Objective To investigate prenatal diagnosis and prognosis of fetus with hyperechogenic kidney.Methods Clinical data of 65 cases prenatally diagnosed with fetal hyperechogenic kidney in Peking University First Hospital between July,2009 and May,2015 were retrospectively analyzed.Results of fetal ultrasound screening and pregnancy outcomes were analyzed and Growth and development status of those babies were followed up until December,2015.Independent-sample-t,Chi-square or Fisher's exact test was applied for statistical analysis.Results Among the 65 cases,including 48(73.8％) bilateral and 17 (26.2％) unilateral,34 cases (52.3％) were diagnosed as non-isolated and 31 cases (47.7％) as isolated fetal hyperechogenic kidney.The primary associated malformations with non-isolated fetal hyperechogenic kidney included cardiac abnormality (14 cases,41.2％),urinary system abnormality (12 cases,35.2％),skeletal system abnormality (nine cases,26.5％),central nervous system abnormality (eight cases,23.5％) and Meckel-Gruber sydrome (one case,2.9％).Amniotic volume,the size and numbers of affected kidney between non-isolated and isolated groups showed no significant differences (all P＞0.05).Twenty out of the 65 cases (30.8％) received fetal karyotyping and one received non-invasive prenatal testing,and no abnormality was detected.Three cases received cord blood array comparative genomic hybridization with negative results.Pathogenic genes were found in two cases who received targeted exome capture with high throughput sequencing,including a TTC21B mutation in cord blood in one case and a HNF1β deletion mutation in peripheral blood after birth in the other.There were 23 (35.4％) terminations of pregnancy and 42 (64.6％) live births among which three died after birth.The rate of live birth was significantly higher in the isolated group than in the non-isolated group[87.1％(27/31) vs 44.1％(15/34),x2=13.101,P＜0.01].Of the fifteen live births in the non-isolated group,there were fourteen survived symptomfree except that one lost to follow-up.Of the 27 live births in the isolated group,follow up study revealed 23 symptom-free survivors,one lost,two neonatal deaths (one died of volvulus neonatorum,and the other due to unknown causes) and one death of renal and liver function failures at the age of two-and-a-half.ConclusionsFetal hyperechogenic kidney is an important prenatal ultrasound marker for congenital renal anomalies,and the prognosis of non-isolated fetal hyperechogenic kidney is poor.The current rate of abnormal karyotype in fetus with hyperechogenic kidney is very low.However,the rate of prenatal genes screening should be encouraged.

ObjectiveTo investigate the change of cervical length (CL) during uncomplicated pregnancy by transvaginal ultrasound and its correlated factors.MethodsData of five hundred and ninety-five normal singleton pregnant women who received vaginal ultrasound examination on CL in their 11-13+6gestational weeks ( Ⅰstage),20-24 gestational weeks ( Ⅱ stage),28-32 gestational weeks (Ⅲ stage) and ≥36 gestational weeks (Ⅳ stage) were collected and retrospectively analyzed.Related factors were recorded at the same time.Repeated measurement data analysis of variance,t-test and Spearman correlation analysis were applied for statistical analysis.Results(1) The mean values of CL at Ⅰ,Ⅱ,Ⅲ and Ⅳ stage were (38.85±3.11) mm,(38.92±4.10) mm,(36.43±4.69) mm and (30.63±6.11) mm,respectively.There were statistical differences between the CL of any two stages (P＜0.01),except for that between Ⅰ and Ⅱ stage.The median values of CL change rates were:Ⅱ-Ⅰ stage0.00％; Ⅲ-Ⅰ stage -5.36％; Ⅳ-Ⅰ stage -20.00％.(2) The CL of pregnant women who were older than 35 was longer than that of those younger than 35 at any stage [ Ⅰ stage:(39.36±3.18) mm　vs (38.77±3.10) mm;Ⅱ stage:(39.89±4.61) mm vs (38.88±4.00) mm;Ⅲ stage:(37.29±4.79) mm vs (36.31 ±4.67) mm;Ⅳ stage:(32.25± 5.95) mm vs (30.38±6.10) mm],while significant difference was found only at Ⅳ stage (t=-2.56,P=0.01).The CL of multiparas was longer than that of primiparas [ Ⅰ stage:(38.95±2.59) mm vs (38.76±3.14) mm;Ⅱ stage:(39.54±3.62) mm vs (38.82±4.11) mm;Ⅲ stage:(37.37±4.21) mm vs (36.34±4.70) mm;Ⅳ stage:(31.77±6.05) mm vs (30.59±6.11) mm],while there was no statistical significance within any stage ( P＞ 0.05). ConclusionsCervix shortens gradually after 28 gestational weeks.Sequential measurement of CL during routine ultrasonic inspection might be helpful in predicting preterm labor.

