Real-time ultrasound demonstration of uterine isthmus contractions during pregnancy.

BACKGROUND: Asymptomatic isthmic contractions are a frequent physiological phenomenon in pregnancy, sometimes triggered by bladder voiding. They can interfere with proper cervical length assessment and may lead to false images of placenta previa. However, there is limited research on the prevalence and characteristics of these contractions. OBJECTIVE: This study aimed to determine the prevalence and characteristics of isthmic contractions after bladder voiding in the second trimester of pregnancy, to evaluate their effect on cervical length assessment, and to propose a new method for the objective assessment of the presence and intensity of isthmic contractions. STUDY DESIGN: In this prospective observational study, long videos of the uterine cervix were recorded in 30 singleton pregnancies during the second trimester of pregnancy after bladder voiding. Isthmic length and cervicoisthmic length changes were assessed over time. The isthmic length was measured using a new approach, which involved calculating the distance from the base of the cervix to the internal os, including the isthmus. RESULTS: Isthmic contractions were observed in 43% of pregnant women (95% confidence interval, 26%-62%) after bladder voiding. The median time for complete isthmus relaxation was 19.7 minutes (95% confidence interval, 15.0 to not available). No substantial differences in maternal characteristics were found between individuals with and without contractions. The proposed method for measuring isthmic length provided an objective assessment of the presence and intensity of isthmic contractions. A cutoff of 18 mm in isthmic length allowed for the distinction of pregnant women presenting a contraction. In addition, the study identified a characteristic undulatory pattern in the relaxation of the isthmus in half of the cases with contractions. CONCLUSION: Isthmic contractions are a common occurrence after bladder voiding in the second trimester of pregnancy and may interfere with proper cervical length assessment. We recommend performing cervical assessment at least 20 minutes after bladder voiding to reduce the risk of bias in cervical length measurement and to avoid false images of placenta previa. The new method for measuring isthmic length provides an objective way to assess the presence and intensity of isthmic contractions. Further research is needed to understand the role of isthmic contractions in the physiology of pregnancy and birth.

Abnormal Maternal Body Mass Index and Customized Fetal Weight Charts: Improving the Identification of Small for Gestational Age Fetuses and Newborns.

BACKGROUND: Obesity and thinness are serious diseases, but cases with abnormal maternal weight have not been excluded from the calculations in the construction of customized fetal growth curves (CCs). METHOD: To determine if the new CCs, built excluding mothers with an abnormal weight, are better than standard CCs at identifying SGA. A total of 16,122 neonates were identified as SGA, LGA, or AGA, using the two models. Logistic regression and analysis of covariance were used to calculate the OR and CI for adverse outcomes by group. Gestational age was considered as a covariable. RESULTS: The SGA rates by the new CCs and by the standard CCs were 11.8% and 9.7%, respectively. The SGA rate only by the new CCs was 18% and the SGA rate only by the standard CCs was 0.01%. Compared to AGA by both models, SGA by the new CCs had increased rates of cesarean section, (OR 1.53 (95% CI 1.19, 1.96)), prematurity (OR 2.84 (95% CI 2.09, 3.85)), NICU admission (OR 5.41 (95% CI 3.47, 8.43), and adverse outcomes (OR 1.76 (95% CI 1.06, 2.60). The strength of these associations decreased with gestational age. CONCLUSION: The use of the new CCs allowed for a more accurate identification of SGA at risk of adverse perinatal outcomes as compared to the standard CCs.

Implications of training for pessary placement and accuracy of cervical length measurements after pessary placement: A prospective, double-blind, randomized clinical trial.

BACKGROUND: Cervical pessary placement as an intervention for preterm birth prevention in women with a short cervix is a simple, painless procedure with few complications and a reasonable cost. Its efficacy depends on the expertise of the obstetrician performing the procedure. Therefore, it is reasonable to assume that untrained obstetricians with no expertise in pessary placement are more likely to insert the pessary incorrectly, thereby reducing its efficacy. Nevertheless, the impact of pessary placement expertise and training, as well as the accuracy of cervival length measurements, has never been evaluated. OBJECTIVE: To evaluate the impact of providing training for pessary placement to obstetricians with no expertise in this intervention. To this end, the percentage of correct pessary placements and accuracy of cervical length measurements after pessary placement achieved by obstetricians who received such training was compared with the results achieved by obstetricians who did not receive any training. METHODS: This prospective, double-blind, randomized clinical trial included 91 pregnant women requiring a cervical pessary due to a short cervix. Patients were assigned at random to a group treated by untrained obstetricians with no expertise in pessary placement (untrained group, n = 45) or to a group treated by trained obstetricians with no expertise in pessary placement (trained group, n = 46). The primary outcomes were the quality of pessary placement and the accuracy of cervical length measurements after pessary placement. RESULTS: Obstetricians in the trained group achieved a significantly higher percentage of correct pessary placements than obstetricians in the untrained group (97.8 % and 65.2 %, respectively; p < 0.001). No significant differences were observed between groups in terms of the accuracy of cervical length measurements after pessary placement (p = 0.661), and both groups showed moderate to good agreement with the expert's measurements (intraclass correlation coefficient 0.840 and 0.749, respectively). No differences in pregnancy outcomes were observed between groups. CONCLUSION: This study showed that providing training in pessary placement to obstetricians with no expertise in this procedure increases the quality of pessary placement. Furthermore, the inconsistent results found in pessary studies may be explained, in part, by a lack of training in pessary placement.

