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 molecular changes that occur during parturition. This study was designed to determine whether myometrial sampling at the time of cesarean delivery increases maternal morbidity. STUDY DESIGN: This is a prospective cohort study including 118 study and 236 control patients. A full-thickness myometrial sample was obtained from the superior edge of a transverse uterine incision at the time of cesarean delivery. Demographics and standard surgical morbidity data were collected. Statistical methods used included univariate and multivariate analysis. RESULTS: The study and control groups did not differ significantly with respect to age, gravidity, parity, birth weight, and Apgar scores. The estimated intraoperative blood loss was greater in the control group (P < .02); however, 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 partum. When study and control patients were stratified into term in labor, term not in labor, preterm in labor, and preterm not in labor categories and compared for maternal morbidity, there were still no significant differences 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 gestational age and the presence or absence of labor.