Umbilical cord hypercoiling and thinning: a rare cause of intrauterine death in the second trimester of pregnancy.

Little attention has been paid to the pathologic features of the umbilical cord, which might fatally damage the fetus. We determined the association of hypercoiling (more than 1 coil per 5 cm) and thinning with consecutive constriction of the umbilical vessels (thin cord syndrome; TCS) and intrauterine fetal death (IUFD). Three hundred and three cases of consecutive fetal autopsies over a 5-year period, including spontaneous and induced abortions of the 2nd trimester of pregnancy, were examined using a standardized protocol. The mean maternal age was 28.5 years and the mean gestational age was 19.1 weeks (range: 12.6 to 24.5 weeks). Thirty-six percent of all cases were induced abortions because of congenital malformations, and 8.9% resulted from legal abortions, as regulated by German law. One hundred sixty-seven cases (55.1%) were spontaneous abortion specimens. The leading cause for IUFD in the spontaneous abortion group was an amnion infection (34.7%), followed by abruptio placentae (15.6%). In 25.1% of cases, placental dysmaturity with consecutive placental insufficiency was responsible for IUFD. Pathologies of the umbilical cord as the cause of IUFD were seen in 10.2% of the cases. Most of these cases (15/17) involved TCS. In 14.4% of all spontaneous abortion specimens the cause of IUFD could not be determined by autopsy. There was an apparent difference in the frequency of TCS in the spontaneous abortion group (15/167 = 9%) compared to the nonspontaneous group (2/136 = 1.5%). A remarkably high percentage (17/303 = 5.6%) of all cases showed TCS. In cases of spontaneous abortions, TCS was causative for intrauterine death in 9% of cases (15/167). Careful pathologic examination of the umbilical cord is recommended to detect TCS and to reduce the cases with unexplained intrauterine death.