EUROCAT Northern Netherlands

COVID-19 research NNL
COVID-19 research NNL
<h3 style="color: black;"><em>Update: July 2023</em></h3><br/>COVID-19 infections during pregnancy and congenital anomalies in the offspring – data from Eurocat Northern Netherlands


In February 2020, the first patient with COVID-19 was registered in the Netherlands. COVID-19 is characterised by airway complaints and fever and is caused by infection with the corona virus SARS-CoV-2. Many people worldwide have been infected with the virus, including pregnant women. We know that other virus infections can be teratogenic. For example, zika virus infection during pregnancy leads to a higher risk of microcephaly (small head circumference, associated with intellectual disability) in the unborn child. Therefore, Eurocat Northern Netherlands is collecting data about COVID-19 infections.


For all Eurocat cases born in 2020 or later, we searched the medical records of the mother and the child for information regarding COVID-19 infection during pregnancy. In our questionnaire, we also asked the mother whether she had a COVID-19 infection in the three months prior to pregnancy or during pregnancy.


At 24 July 2023, we had registered 72 cases whose mother had a COVID-19 infection just prior to or during pregnancy. In 32 cases (44%) the COVID-19 infection was not mentioned in the medical records and was only found via the questionnaire.

Types of congenital anomalies

The children / foetuses whose mother had a COVID-19 infection (COVID cases) had different types of congenital anomalies (Table 1). Heart defects occurred most frequently, followed by genetic disorders and congenital anomalies of kidney and urinary tract (CAKUT).

Table 1: types of congenital anomalies in COVID cases and in Eurocat NNL cases born prior to the COVID-19 pandemic
Type of anomaly Number of COVID cases % COVID cases Number of cases born in 2015-2019* % cases born in 2015-2019
Heart defects 17 23.6% 520 21.4%
Genetic disorders 15 20.8% 560 23.0%
CAKUT 12 16.7% 360 14.8%
Limb anomalies 10 13.9% 420 17.3%
Oro-facial clefts 7 9.7% 130 5.3%
Other anomalies 11 15.3% 440 18.1%
Total 72 100% 2430 100%
* Source:

Pattern of congenital anomalies

Overall, the pattern of congenital anomalies in COVID cases is not different from the cases born prior to the COVID pandemic (2015-2019, Table 1). Oro-facial clefts were overrepresented in the COVID cases, but this was based on only 7 cases. In data from EUROCAT registries across Europe, there were 153 COVID cases (born in 2020 and 2021). In this larger dataset, there were fewer oro-facial clefts in COVID cases than expected. Therefore, we don’t think there is an association between COVID-19 and orofacial clefts.

Timing of COVID-19 infections

Most COVID-19 infections in Northern Netherlands were found in children/foetuses who were born in 2022 (47 cases). This corresponds with the peak of COVID-19 infections in Northern Netherlands. Less than 5 COVID cases were born in 2020.

In 17 cases, the COVID-19 infection took place during the first trimester of pregnancy, which is the most vulnerable period for the occurrence of congenital anomalies. These 17 cases had different types of anomalies and no pattern could be found. Genetic disorders were most frequently seen, which are not expected to be related to the COVID-19 infection.

Reassuring results

The pattern of congenital anomalies in COVID cases registered in the Eurocat Northern Netherlands database (n=72, n=57 non-genetic cases) is not alarming. Also, no pattern was seen in the COVID cases registered in the central EUROCAT database (n=153, n=123 non-genetic cases). However, the number of cases is still relatively low and only few first trimester COVID-19 infections are registered. Therefore, Eurocat Northern Netherlands will keep monitoring COVID-19 infections and the European EUROCAT network will start an ecological study on COVID-19 and congenital anomalies. It is reassuring that scientific studies have so far not reported an increased risk of congenital anomalies after a COVID-19 infection during pregnancy.