Fetal head prior to delivery: precise measurement, using a mathematically extrapolated frontooccipital diameter.

PURPOSE: To find a method that could improve the accuracy of fHC evaluation at term. MATERIAL AND METHODS: This retrospective cohort study was based on data from the University Hospital of Zürich (USZ). Study population included singleton fetuses and newborns at term between 2015 and 2017. Fetal biometry was performed within 1 week prior to delivery. Study data consisted of two cohorts with 200 ultrasound measurements each: 200 performed by an expert, 200 by residents. fHC were compared with the newborn's head circumference (nHC). fHC was estimated using two methods: (1) fHC based on sonographically estimated frontooccipital diameter (FOD) and biparietal diameter (BPD). (2) Expected FOD was calculated as a fixed mean FOD/BPD relation, derived from biometry standards as the 50th percentile. If BPD was < 99 mm, FOD was calculated according to the formula BPD × 1.268557, If BPD was ≥ 99 mm, FOD was calculated according to the formula BPD × 1.20641443. RESULTS: fHC was underestimated compared with nHC in the expert group: percentage error (PE = - 3.68%, SD = 2.79), as well as in the group of residents (PE = - 3.78%, SD = 3.20) using method 1. fHC measurement was significantly more accurate using method 2. In the expert group PE = - 1.17%, SD = 3.08, in the group of residents PE = - 0.95%, SD = 3.33. Bland-Altman analysis showed limits of agreement (LOA) between - 2.41338 and 0.5537828 cm for fHC. CONCLUSIONS: Accuracy of fHC estimation could be improved by extrapolation of FOD when real-time FOD cannot be measured.

Physiological Uterine Involution in Primiparous and Multiparous Women: Ultrasound Study.

PURPOSE: To examine the uterine involution period after uncomplicated delivery in primiparous and multiparous women. METHODS: Longitudinal prospective study. Repeated parameters were measured and endometrial contents and diastolic notch were observed. Measurements of primiparous and multiparous women were carried out after labour on the 1st, 3rd, 10th, 30th, 42nd, and 60th postpartum days. The analysis was performed using SPSS version 21. RESULTS: The median uterus parameters are bigger in multiparous group in physiological puerperium, but the decreasing trend is the same. The endometrial cavity on the 10th day was significantly wider in multiparous women and mainly echo-negative view of the uterine cavity was observed. The evaluation of the uterine angle deviation changes from an extremely retroverted position to a more anteverted position. RI of the uterine artery in both groups was low immediately after labour and significantly increased one month postpartum. Notching of the uterine artery undergoes changes, but diastolic notch does not appear in all postpartum women even after two months following labour. CONCLUSIONS: The puerperium period after normal vaginal delivery depends on parity. The trend of involution in primiparous and multiparous women follows a similar pattern, yet, it lasts longer in the multiparous women. Ultrasound of uterine is certainly a useful tool after labour and may be important in facilitating an early detection of postpartum uterine complications.

Evaluation of fetal anthropometric measures to predict the risk for shoulder dystocia.

OBJECTIVE: To evaluate the quality of anthropometric measures to improve the prediction of shoulder dystocia by combining different sonographic biometric parameters. METHODS: This was a retrospective cohort study of 12,794 vaginal deliveries with complete sonographic biometry data obtained within 7 days before delivery. Receiver-operating characteristics (ROC) curves of various combinations of the biometric parameters, namely, biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference, abdominal diameter (AD), abdominal circumference (AC) and femur length were analyzed. The influences of independent risk factors were calculated and their combination used in a predictive model. RESULTS: The incidence of shoulder dystocia was 1.14%. Different combinations of sonographic parameters showed comparable ROC curves without advantage for a particular combination. The difference between AD and BPD (AD - BPD) (area under the curve (AUC) = 0.704) revealed a significant increase in risk (odds ratio (OR) 7.6 (95% CI 4.2-13.9), sensitivity 8.2%, specificity 98.8%) at a suggested cut-off ≥ 2.6 cm. However, the positive predictive value (PPV) was low (7.5%). The AC as a single parameter (AUC = 0.732) with a cut-off ≥ 35 cm performed worse (OR 4.6 (95% CI 3.3-6.5), PPV 2.6%). BPD/OFD (a surrogate for fetal cranial shape) was not significantly different between those with and those without shoulder dystocia. The combination of estimated fetal weight, maternal diabetes, gender and AD - BPD provided a reasonable estimate of the individual risk. CONCLUSION: Sonographic fetal anthropometric measures appear not to be a useful tool to screen for the risk of shoulder dystocia due to a low PPV. However, AD - BPD appears to be a relevant risk factor. While risk stratification including different known risk factors may aid in counseling, shoulder dystocia cannot effectively be predicted.

