Epidemiological study of factors associated with lifetime stillbirth among women in Isfahan Province, Iran

This study investigated the epidemiological factors of stillbirth, including demographic, socioeconomic, reproductive, clinical, and lifestyle factors, among women in Isfahan province, Iran. A descriptive-analytical cross-sectional study was conducted from September 2023 to May 2024, enrolling 2750 women aged 15 to 55 years with a history of at least one pregnancy. Participants were selected using multistage random sampling. Data were collected through structured interviews covering demographics, socioeconomic status, reproductive history, clinical parameters, and lifestyle factors. Clinical measurements, including fasting blood sugar, body mass index, blood type, platelet count, and blood urea nitrogen, were obtained from the SIB electronic health system during the first-trimester antenatal visit. Associations among variables were analyzed using Chi-square tests, Fisher’s exact tests, t-tests, and Firth’s penalized-likelihood logistic regression. Odds ratios with 95% confidence intervals were reported to present the findings. The proportion of women who reported a lifetime history of stillbirth was 1.38% (95% Confidence Interval: 0.96–1.80). In a multivariable Firth regression analysis, parity emerged as the strongest correlate. Women with three pregnancies exhibited an adjusted odds ratio (AOR) of 3.47 (95% CI: 1.44–8.37; p = 0.006), compared to those with two or fewer pregnancies. Furthermore, women with four or more pregnancies presented an AOR of 7.52 (95% CI: 2.83–20.01; p < 0.001). Additionally, each 1 mg/dL increase in fasting blood sugar during the first trimester correlated with a 3.5% increase in odds (AOR = 1.035; 95% CI: 1.017–1.053; p < 0.001). Each 1-unit increase in body mass index during the first trimester was associated with a 16% increase in odds (AOR = 1.163; 95% CI: 1.085–1.247; p < 0.001). Elevated parity, increased fasting blood sugar during the first trimester, and a higher body mass index in the first trimester are factors associated with stillbirth. These findings indicate valuable avenues for future prospective research, including improved glycemic control, effective weight management strategies, and enhanced antenatal surveillance for multiparous women.