B. Hollis

Placental edge to internal os distance in the late third trimester and mode of delivery in placenta praevia

Objectives To correlate transvaginal ultrasound findings with mode of delivery in cases of placenta praevia.

Maternal ethnic origin and fetal nasal bones at 11–14 weeks of gestation

Objectives  Failure to visualise the fetal nasal bones at 11–14 weeks of gestation is associated with a significant increase in the risk for trisomy 21. However, it is not known whether the ethnic origin of the mother has any effect on the fetal profile and the prevalence of this marker.

Screening for aneuploidy in the first trimester by assessment of blood flow in the ductus venosus

Objective To assess the role of ductus venosus Doppler assessment in screening for fetal aneuploidy in pregnancies at 11–14 weeks of gestation.

First-trimester uterine artery blood flow and birth weight

To determine reference values for first‐trimester uterine artery resistance index (RI) in healthy pregnant women with uncomplicated pregnancies and to investigate the relationship between uterine artery Doppler indices and birth weight.

Effect of parity on second‐trimester uterine artery Doppler flow velocity and waveforms

To investigate the relationship between second‐trimester uterine artery Doppler findings and parity in a large pregnant population.

Feasibility study of a Latest Date of Delivery (LDD) system of managing pregnancy

Background. This study aimed to establish the acceptability of a Latest Date of Delivery (LDD) system of managing pregnancy. An LDD is the date at 42 weeks on which labour will be induced if a woman has not delivered by then. This study examined whether women under conventional expected date of delivery (EDD) management would find an LDD system acceptable in principle, and whether they would prefer it to the EDD system. An additional objective was to examine changes in state anxiety in late pregnancy, post-term, and after delivery. Methods. This was a preliminary survey of womens attitudes towards an LDD system. Sixty-two women under normal pregnancy management completed questionnaires about the acceptability of an LDD system at 36 weeks gestation. In addition, questionnaires measuring state anxiety were completed at 36, 38, 40, and 41 weeks. Results. The majority of women evaluated an LDD system positively, with 64% of women saying they would agree to an LDD and only 11.3% saying they would not. Forty percent of women said they would prefer an LDD to an EDD system and 36% said they were not sure. Women who had not delivered by 41 weeks had significantly more anxiety than those who had delivered. Conclusions. The LDD system appears to be acceptable to women and, for 40% of women, preferable to the EDD. Anxiety appears to increase as women go post-term, but problems of attrition mean the results regarding anxiety should be treated cautiously. Potential difficulties with implementing an LDD system are discussed.

P10.08: First trimester nasal bones and trisomy 21 in a low‐risk population

Objectives: To construct normal reference values for JLS size. To determine JLS size in a study group with an increased NT. Methods: Ultrasound examinations were carried out on 70 singleton pregnancies and 15 pregnancies complicated by an increased NT (> 3 mm). The NT measurement was performed following criteria of the Fetal Medicine Foundation. The size of the JLS, were measured in a transversal view. Normal reference lines were constructed using Altman’s method (1993). The mean Z-scores for the NT and JLS in the increased NT group were calculated and the difference between the means was statistically tested (paired Student-t). Results: The NT and the mean of the JLS outcomes are linear related with gestational age: NT (mm) = 0.306 * GA (wks) −2.278. JLS (mm) = 0.544 * GA (wks) −5.106. In the normal group there is no significant correlation between NT and JLS size, R = 0.16, P = 0.19. However, in the increased NT group a significant (P = 0.02) correlation (R = 0.59) is found. The mean Z-score of the NT size 7.9 (SD = 3.9) is not significant different from the mean Z-score 7.2 (SD = 11.3) of the JLS size (P = 0.77). Conclusion: These data suggests that measuring JLS additional to NT might improve the detection rates in aneuploidy screening.

