Francisco Mauad-Filho

Evolução do comprimento cervical uterino na gestação, avaliado pela ultra-sonografia transvaginal

PURPOSE: to establish a normality curve of cervical length during pregnancy measured by transvaginal ultrasonography. METHODS: we conducted a prospective, longitudinal study on 82 healthy pregnant women who were followed up from the beginning of pregnancy to delivery at four-week intervals, of whom 49 concluded the study. Patients were divided according to parity into nulliparous women and women with one or more previous deliveries. Cervical length was measured in a sagittal view by transvaginal ultrasonography, as the linear distance between internal and external cervical os. RESULTS: no significant difference was observed in mean cervical length or the 5th, 25, 50th, 75th, or 95th percentile according to gestational age between groups (p>0.05). Between the 20th and 24th gestacional week, the 5th, 50th and 95th percentiles of cervical length were 28, 35 and 47.2 mm, respectively. Cervical length decreased progressively during normal pregnancy, with a significant shortening observed after 20 weeks of gestation and being more marked after 28 weeks (p<0.05). CONCLUSION: the pattern of cervical length behavior does not seem to differ between nulliparous women and women with one or more previous deliveries. The numerical values of the normality curve of cervical length according to gestational age reflect the variability in the peculiar characteristics of the studied sample, thus emphasizing the value of the parameters established for different populations.

Modificações no índice de líquido amniótico estimado pela ultra-sonografia em gestantes submetidas a imersão subtotal em água

Purpose: to study the changes in amniotic fluid index (AFI) measured by ultrasonography, mean arterial pressure (MAP) and pulse rate in normal pregnant women submitted to subtotal body immersion in water for different periods of time, and to standardize the technique. Methods: AFI values were studied as recommended by Phelan et al.1 in a group of 52 pregnant women with gestational age of 28 weeks or more considered to be clinically normal, before and after exposure to subtotal immersion in water heated to 32 to 34oC for 30, 45 and 60 min. The patients were seen at the Ultrasonography and Medical Updating School of Ribeirao Preto and in the Department of Gynecology and Obstetrics of the Faculty of Medicine of Ribeirao Preto, University of Sao Paulo. Results: before and after immersion, the average of MAP was 87.8 and 87.1 in the group of 30 min, 76.7 and 66.6 in the group of 45 min and 77.4 and 60.7 in the group of 60 min, with statistical significance. Before and after immersion, the means of pulse rates were 74.9 and 78.7 in the group of 30 min, 83.6 and 85.2 in the group of 45 min and 84.9 and 90.6 in the group of 60 min, with statistical significance. The mean of AFI also showed statistical significance. When submitted to 30-min immersion the means of AFI were 11.7 cm before and 16.8 cm after. In the group of 45 min, the averages were 9.7 cm before and 13.8 cm after immersion. In the group of 60 min, the averages were 9.5 cm before and 13.6 cm after immersion. The time of immersion of 30-min was as effective and ample as 45 or 60 min. Conclusions: subtotal immersion in water is a safe and practical procedure that can mobilize fluids during pregnancy, increasing amniotic fluid volume.

Investigação do fluxo expiratório máximo em gestantes saudáveis

PURPOSE: to investigate the normal peak expiratory flow values in healthy pregnant women employing a portable expiratory apparatus (Mini-Wright Peak Flow Meter), and to relate the obtained measurements to each patients height, body mass index (BMI) and age, along gestation. METHODS: a longitudinal prospective study including 26 pregnant women followed up from the first trimester to the 36th week of gestation and examined every four weeks. On the occasion of seven visits, the pregnant women performed forced exhaling into a portable expiratory apparatus three times, with the highest value being considered the peak expiratory flow. All measurements were made under the same investigators supervision in order to reduce the margin of error. Pearson coefficient was used to calculate the correlation between flow and BMI, between flow and patients height, and between flow and patients age. RESULTS: the variation in flow values during pregnancy can be determined by flow = 328.32 -0.07 x week, with a Pearson coefficient equal to zero. To determine whether there was a difference in the correlation coefficients between BMI and flow, we compared the lowest coefficient (0.47 for week 30, flow = 123.49 + 7.64 x BMI) with the highest coefficient (0.59 for week 34, flow = 87.77 + 9.05 x BMI) of each studied time interval and obtained a value of 0.22, indicating a good correlation between the flow and BMI variables. There was a positive correlation between height and flow (Pearson = 0.61), with flow = -477.47 + 497.38 x height. The correlation coefficient between flow and age was 0.24, with the equation obtained in this case being non-linear. CONCLUSIONS: peak expiratory flow values did not change along gestation. Higher flows were observed in taller women. Pregnant women with a higher BMI before gestation presented higher flows. There was no correlation between flow and maternal age.

