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Revista Brasileira de Ginecologia e Obstetrícia. 2017;39(6):309-314
To describe the prenatal diagnosis of Galen vein aneurysm (GVA) based on ultrasonography and magnetic resonance imaging (MRI) in a series of cases, as well as its postnatal outcomes and follow-up until 4 years of age.
A retrospective longitudinal study was performed, analyzing a database comprising seven cases of prenatal diagnosis of GVA at two Brazilian institutions from February of 2000 to May of 2012. The following data were evaluated: gestational age at diagnosis, GVA dimensions on ultrasonography, associated fetal changes, findings on fetal echocardiography, gestational age at delivery, type of delivery, birth weight, Apgar score at the 1st and 5th minutes, neonatal outcomes, and survival with follow-up until 4 years of age.
The mean gestational age ± standard deviation on the prenatal diagnosis of GVA based on ultrasonography was 25±4.9 weeks. The mean length of GVA was 3.2±0.4 cm. The mean gestational age at birth was 37.5±0.7 weeks, and a cesarean section was performed in 85.7% of the cases (6/7). The mean birth weight was 3,070±240.4 g. The total survival rate was 42.8% (4/7), with three neonatal deaths. Of the four survivors, three presented with normal neuropsychomotor development until 4 years of age and only one showed serious neurological sequelae. Ultrasonography and MRI showed similar findings for all seven cases.
Galen Vein Aneurysm is associated with a high neonatal death rate. Therefore, its prenatal diagnosis is essential for parent counseling and follow-up at tertiary care institutions.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2017;39(6):309-314
To describe the prenatal diagnosis of Galen vein aneurysm (GVA) based on ultrasonography and magnetic resonance imaging (MRI) in a series of cases, as well as its postnatal outcomes and follow-up until 4 years of age.
A retrospective longitudinal study was performed, analyzing a database comprising seven cases of prenatal diagnosis of GVA at two Brazilian institutions from February of 2000 to May of 2012. The following data were evaluated: gestational age at diagnosis, GVA dimensions on ultrasonography, associated fetal changes, findings on fetal echocardiography, gestational age at delivery, type of delivery, birth weight, Apgar score at the 1st and 5th minutes, neonatal outcomes, and survival with follow-up until 4 years of age.
The mean gestational age ± standard deviation on the prenatal diagnosis of GVA based on ultrasonography was 25±4.9 weeks. The mean length of GVA was 3.2±0.4 cm. The mean gestational age at birth was 37.5±0.7 weeks, and a cesarean section was performed in 85.7% of the cases (6/7). The mean birth weight was 3,070±240.4 g. The total survival rate was 42.8% (4/7), with three neonatal deaths. Of the four survivors, three presented with normal neuropsychomotor development until 4 years of age and only one showed serious neurological sequelae. Ultrasonography and MRI showed similar findings for all seven cases.
Galen Vein Aneurysm is associated with a high neonatal death rate. Therefore, its prenatal diagnosis is essential for parent counseling and follow-up at tertiary care institutions.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 1998;20(8):443-448
DOI 10.1590/S0100-72031998000800003
Purpose: to demonstrate the interobserver variation existing in the ultrasonographic measurement of amniotic fluid index (AFI) and in the measurement of pocket area, and to compare these two methods. In addition, an attempt was made to establish the intraobserver variation in the measurement of this index. Methods: values of AFI, described by Phelan et al.18, were studied in a group of 80 pregnant women considered to be clinically normal, seen at the Ultrasonography and Medical Updating School of Ribeirão Preto and in the Department of Gynecology and Obstetrics of the Faculty of Medicine of Ribeirão Preto, University of São Paulo (FMRP-USP). All pregnant women had a gestational age of more than 24 weeks. Fifty of these patients were submitted to AFI evaluation by 5 different ultrasonographists using the same equipment and during the same period of time, in order to determine the interobserver variation of this index. In addition, planimetric measurement of the area was performed by 2 of these 5 ultrasonographists, selected at random, in an attempt to determine interobserver variation in area measurement. Another group of 30 pregnant women was evaluated by the same ultrasonographist in an attempt to evaluate intraobserver variation in terms of AFI measurement. Results: There was a significant interobserver variation in AFI measurement and a significant variation in area measurement. However, the intraobserver variation in AFI measurement was nonsignificant. There was a correlation between AFI and area measurements. Conclusions: we emphasize the obstetrical applicability of this index and the easier execution of this method compared to area measurement, despite the importance of both procedures.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 1998;20(8):443-448
DOI 10.1590/S0100-72031998000800003
