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Background: Ultrasonography of the uterine artery (UtA) in the first and second trimesters of pregnancy can assess uterine-placental blood perfusion and guide early clinical prevention. Establishing normal ranges of the UtA pulsatility index (UtA-PI) at 11-14 weeks of pregnancy is helpful for the early identification of high-risk pregnant women and improving the prognosis. This study aimed to establish a reference range of UtA-PI based on crown-rump length (CRL) for spontaneous and in vitro fertilization (IVF) singleton pregnancy during 11-14 weeks, respectively. Methods: A prospective study was performed at Peking Union Medical College Hospital. Healthy, low-risk women with a singleton pregnancy at 11-14 gestational weeks were consecutively recruited for this study from December 2017 to December 2020. All participants underwent routine prenatal ultrasound examination. The CRL of the fetus and the UtA-PI were measured in both uterine arteries, and average values were calculated. The LMS method was used to fit the percentile (P)5, P10, P25, P50, P75, P90, and P95 curves of the UtA-PI value of spontaneous and IVF singleton pregnancy with CRL changes, respectively. Results: A total of 1,962 pregnant women with normal fetuses were included in this study, including 1,792 pregnancies conceived naturally and 170 IVF fetuses. The UtA-PI reference range in the spontaneous pregnancy group was consistently higher than that in the IVF group during 11-14 weeks, and showed a statistically significant difference in UtA-PI for spontaneous and IVF pregnancies (P<0.001). According to the LMS method, each percentile curve of UtA-PI decreased with the increase of CRL in both the natural pregnancy group and the IVF group. The P95 range of UtA-PI for pregnant women with naturally conceived and IVF pregnancy was 2.74 to 2.11 and 2.50 to 1.94, respectively. The overall change of UtA-PI differentials of the two groups showed a downward trend and decreased slightly with the increase of CRL. Conclusions: This study provided a single-center, large sample of data and constructed a CRL-based reference value of UtA-PI for spontaneous and IVF singleton pregnancy, which provides a reliable basis for early UtA evaluation and early clinical decision-making during 11-14 gestational weeks.
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This study presents a novel approach to automatic detection and segmentation of the Crown Rump Length (CRL) and Nuchal Translucency (NT), two essential measurements in the first trimester US scan. The proposed method automatically localises a standard plane within a video clip as defined by the UK Fetal Abnormality Screening Programme. A Nested Hourglass (NHG) based network performs semantic pixel-wise segmentation to extract NT and CRL structures. Our results show that the NHG network is faster (19.52% < GFlops than FCN32) and offers high pixel agreement (mean-IoU=80.74) with expert manual annotations.
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BACKGROUND: Considering that establishment of reference value of nuchal translucency (NT)-related to the crown rump length (CRL) during the first trimester will be helpful for determining an appropriate cutoff level for screening of increased NT thickness-related abnormalities, we determined the NT thickness and investigated its relation with different chromosomal and nonchromosomal abnormalities among a large sample size of pregnant Iranian women. MATERIALS AND METHODS: In this analytic cross-sectional study, pregnant women who were in their first trimester were enrolled at their antenatal visit. Using an abdominal ultrasonography, the fetal NT thickness of the studied population was measured. Those with increased NT thickness were determined. The reference value of NT thickness (5th, 25th, 50th, 75th, and 95th percentiles) within each 5-mm range of CRL and during the 11th, 12th, and 13th gestational weeks were determined. The presences of the different chromosomal and nonchromosomal abnormalities were compared in women with different percentiles of NT thickness who underwent amniocentesis and those who did not. RESULTS: 1,614 pregnant women were evaluated. The mean NT thickness was 1.30 ± 0.54 mm. Increased NT thickness >2 mm and >95th percentile according to their gestational age (GA) was detected in 89 (5.5%) and 58 (3.6%) pregnant women. The reference 95th percentile value range for NT was 1.8-2.35 and increased NT thickness according to our obtained values was associated significantly with chromosomal abnormalities. CONCLUSION: The obtained reference range in our studied population was different from that reported for other ethnic groups and it is suggested that using this values are more favorable for screening of chromosomal abnormalities during the first trimester of pregnancy than the recommended single cutoff value.
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The crown-rump length(CRL) remains the most accurate parameter used for gestational dating. We aimed to establish the early fetal growth with CRL range in Korean women. The CRL of 48 singleton pregnancies which resulted from in vitro fertilization and e mbryo transfer(IVF-ET) at SNUH were assessed two to six times in the first trimester by trans-vaginal ultrasonography. All women included in this study went on to deliver norma l infa-nts at 37 completed weeks or after weighing over 2.5 kg. And we also studied the r elationship between CRL(in millimeters) and gestational age(in days), and found that the fo llowing second-order polynomial might be applied either to expect CRL using the menstr ual gestational age, or to estimate gestational age using measured CRL(r2=0.980, p=0.000 1). CRL=0.0175(GA)2-1.049(GA)+19.17 GA=7.5593(CRL-3.45)1/2+29.97 Finally we compared our data with some of published articles which assessed CRL in spontaneous and induced pregnancies. In conclusion, this study establish the early fetal growth with CRL range in Korean women on the basis of exact ovulation timing using high resolution transvaginal ultrasonography. And these data will be of great use in the evaluation of fetal growth in the first trimester.