Maternal miscarriage history and risk of anencephaly

Women with a history of reproductive loss may be at an increased risk of having an unfavourable outcome in subsequent pregnancies. Using data from a matched case-control study based on the record of the Epidemiological Surveillance System of Neural Tube Defects, we evaluated the association between history of maternal reproductive loss and the risk of anencephaly in three Mexican states. Mothers of 157 cases of anencephaly and 151 controls born during the period March 2000 to February 2001, were interviewed about their reproductive history and other additional factors, including socio-economic characteristics, prenatal care, use of tobacco and alcohol, presence of chronic diseases, acute illnesses and fever during the periconceptional period, and consumption of multivitamins and medicines during this period; mothers who reported no prior pregnancies were excluded from the analysis; 58 matched case-control pairs were used for the analysis. After adjusting for potential confounders, women with a history of miscarriage in previous pregnancies had 4.58 times more risk of having a child with anencephaly, than those who did not have this history; OR = 4.58, [95% CI 1.22, 17.23]. Our results suggest that a history of previous miscarriages is a risk indicator for anencephaly in future gestations. This does not necessarily mean that the miscarriage itself is the cause, but that common mechanisms could be involved in the aetiology of both events. Thus, women who have had histories of reproductive losses, especially miscarriages, should be a priority group for the primary and secondary prevention of neural tube defects.