Objective To study the value of cervical length(CL) by transvaginal sonography in the mid-trimester and late-trimester for the prediction of preterm delivery.Methods The CL was measured by transvaginal sonography for 5277 pregnant women between 22-24 weeks and 28-32 weeks gestation,who were prenatal cared and delivered at the First Hospital of Peking University from June 2008 to November 2009.The pregnancy outcomes were followed,and the relationship between CL and preterm delivery and preterm premature rupture of membrane was studied.Results ( 1 ) The incidence of preterm delivery was 5.4％ (289/5370) total,among of them the incidence of therapeutic preterm delivery was 1.7％ (93/5370),spontaneously preterm delivery was 1.2％ (62/5370),and preterm premature rupture of membrane was 2.5 ％ (134/5370).There are 4 cases (4/5370) who occured late abortion.(2) Excluding the 93 women who had therapeutic preterm delivery,the mean CL of 22-24 weeks was ( 38.8±4.0) mm.The relative risk for preterm delivery when the CL＜30 mm was 5.2,when CL＜25 mm,the relative risk was 11.1,and when CL ＜15 mm the relative risk for preterm delivery was 13.8.The average CL during 28-32 weeks of gestation was ( 34.6±4.8) mm,was significantly shorter than that of 22-24 weeks ( P＜0.05 ).During this period the relative risk for preterm delivery when the CL＜30 mm was 6.9,when CL＜25 mm,the relative risk was 11.1,and when CL＜15 mm the relative risk for preterm delivery was 20.0.(3) A CL＜30 mm as the cutoff value for predicting preterm delivery during 22-24 weeks of gestation has only a 3％ sensitivity and 19％ positive predictive value,but had a 99％ specificity and 96％ negative predictive value.The sensitivity,positive predictive value,specificity and negative predictive value for a CL ＜ 30 mm as the cut-off value for predicting preterm delivery during 28-32 weeks of gestation was 33％,21％,95 ％ and 97 ％ respectively.(4) The total number of preterm premature rupture of membrane pregnant women was 134 (2.5％ ),who had a mean CL of (38.4 ±4.7) mm during 22-24 weeks of gestation,was similar with the women without preterm premature rupture of membrane ( PPROM),but during 28-32 weeks of gestation the women who occured PPROM had a mean cervical length of ( 30.6 ± 8.1 ) mm,and was significantly shorter than that of women without PPROM ( 34.7 + 4.6 ) mm.Conclusions ( 1 ) CL in 28-32 weeks of gestation issignificantly shorter than that of in the mid-gestation,but more than 90％ of women has a CL≥30 mm.(2)The shorter the CL is,the greater the relative risk of preterm delivery.According to different CL for clinical consulting objective relative risk could be provide.(3) The CL during 28-32 weeks of gestation can also predict preterm delivery,the sensitivity is obviously better than that of 22-24 weeks of gestation.(4) The CL during 28-32 weeks of gestation is valuable for predicting of PPROM.

