-Report on Experiments and Clinical Cases-

Fetal Heart Rate Monitoring as a Predictor of Histopathologic Chorioamnionitis in the Third Trimester

Hidehiko Miyake^1,2, Akihito Nakai¹ and Toshiyuki Takeshita¹

¹Department of Female Reproductive and Developmental Medicine, Nippon Medical School, Graduate School of Medicine
²Department of Obstetrics and Gynecology, Japanese Red Cross Katsushika Maternity Hospital, Tokyo

Chorioamnionitis (CAM) has been recognized as a common cause of neonatal morbidity and mortality. The effect of CAM on fetal heart rate (FHR) remains unclear. The purpose of this descriptive retrospective study was to evaluate the clinical significance of the FHR pattern in cases that involved delivery during the third trimester and the diagnosis of histopathological CAM. The study group consisted of 65 singleton live births delivered at 28 to 41 weeks' gestation from January 2003 through December 2005 in which histopathological CAM was diagnosed at the Nippon Medical School Tama Nagayama Hospital. We reviewed the cases using medical records and examined FHR data and the severity of histopathological CAM. The rate of tachycardia according to the severity of CAM was as follows: 3.0% (1 of 33 cases) in intervillositis, 12.5% (3 of 24 cases) in chorionitis, 37.5% (3 of 8 cases) in CAM (in a narrow sense); however, this tendency had no statistical significance. Baseline variability and decelerations were not correlated with the severity of histopathological CAM. Maternal fever exceeded 38.0°C in only 3 cases, and 1 fetus had exhibited an abnormal FHR pattern. The present study suggests that FHR monitoring is not a reliable means of diagnosing histopathological CAM, because the FHR pattern was normal in most cases of histopathological CAM.

J Nippon Med Sch 2008; 75: 106-110

Keywords
chorioamnionitis, fetal heart rate monitoring

Correspondence to
Hidehiko Miyake, Department of Obstetrics and Gynecology, Japanese Red Cross Katsushika Maternity Hospital, 5-11-12 Tateishi, Katsushika-ku, Tokyo 124-0012, Japan
hidehiko@pluto.dti.ne.jp

Received, October 16, 2007
Accepted, December 13, 2007