Continuous independent quality control for fetal nuchal translucency measurements provided by the cumulative summation technique.

PURPOSE: The cumulative summation technique (CUSUM) is an innovative method for the quality control of nuchal translucency (NT) measurements. CUSUM allows immediate corrective intervention as soon as an unacceptable tendency is noted. The aim of this study was to implement an objective and dynamic quality control method based on the CUSUM technique for prompt analysis of fetal NT measurement which would be compatible with different standards in routine clinical practice. The findings were compared to the standard NT quality control methods currently in use. MATERIALS AND METHODS: Three sets of fetal NT measurements performed by three experienced examiners (I, II and III) were selected for retrospective evaluation. One additional set of NT measurements performed by examiner IV was prospectively assessed to approve the practicability of the method. NT measurements were conducted according to the recommendations of Fetal Medical Foundation (FMF) Germany and London. NT values were converted to Z-scores. For quality and accuracy evaluation, data were fed into the Digisono CUSUM software to create double CUSUM charts of Z-scores. In addition, histograms were composed from the Z-scores of each set of measurements and plotted against a normal Gaussian distribution. RESULTS: Three different patterns of retrospective performance and one set of NT measurements that was evaluated prospectively are presented. The full alignment of Z-scores using CUSUM curves reflected exact periods of under- and overestimation of NT measurements. The CUSUM chart of the prospective data set reveals that prompt corrective intervention of poor performance resulted in reconstitution of optimal results and provided sufficient control. In contrast, histograms of NT Z-scores only showed a minor positive or negative shift as compared to the expected values on the basis of Gaussian distribution, but could not identify poor performance. CONCLUSION: Use of the CUSUM technique analysing the quality of sonographic NT measurements provides the possibility to prospectively observe the development of the examiner's skills, to maintain competence and to promptly define the time when inaccurate measurements start to occur.

[Does a combination of foetal biometry and maternal MRI pelvimetry decrease the frequency of secondary caesarean section?]. / Senkt die Kombination von fetaler Biometrie und MRT-Pelvimetrie die Rate an sekundären Sectiones?

OBJECTIVE: Cephalopelvic disproportion (CPD) is a frequent indication for secondary Caesarean section. The delivery simulation software Anapelvis was developed to predict a CPD on the basis of foetal ultrasound biometry and maternal pelvimetry data. The objective of this retrospective study was to analyse the predictive value of Anapelvis software in consideration of antenatal foetal biometry quality. PATIENTS AND METHODS: 162 pregnant women with suspected CPD who had undergone a magnetic resonance imaging pelvimetry were included in this study. The antenatal foetal biometry was carried out within a week before delivery. RESULTS: The positive predictive value (PPV) for arrest of delivery was 85.7% in the group of 79 pregnancies with planned vaginal delivery. Sensitivity was 56.3%, specificity 60.0% and negative predictive value (NPV) 24.3% accordingly. The highest accuracy [percent error (PE) -0.1%] of fetal weight estimation was found in the group where an arrest of delivery was predicted. The lowest accuracy (PE -4.4%) was detected in the group with the prediction of vaginal delivery. CONCLUSIONS: Labour simulation software can be helpful only in such cases where an arrest of delivery was predicted. The accuracy of delivery simulation with the Anapelvis software was considerably affected by the quality of antenatal foetal ultrasound biometry.

Continuous independent quality control for fetal ultrasound biometry provided by the cumulative summation technique.

