According to a study conducted by Dr Henrietta Svarre Nielsen at the University Hospital, Copenhagen it was found that there was an increase in the risk of miscarriages after a woman gave birth to a baby boy. This study was conducted when doctors at a fertility clinic in Denmark saw a sudden increase in the number of women suffering from miscarriages especially among women whose first born child is a boy. They studied 305 women suffering unexplained recurrent miscarriages and found that 60% had first born children who were boys.
Scientists believe that male genes can trigger an immune reaction that prevents later pregnancies in vulnerable women. In such cases the chance of a second pregnancy was reduced drastically. Recurrent miscarriages are defined as having three miscarriages one after the other. After treatment these women with first born boys had only 37% chance of having a second child. The only treatment for recurrent miscarriages is to diminish the immune system response by a blood product. The findings of the study were presented at the annual meeting of the European Society of Human Reproduction and Embryology in Prague. The woman's immune system is affected after she delivers a male baby.
Immune cells which are highly active against the males are found in her body up to 22 years. The researchers suspect that the immune response is directed towards the genes from the male Y chromosome. This could be the major reason why some bone marrow transplants from women to men were often unsuccessful if the woman had previously given birth to a boy. The researcher said that only a small group of women with defective immune systems were susceptible to the problem.