Stress and Recurrent Miscarriage

Our current understanding into the role of stress in unexplained recurrent miscarriages comes from two different research strategies. The majority of research has examined the role of psychological support within this patient population. This support has been provided in a number of ways ranging from weekly interviews with a psychiatrist or gynaecologist and/or visual re-assurance in the form of ultrasound scans. A comparison of psychological support with an absence of such intervention has found differences in successful pregnancy outcome varying from as great as 84 versus 26%, respectively. It has been assumed that psychological support reduces the miscarriage rate by reducing “stress” within this patient population. In addition it provides indirect support for a role of stress in the aetiology of unexplained recurrent miscarriage. Other studies have attempted to directly assess the effect of personality characteristics on miscarriage rate; these studies have yielded conflicting results. The mechanism by which stress may be causal in the aetiology of unexplained recurrent miscarriage has not been examined in humans. Animal studies, however, have found that psychological distress can alter immune parameters that may be intricately involved with implantation. These parameters include an elevation of the “abortive” cytokine TNF-$aL and a reduction in the “anti-abortive” cytokine TGF-β2. Cells that are involved in the release of TNF-$aL at the feto-maternal interface include T cells, macrophages and mast cells. Mechanisms through which stress may act on these cells are explored and an integrated model is postulated.