P03.16: Comparison of ultrasound, customised and actual birthweight in the prediction of adverse prolonged pregnancy outcome

Objective: to determine whether a single threshold of the sonographic cervical length or different cut-offs for each period of pregnancy are more sensitive in predicting preterm delivery. Methods: We observed 108 patients between the 10th and 34th week of gestational age admitted for threatened preterm labour. The cervical length was determined using ultrasound on admission. Exclusion criteria included multiple pregnancies, singleton pregnancies lacking sonographic determination of the gestational age prior to 22 weeks, ruptured membranes, cervical dilatation 33 cm at digital exploration, vaginal bleeding, placenta previa and prior cervical cerclage. Two cut-offs (15 and 25 mm) and two centiles (2.5◦ and 10◦) of our reference curves were used for predicting delivery within 7 days and before 34 weeks. Results: 76.8% of the patients delivered after 34 weeks, 23.1% before 34 weeks while in 17.5% of the cases delivery occurred within 7 days. The median cervical length at admission was 35 mm, 25 mm, and 21 mm respectively. Univariate analysis of the different cut-offs showed a higher odds ratio for 25 and 15 mm compared to the 2.5 and 10◦P both in predicting delivery within 7 days and before 34 weeks. The diagnostic accuracy was statistically higher for the 15 and 25 mm thresholds both in predicting PTL within 7 days respectively 83 and 76% and before 34 weeks, 77 and 76% respectively. Conclusion: sonographic measurement of the cervical length proved to be a feasible and effective method in identifying the population with an increased risk for PTL both within 7 days and before 34 weeks following the exam. The negative predictive value resulted particularly high90% for the 25 mm cut-off and for the 2.5◦ and 10◦P, giving a likelihood ratio of 93% and 91% respectively that delivery will probably not occur within 7 days. These elements obviously need to be integrated with clinical aspects of each case, for the optimal management of patients with suspected PTL.

P03.17: Post‐term pregnancies: what are the predictors of intrapartum distress?

Objective: to determine whether a single threshold of the sonographic cervical length or different cut-offs for each period of pregnancy are more sensitive in predicting preterm delivery. Methods: We observed 108 patients between the 10th and 34th week of gestational age admitted for threatened preterm labour. The cervical length was determined using ultrasound on admission. Exclusion criteria included multiple pregnancies, singleton pregnancies lacking sonographic determination of the gestational age prior to 22 weeks, ruptured membranes, cervical dilatation 33 cm at digital exploration, vaginal bleeding, placenta previa and prior cervical cerclage. Two cut-offs (15 and 25 mm) and two centiles (2.5◦ and 10◦) of our reference curves were used for predicting delivery within 7 days and before 34 weeks. Results: 76.8% of the patients delivered after 34 weeks, 23.1% before 34 weeks while in 17.5% of the cases delivery occurred within 7 days. The median cervical length at admission was 35 mm, 25 mm, and 21 mm respectively. Univariate analysis of the different cut-offs showed a higher odds ratio for 25 and 15 mm compared to the 2.5 and 10◦P both in predicting delivery within 7 days and before 34 weeks. The diagnostic accuracy was statistically higher for the 15 and 25 mm thresholds both in predicting PTL within 7 days respectively 83 and 76% and before 34 weeks, 77 and 76% respectively. Conclusion: sonographic measurement of the cervical length proved to be a feasible and effective method in identifying the population with an increased risk for PTL both within 7 days and before 34 weeks following the exam. The negative predictive value resulted particularly high90% for the 25 mm cut-off and for the 2.5◦ and 10◦P, giving a likelihood ratio of 93% and 91% respectively that delivery will probably not occur within 7 days. These elements obviously need to be integrated with clinical aspects of each case, for the optimal management of patients with suspected PTL.

P14.67: Ultrasound estimation of fetal weight in prolonged pregnancy

Introduction: When performing fetal biometry measurements, the examiner occasionally has the impression that the sonographic estimation is less accurate due to technical limitations. Our objective was to evaluate the possible association between the examiners assessment of the measurement accuracy and the actual error between fetal weight estimation and actual birth weight. Methods: 186 women, within 10 days of delivery, were examined prospectively using fetal biometric measurements. Fetal weight estimates were calculated using Hadlock’s formula employing FL, AC and BPD. The sonographers were asked to give a subjective score to each measurement; one point if the quality of the measurement was technically good, two points if the measurement was of medium quality and three points if the measurement was of poor quality. The difference between the corrected sonographic fetal weight estimation and the actual birth weight was analyzed with respect to the scoring given by the examiner. Results: As shown in tables 1–3 for none of the three measured parameters did the perceived measurement accuracy predict the actual error in predicting birth weight.