Objective: To investigate the clinical significance and prognosis of ultrasound-identified asymmetric ventricles in fetuses, and to provide evidences for clinical consultation and management. Methods: From January 2014 to May 2017, 142 singleton fetuses were enrolled who were diagnosed with asymmetric ventricles through prenatal ultrasound in Peking University First Hospital and successfully followed up after birth. Asymmetric ventricles included simple lateral ventricular asymmetry [lateral ventricular widths were normal (<10 mm) but with a difference of ≥2 mm between the two lateral ventricles and unilateral ventricular widening (only one lateral ventricle was ≥10 mm in width and the other was <10 mm). All 142 fetuses were divided into two groups according to whether they had other abnormalities (including abnormal ultrasound soft markers and structural abnormalities) or not. Clinical and imaging data of them were analyzed retrospectively. They were followed up for at least six months after birth. Neurological development regarding language, behavior and motor was evaluated using Denver Developmental Screening Test. Results: There were 109 cases without other abnormalities and among them, 38 (35%) spontaneously recovered in utero, two (2%) became worse, and 69 (63%) remained unchanged. Thirty-one of the 109 cases received fetal cranial MRI and abnormal brain development was found in only one case. No abnormal findings were reported in karyotyping in 38 cases and viral detection in 31 cases. One hundred and five fetuses were successfully delivered and four were induced including two cases for wider in unilateral lateral ventricle, one of continued widening, and one with abnormal brain development suggested by fetal cranial MRI. Among the 33 cases with other abnormalities, two were spontaneously recovered in utero, one became worse , 15 unchanged and 15 were induced. Of the 20 cases underwent chromosomal examination, one unbalanced chromosome translocation was identified. Twelve fetuses underwent cranial MRI among which two were found abnormal (periventricular cyst and brain asymmetry). Sixteen cases were aborted including 15 with major abnormalities (major deformity or absence of extremities) and one with mild abnormality (abnormal ultrasound soft markers with progression in lateral ventricular width ≥15 mm in in-utero follow-up). Seventeen cases were born including 16 with mild abnormalities and one with severe abnormality (unilateral renal cystic disease without chromosome abnormality). No significant developmental abnormality in language, behavior and motor was reported during follow-up. Conclusions Asymmetric ventricles have no significant impact on fetal growth and postnatal development. The prognosis of asymmetric ventricles mainly depends on the width of lateral ventricles in utero and concomitant abnormalities. Therefore, close attention should be paid on monitoring and follow-up.

Objective: To investigate the diagnosis, clinical outcomes and factors influencing the prognosis of fetal periventricular pseudocysts (PVPC). Methods: A retrospective analysis was performed on the results of fetal neurosonography (NSG), cranial magnetic resonance imaging (MRI), chromosome karyotype and neonatal cranial ultrasound of 76 PVPC cases detected by prenatal ultrasound in Peking University First Hospital from May 2014 to October 2018. The accuracy of NSG and cranial MRI in PVPC diagnosis was assessed. Prognosis of PVPC and the influencing factors were evaluated. Statistical analysis was performed using Chi-square test or Fisher's exact test. Results: (1) This study involved 51 cases (67.1%) of isolated PVPC and 25 cases (32.9%) of non-isolated PVPC. Among the 25 non-isolated PVPC cases, 15 were complicated by one abnormality and 10 by multiple abnormalities. There were 20 cases with intracranial abnormalities, two with extracranial abnormalities, and three with both intracranial and extracranial abnormalities. (2) Eight out of the 76 pregnancies (10.5%) were terminated and among them, two were isolated PVPC cases, five complicated by determined abnormalities (one case of PVPC complicated with pachygyria and bilateral mild fetal ventriculomegaly, one case of PVPC complicated with pachygyria or agyria and agenesis of corpus callosum, one case of PVPC complicated with arachnoid cyst and vermis dysplasia, one case of PVPC complicated with cortical dysplasia, one case of PVPC complicated with intestinal dilatation) and one by abnormalities of undertermined prognosis (PVPC combined with mild fetal ventriculomegaly and polyhydramnios). A total of 61 neonates (80.3%, 61/76) were born alive and followed up. Seven cases (9.2%, 7/76) were lost to follow-up. (3) As of February 2019, among the 61 followed-up infants, 44 with isolated PVPC and 15 with unclear abnormalities developed well. The other two with determined intracranial abnormalities were diagnosed as having cystic lesions in the brain parenchyma. One of them died of respiratory failure two days after birth and the other suffered from chromosomal disease (13.23 Mb deletion in region q24.3q31.2 of chromosome 2) with mental retardation and delayed growth and development. (4) A total of 44 (57.9%, 44/76) neonates received cranial ultrasound after birth and confirmed the diagnosis of PVPC, among which 11 (25.0%, 11/44) were missed or misdiagnosed in prenatal MRI. Conclusions PVPC may have many comorbidities, particularly intracranial abnormalities, which are closely related to the prognosis. A thorough prenatal ultrasound examination is necessary for fetal PVPC, especially NSG. Isolated PVPC usually has a good outcome. However, PVPC complicated by cystic lesions in the brain parenchyma may be associated with chromosomal abnormalities, hence fetal chromosome examination is required.

