called the "afterbirth".


9. The placenta prepares your body for breastfeeding - The placenta produces a hormone that inhibits the production of breast milk. After the placenta is delivered, the mother's body receives a signal that it is time to produce milk.


10. The placenta can help us fight cancer - The placenta has the unique ability to grow and enter the mother's body without being attacked by the immune system. This ability to evade the immune system is highly regulated, and the placenta knows how to stop intrusion before harming the mother. The researchers hope that a better understanding of how the placenta works will help us fight cancers that elude the immune system.

The placenta is not only a wonderful organ during pregnancy, but for life. If you choose to donate or save placental stem cells, they will not be disposed of as biological waste.

Liat Ben-Senior holds an MBA and MSc in Human Genetics from the Sackler School of Medicine of Tel-Aviv University, Israel. She has over 15 years of experience in Marketing and Digital Marketing in the field of Biotech and Life Sciences.

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