Maternal and Placental Factors Associated with Stillbirth: Evidence from Selected Hospitals in Lusaka, Zambia

Abstract Background: An estimated 3.04 million stillbirths were recorded in 2021 with a global stillbirth rate decline from 21.4 to 13.9/1000 live births from 2000 to 2019. Despite this decline south Asia and sub-Saharan Africa recorded the least progress with an estimated decrease of 24.9%. The region accounts for 77.3% (2.35 million) of the global stillbirths’ total. To have a stillbirth is a devasting experience such that victims desire to understand the cause of death. This study aimed to evaluate the association between maternal and placental factors with stillbirth. Methods : This was a prospective unmatched case-control study conducted from September 2023 to February 2024 in selected hospitals in Lusaka, Zambia. Eligible participants were mothers with pregnancies beyond 28 weeks' gestation who experienced a stillbirth (cases) or a live birth (controls), enrolled at a 1:4 ratio. A purposive sampling technique was employed. Placental specimens were preserved in formaldehyde and sent for histopathological examination. Data were collected using a structured Google Sheets form. Statistical analysis included Chi-square and Fisher’s exact tests to assess associations with stillbirth. Univariate and stepwise multivariable logistic regression models were applied to identify risk factors associated with stillbirth. Results: The 180 participants analysed comprised of 36 stillbirths (cases) and 144 live births (controls). The maternal mean age was 27.6 (SD±6.5: range 18-43). Unmarried participants had lower odds of stillbirth (COR=0.18; 95% CI: 0.05-0.62; p = 0.01). Above ≥5km residence from the hospital had higher odds (2.33; 95% CI: 1.11-4.91; p = 0.03). Early antenatal booking was protective (COR=4.28; 95% CI: 1.96-9.38; p < 0.00), as was early start of iron and folate (COR=2.62; 95% CI: 1.15-5.99; p = 0.02). History of stillbirth (COR=3.17; 95% CI: 1.21-8.28; p = 0.02) or abortion (COR=4.60; 95% CI: 1.39-15.25; p = 0.01) higher risk. Abnormal placental pathology had a strong association with stillbirth (AOR=4.53; 95% CI: 1.13-18.12; p < 0.03). Cord length umbilical cord was protective had lower odds (AOR = 0.07, 95% CI: 0.02–0.35, p = 0.00). Conclusion: Several maternal, obstetric, and placental factors were associated with stillbirth, including late initiation of antenatal care, a history of abortion, and previous stillbirth. Among placental findings, umbilical cord length remained significantly associated in adjusted models, while other abnormalities—such as marginal cord insertion, villous maturation disorders, and chorioamnionitis—showed strong associations only in univariable analyses. Collectively, placental pathologies demonstrated a significant contribution, underscoring the value of exploring the use of Doppler ultrasound for targeted surveillance in high-risk pregnancies.