Doppler velocimetry of the uterine, umbilical and fetal middle cerebral arteries in pregnant women undergoing tocolysis with oral nifedipine

Abstract

Objectives To evaluate Doppler velocimetry (resistance index (RI) and peak systolic velocity (PSV)) in the maternal-fetal circulation before and 5 and 24 h after tocolysis with oral nifedipine. Methods

Hotelling's test, multiple t‐tests, and uterine artery Doppler evaluation

“…Although this observation is correct, in the paper we report that PSV may be useful for interpreting these findings, not that these measurements are directly related to the results 1 . What happened in the first 5 h is that a reduction occurred in systolic velocity that was compensated for by the simultaneous fall in diastolic velocity.…”

“…The standard deviation used for the calculation was indeed 0.05 and not 0.005, and the value found was 44 and not 33 1 . With respect to the reference, it should be explained that these values were obtained from an unpublished pilot study carried out in the first 20 patients, since data found in the literature were insufficient to enable this calculation to be made.…”

“…We appreciate Dr Martins' interest in our paper 1 and would like to take this opportunity to address the points that have been raised. Firstly, the objective of this study was not, even indirectly, to evaluate the fetal safety of nifedipine as a tocolytic agent.…”

“…I read with interest the paper by Lima et al in the September 2009 edition of Ultrasound in Obstetrics and Gynecology 1 . The authors assessed pregnant women showing evidence of premature labor who were given oral nifedipine as a tocolytic agent, performing Doppler ultrasound evaluation before drug administration and after 5 and 24 h. Two Doppler ultrasound parameters, resistance index (RI) and peak systolic velocity (PSV), were recorded from three vessels: maternal uterine, fetal middle cerebral (MCA) and umbilical arteries.…”

Desfechos maternos e perinatais em gestantes com líquido amniótico diminuído

“…Os inibidores da prostaglandina sintetase, como os anti-inflamatórios não hormonais e a dipirona, e os inibidores da enzima conversora de angiotensina provocam redução do fluxo vascular renal fetal e consequente oligohidrâmnio 10,11 . Outra droga pouco estudada, mas que pode causar o oligohidrâmnio, é a nifedipina 12 . O líquido amniótico reduzido pode se associar aos resultados perinatais desfavoráveis, tanto devido às causas como pelas suas consequências sobre o feto 8,9,13,14 .…”