What Does the Placenta Do?
The placenta channels oxygen and nutrients from the mother’s bloodstream and delivers them to the baby through the umbilical cord. It also receives the baby’s waste products and de-oxygenated blood and sends them out into the mother’s bloodstream for processing.
The placenta is an organ that forms only during pregnancy. It is made up of tissue from both the mother and the baby. Placentas are disc-shaped, about eight inches in diameter, and almost one inch thick. They attach to the uterus wall and the umbilical cord attaches to them.
Where the Placenta Attaches
When the mass of cells that’s becoming a baby implants in the uterine wall around week 4, some of these cells split away and begin forming the placenta. By week 12, the placenta takes over all baby-nurturing functions.
When a placenta attaches to the back (towards the mother’s spine), it’s called a fundal or posterior placenta; to the front (toward the mother’s belly) is an anterior placenta. There are lateral, or side-attached, placentas as well. Posterior placentas are most common and considered “least likely to cause complications,” but they are associated with premature labor.
Since the placenta can move or grow outward during pregnancy, anterior placentas are at more risk for placenta previa as well as high blood pressure, gestational diabetes, placental abruption, and fetal growth problems.
But anterior placenta pregnancies are often successful, though sometimes the ultrasound can’t read through the placenta and the doctors mistakenly think the baby is in danger! Variations in the location of the placenta are natural, and it is able to do its job…most of the time. Doctors cannot change the location of a placenta or treat it, so placenta risks cannot be fixed, only monitored.
What Increases the Odds of Placental Complications?
These factors can increase the risk of placental complications:
- Twins or multiple births
- Smoking cigarettes or using drugs
- Injury to abdomen
- High blood pressure
- Over 35
- Not the first pregnancy
- Having had a previous Cesarean section or any scars in the uterus
Common Placenta Complications
To be clear, placental complications are not common. Placenta previa, for example, occurs in 1% of pregnancies, and most can be monitored for a happy outcome. However, doctors and medical providers need to be vigilant in checking the baby’s health throughout pregnancy, and be ready to act if the baby is in distress (not getting enough oxygen or nutrients). Here are possible placenta complications:
- Placenta previa: When the placenta partially or completely blocks the entrance to the birth canal (cervix opening), that’s placenta previa. Also known as a “low-lying placenta.” Affects only 1 in 200 births. During labor, the cervix dilates, and blood vessels in a placenta previa can tear and bleed heavily. Also, if the placenta is completely blocking the baby’s way out, he or she cannot be delivered vaginally. C-sections are recommended for all cases of placenta previa to prevent fetal distress and maternal bleeding.
- Placental abruption: When the placenta detaches partially or completely from the uterus wall before the birthing process. Placentas normally detach in the last stage of labor and are delivered as afterbirth. Mild abruption, if properly monitored, may not affect your baby, but complete abruption can cause serious bleeding in the uterus, and it also severs the baby’s supply of oxygen and nutrients. This can cause growth problems, premature birth, severe birth injury, or death. Severe placental abruption is considered an emergency and the baby must be delivered right away.
- Placenta accreta: When part or the entire placenta is too deeply implanted in the uterus wall and cannot be removed. It is a potentially life-threatening condition that causes uncontrollable bleeding after birth. Placenta accreta often forms over uterine scars, and it is on the rise in the United States (1 in 533 pregnancies) because more women are having C-sections—and multiple C-sections greatly increase the risk. It can be diagnosed by ultrasound and MRI. A whole medical team is necessary to successfully deliver the baby via planned C-section and keep the mother from losing too much blood. Risks for a mother with placenta accreta include massive blood loss, hysterectomy, and death.
- Retained placenta: When some of the placental tissue is left inside the mother’s uterus for more than 30 minutes after birth. This can happen after a case of placenta accreta or in a normal birth if the uterus doesn’t contract enough. This tissue can cause extreme bleeding or infection. If it doesn’t come out soon, the mother’s life is in danger. Manual removal, medications, or surgery may be used.
- Malformation of the placenta: When the placenta may not have developed correctly. It can be too thin, too thick, have an extra lobe, or have extra membranes. Usually, a malformed placenta is associated with decreased blood flow to the baby, and greater chances of the mother bleeding out or being infected during childbirth. Medical providers need to carefully screen for any placental problems during pregnancy and treat any symptoms to keep the mother and baby healthy.
Protecting Mothers and Babies
Some dangers cannot be prevented. Others can.
Ultrasound can pick up most placenta problems. As early as 8 weeks, the placenta can be seen on abdominal scans. Most placental problems develop in the third trimester, so the good news is there’s usually plenty of time to keep you and your baby safe. Proper medical monitoring can save lives—but negligent monitoring or treatment can turn a placental problem into birth injury or death.
If your baby suffered injury or trauma and you suspect that better medical attention could have prevented it, call Birth Injury Safety. Attorney Laura Brown dedicates her time and passion to fighting against preventable birthing mistakes, and she can sit down with you and review your child’s case.
- National Institutes of Health: Placenta Location and Pregnancy Outcomes
- Patient Info: Placenta and Placental Problems
- March of Dimes: Placental Abruption
- March of Dimes: Placenta Previa
- American Congress of Obstetricians and Gynecologists: Placenta Accreta
- Healthline: Retained Placenta