Effect of maternal body mass index on in vitro response to tocolytics in term myometrium

ObjectiveWe sought to investigate the effect of body mass index (BMI) on in vitro response to tocolytics.Study DesignMyometrial biopsies were obtained at the time of scheduled cesarean deliveries from term nonlaboring women with BMI ≤29.9 (26.3 ± 1.3; n = 7), 30-34.9 (31.8 ± 1.2; n = 16), and ≥35 (39.5 ± 4.9; n = 9). Tissue strips were suspended in organ chambers for isometric tension recording. The effects of cumulative doses (10−10 to 10−5 mol/L) of nifedipine or indomethacin on spontaneous uterine contractility were determined. Areas under the contraction curve were compared using 1-way analysis of variance with Tukey post hoc test.ResultsMyometrial response to tocolytics did not differ between the BMI groups. Nifedipine, but not indomethacin, significantly inhibited myometrial contractility independent of BMI.ConclusionBMI does not affect uterine response to tocolytics in isolated uterine tissue from term nonlaboring women.