Second trimester cervical length measurement for prediction spontaneous preterm birth in an unselected risk population.

OBJECTIVE: To assess the predictive capacity of cervical length (CL) measurement underwent during the second trimester ultrasound for prediction preterm birth <32, 34, and 37 weeks of gestation in an unselected risk population. METHODS: A retrospective cohort study was performed with 751 singleton pregnancies between 20 and 24+6 weeks of gestation. The CL measurement (mm) using the transvaginal route was obtained in a sagittal view and the calipers positioned to measure the linear distance between the triangular area of echodensity at the external os and the internal os. To compare the preterm (<37 weeks) and term births (≥37 weeks), we used unpaired t test. We assessed whether the CL measurement was dependent of gestational age by performing a linear regression and assessing the coefficient of determination (R2). We additionally assessed the accuracy of CL measurement to predict preterm birth by assessing the area under receiver operating characteristics curves with its respective confidence intervals (CIs) 95%. RESULTS: Preterm birth <37 weeks was found in 13.6% (102/751) of pregnant women. Short cervix (≤25 mm) was found in 2.7% (20/751) of pregnancies. Only 30% (6/20) of pregnant women with short cervix have used progesterone to prevent preterm birth. There was a weak correlation between CL measurement and gestational age at delivery (R2=0.01, P=0.002). Receiver operating characteristics curve analysis of the ability of CL measurement to predict preterm birth <32, 34, and 37 weeks, showed an area under the curve of 0.693 (95% CI, 0.512 to 0.874), 0.472 (95% CI, 0.353 to 0.591), 0.490 (95% CI, 0.426 to 0.555), respectively. CONCLUSION: There was a weak correlation between CL measurement and gestational age at delivery. In an unselected population, CL measurement screening at 20 to 24+6 weeks of gestation does not seem to be a good predictor of preterm birth.

Fetal biometric parameters: Reference charts for a non-selected risk population from Uberaba, Brazil.

OBJECTIVE: To establish reference charts for fetal biometric parameters in a non-selected risk population from Uberaba, Southeast of Brazil. METHODS: A retrospective cross-sectional study was performed among 5656 non-selected risk singleton pregnant women between 14 and 41 weeks of gestation. The ultrasound exams were performed during routine visits of second and third trimesters. Biparietal diameter (BPD) was measured at the level of the thalami and cavum septi pellucidi. Head circumference (HC) was calculated by the following formula: HC = 1.62*(BPD + occipital frontal diameter, OFD). Abdominal circumference (AC) was measured using the following formula: AC = (anteroposterior diameter + transverse abdominal diameter) × 1.57. Femur diaphysis length (FDL) was obtained in the longest axis of femur without including the distal femoral epiphysis. The estimated fetal weight (EFW) was obtained by the Hadlock formula. Polynomial regressions were performed to obtain the best-fit model for each fetal biometric parameter as the function of gestational age (GA). RESULTS: The mean, standard deviations (SD), minimum and maximum of BPD (cm), HC (cm), AC (cm), FDL (cm) and EFW (g) were 6.9 ± 1.9 (2.3 - 10.5), 24.51 ± 6.61 (9.1 - 36.4), 22.8 ± 7.3 (7.5 - 41.1), 4.9 ± 1.6 (1.2 - 8.1) and 1365 ± 1019 (103 - 4777), respectively. Second-degree polynomial regressions between the evaluated parameters and GA resulted in the following formulas: BPD = -4.044 + 0.540 × GA - 0.0049 × GA2 (R2 = 0.97); HC= -15.420 + 2.024 GA - 0.0199 × GA2 (R2 = 0.98); AC = -9.579 + 1.329 × GA - 0.0055 × GA2 (R2 = 0.97); FDL = -3.778 + 0.416 × GA - 0.0035 × GA2 (R2 = 0.98) and EFW = 916 - 123 × GA + 4.70 × GA2 (R2 = 0.96); respectively. CONCLUSION: Reference charts for the fetal biometric parameters in a non-selected risk population from Uberaba, Southeast of Brazil, were established.

