Maternal and fetal parameters in pregnant woman undergoing tocolysis with nifedipine

Alex Sandro Rolland Souza,Gabriela Correia Wanderley,Débora Ialle Pessoa De Sousa,Marcela Rezende Franco,Gláucia Virgínia De Queiroz Lins Guerra,Ellen Caroline Da Silva Girão,Gustavo Fonseca De Albuquerque Souza,Maria Eduarda Vilanova Da Costa Pereira

doi:10.1590/1806-93042020000200007

Abstract

Abstract Objectives: to evaluate the effects of nifedipine with tocolysis under maternal and fetal parameters. Methods: a cohort study with 40 pregnant women admitted at a high-risk pregnancy ward to inhibit premature labor between September/2010 to May/2012. Nifedipine was used as a 20mg sublingual attack dose and maintained 20mg every six and eight hours orally. The variables of the analysis were fetal heart rate (FHR), maternal heart rate (MHR), systolic blood pressure (SBP) and diastolic blood pressure (DBP), and amniotic fluid index (AFI). All the variables were evaluated prior to administrating nifedipine and approximately after 6 hours and every 24 hours, until hospital discharge. Results: there were no modification of the FHR (p=0.48) and the SBP (p=0.29). The MHR increased after 24 hours, but with no statistical difference (p=0.08), returning to similar levels as at admission within 48 hours. The DBP decreased at 6 (p=0.04) to 72 hours, being stable afterwards. The AFI decreased significantly at 24, 48 and 72 hours. Conclusions: the use of high doses of nifedipine with tocolysis causes a decrease of the maternal’s diastolic blood pressure and consequently decreases the amniotic fluid index, but probably without any clinical repercussions.

Highlights

Premature childbirth (PCB) is defined as a pregnancy termination of until the 37th week or 259 days, counting from the first day of the last menstrual period.[1]
It was observed that the use of nifedipine to inhibit premature labor causes a decrease in the maternal diastolic blood pressure levels and a decrease in the amniotic fluid index (AFI), but probably with few clinical repercussions, as the differences were minimal
It is noteworthy that the reduction in the AFI was significant from 24 to 72 hours, being associated with a decrease in the maternal diastolic blood pressure, which began to decrease after 6 hours

Summary

Introduction

Premature childbirth (PCB) is defined as a pregnancy termination of until the 37th week or 259 days, counting from the first day of the last menstrual period.[1]. Nifedipine is a dihydropyridine blocker with low toxicity and teratogenicity which blocks the extracellular calcium influx into the myometrial cell membrane, as well as interacting with intracellular calcium fixed proteins.[9,10,11] This action leads to the relaxation of soft muscles, mainly vascular, uterine and bladder.[9,10,11] The drug has a vasomotor action, maternal and fetal, and a coronary and peripheral vasodilator effect.[9,10] a decrease in the blood pressure is observed in hypertensive pregnant women which is controversial in normotensive.[9,10,11,12,13]

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Results

Conclusion