Objective:To explore the application effect of interactive group management mode in puerpera with postpartum diastasis recti abdominis, and to provide reference for optimizing the health management of puerpera with rectus abdominis separation.Methods:This study was a randomized controlled trial. Convenience sampling method was used to select 114 puerpera with postpartum diastasis recti abdominis who were treated in Maternal and Child Health Hospital of Zhenjiang City from January to June 2022 as the research objects. According to the random number table method, the postpartum women were divided into an intervention group and a control group with 57 cases each. The intervention group received interactive group management for 12 weeks, while the control group received routine health guidance. Before and after the intervention, the two groups were evaluated by diastasis recti abdominis, rehabilitation knowledge-attitude-practice, general self-efficacy, and the duration of the first-level test results of the eight-level abdominal bridge.Results:The 55 cases were included in the final intervention group, while 56 cases were included in the control group. After intervention, the separation distance of rectus abdominis of the intervention group was (2.27 ± 0.47) cm, and that of the control group was (2.48 ± 0.39) cm. The difference between the two groups was statistically significant ( t = 2.53, P<0.05). The knowledge-attitude-practice total score and each item score of diastasis recti abdominis rehabilitation in the intervention group were (106.84 ± 5.78), (61.53 ± 4.29), (25.42 ± 2.26), (19.89 ± 1.89) points respectively while in the control group were (73.77 ± 8.33), (38.48 ± 7.56), (20.73 ± 3.07), (13.55 ± 1.99) points. The differences between the two groups were statistically significant ( t values were 9.16 -24.28, all P<0.01). The general self-efficacy score of the intervention group was (27.47 ± 3.16) points, and that of the control group was (26.05 ± 3.43) points. The difference between the two groups was statistically significant ( t = 2.26, P<0.05). The first-level test time of eight-level abdominal bridge in the intervention group was (80.29 ± 11.50) s, which was significantly higher than (29.39 ± 6.09) s in the control group, and the difference was statistically significant ( t = 29.20, P<0.01). The completion rate of exercise in the intervention group was (90.20 ± 1.83)%. Higher than (69.52 ± 8.04)% in the control group, with a statistically significant difference ( t = 13.73, P<0.01). Conclusions:Interactive group management can significantly ameliorate the separation distance of diastasis recti abdominis, increase the level of knowledge-attitude-practice of diastasis recti abdominis rehabilitation and the compliance of rehabilitation exercise, improve the self-efficacy, prolong the first-level test time of eight-level abdominal bridge, and improve the abdominal core muscle strength for puerpera.

Objective:To investigate the pregnancy outcomes of pregnant women with cesarean scar diverticulum (CSD) and to find the relevant factors that predict the occurrence of adverse pregnancy outcomes.Methods:From January 2015 to March 2019, 501 singleton pregnant women with a history of cesarean section who underwent regular prenatal examination in early pregnancy and eventually delivered in Peking University First Hospital were prospectively collected. According to the presence or absence of CSD in the first trimester of pregnancy, the pregnant women were divided into the CSD group ( n=127, 25.3%) and the non-CSD group ( n=374, 74.7%). According to the mode of delivery and the classification of the lower uterine segment seen during cesarean section, the CSD group was further divided into the non-rupture group (including spontaneous delivery and lower uterine segment grade Ⅰ; n=108, 85.0%) and rupture group (including lower uterine segment grade Ⅱ-Ⅳ; n=19, 15.0%). The general clinical data, pregnancy outcomes, diverticulum-related indexes [including length, width, depth (D), average diameter, volume, and residual myometrial thickness (RMT)] were compared. The predictive values of D/adjacent myometrial thickness≥50%, RMT≤2.2 mm and D/RMT>1.3 for uterine rupture in CSD pregnant women were verified. Results:(1) Comparison between CSD group and non-CSD group: the lower uterine segment thickness in the third trimester of pregnancy in the CSD group was lower than that in the non-CSD group [(1.2±0.5) vs (1.4±0.6) mm, respectively], and the incidence of uterine rupture was higher than that in the non-CSD group [15.0% (19/127) vs 8.0% (30/374), respectively], and the differences were statistically significant (both P<0.05). There were no significant differences in other clinical data and pregnancy outcomes between the two groups (all P>0.05). (2) Comparison of rupture group and non-rupture group: the lower uterine segment thickness in the third trimester of pregnancy in rupture group [(0.6±0.5) mm] was lower than that in non-rupture group [(1.2±0.6) mm], and the difference was statistically significant ( t=3.486, P=0.001). There were no significant differences in diverticulum-related indexes between the two groups (all P>0.05). (3) Relationship between high risk predictors of uterine rupture and actual uterine rupture: the sensitivity of D/adjacent muscle thickness ≥50%, RMT≤2.2 mm and D/RMT>1.3 in predicting the high risk of uterine rupture were 94.7%, 57.9% and 73.6%, the specificity were 12.0%, 40.7% and 24.1%, the positive predictive value were 15.9%, 14.7%, 14.6%, and the negative predictive value were 92.8%, 84.6%, 83.9%, respectively. Conclusions:The risk of uterine rupture in pregnant women with CSD is higher than that in those without CSD. There is no significant correlation between CSD related indexes and uterine rupture in the first trimester. Monitoring the lower uterine segment thickness in the third trimester might be helpful to predict the occurrence of adverse pregnancy outcomes.