Reference values for the cervical length measurement in the second trimester of pregnancy using the transvaginal ultrasound in a large Brazilian population.

To establish reference values for the cervical length (CL) measurement by transvaginal ultrasound between 20 and 24+6 weeks of gestation in a large Brazilian population. A retrospective cross-sectional study was performed with 996 singleton pregnancies. The CL measurement (mm) using the transvaginal ultrasound was obtained in a sagittal view and the calipers positioned to measure the linear distance between the triangular area of echodensity at the external os and the internal os. The median±standard deviation and ranges for the CL measurement (mm) was 37.0±10.7 (range, 8 to 51). CL measurement did not modify significantly with gestational age. The observed percentiles for the CL measurement (mm) considering all number case were the following: 5th, 28 mm; 50th, 37 mm; and 95th, 45 mm. Reference values for the CL measurement by transvaginal ultrasound between 20 and 24+6 weeks of gestation in a large heterogeneous Brazilian population were established.

Reference range for uterine artery Doppler pulsatility index using transvaginal ultrasound at 20-24w6d of gestation in a low-risk Brazilian population.

OBJECTIVE: To establish reference range for uterine artery (UtA) Doppler pulsatility index (PI) using transvaginal ultrasound at 20-24w6d of gestation in a Brazilian population. MATERIAL AND METHODS: A retrospective cross-sectional study in 847 low-risk pregnant women undergoing routine second trimester ultrasound examination was conducted from February 2012 through March 2015. The mean UtA PI was calculated using color Doppler ultrasound with UtA gated at the level of the internal os. Mean±standard deviation and ranges for UtA Doppler PI in relation to gestational age (GA) are reported. Polynomial regression was used to obtain the best fit using mean UtA Doppler PI and GA (weeks) with adjustments performed using determination coefficient (R(2)). The 5(th), 50(th), and 95(th) percentiles for the mean UtA Doppler PI in relation to GA were determined. RESULTS: The mean UtA Doppler PI ranged from 1.14 at 20 weeks to 0.95 at 24 weeks of gestation. The best-fit curve of mean UtA Doppler PI as a function of GA was a first-degree polynomial regression: mean UtA Doppler PI=1.900-0.038×GA (R(2)=0.01). CONCLUSION: In summary, when the mean UtA PI Doppler values were measured by transvaginal ultrasound at 20-24w6d of gestation, decrease in UtA Doppler PI values with advancing GA was observed. Reference range for the mean UtA Doppler PI at 20-24w6d of gestation using the transvaginal ultrasound in a low-risk Brazilian population was established. We believe that this reference range may be of clinical value in daily obstetric practice.

Reference values for the single deepest vertical pocket to assess the amniotic fluid volume in the second and third trimesters of pregnancy.

AIM: To establish reference values for the single deepest vertical pocket to assess the amniotic fluid volume in the second and third trimesters of pregnancy. METHODS: We performed a retrospective cross-sectional study with 3554 consecutive singleton low-risk pregnant women between 14 and 41 weeks of gestation. To perform the largest deepest vertical pocket measurement, the transabdominal convex probe was positioned vertical to the uterine contour of abdomen and parallel to the maternal sagittal plane. In order to obtain reference values for the largest deepest vertical pocket measurement and gestational age (GA), we have used a polynomial regression model. RESULTS: The mean±standard deviation for the largest deepest vertical pocket measurement (cm) ranged from 3.1±1.1 (1.5-4.9) at 14-14+6 to 3.7±1.6 (0-6.7) at 41-41+6 weeks, respectively. A best-fit was a second-degree polynomial regression: largest deepest pocket=-1.478+0.197*GA-0.0030*GA2 (R2=0.014). CONCLUSION: Reference values for the single deepest vertical pocket to assess the amniotic fluid volume in the second and third trimesters of pregnancy in a large heterogeneous population were established.