Maternal and perinatal characteristics associated with congenital anomalies: a case-control study

Abstract

Objective: This study aimed to identify the patterns and factors associated with congenital anomalies in newborns from a tertiary hospital maternity ward.

Methods: A case-control study was conducted at the Hospital Regional do Sudoeste Walter Alberto Pecóits in Francisco Beltrão (PR), between December 2023 and September 2024. Among the 1,400 births that occurred in the hospital's delivery room between December 1, 2023, and the end of September 2024, 37 newborns (2.6%) with congenital anomalies were identified during the study period. A total of 37 case mothers and 120 controls were included (a ratio of approximately 1:3). The sociodemographic variables included maternal age, residence, marital status, race, education level, family income, and maternal occupation. The behavioral variables considered smoking, alcohol consumption, and the use of drugs or medications during pregnancy. The fetal variables included the number of pregnancies, gestational age, type of delivery, miscarriage, Apgar score, birth weight, sex, fetal status, congenital anomalies, and the number of prenatal visits, with a minimum of six (one in the first trimester, two in the second, and three in the third), following the Ministry of Health guidelines.

Results: Among 1,400 live births, 37 cases of congenital anomalies were identified (2.6%, 95% CI: 1.80-3.48), while the control group included 120 women with newborns without congenital anomalies. Among cases, isolated anomalies were most common (62.2%), predominantly affecting the cardiovascular system (27.0%), followed by recognized syndromes (21.6%) and multiple malformations (16.2%). Data were collected through face-to-face interviews and medical record reviews. Bivariate analysis revealed significant associations between congenital anomalies and a family history of congenital anomalies (p = 0.02), low apgar scores at the 1st and 5th minutes (p < 0.01), and fetal status at birth (p < 0.01). Model 1, which integrates family history of congenital anomalies, apgar score at the 5th minute, and fetal status, showed the best predictive fit, consistent with previous findings. Bayesian logistic regression highlighted this model with the lowest AIC (295.98) and BIC (326.22) values, achieving 89% predictive accuracy.

Conclusion: These results reinforce the importance of family history and neonatal vitality in the context of congenital anomalies, indicating the need for future studies to confirm these findings and improve prevention strategies.

Keywords: Congenital abnormalities; Infant, newborn; Maternal and child health; Perinatal care; Pregnancy; Primary prevention.

Figure 1. Flowchart of the case-control study population