The placenta, a temporary organ that develops in the uterus during pregnancy, forms a vital connection between the birthing parent and the developing baby. It plays a crucial role in transferring oxygen and nutrients to the fetus while removing waste products. Sometimes, the placenta undergoes a process called calcification, where calcium deposits accumulate within its tissues.
Understanding Placental Calcification
Placental calcification involves the deposition of calcium-phosphate minerals within the placental tissue, causing it to gradually harden. This process is a common and normal part of placental aging, especially as a pregnancy approaches full term. More than half of placentas show some degree of calcification by the end of a full-term pregnancy.
Medical professionals use a system called Grannum grading, from Grade 0 to Grade 3, to assess the extent of these calcium deposits and the placenta’s maturity. While some calcification is expected with advancing gestation, its appearance earlier in pregnancy, typically before 36 weeks, can be a point of medical concern. This premature calcification occurs in a range of 3.8% to 23.7% of pregnancies. When calcification happens prematurely, it might signal underlying factors that could influence pregnancy outcomes.
Primary Causes of Calcification
The exact mechanisms that trigger placental calcification are not fully understood, but several factors contribute to or accelerate this process.
Maternal and Lifestyle Factors
Maternal age can play a role, with pregnancy at a young age being a risk factor. Lifestyle choices, such as smoking during pregnancy, are strongly linked to increased placental calcification, as smoking can reduce blood flow and impair nutrient and oxygen exchange.
Medical Conditions
Various maternal medical conditions also increase the likelihood of calcification. Pregnancy-induced hypertension and preeclampsia, characterized by high blood pressure, are frequently observed alongside calcified placentas. These conditions often involve impaired placental function and altered blood flow, contributing to calcium deposition. Pre-existing conditions like diabetes can also influence the risk, sharing common pathways with vascular calcification elsewhere.
Infections and Other Factors
Infections, both bacterial and viral, are potential contributors. Viruses such as Zika, Cytomegalovirus (CMV), Rubella, and SARS-CoV-2 have been observed to induce calcium deposits due to cellular damage or inflammatory responses. Other contributing elements may include environmental exposures like radiation, reactions to certain medications, excessive calcium supplementation, or prenatal stress.
Implications for Pregnancy
While often a normal finding at term, extensive or premature placental calcification can have implications for the pregnancy. Significant or early calcification may lead to reduced blood flow and nutrient transfer to the fetus, potentially resulting in fetal growth restriction. Premature calcification is also associated with a higher incidence of low birth weight.
It may increase the risk of other complications, including premature birth and a lower Apgar score. Less commonly, severe early calcification has been linked to postpartum hemorrhage, placental abruption, fetal distress, or, rarely, stillbirth. However, many pregnancies with some degree of calcification, even early on, proceed without complications with appropriate monitoring.
Monitoring and Management
Placental calcification is typically detected during routine ultrasound examinations, revealing white spots or echogenic areas. The Grannum grading system classifies the degree of calcification. Once identified, there is no direct treatment to reverse the process.
Instead, management focuses on closely monitoring fetal well-being. This involves increasing ultrasound scans to assess fetal growth and amniotic fluid levels. Doppler studies evaluate blood flow within the umbilical cord and placenta. Non-stress tests, monitoring the baby’s heart rate, also ensure fetal health.
Addressing underlying maternal medical conditions, such as hypertension or diabetes, is part of the management strategy. In cases where calcification is extensive and negatively impacts fetal health, particularly early in pregnancy, medical professionals may consider inducing labor or performing a Cesarean section for safe delivery.