gynecology and obstetrics
Spontaneous Abortion
Etiology of Spontaneous Abortion
Early spontaneous abortion is often caused by a Overview of Chromosomal Abnormalities . Maternal reproductive tract abnormalities (eg, bicornuate uterus, fibroids, adhesions) may also cause pregnancy loss through 20 weeks gestation. Isolated spontaneous abortions may result from certain viral infections—most notably cytomegalovirus, herpesvirus, parvovirus, and rubella virus. Other causes include immunologic abnormalities and major physical trauma. Most often, the cause is unknown. Risk factors for spontaneous abortion include Extremes of maternal age History of spontaneous abortion Cigarette smoking Use of certain substances (eg, Social and Illicit Drugs During Pregnancy , A poorly controlled chronic disease (eg, Diabetes Mellitus in Pregnancy , In a national database study, the risks of miscarriage across maternal age groups were as follows: < 20 years (17%); 20 to 24 (11%); 25 to 29 (10%); 30 to 34 (11%); 35 to 39 (17%); 40 to 44 (33%); > 45 (57%) ( Etiology reference ). Subclinical thyroid disorders, a retroverted uterus, and minor trauma have not been shown to cause spontaneous abortions. 1.Magnus MC, Wilcox AJ, Morken NH, et al: Role of maternal age and pregnancy history in risk of miscarriage: Prospective register based study.BMJ364:l869, 2019. doi: 10.1136/bmj.l869 