The dosage used in this study is equivalent to that commonly used, intravenous salbutamol infusion dose of 6-30 μg/min, to inhibit preterm labor.18 Beta-adrenergic agonists increase the blood glucose levels by promoting glucagon release, gluconeogenesis and insulin resistance.19 Although none of our patients developed increased blood glucose, it must be kept in mind that women with diabetes were excluded from the study. This evidence concerns the gene INS and diabetes mellitus.