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No higher risk of miscarriage after COVID-19

LUMC research has shown that women who previously had a miscarriage due to COVID-19 are not at increased risk of having another miscarriage or a stillbirth. Nor are preventive drugs needed during the pregnancy.

The long-term effects of miscarriages caused by COVID-19 were not previously known. LUMC gynaecologist Marie-Louise van der Hoorn explains the uncertainty this caused, ‘Parents thought: “It’s not going to happen again, is it?” and doctors thought: “Let’s prescribe immunosuppressant drugs so that the placenta will hopefully continue to work properly”. But these drugs also cause all sorts of side effects.’

No oxygen

So a study was started in Leiden. In 2021, researchers from the LUMC and Erasmus MC discovered a link between COVID-19 and placental insufficiency. LUMC pathologist Lotte van der Meeren explains what happens when coronavirus invades the placenta, ‘A placenta is a kind of tree with lots of tufts and the virus settles on these tufts. You can compare it with a tree full of caterpillars, with the caterpillars as the coronavirus. Once the tree is full, oxygen exchange is no longer possible and the placenta literally fails. And if the placenta fails, things also go wrong with the baby.’

Chronic placenta disease

Infectious diseases such as malaria, CMV and listeria can cause placenta disease. We know that the chance of the disease returning in a subsequent pregnancy is very low. But there is also a rare variant in which the recurrence rate is very high.

The new study aimed to research the recurrence rate of COVID-19-related placenta disease. It included parents who were affected by the effects of the virus. Of the 19 new pregnancies, 17 ended in a live birth. The two miscarriages that occurred were due to other causes, says Van der Hoorn.


The study was small but worthwhile, says Van der Hoorn. ‘You remove a lot of uncertainty, drugs are no longer needed and how fantastic is that moment when parents can hold a healthy child in their arms.’

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