Antiretroviral agents and acid-base balance at delivery of the neonate

Limited evidence is available regarding antiretroviral (ARV) safety for uninfected infants exposed to these drugs in utero. Our objective was to determine if ARV administered to pregnant women is associated with decreasing umbilical arterial pH and base excess in uninfected infants. A prospective study was conducted on 57 neonates divided into three groups: ZDV group, born to mothers taking zidovudine (N = 20), triple therapy (TT) group, born to mothers taking zidovudine + lamivudine + nelfinavir (N = 25), and control group (N = 12), born to uninfected mothers. Umbilical cord blood was used to determine umbilical artery gases. A test was performed to calculate the sample by comparing means by the unpaired one-tailed t-test, with alpha = 0.05 and beta = 20%, indicating the need for a sample of 18 newborn infants for the study groups to detect differences higher than 20%. The control and ARV groups were similar in gestational age, birth weight, and Apgar scores. Values of pH, pCO2, bicarbonate, and base excess in cord arterial blood obtained at delivery from the newborns exposed to TT were 7.23, 43.2 mmHg, 19.5 mEq/L, and -8.5 nmol/L, respectively, with no significant difference compared to the control and ZDV groups. We conclude that intrauterine exposure to ARV is not associated with a pathological decrease in umbilical arterial pH or base excess. While our data are reassuring, follow-up is still limited and needs to be continued into adulthood because of the possible potential for adverse effects of triple antiretroviral agents.

Effects of maternal and fetal plasma from toxemic patients on the vasomotility of the human umbilical artery

Maternal and fetal plasmas from patients with specific hypertensive disease of pregnancy (SHDP) are shown to have a greater vasoconstrictive effect on perfused human unbilical artery than plasma from normal parturients. The vasomotility of isolated segments of artery was determined by measuring perfusion pressure at constant flow rate. The differences were demonstrable with plasmas and artery segments from the same parturients and also when plasma from patients with SHDP and arteries from normal parturients were used. These results, which show that plasmas from SHDP patients have a larger vasoconstrictive effect on human umbilical artery than normal plasma, support and extend the suggestion that there may be humoral mechanism which participates in the physiopathology of SHDP. This humoral factor can be detected with human umbilical artery from both normal and SHDP parturients.

Efeitos da ingestão de glicose sobre a circulação materno-fetal

PURPOSE: to analyze the effect of glucose in the materno-fetal hemodynamics through dopplervelocimetric assessment of the materno-fetal and fetoplacentary circulation. METHODS: the study was carried out by a single observer on 31 clinically healthy pregnant women from the 28th to the 36th gestational week. Parameters were assessed immediately before or 60 minutes after the ingestion of 50 g of glucose. The including criteria comprised normal clinical and laboratorial evaluation, the presence of only one fetus, gestational age between 28 and 36 weeks confirmed by ultrasonography and/or the date of the last menstruation, fasting glycemia less or equal to 110 mg/dL and less than 140 mg/dL after 50 g of glucose overload. The excluding criteria consisted of the presence of fetal malformation or development alterations, labor, diabetes as a family predisposition, pathologies due to or underlying gestation and use of tobacco, alcohol and/or other substances. The mother´s common carotid artery and uterine arteries, the umbilical artery and the fetal medial cerebral artery and abdominal aorta were evaluated. In each blood vessel, the following parameters were analyzed: resistance index, pulsatility index, maximum systolic speed, final diastolic speed and acceleration time. The fetal heart rate was evaluated by M Mode ultrasonography. For the statistical analysis, the Students t test was used when the variable presented normal distribution in Kolmogorov-Smirnovs test. When normality was rejected, the Wilcoxons non-parametric test was used, with the significance level always established at p<0.05. RESULTS: the maternal glycemia increased after the ingestion of 50 g of glucose (before: 68.0±10.1 mg/dL and after: 104.6±28.2 mg/dL; p<0.001), and fetal heart rate decreased after the glucose ingestion (before: 137.9±6.1 bpm and after: 134.5±6.9 bpm; p<0.001). The umbilical artery presented an increase in the pulsatility index (before: 0.8±0.1 and after: 0.9±0.2; p=0.03). Significant velocimetric alterations were not found in the other vessels or in the other indexes investigated. CONCLUSIONS: in spite of the variation in the levels of maternal glycemia and in the fetal heart rate following glucose ingestion, no significant flow alteration occurred in the following vessels: umbilical artery, fetal medial cerebral artery and aorta; nor in the carotid and uterine maternal arteries. We conclude that the glucose concentration used was released without hemodynamic interference in the materno-fetal compartment.