Purpose: to demonstrate the interobserver variation existing in the ultrasonographic measurement of amniotic fluid index (AFI) and in the measurement of pocket area, and to compare these two methods. In addition, an attempt was made to establish the intraobserver variation in the measurement of this index. Methods: values of AFI, described by Phelan et al.18, were studied in a group of 80 pregnant women considered to be clinically normal, seen at the Ultrasonography and Medical Updating School of Ribeirão Preto and in the Department of Gynecology and Obstetrics of the Faculty of Medicine of Ribeirão Preto, University of São Paulo (FMRP-USP). All pregnant women had a gestational age of more than 24 weeks. Fifty of these patients were submitted to AFI evaluation by 5 different ultrasonographists using the same equipment and during the same period of time, in order to determine the interobserver variation of this index. In addition, planimetric measurement of the area was performed by 2 of these 5 ultrasonographists, selected at random, in an attempt to determine interobserver variation in area measurement. Another group of 30 pregnant women was evaluated by the same ultrasonographist in an attempt to evaluate intraobserver variation in terms of AFI measurement. Results: There was a significant interobserver variation in AFI measurement and a significant variation in area measurement. However, the intraobserver variation in AFI measurement was nonsignificant. There was a correlation between AFI and area measurements. Conclusions: we emphasize the obstetrical applicability of this index and the easier execution of this method compared to area measurement, despite the importance of both procedures.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2006;28(10):575-580
DOI 10.1590/S0100-72032006001000002
PURPOSE: To determine the values of amniotic fluid in normal fetuses during the first trimester of pregnancy by three- and bi-dimensional ultrasonography. METHODS: In a prospective longitudinal study, 25 normal fetuses were evaluated from the 8th to the 11th week of gestation. Amniotic fluid volume was measured by endovaginal ultrasonography with the three- and two-dimensional modes. The two-dimensional study consisted of volumetric determination by mathematical calculation based on an ellipsoidal shape (constant 0.52) to obtain the amniotic sac and embryo volumes. In the three-dimensional study, the amniotic fluid volume was determined by the VOCAL technique using 6, 9, 15, and 30 degrees of rotation. The amniotic fluid volume obtained by 6-degree rotations was considered to be the final result. In both modes, amniotic fluid volume was obtained by subtracting the volume of the embryo from the volume of the amniotic sac. Data were analyzed statistically for variance (ANOVA), correlation and regression analysis. The level of significance was set at p < 0.05. RESULTS: The amniotic fluid volume as measured by two-dimensional ultrasonography increased from 5.45 to 39.52 cm³ in the range from the 8th to the 11th week (ANOVA - p < 0.05). There was a correlation between gestational age and amniotic fluid volume (p < 0.001, r² = 88.3%). In the three-dimensional study, the amniotic fluid volume increased from 5.7 to 42.9 cm³ in the range from the 8th to the 11th week (ANOVA - p < 0.05), and again a correlation between gestational age and amniotic fluid volume (p < 0.001, r² = 98.1%) was observed. CONCLUSION: an increase in amniotic fluid volume occurs during the first trimester of pregnancy, as determined by the two- and three-dimensional modes. In addition, we have demonstrated that the higher the gestational age, the larger the amniotic fluid volume.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2006;28(10):575-580
DOI 10.1590/S0100-72032006001000002
PURPOSE: To determine the values of amniotic fluid in normal fetuses during the first trimester of pregnancy by three- and bi-dimensional ultrasonography. METHODS: In a prospective longitudinal study, 25 normal fetuses were evaluated from the 8th to the 11th week of gestation. Amniotic fluid volume was measured by endovaginal ultrasonography with the three- and two-dimensional modes. The two-dimensional study consisted of volumetric determination by mathematical calculation based on an ellipsoidal shape (constant 0.52) to obtain the amniotic sac and embryo volumes. In the three-dimensional study, the amniotic fluid volume was determined by the VOCAL technique using 6, 9, 15, and 30 degrees of rotation. The amniotic fluid volume obtained by 6-degree rotations was considered to be the final result. In both modes, amniotic fluid volume was obtained by subtracting the volume of the embryo from the volume of the amniotic sac. Data were analyzed statistically for variance (ANOVA), correlation and regression analysis. The level of significance was set at p < 0.05. RESULTS: The amniotic fluid volume as measured by two-dimensional ultrasonography increased from 5.45 to 39.52 cm³ in the range from the 8th to the 11th week (ANOVA - p < 0.05). There was a correlation between gestational age and amniotic fluid volume (p < 0.001, r² = 88.3%). In the three-dimensional study, the amniotic fluid volume increased from 5.7 to 42.9 cm³ in the range from the 8th to the 11th week (ANOVA - p < 0.05), and again a correlation between gestational age and amniotic fluid volume (p < 0.001, r² = 98.1%) was observed. CONCLUSION: an increase in amniotic fluid volume occurs during the first trimester of pregnancy, as determined by the two- and three-dimensional modes. In addition, we have demonstrated that the higher the gestational age, the larger the amniotic fluid volume.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2006;28(1):38-43
