Is there a link between the occurrence of birth defects and recurrent miscarriage?

This study investigated if fetal congenital malformations (FCM) are linked to recurrent miscarriage (RMC). They found that FCM was more likely in women with a history of RMC and birth defects.

Recurrent miscarriage (RMC) is defined by 2 or more failed pregnancies. RMC can be caused by a number of issues. Genetic abnormalities are one possible cause. Some genetic abnormalities lead to conditions that are not compatible with life. In this case, a miscarriage occurs. It is not always possible to detect genetic abnormalities in the miscarried fetus.

In 50% of cases, the cause of RMC is not clear. Some studies suggest that women with a history of RMC are more likely to have a baby with birth defects. Birth defects are caused by fetal congenital malformations (FCM). It has also been suggested that FCM could be the cause of previous RMC. Maternal age may also affect these parameters. It is unclear if RMC is associated with FCM and maternal age.   

This study included 466 patients with RMC. Women were categorized based on the history of pregnancy, RMC, and birth defects. Maternal age was also taken into account in the analysis. The authors evaluated if certain factors were associated with RMC.

Mothers with RMC were more likely to be older and have thrombophilia (TBP). TBP is an increased tendency to form blood clots. 7.1% of patients had a history of FCM. These patients were 3.8-times more likely to experience RMC.

The authors concluded that FCM was more likely in women with a history of RMC and birth defects.

This study did not analyze tissue from miscarried fetuses. This means we cannot confirm FCM occurred in miscarriages. The relationship between RMC and FCM may not be causal. This means that even though there is a link they may not actually affect each other. Another unknown factor could affect both of these. More controlled studies are needed.