Objective To investigate the effect of enhanced external counterpulsation (EECP) on plasma lipoprotein phospholipase A2 (LP-PLA2) levels, vascular endothelial diastolic function in patients with unstable angina. Methods One hundred patients with unstable angina treated in our hospital were randomly divided into routine treatment group (control group n-49) and external counterpulsation group (observation group n = 51, routine treatment plus external counterpulsation therapy, 60 min/time, a total of 30 times). All selected subjects were tested for LP-PLA2 levels on the day of enrollment and on the 30 th day after treatment, and color Doppler ultrasonography was used to detect arterial blood flow-mediated vasodilation (FMD) and nitroglycerin-mediated vasodilation (NMD). Results After treatment in the observation group, LP-PLA2 decreased compared with before treatment, the difference was statistically significant (P < 0.05) , but FMD, NMD were higher than those before treatment, which had statistical difference (P < 0.05). In control group treatment afterwards, LP-PLA2, endothelium-dependent vasodilatation and non-endothelium-dependent vasodilatation did not change significantly before treatment (P> 0.05). Observations between groups showed that the increase in FMD and NMD in the observation group was significantly greater than that in the control group. P < 0.01) , plasma LP-PLA2 levels in the observation group also decreased compared with the control group (P < 0.05). Conclusion Enhanced external counterpulsation can reduce the level of LP-PLA2 in patients and improve endothelial diastolic function under the action of blood flow shear stress.

Objective To investigate the relationship between the previous cesarean scar thickness, previous cesarean scar defect and the occurrence of uterine rupture for pregnancy women after previous cesarean section and to predict the occurrence of uterine rupture in the third trimester for pregnancy women after previous cesarean section by analyzing the lower uterine segment (LUS) situation or quantitatively measure LUS myometrium thickness. Methods A total of 154 pregnant women who have a prior cesarean from January 2015 to March 2016 were selected, all of them regularly did the prenatal examination in the pregnancy period and finally gave birth in hospital. By the transvaginal sonograph, the LUS myometrium thickness (transverse and longitudinal thickness) and the size of the previous cesarean scar defect were measured in the first trimester, the LUS myometrium thickness (longitudinal thickness) and qualitatively analysis LUS condition were measured in the third trimester. They were divided into two groups according to the pregnancy outcome: uterine rupture group (found in the cesarean operation or during the pregnancy) and without uterine rupture group (including the vaginal delivery women and those without uterine rupture in the cesarean operation period). The sensitivity and specificity of LUS myometrium thickness in the first trimester and the qualitative analysis LUS situation, the quantitative measurement of LUS myometrium thickness in the third trimester were compared in the prediction of occurrence of uterine rupture (dehiscence or complete rupture). Results The group without uterine rupture included 134 women (6 vaginal delivery and 128 cesarean delivery), and the group with uterine rupture included 20 women (all of them cesarean delivery). The LUS myometrium thickness in the third trimester in the group without uterine rupture was (1.6±0.5) mm, and was (1.1±0.7) mm in the uterine rupture group (P=0.004). There were no significant difference between two groups in the mean value of age, height, weight, the interdelivery interval, the LUS myometrium thickness (transverse and longitudinal thickness) in the first trimester. Qualitative analysis of LUS condition had higher specificity (99%), higher positive predictive value (92%), higher negative predictive value (94%) and slightly lower sensitivity (60%) than quantitative measure of LUS myometrium thickness in predicting uterine rupture. Conclusions Measurement of the LUS myometrium thickness in the first trimester is helpful for predicting the occurrence of uterine rupture, so it is not necessary to terminate the pregnancy because of the thin LUS or the little prior cesarean scar defect in the first trimester. However it should be paid close attention to the LUS situation during the whole gestation. Qualitatively analyzing LUS situation is more meaningful than quantitatively measuring LUS myometrium thickness in predicting the uterine rupture in the third trimester.