OBJECTIVE: To apply the cumulative summation (CUSUM) technique for an evaluation of the learning process of sonographic fetal weight estimation at term in combination with the z-scores of biometry determinants and to assess the time of appearance and sources of errors. METHODS: Learning curve (LC-CUSUM) and double CUSUM charts for systematic error detection based on absolute and signed mean percentage error were generated to retrospectively estimate the longitudinal accuracy of sonographic fetal weight estimation conducted by three trainees and one experienced examiner. For LC-CUSUM analysis an examination was considered to be a failure when there was an absolute error in birth weight estimation >/= 15%. Fetal biometry measurements (head circumference, abdominal circumference (AC) and femur length (FL)) from 227 routine ultrasound scans of one examiner were separately transformed into z-scores and double CUSUM charts were generated to assess the systematic errors for each determinant. RESULTS: The LC-CUSUM charts revealed that different numbers of scans are required for different examiners to achieve competence in estimating birth weight. AC and FL deviated most significantly from expected values (P < 0.05). The double CUSUM charts revealed exact periods of systematic errors in the measurement of biometry determinants, clearly reflecting errors of fetal weight estimation. CONCLUSIONS: The use of CUSUM techniques in the analysis of sonographic data allows observation of the development of an examiner's skill and maintenance of competence. The CUSUM technique not only allows the reasons for impaired fetal weight estimation to be revealed but also allows determination of the exact time when inaccurate measurements start to occur. We suggest that CUSUM charts should be implemented in routine clinical practice as a measure of objective quality evaluation of sonographic fetal biometry.

Sonographic prediction of macrosomia cannot be improved by combination with pregnancy-specific characteristics.

OBJECTIVE: To evaluate the predictive value of a combination of sonographic, clinical and demographic data for detecting fetal macrosomia compared to ultrasound fetal weight estimation alone. METHODS: Retrospective cohort data were obtained from 1062 pregnancies in an unselected population. Estimated fetal sonographic weight was obtained within the last week prior to delivery. Two different combination models-published by Mazouni et al. and Nahum and Stanislaw-were employed to predict the presence of macrosomia at birth in these infants. Receiver-operating characteristics (ROC) curves were generated to compare the prediction of macrosomia when using different observation methods and sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy were calculated. RESULTS: Macrosomia (birth weight >or= 4000 g) was present in 135/1062 (12.7%) newborns. ROC curve analysis revealed the prediction of macrosomia using ultrasound alone to be significantly superior to the combined method of Mazouni et al. (area under the curve (AUC) 0.922, 95% CI 0.902-0.943 vs. 0.747, 95% CI 0.700-0.794, respectively; P < 0.0005), whereas the performance of the Nahum and Stanislaw equation was similar but not superior to ultrasound alone (AUC 0.895, 95% CI 0.839-0.950 vs. 0.912, 95% CI 0.867-0.958, respectively; P > 0.05). The accuracy of macrosomia prediction was similar for ultrasound alone and the Nahum and Stanislaw equation (approximately 90%), whereas the nomogram of Mazouni et al. reached only 51.7% accuracy (using a probability cut-off level of 50%). The NPV was found to be over 90% for all methods. CONCLUSIONS: Combination of sonographic estimates with clinical and demographic variables does not improve the prediction of macrosomia at delivery in comparison with a routine ultrasound scan within a week before delivery, at least in unselected populations.

[Abdominal pain in pregnancy--ultrasound as the diagnostic tool of choice for rapid decision making]. / Akutes Abdomen in der Schwangerschaft--Ultraschall als Mittel zur raschen Entscheidungsfindung.

Pregnant women with abdominal pain profit by using ultrasound as a first line diagnostic tool. Together with the clinical evaluation the ultrasound examination in the same room reduces time until a diagnostic decision can be made. By a systematic approach and the classification in pregnancy-related sources of pain and pregnancy-unrelated sources of pain the risks for mother and child can be quickly recognised and the necessary diagnostic and therapeutic steps can be taken. The sonographer must be experienced and a good ultrasound equipment must be available at the site.

[Computer based documentation of ultrasound data]. / EDV-unterstützte Dokumentation von Ultraschalluntersuchungen.

Usually, hospitals and private doctors are well equipped with computers. However, the documentation of ultrasound data is commonly paper-based. The paper presents a computer-based ultrasound data recording and reporting, using the ultrasound documentation software Digisono.

New nomogram for foetal weight estimation based on Hadlock's two-parameter formula.

