Prevalence of Hypotension in Threatened Preterm and Preterm Labour Treating with Nifedipine Loading Dose of 30 mg and 40 mg - อุบัติการณ์ความดันโลหิตต่ำ ในสตรีตั้งครรภ์ ที่เจ็บครรภ์คลอดก่อนกำหนดที่ได้รับการรักษา ด้วยยาไนเฟดดิปี นขนาด 30 และ 40 มิลลิกรัม

Abstract

        The purpose of this study was to determine the prevalence of hypotension in threatened preterm and preterm labor treated with nifedipine loading dose 40 mg and 30 mg in the first hour. A total of 92 pregnant women with threatened preterm labour or preterm labour who visited Khon Kaen Hospital between October 2011 – June 2012 were included and randomly assigned to receive either high (40 mg) or low (30 mg) initial loading dose of nifedipine. Blood pressure was evaluated every 30 minutes in the first 2 hours, then every 2 hours until completely 48 hours for detection of hypotension. The medical data of 46 pregnant women in low dose group and 44 in high dose group were analyzed (2 cases in high dose group were excluded). Baseline characteristics were similar between the two groups. The incidence of hypotension in the first hour were lower in the low dose group, 6.5% as compared to 11.4% in the high dose group (p=0.56). The success rate of inhibition of labour was 78.3% and 90.9% in low dose and high dose groups, respectively (p=0.19). Other adverse events were not significantly difference in both groups. Therefore, the incidence of hypotension was similar in both groups; and there was no statistically significant difference for inhibiting preterm labour. Thus, the lower dose regimen of nifedipine was recommended for the management of threatened preterm and preterm labour.

Key words: Nifedipine, hypotension, preterm labour, threatened preterm labour