Maternal factors associated with labor dystocia in low-risk nulliparous women. A systematic review and meta-analysis.

OBJECTIVE: To identify maternal factors associated with labor dystocia in low-risk nulliparous women. METHODS: MEDLINE, Embase, ClinicalTrials.gov, Cochrane, and CINAHL were searched for intervention studies and observational studies published from January 2000 to January 2022. Low-risk was defined as nulliparous women with a singleton, cephalic birth in spontaneous labor at term. Labor dystocia was defined by national or international criteria or treatment. Countries were restricted to OECD members. Two authors independently screened 11,374 titles and abstracts, extracted data, and assessed risk of bias using the Newcastle-Ottawa Scale. Results were presented narratively and by meta-analysis when compatible. RESULTS: Seven cohort studies were included. Overall, the certainty of the evidence was moderate. Three studies found that higher maternal age was associated with an increased frequency of labor dystocia (relative risk 1.68; 95% CI 1.43-1.98). Further three studies found that higher maternal BMI was associated with increased frequency of labor dystocia (relative risk 1.20; 95% CI 1.01-1.43). Maternal short stature, fear of childbirth, and high caffeine intake were also associated with an increased frequency of labor dystocia, while maternal physical activity was associated with a decreased frequency. CONCLUSION: Maternal factors associated with an increased frequency of labor dystocia were mainly maternal age, physical characteristics, and fear of childbirth. Maternal physical activity was associated with a decreased frequency. Intervention studies targeting these maternal factors would need to be initiated before or early in pregnancy to test the causality of the identified factors and labor dystocia.

Lifestyle Habits among Pregnant Women in Denmark during the First COVID-19 Lockdown Compared with a Historical Period-A Hospital-Based Cross-Sectional Study.

The first national lockdown in Denmark due to the COVID-19 pandemic was declared on 11 March 2020. From this date, national restrictions were imposed. We aimed to assess the potential influence of this first nationwide lockdown on exercise, alcohol consumption, and smoking in early pregnancy. Using a cross-sectional study based on routinely collected patient-reported data, we compared the lifestyle habits of women who were pregnant during the first phase of the pandemic (COVID-19 group) (n = 685) with those of women who were pregnant the year before (Historical group) (n = 787). We found a reduction in any exercise (PR = 0.91, 95% CI (0.84 to 0.99), in adherence to national recommendations of exercise (PR = 0.89, 95% CI (0.80 to 0.99), in cycling (15% vs. 28%, p < 0.0001), and swimming (0.3% vs. 3%, p = 0.0002) in the COVID-19 group compared with the Historical group. The prevalence of binge drinking was reduced in the COVID-19 group compared with the Historical group (PR = 0.80, 95% CI (0.68 to 0.93). In contrast, the prevalence of any weekly alcohol consumption and smoking cessation during pregnancy was similar between groups. Our findings indicate that national restrictions due to the COVID-19 pandemic influenced the lifestyle habits of pregnant women and should be addressed in antenatal counseling.

Intrapartum transfer of oxytocin across the human placenta: An ex vivo perfusion experiment.

INTRODUCTION: Investigation of the maternal to fetal transfer of oxytocin across the dually perfused term human placenta. METHODS: Human placentae obtained from term singleton pregnancies were utilized in a dual recirculating model of ex vivo placental perfusion. Six placentae from women delivering by elective cesarean at term were perfused, one blank and five with the test substance synthetic oxytocin (0.8 ng/mL) (OX) added to the maternal perfusate for 180 min. Antipyrine was used as positive control to validate overlap of the maternal and fetal circuits. The concentration of OX was determined by radioimmunoassay. RESULTS: A fall in maternal concentration of OX was seen throughout the experiment. At 90 min of perfusion a state of equilibrium was reached between maternal and fetal concentrations; however after 180 min the fetal concentration of OX was higher than that of the maternal. 31 % of the test substance was accounted for at the end of the experiment - suggesting OX protein binding and a high degree of oxytocinase activity. DISCUSSION: The ex vivo perfusion experiments revealed low transfer of OX to the fetal circuit below physiologically relevant concentrations.