Miscarriage leads to trouble in next pregnancy

Pregnant women who suffer a miscarriage in the second-trimester are at high risk of repeat second-trimester miscarriage or spontaneous preterm birth during a subsequent pregnancy. American researchers studied three groups of women from 2002 to 2005: 38 women who had a spontaneous second-trimester miscarriage; 76 women with a spontaneous preterm birth; and 76 women with full-term deliveries. All of the women had a subsequent pregnancy beyond 14 weeks' gestation. The frequency of subsequent second-trimester loss was highest (27 percent) in women who suffered a second-trimester loss in the first pregnancy. The frequencies of subsequent second-trimester loss were 3 percent and 1 percent in the spontaneous preterm birth, and full-term delivery groups, respectively. Corresponding frequencies of subsequent spontaneous preterm birth were 33 percent, 40 percent and 9 percent for the three groups, respectively. Of great clinical concern is that women with prior second-trimester pregnancy loss have a high frequency of very early preterm birth. In this group, spontaneous preterm birth at less than 28 weeks was 10 percent, versus 1 percent in the other two groups. The researchers suggest that the biologic mechanism for second-trimester losses may be similar to that of spontaneous preterm birth, possibly related to cervical ripening as a primary event. If so, women with second-trimester loss would be candidates for therapy that reduces subsequent preterm birth.