Introduction: Routine third-trimester ultrasound (T3US) is not recommended in evidence-based clinical guidelines despite occurring frequently. This study investigated the incidence, indication for, results and follow-up needs of T3US performed at a Sydney metropolitan teaching hospital. Methods: Audit of T3US amongst singleton pregnancies at St George Hospital, Sydney: retrospective review October-December 2012, prospective cohort with clinician survey February-April 2013. Data included are as follows: maternal demographics, aneuploidy screening results, T3US ordering patterns, results, follow-up management and pregnancy outcomes. Comparison of demographic characteristics and pregnancy outcomes was performed for women undergoing T3US vs. no T3US. Results: One thousand and thirty-five women (623 retrospective, 412 prospective) were included, of whom 560 (54%) received at least one T3US. Characteristics of retrospective and prospective cohorts were similar, so combined data are presented. Most initial T3USs were for valid indications (463 of 560; 83%), most frequently low-lying placenta at morphology (19%), reduced fundal height (10%) and to follow-up fetal concerns at morphology ultrasound (9%). One hundred and sixty-two out of 560 (29%) of initial T3US were not normal, predominantly related to accelerated or reduced fetal growth. Detection of SGA babies was significantly higher in the T3US group (32% SGA babies detected vs. 0% if no T3US, P < 0.001). However, overall detection rates remained low, with 5.2% and 3.0% of babies who had a T3US unexpectedly <10 th and <3 rd centile birthweight, respectively. Discussion/Conclusion: The majority of women received at least one, usually indicated, T3US in routine practice at our metropolitan Sydney hospital. This may impact obstetric care, resource allocation and patient well-being. Detection of small for gestational age fetuses was poor.

Objectives:The clinical importance of assessing the fetal KEL genotype is to diagnose ''K'' positive fetuses (genotype KEL1/KEL2) in ''K'' alloimmunised pregnant women (genotype KEL2/KEL2). Just these fetuses (only 5%) are at risk of hemolytic disease and the fetal anemia should be diagnosed by Doppler ultrasound measurement of Middle Cerebral Artery Peak Systolic Velocity (MCA-PSV). Non-invasive assessment of the fetal KEL genotype is not standardly available to date. The aim of this study is to assess the fetal KEL1/KEL2 genotype from cell free fetal DNA in plasma of KEL2/KEL2 pregnant women. Methods: The fetal genotype was assessed by TaqMan Real-Time PCR and mini-sequencing (dilution series and control samples were used). A total of 138 pregnant women (between the 8 th and the 23 th gestational week) were tested by mini-sequencing. Fetal genotype was further verified by buccal swab of the newborn. Results: TaqMan probes showed fluorescence background and the method was not able to discriminate between the background and the fetal DNA admixture. The mini-sequencing proved to be a reliable method. In 2.2% of the examined women (3/138) testing of plasma samples failed, 94.8% of women (128/135) were KEL1 negative and a total of 3.1% fetuses (4/128) were KEL1 positive. Sensitivity and specificity reached 100%, p < 0.001. Conclusions: Mini-sequencing is a reliable method for the assessment of the fetal KEL1 allele from plasma of KEL2/KEL2 pregnant women.Supported Objectives: To examine the relation between maternal height and weight on cervical length measurement in a routine population of normal low-risk singleton pregnancies. Methods: Cervical length (CL) was prospectively measured by transvaginal sonography in singleton pregnancies with normally grown fetuses, as part of routine antenatal care. Measurements were taken at gestational age (GA) ranging from 18 to 22 weeks and only one measurement per pregnancy was used in the analysis. Cases with short CL (< 25 mm), congenital malformations or chromosomal abnormalities were excluded. Body mass index (BMI) was calculated by self-reported pre-pregnancy weight in kilograms divided by height in meters squared. The independent relationship of maternal height, weight and BMI with CL was evaluated by linear regression analysis adjusted by GA. Results: We studied a cross-sectional sample of 485 pregnant women, including 242 (49.9%) nulliparous and 243 (50.1%) multiparous women. In all cases, the CL was measured successfully at a mean gestational age of 20.4 (18.1-21.9) weeks. CL was significantly correlated with maternal height (r = −0.099, p = 0.01) and such correlation remains significant after adjusting for GA (p = 0.03). No significant correlation was observed between CL and maternal weight (p = 0.19) or BMI (p = 0.82). Conclusions: Maternal height has an independent effect on cervical length, which supports the need for individual normal references ranges adjusted by GA and maternal characteristics. Objectives: To assess current use and utility of T3US in a metropoli...