Unexpected fetal death during pregnancy--a problem of unrecognized fetal disorders during antenatal care?

To investigate the causes of ante partum fetal death (APFD) and to evaluate the diagnostic methods for prevention.

A population-based retrospective study was conducted in 293091 deliveries from 1996 to 2000 in the State of Hesse, Germany. The investigations focus on mortality of infants during pregnancy, separated between singletons of 37-42 weeks (n=361) and 23-36 weeks (n=550), and multiple births (n=76). In 44 cases, the gestational age was unknown and in 19 cases lower than 23 weeks or greater than 43 weeks. In total 1006 cases remained and were subject for evaluation.

Perinatal mortality (PM) was 0.56%. APFD occurred in 1050 cases (0.3%), i.e. 63.5% of PM. Risk factors from the medical history during pregnancy could be identified in 515 cases (51.2%). Significant risk factors were social burden (odds ratio (OR) 58.3), diabetes mellitus (OR 5.4) and gestational diabetes (OR 2.1), psychological burden (OR 4.8), proteinuria (OR 2.8), maternal age (OR 1.7) and maternal smoking, depending on the number of cigarettes. The risk factors show a difference in significance, if related to the gestational age and multiple pregnancies. The contribution of malformations to APFD was 7.8%. There was however a number of unexpected fetal deaths with unidentified risk factors: n=415 (41.3%). In this group, fetal growth restriction was observed in 38.1%. Compared to control, APFD was three to five times higher in fetal growth retardation below the 10th percentile. Fetal death was closely related to fetal surveillance, i.e. the number of antenatal visits, ultrasound measurements, and fetal heart rate monitoring.

Fetal ante partum fetal death can be reduced at least by 50%, if the available methods for fetal surveillance are employed aiming to detect indications of fetal oxygen deprivation at an early stage.