DOI 10.1590/S0100-72032006000100007
PURPOSE: to determine the intraobserver and interobserver reproducibility of endometrial volume measurements using the VOCAL®-imaging program (Virtual Organ Computer-aided AnaLysis). METHODS: one three-dimensional (3-D) ultrasound dataset of the endometrium was obtained from each of five infertile women with different endometrial volumes. For each 3-D dataset, the endometrial volume was calculated by two different observers using the manual mode in four different rotational steps (30º, 15º, 9º and 6º). Ten measurements were obtained with each method and observer from each 3-D dataset. We have used one-way ANOVA and the Tukey post-test to verify the differences among means and the intraclass correlation coefficient to test reliability. RESULTS: rotational methods employing a rotation step of 30º were associated with lower endometrial volume readings in 3 of the 5 patients. There were no significant differences between the means obtained by the 15º, 9º or 6º step rotation. No significant difference was found between the means obtained by the two different observers. The intraclass correlation coefficients were significantly lower with 30º (all under 0.984) than with the other step rotations (all above 0.996). CONCLUSIONS: the use of a rotational step of 15º or less provides reliable readings of endometrial volume: there were no significant differences between the means calculated by the two observers, associated with highintraclass correlation coefficient (>0.996). We recommend the 15º step rotation because it is quicker to be performed than 6º and 9º.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2006;28(1):38-43
DOI 10.1590/S0100-72032006000100007
PURPOSE: to determine the intraobserver and interobserver reproducibility of endometrial volume measurements using the VOCAL®-imaging program (Virtual Organ Computer-aided AnaLysis). METHODS: one three-dimensional (3-D) ultrasound dataset of the endometrium was obtained from each of five infertile women with different endometrial volumes. For each 3-D dataset, the endometrial volume was calculated by two different observers using the manual mode in four different rotational steps (30º, 15º, 9º and 6º). Ten measurements were obtained with each method and observer from each 3-D dataset. We have used one-way ANOVA and the Tukey post-test to verify the differences among means and the intraclass correlation coefficient to test reliability. RESULTS: rotational methods employing a rotation step of 30º were associated with lower endometrial volume readings in 3 of the 5 patients. There were no significant differences between the means obtained by the 15º, 9º or 6º step rotation. No significant difference was found between the means obtained by the two different observers. The intraclass correlation coefficients were significantly lower with 30º (all under 0.984) than with the other step rotations (all above 0.996). CONCLUSIONS: the use of a rotational step of 15º or less provides reliable readings of endometrial volume: there were no significant differences between the means calculated by the two observers, associated with highintraclass correlation coefficient (>0.996). We recommend the 15º step rotation because it is quicker to be performed than 6º and 9º.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2004;26(2):147-151
DOI 10.1590/S0100-72032004000200010
PURPOSE: to assess the length of the uterine cervix by transvaginal ultrasonography in pregnant women with preterm premature rupture of membranes. METHODS: the study group (Ge) consisted of 26 pregnant women with gestational age between 24 and 36 weeks and the control group (Gc) of 49 clinically normal patients at the same gestational age. The patients were evaluated between the 24th to 28th, 28th to 32th and 32th to 36th weeks. The groups were divided into subgroups Ge24-28, Ge28-32, Ge32-36 and Gc24-28, Gc28-32, Gc32-36, according to the study or control group. The cervix length was measured by transvaginal ultrasonography as the linear distance between the internal and external cervical os. RESULTS: we observed significant differences in cervix length between Ge24-28 and Gc24-28 groups whose values were, respectively, 24.3 and 33.0 mm (p=0.04), and between Ge32-36 and Gc32-36, 20.1 and 28.0 mm, respectively (p=0.005). The latency periods of Ge24-28, Ge28-32 and Ge32-36 were, respectively, seven, five and three days, showing a positive correlation with cervix length (r=0.66) and a negative correlation with gestational age (r=-0.27). CONCLUSIONS: the length of the uterine cervix varied with the gestational age when premature preterm rupture of the membranes was detected, with the length being shorter in the study group than in the control group betweeen the 24th and 28th and 32th and 36th weeks. In addition, it was demonstrated that, the shorter the cervix length, the shorter the latency time, with a reduction in the latency period with increasing gestational age at the time of rupture.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2004;26(2):147-151
