Types of placenta previa
Medically Reviewed by Dr Sravya, MBBS, MS
Introduction
Pregnancy is a remarkable journey, filled with numerous developments and changes within the mothers body to support the growth of the baby. One critical aspect of pregnancy is the placenta; It supplies vital nutrients and oxygen to the developing fetus.
Typically, the placenta attaches to the upper or side wall of the uterus, away from the cervix. However, there are cases when the placentas
placement is abnormal, leading to a condition known as placenta previa. Placenta previa is a classification-based condition, with different types determined by the proximity of the placenta to the cervix and its potential implications for both pregnancy and childbirth. In this article, we will explore the various types of placenta previa, their causes, associated risks, and the strategies employed for their management.
What is Placenta Previa?
A pregnancy issue known as placenta previa occurs when the placenta totally or partially blocks the opening of the uterus (cervix). An organ that grows in the uterus during pregnancy is the placenta. The placenta often connects at the top or side of the uterus during pregnancy. The placenta attaches low in the uterus in placenta previa. The cervix, or opening to the uterus, may be entirely or partially covered by the placenta. The woman may experience heavy bleeding due to placenta previa prior to, during, or after delivery.
There are 4 types of Placenta Previa: Complete Placenta Previa, Partial Placenta Previa, Marginal Placenta Previa, and Low-Lying Placenta. During pregnancy, an organ called the placenta grows inside the uterus. It functions of give the newborn nutrition and oxygen as well as to remove waste. Your baby and the placenta are linked by the umbilical cord. The placenta is often fastened to the top or side of the uterus inner wall.
The placenta attaches lower in the uterus in cases of placenta previa. As a result, the cervix is partially covered by placental tissue. It may lead to bleeding during labor, during pregnancy, or after delivery.
Pregnancy-related alterations to the uterus and placenta may cause the issue to resolve itself. If it doesnt, a cesarean section (C-section) is used to deliver the child.
Symptoms of Placenta Previa:
After 20 weeks of pregnancy, bright crimson vaginal bleeding that usually causes little pain is the primary symptom of placenta previa. Spotting can occasionally occur before a situation involving significant blood loss. The painful uterine contractions that precede labor may also cause bleeding. Other factors that can cause bleeding include intercourse and being examined by a doctor. Bleeding may not start until labor for some women. There is frequently no obvious trigger for bleeding.
Different types of Placenta Previa:
There are 4 types of Placenta Previa, There are:
1.Complete Placenta Previa:
Complete placenta previa is the most critical form of the condition. In this case, the placenta entirely covers the cervix, obstructing the babys path through the birth canal. This situation is considered high-risk and typically necessitates a planned C- section for delivery. Attempting a vaginal birth with complete placenta previa can result in severe bleeding, posing a serious risk to both peoples health and safety, the mother and the baby. Consequently, a C-section is the safest and most common approach for these cases. In this type of placenta previa, the placenta entirely covers the cervical opening. It poses the highest risk for complications.
- Causes: The exact cause is often unclear, but it may be associated with previous uterine surgeries, multiple pregnancies, or abnormalities in the uterine shape.
- Risks: Vaginal bleeding is more likely and can be severe, leading to life-threatening situations for both mother and baby.
- Management: A planned caesarean section is almost always recommended to avoid the risk of heavy bleeding during vaginal delivery.
2.Partial Placenta Previa
Partial placenta previa represents the next level of severity. Here, a portion of the placenta covers the cervix, while another part remains attached to the uterine wall. This partial coverage can result in complications, including vaginal bleeding. Healthcare providers closely monitor individuals with partial placenta previa throughout their pregnancies. The need for a caesarean section (C-section) is often determined based on the placentas position as the pregnancy progresses. This careful management ensures a safe delivery for both the mother and the baby. In this type of placenta previa, the placenta partially covers the cervix, leaving a portion of the cervical opening uncovered.
- Causes: Similar to complete previa, it can be linked to uterine surgeries, scarring, or other uterine abnormalities.
- Risks: While the risk of bleeding is lower compared to complete previa, its still present and can be significant.
- Management: Management depends on factors like the degree of coverage and the mothers health. A caesarean section is often considered, but in some cases, vaginal delivery might be an option if the placenta is not too close to the cervix.
3.Marginal Placenta Previa
Marginal placenta previa is a term used when the placentas edge abuts or is right at the margin of the cervix but does not completely cover it. While this condition can cause some bleeding, it is generally considered a variation of the low-lying placenta. Marginal placenta previa, like its milder counterpart, is closely monitored throughout pregnancy. The management plan may depend on how close the placenta is to the cervix and whether it resolves or persists as the pregnancy progresses. In this type of placenta previa, the placenta nearly reaches the cervical edge but does’nt cover it.
- Causes: It can also be linked to scarring, surgeries, or uterine abnormalities.
- Risks: The risk of bleeding is relatively low but still exists, especially as the pregnancy progresses.
- Management: Close monitoring is crucial, and a vaginal delivery may be possible if as the uterus grows, the placenta travels further from the cervix. However, many cases still require a caesarean section.
4.Low-Lying Placenta:
Low-lying placenta is the most common and mildest form of placenta previa. In this scenario, the placenta is situated close to the cervix, but it does not fully cover it. Typically detected during a routine prenatal ultrasound, usually in the second trimester, a low-lying placenta can often resolve itself as the uterus expands throughout pregnancy. As the organ grows, the placenta tends to migrate upward, away from the cervix. This natural movement often alleviates the issue, and by the time of delivery, the condition may no longer be present. In this type, the placenta is located near the lower part of the uterus but does’nt necessarily touch or cover the cervix.
- Causes: Low-lying placenta can be due to several factors, including uterine scarring or multiple pregnancies.
- Risks: The risk of bleeding is lower compared to other types of placenta previa, but can still occur.
- Management: Monitoring throughout pregnancy is essential. Most women with a low-lying placenta at term will require a caesarean section.
Conclusion
Understanding the different types of placenta previa is essential for expectant mothers and healthcare providers. It enables them to tailor their approach to managing the condition based on its specific characteristics and the individual needs of the mother and baby. While placenta previa can introduce uncertainty and concerns during pregnancy, timely diagnosis, careful monitoring, and informed decision-making can help ensure a safe and healthy outcome for both mother and child. Expectant mothers are encouraged to maintain open communication with their healthcare providers to address any questions or concerns regarding their pregnancy and the management of placenta previa.