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.

Physical activity during pregnancy and intelligence in sons; A cohort study.

The purpose was to examine the association between exercise during pregnancy and intelligence score in offspring. We analyzed data from 4008 women from the Aarhus Birth Cohort, Aarhus University Hospital, Denmark, recruited during pregnancy from July 1989 to November 1991 and their sons who were registered at conscription at 17-20 years of age. The women gave information by self-administered questionnaires during the first trimester including leisure-time physical activity and weekly hours of sport. This information was linked to the sons' measures of intelligence by Børge Priens test scores from the Danish Conscription Registry. Only sons were included since very few women register at conscription in Denmark. The main outcome measure was the Børge Priens test score as a continuous variable and with a low score defined as <10% of the population score. Analyses were adjusted for maternal body mass index, years in school, and smoking. Sons of women with light and moderate to heavy leisure-time physical activity had lower risk of having a low intelligence score compared with sons of women with sedentary activity: adjusted odds ratio (aOR) 0.66 (95% CI 0.49;0.88) and 0.46 (95% CI 0.23;0.93), respectively. Furthermore, sons of women engaged in sports had lower risk of a low intelligence score: aOR 0.50 (95% CI 0.30; 0.83) for 1-2 h/wk and 0.62 (95% CI 0.35; 1.10) for ≥3 h/wk compared with no weekly sports activity. In conclusion, a higher level of physical activity during pregnancy was associated with a lower risk of low intelligence score in early adulthood in sons.