DOI 10.1590/S0100-72032004000200010
PURPOSE: to assess the length of the uterine cervix by transvaginal ultrasonography in pregnant women with preterm premature rupture of membranes. METHODS: the study group (Ge) consisted of 26 pregnant women with gestational age between 24 and 36 weeks and the control group (Gc) of 49 clinically normal patients at the same gestational age. The patients were evaluated between the 24th to 28th, 28th to 32th and 32th to 36th weeks. The groups were divided into subgroups Ge24-28, Ge28-32, Ge32-36 and Gc24-28, Gc28-32, Gc32-36, according to the study or control group. The cervix length was measured by transvaginal ultrasonography as the linear distance between the internal and external cervical os. RESULTS: we observed significant differences in cervix length between Ge24-28 and Gc24-28 groups whose values were, respectively, 24.3 and 33.0 mm (p=0.04), and between Ge32-36 and Gc32-36, 20.1 and 28.0 mm, respectively (p=0.005). The latency periods of Ge24-28, Ge28-32 and Ge32-36 were, respectively, seven, five and three days, showing a positive correlation with cervix length (r=0.66) and a negative correlation with gestational age (r=-0.27). CONCLUSIONS: the length of the uterine cervix varied with the gestational age when premature preterm rupture of the membranes was detected, with the length being shorter in the study group than in the control group betweeen the 24th and 28th and 32th and 36th weeks. In addition, it was demonstrated that, the shorter the cervix length, the shorter the latency time, with a reduction in the latency period with increasing gestational age at the time of rupture.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2003;25(9):673-678
DOI 10.1590/S0100-72032003000900009
PURPOSE: to evaluate the uterine volume in women between 10 and 40 years in order to observe if the uterine volume in adolescents is smaller than the uterine volume in women between 20 and 40 years. We intend to emphasize the differences between the uterine volume of adolescents and that of adult women and to correlate with the immaturity of the genital tract of adolescents regarding gestation and delivery. METHOD: a cross-sectional study, which included 828 patients between 10 and 40 years old divided into two groups and examined using abdominal ultrasound to obtain the uterine volume measure. The first group consisted of 477 (57.7%) adolescents, and the second group of 351 (42.3%) adult women between 20 and 40 years old. In the adolescent group, ultrasound examination was performed by a single observer and in the group of adult women ultrasound examination was performed by a group of observers who used the same methodology as that of group 1. Image Point HX (Hewlett Packard) and Hitachi 525 ultrasound equipment were used with a multiple frequency probe. For the calculation of the uterine volume we used the longitudinal diameter (LD), anteroposterior diameter (APD) and transverse diameter (TD) with the (LD x APD x TD) x 0.45 formula. RESULTS: adolescents aged 10 to 17 years had a smaller uterine volume than women aged 20 to 40 years (p<0.05). Adolescents who delivered twice had a uterine volume similar to that of the patients between 20 and 40 years old with respective mean values of 62.6 ± 20.6 and 69.0±22.9 (p>0.05). CONCLUSION: adolescents less than 18 years old or primiparous have a smaller uterine volume than women between 20 to 40 years old. However, adolescents aged 18 years or older, or secundipara, have a uterine volume similar to that of women aged 20 to 40 years.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2003;25(9):673-678
DOI 10.1590/S0100-72032003000900009
PURPOSE: to evaluate the uterine volume in women between 10 and 40 years in order to observe if the uterine volume in adolescents is smaller than the uterine volume in women between 20 and 40 years. We intend to emphasize the differences between the uterine volume of adolescents and that of adult women and to correlate with the immaturity of the genital tract of adolescents regarding gestation and delivery. METHOD: a cross-sectional study, which included 828 patients between 10 and 40 years old divided into two groups and examined using abdominal ultrasound to obtain the uterine volume measure. The first group consisted of 477 (57.7%) adolescents, and the second group of 351 (42.3%) adult women between 20 and 40 years old. In the adolescent group, ultrasound examination was performed by a single observer and in the group of adult women ultrasound examination was performed by a group of observers who used the same methodology as that of group 1. Image Point HX (Hewlett Packard) and Hitachi 525 ultrasound equipment were used with a multiple frequency probe. For the calculation of the uterine volume we used the longitudinal diameter (LD), anteroposterior diameter (APD) and transverse diameter (TD) with the (LD x APD x TD) x 0.45 formula. RESULTS: adolescents aged 10 to 17 years had a smaller uterine volume than women aged 20 to 40 years (p<0.05). Adolescents who delivered twice had a uterine volume similar to that of the patients between 20 and 40 years old with respective mean values of 62.6 ± 20.6 and 69.0±22.9 (p>0.05). CONCLUSION: adolescents less than 18 years old or primiparous have a smaller uterine volume than women between 20 to 40 years old. However, adolescents aged 18 years or older, or secundipara, have a uterine volume similar to that of women aged 20 to 40 years.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2003;25(6):437-442
