The effect of maternal age and duration of labor on perinatal and neonatal outcomes: a retrospective cohort study

BACKGROUND: This study aimed to investigate the effect of maternal age and duration of labor on perinatal and neonatal outcomes. The results of this study are expected to provide a basis to aid maternal and child health care personnel to implement health education for late childbearing women. METHODS: This was a retrospective observational study, wherein 9,241 parturients were included from 2016 to 2018. Parturients were divided into three groups based on age: <28 (n=2,911), 28–30 (n=3,631), and >30 (n=2,699) years. According to the total duration of labor, those who did not undergo cesarean section (CS) were subgrouped into <420 minutes (n=4,065) and ≥420 minutes (n=4,094) groups. A multivariate logistic regression model was used to investigate associations between age/total duration of labor group factors to different postpartum outcomes, including a switch to emergency CS, puerperal morbidity, abnormal fetal heart rate, and meconium-stained amniotic fluid (MSAF). RESULTS: The rates of postpartum outcomes significantly differed in maternal age groups, including switch to emergency CS (9.07% vs. 13.03% vs. 11.23%; P<0.001), puerperal morbidity (6.32% vs. 6.46% vs. 5.00%; P=0.035), and abnormal fetal heart rate (25.34% vs. 28.21% vs. 25.67%; P=0.017). Of the comparisons between labor time groups, it was found that participants with longer labor time were also significantly higher in the use of episiotomy/forceps (46.61% vs. 69.77%; P<0.001), bleeding amount (381.35±108.02 vs. 389.60±146.40 mL; P=0.004), oxytocin use (25.03% vs. 39.56%; P<0.001), puerperal morbidity (1.98% vs. 6.86%; P<0.001), abnormal fetal heart rate (20.07% vs. 25.15%; P<0.001), and MSAF (26.53% vs. 31.91%; P<0.001). Multivariate logistic regression analysis showed that as age increased, the ORs of switching to emergency CS (1.58 and 1.87, both P<0.001) and having abnormal fetal heart rate (1.20 and 1.38; both P<0.01) also increased. Participants with longer labor time groups the ORs of puerperal morbidity (2.33; P<0.001) and MSAF (1.13; P=0.023) also increased. CONCLUSIONS: With the adjustment of covariates. Higher maternal age seems associated to the risk of switching to emergency CS and having abnormal fetal heart rate; longer total duration of labor seems associated to the risk of puerperal morbidity and MSAF.