AIM: To develop and validate a graphical method for ultrasonic foetal weight estimation with predictive qualities comparable to state-of-the-art computational methods. METHOD: Study data were obtained from 3839 consecutive singleton pregnancies with ultrasound examination within 7 days of delivery. We translated the well established Hadlock 2-parameter formula based on abdomen circumference and femur length into a nomogram [corrected]. We compared the measured foetal weight with estimations obtained from this new nomogram and three other methods. RESULTS: Measured by the foetal weight percentage error the new nomogram underestimates the foetal weight on average by 2.5 % (9.86) (mean [SD]) with uniform results over the complete birth weight spectrum. By the same measurement the Hadlock 4-parameter formula underestimates the foetal weight by 1.2 % (9.3) whereas the Hansmann nomogram overestimates the foetal weight by 14.5 % (16.1) The difference between the estimated foetal weight percentage error obtained from the new nomogram and from the Hadlock 2-parameter formula is 0.06 % (0.27) and hence clinically irrelevant. CONCLUSION: The new nomogram has predictive qualities comparable to state-of-the-art computational methods and is thus not only as reliable but also easy to use in situations when computers are not available. It can be recommended for foetal weight estimation over the whole spectrum of birth weight.

Volume sonography of the pelvic floor in nulliparous women and after elective cesarean section.

OBJECTIVE: To describe the sonographic appearance of the pelvic floor which has not been stressed by forces of labor or vaginal delivery in pregnant women and after childbirth. SUBJECTS AND METHODS: In a prospective observational study 14 nulliparous women during first trimester pregnancy and 26 primiparous women after elective cesarean were examined within the first week postpartum. The integrity of the internal anal sphincter expressed as the ratio between the anterior and the posterior internal anal sphincter muscle thickness (a/p-ratio), asymmetry of the levator ani muscle and the paraurethral fixation of the lateral vaginal edges at the arcus tendineus were assessed using volume sonography. RESULTS: The a/p-ratio in nulliparous women was significantly higher (p<0.01) than after elective cesarean section. Asymmetry of the levator ani muscle did not differ between both groups but was more frequently in the nulliparous patients with an odds-ratio of 1.16 (CI 0.74-1.82). In both groups of women the paraurethral fixation of the lateral vaginal edges were above the suburethral level of the vagina. CONCLUSIONS: This study gives sonographic features of the pelvic floor in nulliparous women and in primigravidae after elective cesarean section. Data from the post-cesarean group can serve as reference values for further studies evaluating pelvic floor damage after various modi of vaginal delivery.

Reference values of fetal peak systolic blood flow velocity in the middle cerebral artery at 19-40 weeks of gestation.

OBJECTIVES: The objectives of this prospective study were (i) to establish new reference values of peak systolic blood flow velocity measurement in the fetal middle cerebral artery (MCA-PSV) following validated methodological guidelines and (ii) to develop a method to calculate Z-scores of MCA-PSV. PATIENTS AND METHODS: Cross-sectional data were obtained from 331 pregnant women between 19 and 40 weeks' gestation. Reference ranges for MCA-PSV were constructed and for each measurement linear regression models were fitted separately to the mean and standard deviations (SD) as a function of gestational age. An application to calculate Z-scores was developed. A comparison was made between the reference ranges produced in our study and those of a previous one. RESULTS: A new chart, table of centiles and regression equations of MCA-PSV are presented. Comparison of our reference ranges with ones produced in a previous study showed similar 5th centile values. However, the values for the 50th and 95th centiles between 19 and 28 gestational weeks were lower in our study. CONCLUSIONS: We have constructed reference ranges for MCA-PSV which, because they are derived from a larger number of examinations in the 15-20-week period and because the methodological flaws of the previously published study have been eliminated, we consider to be more accurate and therefore more useful for clinical practice.

Dandy-walker malformation: prenatal diagnosis and outcome.

Prenatal ultrasound identified Dandy-Walker malformation (DWM) in ten singleton pregnancies with concurrent central nervous system (CNS) anomalies and extra-CNS anomalies in eight cases. DWM was confirmed by postnatal magnetic resonance imaging (MRI) or pathological examination in nine cases. Karyotypes were normal in the seven infants tested. Postnatal neurological and developmental testing in the five survivors showed a spectrum of clinical outcome from minor defects to severe handicap. Postnatal investigation also disclosed additional CNS and extra-CNS findings not detected on ultrasound, as did autopsy in the other five infants. However, ultrasound diagnosis of DWM is accurate and is an indication for exhaustive screening for concurrent anomalies both within and outside the CNS and in chromosome structure and number, as the prognosis is heavily dependent on associated malformations and karyotype.

