A. Insunza

Infection and labor: VII. Microbial invasion of the amniotic cavity in spontaneous rupture of membranes at term

OBJECTIVEnThe purpose of this study was to determine the frequency, microbiologic characteristics, and clinical significance of microbial invasion of the amniotic cavity in women with premature rupture of membranes at term.nnnSTUDY DESIGNnAmniocentesis was performed in 32 women with term premature rupture of membranes and amniotic fluid cultured for aerobic and anaerobic bacteria and Mycoplasmas.nnnRESULTSnThe prevalence of positive amniotic fluid cultures was 34.3% (11/32). The most common isolates were Ureaplasma urealyticum, Peptostreptococcus sp., Lactobacillus sp., Bacteroides fragilis, and Fusobacterium sp. Clinical chorioamnionitis occurred only in one patient with a positive amniotic fluid culture. Her neonate had ophthalmitis. Three patients (9.4%) had endometritis. Among women who were delivered vaginally, those with a positive amniotic fluid culture had a significantly higher rate of endometritis than those with a negative culture (33% [3/9] vs 0% [0/20], respectively, p = 0.023).nnnCONCLUSIONSnThese data indicate that microbial invasion of the amniotic cavity occurs in approximately one third of patients with preterm premature rupture of membranes. Microbial invasion of the amniotic cavity is a risk factor for endometritis in women with term premature rupture of membranes.

The value of amniotic fluid interleukin-6, white blood cell count, and Gram stain in the diagnosis of microbial invasion of the amniotic cavity in patients at term

PROBLEM: Subclinical microbial invasion of the amniotic cavity occurs in 18.8% of women with term labor and intact membranes and in 34% of patients with term PROM and is a risk factor for the development of puerperal infection related morbidity. Although amniotic fluid white blood cell count, interleukin‐6 determination, and Gram stain examination have been used for the diagnosis of intrauterine infection in patients with preterm labor and preterm premature rupture of membranes, no information is available about the accuracy and specific cut‐off values for these tests in patients at term. The purpose of this study was to compare the performance of the amniotic fluid Gram stain examination, white blood cell count, and interleukin‐6 determination in the identification of microbial invasion of the amniotic cavity in patients at term with and without PROM.

Intrathoracic Pressure in Congenital Chylothorax: Keystone for the Rationale of Thoracoamniotic Shunting?

Thoracoamniotic shunting in fetal pleural effusion has poor results, with an overall survival of less than 50% when hydrops is associated. Those cases without hydrops presented the best evolution, but the indication in these cases remains controversial. We present a dichorionic diamniotic twin pregnancy at 29 weeks’ with right pleural effusion and hydrops, in which one fetus presented diaphragm inversion and mediastinal shift, both considered as ultrasonographic signs of thoracic hypertension. A thoracoamniotic shunt reversed these signs immediately. Nevertheless, 1 week after, these signs and skin edema reappeared and the effusion increased, leading to a second thoracocenthesis for drainage and intrathoracic pressure measurement. Amniotic fluid and intrathoracic pressures were found at 21 and 39 mm Hg, respectively. A cesarean section was performed and the catheter was found to be obliterated by cellular detritus of leukocytes and fibrin. Our conclusion is that ultrasonographic signs of elevated thoracic pressure are a keystone for the shunt indication, and that this could be corroborated by direct measurements. This can be an important parameter for precise indication of thoracoamniotic shunting.

Error introduced into velocity measurements by inappropriate Doppler angle assignment

Doppler flow measurements require precise estimates of the flow velocity as well as of the vessel’s area in a transverse cross-section. The angle assignment feature has been implemented in all ultrasound equipment for velocity measurements, which are used increasingly in the management of many medical conditions1. Even though the technique has been improved, faulty velocity measurements still occur, and this may lead to unnecessary intervention2. If the operator introduces an error of e into the θ angle, the velocity will vary. The measured velocity (Vm) for angle (θ + e), corrected by Cos (θ + e), is calculated as: Vm = Df × C 2 × fe × Cos (θ + e) ,

OC06.02: Cervix measurement in spontaneous labor prediction in a large population of twins from a metropolitan hospital from Santiago, Chile

