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dcyphr | Placental Pathology in COVID-19

Abstract

In this study, the researchers wanted to understand if there were differences in the placentas of pregnant women with and without COVID-19. They identified pregnant women with COVID-19 and examined their placentas. The researchers compared these placentas with controls and with placentas of women with a history of melanoma (skin cancer). They found that placentas of women with COVID-19 were more likely to show signs of maternal vascular malperfusion (MVM), a form of placental injury related to altered blood flow that can cause maternal and fetal complications. 

Aims

The researchers wanted to describe tissue-related changes in the placentas of pregnant women with COVID-19.

Introduction

There is a growing interest in how COVID-19 affects pregnant women and their infants. SARS, MERS, and COVID-19 are all related coronaviruses. In the 2003 SARS epidemic, around 100 pregnant women were infected and some had higher risk of severe infection, maternal death, and loss of pregnancy. MERS infection in pregnant women was also associated with poor maternal and perinatal (immediately after birth) outcomes. The effect of COVID-19 on mothers and infants is still unknown.

Examining the placental tissue can give people information about the health of mothers and their infants. There is little information about the relationship between coronavirus infection and changes in placental tissue. In this report, the researchers present what they found in the placentas of 16 women with COVID-19 during pregnancy.

Results

16 placentas from women with COVID-19 were examined. 14 patients delivered at term, 1 delivered pre-term, and 1 lost her pregnancy. Fifteen cases were compared with 2 control populations. Symptoms of MVM were present in 12 patients, significantly higher than the controls. In addition, rates of insufficient supply of oxygen and nutrition to the placenta, arterial disease in the lining of the uterus, vascular lesions and cell death, and enlargement of blood vessels were higher in women with COVID-19.

Discussion

The most significant finding was that pregnant women with COVID-19 had an increase in symptoms of MVM. MVM is associated with many fetal complications before and during birth. Of these symptoms, arterial disease in the lining of the uterus was most strongly related to COVID-19.

Pregnant women with COVID-19 also showed an increase in the formation of blood clots in the space between villi (projections from the outer surface of the placenta) containing the vessels of the mother and infant. This may be in response to the virus.

There was also an increase in chorangiosis, an increase in the number of blood vessels in the placenta, which is associated with decreased oxygen levels in the mother. However, it is difficult to draw any conclusions between COVID-19 and chorangiosis.

One patient in the study lost her pregnancy. This may have been caused by acute inflammation from COVID-19. More research is necessary to define this relationship.

No infants showed infection after birth, which agrees with existing evidence that COVID-19 transmission from mother to child is rare.

These findings suggests that it may be necessary to keep a close eye on pregnant women diagnosed with COVID-19 and their infants.

Methods

Pregnant women with COVID-19 were tested and identified.

The researchers used historical controls, which means they used data from pregnant women who were examined in the past. Patients with a history of melanoma were also used, since their condition is unrelated to pregnancy complications.

Placentas were examined using routine clinical examination.

The researchers made comparisons between placentas of women with COVID-19 and historical controls as well as between placentas of women with COVID-19 and placentas of women with a history of melanoma.