Fetal ultrasound biometry: 1. Head reference values.

OBJECTIVE: To create reliable reference ranges and calculate Z scores for fetal head ultrasound biometry using a large sample size which is evenly distributed from 12 to 42 weeks of pregnancy. DESIGN: A prospective, cross-sectional study. SETTING: Obstetric clinics (outpatient and delivery units) at the University Hospital of Zurich. SAMPLE: The study data were obtained from 6557 pregnant women. METHODS: Only the first ultrasound examination between 12 and 42 weeks of each fetus with exactly established gestational age was used for analysis. No exclusions were made on the grounds of small-for-date birthweight, prematurity or other events several weeks after the examination. Separate regression models were fitted to estimate the mean and standard deviation at each gestational age for each parameter. RESULTS: A total of 6217 fetal head biparietal diameters and 5510 occipito-frontal diameters were measured. Both head circumference and cephalic index were derived in 5462 cases where both biparietal diameter and occipito-frontal diameter could be measured on the same fetus. The centile charts, tables and regression formulae for biparietal and occipito-frontal diameters, head circumference and cephalic index are presented. An application to calculate Z scores was developed using Excel (Microsoft Corporation, USA) and macros are presented in detail in the Figure 8 footnote. The comparison of our charts with those of the two most recent studies revealed almost no differences in biparietal diameter centiles. In one publication, occipito-frontal diameter charts, and in another, head circumference charts were different from the current study. CONCLUSIONS: We have presented centile charts, tables and regression formulae for fetal head ultrasound biometry derived from a large and minimally selected sample size in a carefully designed cross-sectional study. Complete tables and regression formulae to calculate reference ranges and Z scores are presented for use in computer-aided evaluation of fetal ultrasound biometry.

Fetal ultrasound biometry: 2. Abdomen and femur length reference values.

OBJECTIVE: To create reliable reference ranges and calculate Z scores for fetal abdomen and femur ultrasound biometry using a large sample size which is evenly distributed from 12 to 42 weeks of pregnancy. DESIGN: A prospective, cross-sectional study. SETTING: Obstetric clinics (outpatient and delivery units) at the University Hospital of Zurich. SAMPLE: The study data were obtained from 6557 pregnant women. METHODS: Only the first ultrasound examination between 12 and 42 weeks of each fetus with certainly established gestational age was used for analysis. No exclusions were made on the grounds of small-for-date birthweight, prematurity or other events several weeks after the examination. Separate regression models were fitted to estimate the mean and standard deviation at each gestational age for each parameter. RESULTS: A total of 5807 mean abdominal diameters and abdominal circumferences were derived from fetal transverse and anterio-posterior fetal abdominal diameter measurements. Fetal femur length was measured in 5860 instances. The charts, tables and regression formulae of the biometrical measurements are presented. A comparison of our charts with others showed no significant difference. Only Merz's centiles for abdominal biometry were lower and for femur length higher than ours. An application to calculate Z scores was developed using Excel (Microsoft Corporation, USA); the macros are presented in detail in the Figure 6 footnote. CONCLUSIONS: We have presented centile charts, tables and formulae for fetal abdominal diameter and circumference and femur length derived from a large and minimally selected sample size in a carefully designed cross-sectional study. Complete tables and regression formulae to calculate reference ranges and Z scores are presented to use in computer-aided evaluation of fetal ultrasound biometry.

Use of 3D ultrasound as a new approach to assess obstetrical trauma to the pelvic floor.