K. Klein1, L. Rode2,3, K. Nicolaides4, E. Krampl-Bettelheim1, H. Larsen5, A. Holmskov6, K. Riis Andreasen7, N. Uldbjerg8, J. Ramb9, B. Bødker10, L. Skibsted11, L. Sperling12, S. Hinterberger13, L. Krebs14, H. Zingenberg15, E. Weiss16, I. Strobl17, L. Laursen18, J. Tranberg Christensen19, I. Vogel20, B. M. Hansen21, A. Lando21, A. Tabor2,3 1Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria; 2Department of Fetal Medicine 4002, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; 3Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; 4Harris Birthright Research Centre for Fetal Medicine, King’s College Hospital, London, United Kingdom; 5Department of Obstetrics and Gynecology, Aalborg Hospital, Aalborg, Denmark; 6Department of Obstetrics and Gynecology, Viborg Hospital, Viborg, Denmark; 7Department of Obstetrics and Gynecology, Hvidovre Hospital, Hvidovre, Denmark; 8Department of Obstetrics and Gynecology, Aarhus University Hospital Skejby, Aarhus, Denmark; 9Department of Obstetrics and Gynecology, Sønderborg Hospital, Sønderborg, Denmark; 10Department of Obstetrics and Gynecology, Hillerød Hospital, Hillerød, Denmark; 11Department of Obstetrics and Gynecology, Roskilde University Hospital, Roskilde, Denmark; 12Department of Obstetrics and Gynecology, Herlev Hospital, Herlev, Denmark; 13Department of Obstetrics and Gynecology, General Hospital of Klagenfurt, Klagenfurt, Austria; 14Department of Obstetrics and Gynecology, Holbæk Hospital, Holbæk, Denmark; 15Department of Obstetrics and Gynecology, Glostrup Hospital, Glostrup, Denmark; 16Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria; 17Department of Obstetrics and Gynecology, Medical University of Innsbruck, Innsbruck, Austria; 18Department of Obstetrics and Gynecology, Odense University Hospital, Odense, Denmark; 19Department of Obstetrics and Gynecology, Gentofte Hospital, Gentofte, Denmark; 20Department of Clinical Genetics, Aarhus University Hospital Skejby, Aarhus, Denmark; 21Department of Neonatology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark

OP19.11: Umbilical venous blood flow measurements: comparison between free and intra‐abdominal portion

Objective: To compare fetal umbilical vein flow measurement on free-floating (FF) and intra-abdominal (IA) portions. Methods: Prospective measurement of the umbilical venous volume flow (UVVF) in 13 normal pregnancies during routine antenatal ultrasounds. Umbilical vein cross-sectional diameter was measured in the IA umbilical vein, and in perpendicular views of FF portions of the cord. Velocity measurements were obtained using angle correction. Means were compared using Student T-test for related measures and intra-class correlation coefficient (ICC) was calculated by a two-way ANOVA model. Results: All measurements were done by two operators, blind to each other (MY and JC). For FF, mean vessel diameter showed an inter-observer ICC of 0.96. Mean blood velocity showed an interobserver ICC of 0.88. Mean angle correction used for Operator 1 was of 25,5◦, and for Operator 2 the mean correction reached 22.38◦, with an inter-observer ICC of 0.48. Vessel area and UVVF displayed an inter-observer ICC of 0.96 and 0.93, respectively. For IA, mean vessel diameter measurement showed an inter-observer ICC of 0.91. Mean blood velocity inter-observer ICC was of 0.45. Mean angle correction used was of 32.15◦ and 27.80◦, a non significant difference (p = 0.47), but with a poor inter-observer ICC (slight to none correlation, −0.98). Regarding vessel area and UVVF results, inter-observer ICC resulted of 0.91 and 0.74, respectively. Conclusions: When comparing UV blood flow between free-floating and intra-abdominal portions, our study shows a difference in UVVF calculations (inter-observer ICC 0.93 versus 0.74), attributable to the significant difference in the reliability of insonation angles for measuring IA portions (inter-observer ICC −0.98). These results validate the special attention to be addressed for a correct insonation angle for obtaining the blood velocity.

OP03.03: Neurosonographic fetal assessment with the “single shot” technique in transabdominal 3‐D multiplanar ultrasound during routine 20–24 weeks' gestation scan

to four different reference range, for all head circumferences. Based on the reference chart that best fitted our practice during the study period, we identified all cases with HC below the 5th centile (Z score < 1.645). Outcomes were collected and analyzed according to HC Z scores at US examination. Results: 33 720 patients underwent ultrasound examinations during the study period and were included in the study. Based on the most appropriate reference range, 1102 foetuses (3.3%) had a HC under the 5th percentile and were selected. Using that reference charts, HC Z scores of the selected fetuses ranged from −4 to −1.645. Outcomes varied according to the degree of HC smallness. Neurological abnormalities were more frequent when Z scores were below −3, whereas normal outcome or isolated growth restrictions were more frequent when Z scores were between −1.645 and −2. Conclusions: Outcome is highly different according to the degree of HC smallness. The use of Z scores may help in predicting the outcome of those fetuses with antenatally diagnosed HC below the 5th centile.

