Spontaneous abortions during the second trimester of gestation.

To determine the factors causing spontaneous abortions, 422 consecutive second-trimester abortions and the corresponding clinical data were studied prospectively. All of the fetuses and placentas were referred to a single pathologist and microbiological cultures were carried out in 205 of these cases. One hundred twenty-one medically included abortions were used as controls for the interpretation of the investigations relating to infection. According to the degree of maceration, two groups could be isolated and seemed to represent different diseases and mechanisms of spontaneous abortions. In the largest group (78.6%) without long intrauterine retention, one explanation could be given for 85% of these cases. Ascending infections occurred through unruptured membranes, whether or not they were associated with obstetric complications. The second group (21.4%) included severely macerated fetuses where a cause of death could only be determined in 44% of the cases that had a predominance of fetal abnormalities and maternal factors.