Cervical pessary and cerclage placement for preterm birth prevention and cervicovaginal microbiome changes.

INTRODUCTION: Our objective was to compare the vaginal microbiome in low-risk and high-risk pregnant women and to explore a potential association between vaginal microbiome and preterm birth. MATERIAL AND METHODS: A pilot, consecutive, longitudinal, multicenter study was conducted in pregnant women at 18-22 weeks of gestation. Participants were assigned to one of three groups: control (normal cervix), pessary (cervical length ≤25 mm) and cerclage (cervical length ≤25 mm or history of preterm birth). Analysis and comparison of vaginal microbiota as a primary outcome was performed at inclusion and at 30 weeks of gestation, along with a follow-up of pregnancy and perinatal outcomes. We assessed the vaginal microbiome of pregnant women presenting a short cervix with that of pregnant women having a normal cervix, and compared the vaginal microbiome of women with a short cervix before and after placement of a cervical pessary or a cervical cerclage. RESULTS: The microbiome of our control cohort was dominated by Lactobacillus crispatus and inners. Five community state types were identified and microbiome diversity did not change significantly over 10 weeks in controls. On the other hand, a short cervix was associated with a lower microbial load and higher microbial richness, and was not correlated with Lactobacillus relative abundance. After intervention, the cerclage group (n = 19) had a significant increase in microbial richness and a shift towards community state types driven by various bacterial species, including Lactobacillus mulieris, unidentified Bifidobacterium or Enterococcus. These changes were not significantly observed in the pessary (n = 26) and control (n = 35) groups. The cerclage group had more threatened preterm labor episodes and poorer outcomes than the control and pessary groups. CONCLUSIONS: These findings indicate that a short cervix is associated with an altered vaginal microbiome community structure. The use of a cerclage for preterm birth prevention, as compared with a pessary, was associated with a microbial community harboring a relatively low abundance of Lactobacillus, with more threatened preterm labor episodes, and with poorer clinical outcomes.

The Overlooked Impact of Lower Uterine Segment Contractions on Second Trimester Cervical Assessment.

INTRODUCTION: Asymptomatic contractions in the lower uterine segment (LUS) may affect uterocervical angle and cervical length (CL); however, this has never been investigated. Therefore, the aim of this study was to evaluate the effect of LUS contractions on uterocervical angle, CL, and LUS thickness. MATERIALS AND METHODS: This was a prospective, observational, single-cohort study conducted on 102 asymptomatic singleton pregnancies between 19.0 and 22.6 weeks of gestation. Uterocervical angle and CL were measured by transvaginal ultrasound at two different time points with an interval of at least 20 min. LUS thickness was also measured as an indirect marker of myometrial contraction. A linear and curvilinear regression were performed to explore a potential association between LUS contractions, measured as increments in LUS thickness, and changes in CL and uterocervical angle. RESULTS: The linear regression between changes in LUS thickness and changes in CL showed that LUS contractions impact CL; for every 1-mm increase in LUS thickness, CL increased by 0.909 mm, when the isthmus was included in the CL measurement (R2 = 0.358; ß = 0.909; p < 0.001). By contrast, when the isthmus was not included in the measurement, a curvilinear relation between changes in LUS thickness and changes in CL was found (R2 = 0.077; ß1 = 0.575, ß2 = 0.038; p = 0.018). The relation between changes in uterocervical angle and changes in LUS thickness was not significant. DISCUSSION/CONCLUSION: LUS contractions can be observed in many asymptomatic women during the second trimester of pregnancy. LUS contractions lead to an increase in CL and LUS thickness, thus impacting ultrasound cervical assessments. These contractions do not affect the uterocervical angle.

Angiogenic factors for planning fetal surveillance in fetal growth restriction and small-for-gestational-age fetuses: A prospective observational study.

OBJECTIVE: The aim of this study was to assess the added value of the soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) ratio for adjusting the periodicity of ultrasound examinations in early-onset fetal growth restriction (FGR) and small for gestational age (SGA). DESIGN: A prospective, observational study. SETTING: Tertiary referral hospital. POPULATION: One hundred and thirty-four single pregnancies with ultrasonographic estimated fetal weight (EFW) below the 10th centile between 20+0 and 31+6  weeks of gestation with antegrade umbilical artery flow. METHODS: The time from Doppler and sFlt-1/PlGF assessment to delivery was recorded and classified into four ranges: <1, <2, <3 and <4 weeks. MAIN OUTCOME MEASURES: Sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of sFlt-1/PlGF values to predict the time to delivery. RESULTS: In the SGA cohort, the NPV calculated for an sFlt-1/PlGF cut-off value of 38 was 100% for delivery before 3 weeks, and 98% for delivery before 4 weeks after diagnosis (95% CI 0.89-1.00). In the FGR cohort, the NPV calculated for an sFlt-1/PlGF cut-off value of 38 was 100% for delivery before 2 weeks after diagnosis (95% CI 0.92-1.00). By contrast, more than 50% of cases with an sFlt-1/PlGF value of >85 required an elective delivery before 1 week. CONCLUSIONS: sFlt-1/PlGF values in early-onset SGA and FGR are predictive of the time to delivery and could be used for planning fetal surveillance, by reducing the frequency of ultrasound in cases with sFlt-1/PlGF < 38 and by providing closer follow-up in cases with sFlt-1/PlGF >85. TWEETABLE ABSTRACT: sFlt-1/PlGF values in early-onset SGA/FGR could be used in addition to Doppler for planning fetal surveillance.