An ultrasound may show placental lakes in pregnancy; these are enlarged blood-filled spaces in the placenta. Placental lakes can be visible on the ultrasound image as one or several black areas. The placenta nourishes the unborn baby, and it is essential to have a healthy placenta for optimal growth and development. Having one or two smaller placental lakes is not a cause of concern. However, many women may have them in the third trimester. The OBG/GYN recommends the following step based on your gestational age, fetus size, and the size of the placental lakes present. Read on to know more about placental lakes in pregnancy, when it is a concern and how it affects the pregnancy.
What Are Placental Lakes?
Placental lakes or placental venous lakes are spaces within the placenta filled with maternal blood. A placental lake could contain small dilated veins with maternal blood flowing through them (1) (2).
How Common Are Placental Lakes?
Placental lakes are less common. A few studies indicate that placental lakes can have an occurrence rate of 2.2% to 17.8% (3).
What Causes Placental Lakes?
The causes of placental lakes are not entirely known. It is usually believed that they are avillous vascular spaces, that is, spaces within the placenta with no placental tissue but only blood vessels flowing through (3). Placental lakes may occur when the placenta is a bit thicker than usual (4). Dr. Michael Green, MD, the site director for OBHG at Northridge Medical Center in Northridge, CA, informs, “According to a 2012 medical study, larger placental lakes were linked to small-for-gestational-age status.”
Are Placental Lakes Harmful During Pregnancy?
The occurrence of a placental lake is a normal feature, and seldom a point of concern. Experts state that placental lakes have little to no clinical significance (5). Dr. Green confirms, “Placental lakes are usually not a cause for concern during pregnancy. In fact, some of them reduce in size before ultimately disappearing altogether.” Research has found no difference in the pregnancies of women with placental lakes and those without placental lakes. There was no adverse event during the pregnancy due to placental lakes. No anomalies in the baby’s gestational age and birth weight were observed (6).
When Can Placental Lakes Be Dangerous?
Placental lakes can be of concern in the following situations (4) (7).
They occur early, in the first trimester or early second trimester Presence of more than three placental lakes The diameter is more than two centimeters Large placental lakes with a diameter greater than five centimeters
In such cases, Dr. Green advises, “If placental lakes persist or become larger, it’s important to keep up with doctor’s visits to ensure everything is going smoothly. However, most pregnancies remain healthy despite the presence of placental lakes.”
Complications Of Placental Lakes
Placental lakes can be a complication only if they are affecting the growth of the fetus. The problems caused by them may or may not happen, and you may even give birth to a healthy baby. Therefore, do not panic if you have placental lakes. Any complication related to the pregnancy is quite likely to be detected and treated early if you visit the doctor for regular ultrasound examination.
Can Placental Lakes Be Treated?
There is no specific treatment for placental lakes. If your doctor finds a placental lake during a routine ultrasound, then your pregnancy may be monitored more closely.
Do Placental Lakes Go Away?
A study monitoring placental lakes in pregnant women found that some lakes tend to decrease in size, some disappear, while some remain (7). Any changes to the size and presence of placental lakes will be detected during your routine ultrasound examination.