OBJECTIVE: To determine whether 3D ultrasound examination of pelvic floor anatomy after vaginal delivery allows detection of childbirth trauma. STUDY DESIGN: Pelvic floor anatomy was examined in 16 women during the puerperium with a 3D transrectal ultrasound probe. Images were acquired via the vaginal route for the assessment of anal morphology and the transrectal route to determine paravaginal fixation. Images of the anterior pelvic floor were calculated from the information stored in the volume block. Paravaginal defect is defined as a descent of the lateral vaginal wall below the suburethral vagina, whereas sphincter defects are characterised as thinning, or as gap formation of the anterior part of the internal anal sphincter. RESULTS: This new approach allowed the examination of a horizontal plane through the urethra and the periurethral tissue which is inaccessible with 2D ultrasound techniques. Morphology of the normal and traumatised anal sphincter could be demonstrated using reference planes perpendicular to the anal canal. CONCLUSIONS: Whereas in the past, defects of the vaginal attachment to the pelvic side wall could not be examined sonographically, 3D ultrasound can now be used to examine pelvic floor anatomy and to detect changes associated with trauma to the pelvic floor following vaginal delivery.

Pulsatility index in the fetal anterior tibial artery during the second half of normal pregnancy.

The objective of this prospective study was to establish reference values for the pulsatility index in the fetal anterior tibial artery during the second half of pregnancy. Pulsed Doppler waveform analysis of 203 fetuses at 23-42 weeks of pregnancy was performed, each fetus being examined just once. There were neither fetal nor maternal complications detectable at the time of the examination. In the first 14 fetuses from which recordings were taken, Doppler examination was performed on both fetal legs in order to evaluate systematic differences between the right and left legs. Intraobserver variability was analyzed by repetition of the measurements by the same examiner in the first 130 cases. There was no difference between right and left tibial circulation. The repeatability coefficient, defined as the 95% range for the difference in two repeat measurements, was 1.08. The pulsatility index of the anterior tibial artery (50th centile) increased slightly from 3.29 at 23 weeks of pregnancy to 4.09 at 42 weeks. The 5th and 95th centiles were calculated, as was the 95% confidence interval of the 5th and 95th centiles. Examination of the fetal peripheral circulation during the second half of pregnancy is possible with a high degree of precision. Whether there are changes in peripheral arterial circulation in compromised fetuses remains to be evaluated.

Successful treatment of fetal megavesica in the first half of pregnancy.

OBJECTIVE: Our goal was to assess fetal kidney function in fetuses with megavesica diagnosed during the first half of pregnancy before treatment. STUDY DESIGN: In a prospective interventional study 9 fetuses with megavesica diagnosed during the first half of pregnancy underwent vesicocentesis. Fetal urine biochemical markers (urine electrolytes, osmolarity, and beta 2-microglobulins) were determined after diagnostic vesicocentesis of the fetal megavesica. RESULTS: Surprisingly, in four fetuses who underwent sampling at 13 to 18 postmenstrual weeks, vesicocentesis proved both diagnostic and therapeutic. Pregnancy proceeded with normal amniotic fluid volume, a normal-sized urinary bladder with normal dynamics, and normal postnatal renal function. A fifth fetus had trisomy 18. In three of the remaining four fetuses in whom sampling was performed at 16 to 20 postmenstrual weeks, biochemical markers indicated a poor prognosis. In the remaining fetus marginal results of biochemical studies prompted intrauterine treatment, but death from respiratory problems ensued after premature delivery at 31 weeks. CONCLUSIONS: Fetal megavesica in the first half of pregnancy is an indication for an immediate diagnostic vesicocentesis. This is the first report emphasizing early diagnosis of fetal megavesica with subsequent fetal vesicocentesis and demonstrating that this minimally invasive procedure can be life-saving if performed in early pregnancy.

Reference resistance indices of the umbilical, fetal middle cerebral and uterine arteries at 24-42 weeks of gestation.

The objective of this cross-sectional study was to construct new reference ranges for Doppler flow velocity waveform resistance indices for the fetal umbilical artery, middle cerebral artery, placental and non-placental uterine arteries and the placentocerebral ratio in a large and minimally selected population attending a single clinic. Study design and data analysis adhered to a number of stringent and validated methodological recommendations derived both from the recent literature and from a review of earlier publications in this field. The final database comprised initial routine Doppler velocimetry at 24-42 weeks' gestation in 1675 pregnancies. Separate regression models were fitted to estimate the mean and standard deviation at each gestational age for each vessel. New charts, centile tables and regression equations are presented for the resistance indices of the fetal umbilical artery, middle cerebral artery, placental and non-placental uterine arteries and the mean of both uterine arteries and for the placentocerebral ratio.