DOI 10.1590/S0100-72032003000600009
PURPOSE: to study the evolution of the resistance and pulsatility indices, maximum velocity, final diastolic velocity and time of acceleration of the middle cerebral artery of fetuses between 22 and 38 weeks of gestation. METHODS: a prospective and longitudinal observational study was conducted on 33 fetuses of normal pregnant women evaluated between 22 and 38 weeks of pregnancy. The gestational age was determined on the basis of the date of the last menstruation and/or by ultrasound examination during the first trimester. Doppler ultrasound examination was performed by a single observer using an Image Point 1800 (Hewlett Packard) apparatus equipped with a multiple frequency transducer. For the acquisition of the Doppler tracing of the middle cerebral artery, the sample indicator was calibrated for a sample volume of 1 mm³ and placed on the anterior middle cerebral artery as close as possible to the skullcap. The insonation angle was kept between 5º and 19º and the filter was adjusted to a frequency of 50-100 Hz. The newborn infants were evaluated in order to confirm that the fetuses were vigorous and adequate for gestational age. RESULTS: the results obtained for the resistance and pulsatility indices revealed a 2nd-degree equation, representing a parabola whose values for the resistance index were 0.81 during the 22nd week and 0.75 during the 38th week. The pulsatility index was 1.59 during the 22nd week and 1.45 during the 38th week. Maximum systolic velocity increased progressively along pregnancy, with values of 26.3 cm/s during the 22nd week and 57.7 cm/s during the 38th week. Final diastolic velocity increased progressively from the 26th week (5.21 cm/s) to term (14.6 cm/s). Acceleration time increased significantly only between 26 and 30 weeks, with values of 0.04 s during the 26th week and 0.05 s during the 30th week. CONCLUSION: it was concluded that the evolution of the resistance and pulsatility indices and of maximum systolic velocity were similar to those of most studies described in the literature. Acceleration time presented few modifications during the evaluated gestational weeks.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2003;25(6):437-442
DOI 10.1590/S0100-72032003000600009
PURPOSE: to study the evolution of the resistance and pulsatility indices, maximum velocity, final diastolic velocity and time of acceleration of the middle cerebral artery of fetuses between 22 and 38 weeks of gestation. METHODS: a prospective and longitudinal observational study was conducted on 33 fetuses of normal pregnant women evaluated between 22 and 38 weeks of pregnancy. The gestational age was determined on the basis of the date of the last menstruation and/or by ultrasound examination during the first trimester. Doppler ultrasound examination was performed by a single observer using an Image Point 1800 (Hewlett Packard) apparatus equipped with a multiple frequency transducer. For the acquisition of the Doppler tracing of the middle cerebral artery, the sample indicator was calibrated for a sample volume of 1 mm³ and placed on the anterior middle cerebral artery as close as possible to the skullcap. The insonation angle was kept between 5º and 19º and the filter was adjusted to a frequency of 50-100 Hz. The newborn infants were evaluated in order to confirm that the fetuses were vigorous and adequate for gestational age. RESULTS: the results obtained for the resistance and pulsatility indices revealed a 2nd-degree equation, representing a parabola whose values for the resistance index were 0.81 during the 22nd week and 0.75 during the 38th week. The pulsatility index was 1.59 during the 22nd week and 1.45 during the 38th week. Maximum systolic velocity increased progressively along pregnancy, with values of 26.3 cm/s during the 22nd week and 57.7 cm/s during the 38th week. Final diastolic velocity increased progressively from the 26th week (5.21 cm/s) to term (14.6 cm/s). Acceleration time increased significantly only between 26 and 30 weeks, with values of 0.04 s during the 26th week and 0.05 s during the 30th week. CONCLUSION: it was concluded that the evolution of the resistance and pulsatility indices and of maximum systolic velocity were similar to those of most studies described in the literature. Acceleration time presented few modifications during the evaluated gestational weeks.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2003;25(2):115-121
DOI 10.1590/S0100-72032003000200007
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 20thand 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.
Summary
Revista Brasileira de Ginecologia e Obstetrícia. 2003;25(2):115-121
DOI 10.1590/S0100-72032003000200007
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 20thand 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.