Objective:To explore the predictive value of transvaginal ultrasound measurement of cervical length (CL) in the first and second trimester on spontaneous preterm birth in singleton pregnant women.Methods:This study retrospectively recruited 2 254 singleton pregnancies without severe comorbidities at Peking University First Hospital from January 2019 to June 2019. CL was measured for all subjects using transvaginal ultrasound in the first (11-13 +6 weeks) and second trimester (21-23 +6 weeks). Differences in CL between women with preterm (preterm group) and full-term delivery (full-term group) as well as the CL during the first and second trimester were compared. The independent risk factors for preterm birth and the predictive value of CL in the first and second trimester for spontaneous preterm birth were also explored. Fisher's exact test, t-test, χ2 test, and logistic regression analysis, etc, were adopted for statistical analysis. Results:(1) For the 2 254 subjects, CL measured in the first trimester and second trimester were (36.1±4.2) mm (22.4-52.6 mm) and (36.9±5.3) mm (2.9-59.7 mm), respectively. The incidence of short cervix in the first trimester and second trimester were 0.31% (7/2 254) and 1.46% (33/2 254), respectively. When CL was ≤25.0 mm ( OR=43.92, 95% CI:6.83-282.49) or >25.0-≤30.3 mm ( OR=6.59, 95% CI:1.97-22.0) in the first trimester, the risk of short cervix increased in the second trimester (both P<0.05). (2) The total incidence of preterm delivery was 3.06% (69/2 254). CL and the incidence of short cervix did not differ significantly in the first trimester between the preterm and full-term group [(35.2±4.5) and (36.1±4.1) mm, t=－1.78, P=0.076; 1.5% (1/69) and 0.3% (6/2 185), χ 2=2.98, P=0.084]. Compared with the full-term group, CL was shorter and the incidence of short cervix was higher in the second trimester in the preterm group [(33.6±6.7) vs (37.0±5.2) mm, t=－5.12;8.7% (6/69) vs 1.2% (27/2 185), χ 2=25.80, P<0.001]. (3) Multivariate regression analysis showed that age ≥35 years ( OR=2.05, 95% CI:1.22-3.46), history of spontaneous preterm birth ( OR=25.25, 95% CI:5.01-127.28), conception assisted by reproductive technology ( OR=10.39, 95% CI:2.39-50.33), and short cervix during the second trimester were independent risk factors for premature delivery. (4) There was no significant difference in the risk of preterm delivery when comparing to those with CL≤25.0 mm, >25.0-≤30.3 mm, >30.3-≤33.0 mm, >33.0-≤35.7 mm, >35.7-≤38.7 mm women with CL>38.7 mm during the first trimester (all P>0.05). The risk of premature delivery was relatively increased for those with CL≤25.0 mm,>25.0-≤29.5 mm, >29.5-≤33.6 mm, >33.6~≤36.8 mm, >36.8~≤40.1 mm during the second trimester compared to those with CL>40.1 mm [ OR (95% CI):17.64 (4.99-62.32), 6.89 (2.11-22.55), 3.58 (1.34-9.59), 4.04 (1.58-10.32), 3.34 (1.28-8.67), respectively , all P<0.05]. (5) When CL≤25.0 mm and ≤29.5 mm in the second trimester were used as the cut-off value, the prediction of preterm delivery was with a sensitivity of 8.70% and 17.39%, specificity of 98.80% and 95.29%, positive predictive value of 18.20% and 10.43%, negative predictive value of 97.16% and 97.34%, and the accuracy rate of 96.01% and 92.90%, respectively. Conclusions:There were no significant differences in CL and the incidence of short cervix during the first trimester among women with preterm or full-term delivery. CL in the first trimester is not an independent risk factor for preterm birth, but the risk of short cervix in the second trimester is increased when CL≤30.3 mm in the first trimester. The shorter the cervix during the second trimester, the greater the risk of preterm birth.