Causes of intrauterine fetal death (IUFD) in term singleton pregnancies (2014-2023): a retrospective study

The risk factors of intrauterine fetal death (IUFD) at term remain uncertain. The cause of death is often difficult to accurately define. This study analyzed the clinical characteristics and the causes of stillbirth at a tertiary maternity center over a 10-year period.

A retrospective study included 70 women with unexpected intrauterine fetal death (IUFD) in singleton term pregnancies (2014 - 2023) at Women's Hospital, Zhejiang University School of Medicine. Cases with fetal anomalies or intrapartum death were excluded. Fetal and maternal variables were analyzed to assess the possible causes of death.

The majority of mothers were aged 21-34 and of normal weight. Most deliveries occurred before or at 38 weeks . Umbilical cord abnormalities were present in 72.9% of cases. Among the causes of IUFD, unknown causes predominated (61.4%, n = 43), followed by umbilical cord abnormalities (27.1%, n = 19), with hypercoiling being the most frequent specific finding (28.6%, n = 20). Placental abruption accounted for 7.1%. Reduced fetal movement was reported in 61.4% of cases. The high rate of unknown causes must be interpreted in the context of limited placental pathology evaluation (available in only 47.1% of cases).

The high proportion of unexplained term stillbirths (61.4%) primarily reflects limited diagnostic investigation, particularly the lack of comprehensive placental pathology. Umbilical cord abnormalities, notably hypercoiling (28.6%), were the most common identifiable cause. Implementing standardized placental examination protocols is critical to elucidate true causes. Monitoring fetal movement remains vital, and enhanced detection of cord abnormalities may aid intervention.