Clinical effectiveness of adding azithromycin to antimicrobial prophylaxis for cesarean delivery.

BACKGROUND: A recent large clinical trial demonstrated an approximately 50% decrease in the rate of postoperative infection in women who were laboring and/or had rupture of membranes for >4 hours and who received azithromycin in addition to standard preoperative antibiotic prophylaxis at the time of cesarean delivery. Given these results, our institution made a policy change in May 2017 to add azithromycin to standard preoperative prophylaxis for all cesarean deliveries. OBJECTIVE: This study aimed to evaluate the clinical effectiveness of adding azithromycin to preoperative antibiotic prophylaxis for cesarean delivery. STUDY DESIGN: We conducted a before-and-after cohort study of women delivered via cesarean delivery at our institution. The preimplementation group included women who delivered from March 1, 2016, to February 28, 2017, (before an institutional practice change of adding azithromycin to standard preoperative prophylaxis), and the postimplementation group included women who delivered from September 1, 2017, to August 31, 2018 (allowing a 6-month period for uptake of the practice change). The primary outcome was a composite of postoperative infections (endometritis, wound infection, other maternal infections). Unadjusted and adjusted risk ratios and 95% confidence intervals were estimated using a modified Poisson regression model. RESULTS: In the preimplementation (n=1171) and postimplementation (n=1168) groups, the incidence rates of the composite outcomes were 4.7% and 5.3%, respectively (P=.49). Both unadjusted (relative risk, 1.13; 95% confidence interval, 0.78-1.62) and adjusted (adjusted relative risk, 1.06; 95% confidence interval, 0.74-1.52) comparisons were not significantly different. In addition, results were statistically nonsignificant, but in the direction of lower rates of infection, in the after cohort for women in labor and/or with rupture of membranes for ≥4 hours (relative risk, 0.88 [95% confidence interval, 0.56-1.39]; adjusted relative risk, 0.82 [95% confidence interval, 0.52-1.30]) and for women with clinical chorioamnionitis (relative risk, 0.37 [95% confidence interval, 0.08-1.67]; data too sparse for adjusted analysis). In the subgroup of women who were not in labor, the after cohort had a statistically nonsignificant increased risk of the composite outcome in both unadjusted (relative risk, 1.53; 95% confidence interval, 0.86-2.72) and adjusted (adjusted relative risk, 1.48; 95% confidence interval, 0.83-2.65]) comparisons. CONCLUSION: In clinical practice, the addition of azithromycin to standard preoperative antibiotic prophylaxis for cesarean delivery may have an effect size smaller than seen in the large clinical trial prompting this practice change. Extrapolation of this regimen to women not in labor may be ineffective.

Infant sex differences in human milk intake and composition from 1- to 3-month post-delivery in a healthy United States cohort.

BACKGROUND: Macronutrient composition of human milk differs by infant sex, but few studies have examined sex differences in other milk components, or their potential modification by maternal body mass index (BMI). AIM: We compared milk intake and human milk hormone and cytokine concentrations at 1- and 3-month post-delivery and tested infant sex by maternal BMI (OW/OB vs. NW) interactions. SUBJECTS AND METHOD: Data were analysed for 346 mother-infant dyads in the Mothers and Infants Linked for Healthy Growth (MILk) Study at 1- and 3-month post-delivery. Infant milk intake was estimated by the change in infant weight after test feedings. Concentrations of glucose, insulin, leptin, adiponectin, interleukin-6 (IL-6), and C-reactive protein (CRP) were measured using ELISA. Multivariable linear regression and linear mixed models were used to estimate sex main effects and their interaction with maternal BMI. RESULTS: Mean glucose concentration at 1 month was 2.62 mg/dl higher for male infants, but no difference at 3 months was observed. Milk intake and concentrations for the other milk components were similar for males and females at both time points. Associations with infant sex did not differ significantly by maternal BMI. CONCLUSIONS: Among healthy United States mother-infant dyads, appetite, and growth-regulating factors in human milk did not differ significantly by infant sex.