OBJECTIVE: To determine a reference curve for the peak systolic velocity of fetal middle cerebral artery. MATERIALS AND METHODS: The authors developed a cross-sectional study with 143 healthy pregnant women between the 23rd and 35th gestational weeks. A bidimensional axial scan of the fetal skull was performed, including the thalami and pellucid septum. Subsequently, the middle cerebral artery was visualized with the color Doppler mode. The pulsed-wave Doppler transducer was positioned over the origin of this vessel, at < 20° insonation angle. The correlation between the peak systolic velocity of the middle cerebral artery and gestational age was evaluated by means of the Pearson's correlation coefficient (r). Regression models were utilized in the construction of a table with multiples of the medians of the middle cerebral artery peak systolic velocity for each gestational age. Additionally, reference values for this variable were determined. RESULTS: A strong correlation was observed between the middle cerebral artery peak systolic velocity and gestational age (r = 0.70; p < 0.001). Values of middle cerebral artery peak systolic velocity were calculated for the following multiples of the medians: 1.0, 1.29, 1.5, 1.55. The 2.5th and 97.5th percentiles were determined for the middle cerebral artery peak systolic velocity ranging between 24.33 cm²/s and 78.36 cm²/s. CONCLUSION: A nomogram for the fetal middle cerebral artery peak systolic velocity during the second half of pregnancy was generated.

Keywords: Middle cerebral artery, Doppler, Ultrasonography, Nomogram, Fetus

OBJECTIVE: To evaluate and compare existing ultrasound findings in women with Rh-alloimmunized pregnancies with diagnosis of fetal anemia by spectrophotometric analysis of amniotic fluid or Doppler ultrasound of the fetal middle cerebral artery. MATERIALS AND METHODS: This was an observational descriptive study involving 99 patients evaluated between January 1995 and January 2004. Patients were divided into two groups: 74 Rh-isoimmunized women submitted to spectrophotometry of the amniotic fluid (group S) and 25 Rh-isoimmunized women submitted to Doppler ultrasound of fetal middle cerebral artery (group D) to evaluate fetal anemia. Ultrasound findings in the two groups were compared. RESULTS: Placental anomalies, mainly placentomegaly and textural irregularities were more frequently seen in pregnant women followed up with spectrophotometry of the amniotic fluid compared to those followed up with Doppler ultrasound (64% X 32%, p = 6,294). CONCLUSION: The frequency of abnormal ultrasound findings was 2-fold higher in pregnancies evaluated with spectrophotometry of the amniotic fluid compared to those followed up with Doppler ultrasound.

Keywords: Red blood cell isoimmunization, Fetal anemia, Middle cerebral artery, Doppler ultrasonography, Isoantibodies, Fetal erythroblastosis

Objective: To evaluate the possible repercussions of the previous cesarean scar at uterine arteries Doppler velocimetry between the 26th and 32nd gestational weeks. Materials and Methods: Prospective cross-sectional study including 45 women between 11 and 14 weeks of gestation, divided into three groups: 17 pregnant women with uterine scar resulting from a previous elective cesarean section (group A); 14 with uterine scar resulting from a previous cesarean section performed during labor (group B); and 14 pregnant women with a single previous vaginal delivery (group C). Uterine arteries Doppler velocimetry was performed with transabdominal approach. Means, medians and standard deviation (SD) were calculated for each group in the study. The groups comparison regarding pulsatility index was performed with the non-parametric Kruskal-Wallis test. Results: In group A, the pulsatility index ranged from 0.60 to 1.60 (mean: 0.90; SD: 0.29), in group B, from 0.53 to 1.43 (mean: 0.87; SD: 0.24), and in group C, from 0.65 to 1.65 (mean: 1.01; SD: 0.37); with p = 0.6329. Conclusion: No repercussion of previous cesarean scar was observed at uterine arteries Doppler velocimetry performed in the period between the 26th and 32nd gestational weeks.

Keywords: Pregnancy; Uterine scar; Previous cesarean section; Uterine arteries Doppler velocimetry.