OP20.03: Reliability of the fetal umbilical vein volume flow measurement between different operators

measurements and time-averaged blood velocity. Pearson correlation coefficient was used to assess the relationship between umbilical volume flow and arterial velocities. Results: Median gestational age at examination was 33 + 6 weeks and 13 had UA PI > 90 centile. At the placental end, the correlation between umbilical flow and umbilical artery S, D and TAM was r = 0.51, 0.63 and 0.64 (P < 0.01), respectively. Correspondingly, at the free loop: r = 0.56, 0.66 and 0.61 (P < 0.001), and for the intra-abdominal portion: r = 0.22 (P = 0.3), 0.54 (P = 0.01) and 0.41 (P = 0.07). The success rates for measuring at the three sites, placental, free loop and intra-abdominal, were 71%, 100% and 66%, respectively. Conclusions: Absolute velocities in the UA reflect umbilical volume flow and could constitute another useful information in the assessment of IUGR, the measurements in the free loop of the cord being the preferred method.

OC143: Comparable estimated fetal weight from biometries of preterm and term singleton pregnancies support the use of birth weight charts for normal fetuses

Objectives: To evaluate the correlation between fetal head rotation and direction sonographically detected during the second stage of labour. Methods: A group of unselected women in the second stage of labour underwent serial digital examinations followed by translabial ultrasound. In a sagittal section of the maternal pelvis, the direction of the head was categorized as downward, horizontal or upward. In the transverse plane the angle between the midline of the fetal brain and the anteroposterior diameter of the pelvis was noted and the rotation of the head was established (< or ≥ 45◦). Clinical and ultrasound data were compared using Somer’s d test. Results: Sixty women were included in the study group with a total of 168 and a median of 3 ultrasound and clinical examinations performed for each fetus (see table 1). When rotation was sonographically undetectable on the axial plane (28/168 or 16.6%), fetal head was always directed downward on the sagittal plane (28/28). With a rotation ≥ 45◦ (75 cases), fetal head direction was mostly horizontal (44 or 58.7%), while a rotation < 45◦ was usually associated with upward direction of fetal head (45/65 or 69.2%). Rotation < 45◦ and upward direction of the head were more strongly correlated if only cases with occiput anterior were considered. In these cases, the probability of a clinically established low station (≥ 3 cms) was particularly high when an upward direction of the head was seen in combination with a rotation of < 45◦ (40/42 examinations or 95%). All comparisons demonstrated a statistically significant relationship with P < .0001. Conclusions: Fetal head rotation and direction as sonographically determined in the second stage of labour show a significant correlation with each other as with clinically established station, particularly in fetuses with occiput anterior.

OP10.02: Cervical shortening rate as a predictor for preterm delivery in twin pregnancies

Objectives: To determine if sonographic cervical length (CL) values in twins correlate with risk for delivery < 34 weeks. Methods: A retrospective review of twin gestations with CL on transvaginal ultrasound from January 2002–June 2006 was performed. All measurements were performed with a Voluson 5–9 Mhz transvaginal probe. Inclusion criteria were asymptomatic twins with sonographic CL determinations and who delivered at our institution. Cases with known mullerian anomalies, prophylactic cerclage, history of cervical insufficiency, prior preterm delivery, fetal aneuploidy, fetal anomalies or maternal or fetal complications such as preeclampsia necessitating delivery were excluded. Patients were stratified based on CL values and delivery at < 34 wks vs. ≥ to 34 wks. Results: 366 twin pregnancies were reviewed; a total of 69 patients met inclusion criteria. 35 (50.7%) twin pregnancies delivered ≥ 34 wks and 34 (49.3%) delivered < 34 wks. Figure 1 demonstrates CL values at various GA and the correlation with delivery < or ≥ 34 wks. There were no deliveries < 34 wks in patients with a CL ≥ 2.5 cm at 26 weeks. Conversely, all patients with CL < 2.5 cm prior to 19 wks delivered < 34 wks. 80% of patients with CL < 2.5 cm at 16–22wks delivered < 34 wks, and of those, 91.7% delivered ≤ 28 wks. A CL ≥ 2.0 cm at 24 wks correlated with a 83% incidence of delivery ≥ 34 wks. Conclusions: The clinical significance of sonographic CL values in twins remains controversial. This study demonstrates a CL < 2.5 cm at 16–22 wks correlated with 80% of these twins delivering before 34 wks and all patients with CL < 2.5 prior to 19 wks delivered < 34 wks. We also found an absolute correlation between a CL ≥ 2.5 cm at 26 wks and delivery ≥ 34 wks. Therefore, in twins gestations, a second trimester sonographic CL value may be a useful indicator for increased risk of preterm delivery < 34 wks.