A new study published in the journal Nature Communications has shown that a mother’s immune system reacts to her foetus’ cells as if they are foreign invaders and sends antibodies to attack and destroy them.

The condition which is called foetal and neonatal alloimmune thrombocytopenia (FNAIT) not only causes miscarriages but can cause the brain to bleed in live births, resulting in lifelong disability or even death of the child. The lead researcher of the study Dr Heyu Ni says that now she knows why the mother’s immune system launches an attack on the foetus.

According to her, natural killer cells during pregnancy in mammals were important for early placental development but should decrease with later stages of pregnancy. However, they found that in case of FNAIT, the natural killer cells were not decreased but remained prevalent.

FNAIT is known to occur with one child in every 1,000 births, but this does not include women who miscarry. They estimate 2-3 percent of women are at risk for FNAIT and up to 30 percent of those affected miscarry.

The study carried out by the Keenan Research Centre for Biomedical Science of St Michael’s Hospital in Ontario found out that the immune attack can cause the placenta to deform and can disrupt the flow of nutrients to the foetus – both of which may limit the baby’s growth in the womb and increase the likelihood of miscarriage.

The study authors suggest treatment options that might effectively prevent FNAIT-related miscarriages by targeting natural killer cells.

The first is to use intravenous immunoglobulin G (IVIG), a blood product prepared from pools of plasma from more than 1,000 healthy donors.

IVIG blocks the sensors of natural killer cells, disorienting them and preventing them from targeting placental cells. It also decreases maternal anti-foetal antibodies.

The study carried out by the Keenan Research Centre for Biomedical Science of St Michael’s Hospital in Ontario found out that the immune attack can cause the placenta to deform and can disrupt the flow of nutrients to the foetus – both of which may limit the baby’s growth in the womb and increase the likelihood of miscarriage.