The incidence and risk factors of meconium amniotic fluid in singleton pregnancies: An experience of a tertiary hospital in Iran

Background: Several common maternal or neonatal risk factors have been linked to MAF development; however, the results were contradictory, depending on the study. This study aimed to assess the prevalence and risk factors of MAF in singleton pregnancies. Methods: : We retrospectively assessed singleton pregnant mothers who gave birth at Khaleej-e-Fars Hospital (a tertiary hospital) in Bandar Abbas, Iran, between January 1st, 2020, and January 1st, 2022. Mothers were divided into two groups: 1) those diagnosed with meconium amniotic fluid and 2) those diagnosed with clear amniotic fluid. Mothers with bloody amniotic fluid were excluded. Demographic factors (age, educational level, residency place, medical insurance, access to prenatal care facilities, smoking status), obstetrical factors (gestational age, parity, newborn sex, oligohydramnios, preeclampsia, gestational diabetes mellitus (GDM), abnormal placentation, placenta abruption, chorioamnionitis, intrauterine growth restriction (IUGR), and intrauterine fetal death (IUFD)) and maternal comorbidities (overt diabetes mellitus, chronic hypertension, cardiovascular disease, thyroid dysfunction, drug addiction, hepatitis, anemia, infertility, and COVID-19 at the time of admission) were extracted from electronic data of each mother. The Chi-square test was used to compare differences between the groups for categorical variables. Logistic regression models were used to assess meconium amniotic fluid risk factors. Results: : Of 8888 singleton deliveries during the study period, 1085 (12.2%) were MAF. MAF was more common in adolescents, mothers with post-term pregnancy, and primiparous mothers, and it was less common in mothers with GDM and overt diabetes. The odds of having MAF in adolescents were three times more than mothers of 20-34 years old (aOR: 3.07, 95%CI: 1.87–4.98). Likewise, the odds of the presence of MAF in mothers with post-date pregnancy (40+1-41 weeks) were (aOR: 5.12, 95%CI: 2.76–8.94), and mothers with post-term pregnancy (more than 41 weeks) were (aOR: 7.09, 95%CI: 3.92–9.80). Primiparous women were also more likely than multiparous mothers to have MAF (aOR: 3.41, 95%CI: 2.11–4.99). Conclusions: : Adolescents, primiparous mothers, and mothers with post-term pregnancies had a higher risk of MAF. Maternal comorbidities resulting in early termination of pregnancy can reduce the incidence of MAF.