Is human myometrial sampling at the time of cesarean delivery safe?

OBJECTIVE: The mechanism for the initiation of human labor remains unknown and is under extensive investigation. Myometrium from patients in labor and not in labor is the ideal tissue to study structural, cellular, and molecu lar changes that occur during parturition. This study was designed to deter mine whether myometrial sampling at the time of cesarean delivery increases maternal morbidity. STUDY DESIGN: This is a prospective cohort study including 118 study and 23 6 control patients. A full-thickness myometrial sample was obtained from th e superior edge of a transverse uterine incision at the time of cesarean de livery. Demographics and standard surgical morbidity data were collected. S tatistical methods used included univariate and multivariate analysis. RESULTS: The study and control groups did not differ significantly with res pect to age, gravidity, parity, birth weight, and Apgar scores. The estimat ed intraoperative blood loss was greater in the control group (P < .02); ho wever, the change in hematocrit level (preoperative vs postoperative values ) was not different. There were no significant differences in the rates of endometritis, wound infection, and venous thrombosis up to 6 weeks post par tum. When study and control patients were stratified into term in labor, te rm not in labor, preterm in labor, and preterm not in labor categories and compared for maternal morbidity, there were still no significant difference s for any of the outcome measures evaluated. CONCLUSION: On the basis of our data, human myometrial sampling at cesarean delivery does not increase overall maternal morbidity, irrespective of ges tational age and the presence or absence of labor.