Objective: To assist clinicians in assigning gestational age based on ultrasound biometry.
Outcomes: To determine whether ultrasound dating provides more accurate gestational age assessment than menstrual dating with or without the use of ultrasound. To provide maternity health care providers and researchers with evidence-based guidelines for the assignment of gestational age. To determine which ultrasound biometric parameters are superior when gestational age is uncertain. To determine whether ultrasound gestational age assessment is cost effective. Fetal Soft Markers can be assessed during the mid trimester ultrasound Assessment of fetal soft markers should evaluate 8 markers, 5 of which (thickened nuchal fold, echogenic bowel, mild ventriculomegaly, echogenic focus in the heart, and choroid plexus cyst) are associated with an increased risk of fetal aneuploidy, and in some cases with non-chromosomal problems, while 3 (single umbilical artery, enlarged cisterna magna, and pyelectasis) are only associated with an increased risk of nonchromosomal abnormalities when seen in isolation Timely referral and/or consultation for confirmation, patient education, and investigation are recommended to maximize pregnancy management options 1 Nuchal fold (measured in mm) (aka nuchal thickness)
A nuchal fold measurement is obtained in a transverse section of the fetal head at the level of the cavum septum pellucidum and thalami, angled posteriorly to include the cerebellum The measurement is taken from the outer edge of the occiput bone to the outer skin limit directly in the midline Significant at 18 -24 wks = 6 mm or greater Significant at 16 -18 wks = 5 mm or greater NOTE: A nuchal translucency (NT) can be measured when the CRL is between 45.0 and 84.0 mm. To be used in the generation of a Prenatal Genetic Screening report, an NT must be performed by an individual certified by the FMF (Fetal Medicine Foundation) to perform NT measurements. Please see Appendix 5 for the "Minimum Reporting Standards for First Trimester Ultrasound Scans which include NT Measurements".
2 Echogenic bowel (reported as: grade 2 or 3 vs normal)
Echogenic bowel should be identified by comparison with the echogenicity of surrounding bone using an appropriate transducer (5 MHZ or less) and gain setting Bowel echogenicity equal to (grade 2), or greater than (grade 3) bone is significant Grade 1 echogenic bowel (bowel echogenicity less than bone) is not significant and should not be reported 3 Mild ventriculomegaly (MVM) (measured in mm)
Mild ventriculomegaly is defined as measurements greater than 10mm and less than or equal to 15 mm Measurements are obtained from an axial plane at the level of the thalamic nuclei just below the standard image to measure the BPD Ventricular measurements are usually obtained in the far image field because of "typical" near-field artifacts Cursors are positioned perpendicular to the long axis of the ventricle at the edges of the ventricular lumen, near the posterior portion of the choroid plexus 4 Echogenic intracardiac focus (EICF)
Defined as a focus of echogenicity comparable to bone Using an appropriate transducer frequency, 5 MHz or less, and appropriate gain setting, an EICF can be diagnosed on the standard 4-chamber view of the fetal heart Echogenicity less than that of bone is not significant and should not be reported 5 Choroid plexus cyst (CPC) (measured in mm) Cysts (greater than or equal to 3 mm) found in the choroid plexus within the lateral cerebral ventricles of the developing fetus at 14 to 24 weeks gestation Imaging of the choroid plexus is performed in the transverse plane of the fetal head at the same level that the lateral cerebral ventricle is evaluated Appendix 11 -Fetal Soft Markers 6 Enlarged cisterna magna (measured in mm)
The cisterna magna is measured on a transaxial view of the fetal head angled 15 degrees caudal to the canthomeatal line The anterior/posterior diameter is taken between the inferior/posterior surface of the vermis of the cerebellum to the inner surface of the cranium An enlarged cisterna magna is defined by an anterior/posterior diameter of greater than (or equal to) 10 mm The measurement will be falsely exaggerated by a steep scan angle through the posterior fossa or dolichocephaly 7 Pyelectasis (measured in mm)
Mild pyelectasis is defined as a hypoechoic spherical or elliptical space within the renal pelvis that measures greater than (or equal to) 5mm and less than (or equal to) 10 mm The measurement is taken on a transverse section through the fetal renal pelvis using the maximum anterior-toposterior measurement Measurements less than 5 mm are normal, should not be designated as pyelectasis, and should not be reported The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) is a scientific organization that encourages sound clinical practice, teaching and research related to diagnostic imaging in women's healthcare. The ISUOG Clinical Standards Committee (CSC) has a remit to develop Practice Guidelines and Consensus Statements as educational recommendations that provide healthcare practitioners with a consensus-based approach for diagnostic imaging. They are intended to reflect what is considered by ISUOG to be the best practice at the time at which they are issued. Although ISUOG has made every effort to ensure that Guidelines are accurate when issued, neither the Society nor any of its employees or members accepts any liability for the consequences of any inaccurate or misleading data, opinions or statements issued by the CSC. They are not intended to establish a legal standard of care because interpretation of the evidence that underpins the Guidelines may be influenced by individual circumstances and available resources. Approved Guidelines can be distributed freely with the permission of ISUOG (info@isuog.org).

# SCOPE OF THE DOCUMENT
This document summarizes Practice Guidelines regarding how to perform Doppler ultrasonography of the fetoplacental circulation. It is of utmost importance not to expose the embryo and fetus to unduly harmful ultrasound energy, particularly in the earliest stages of pregnancy. At these stages, Doppler recording, when clinically indicated, should be performed at the lowest possible energy levels. ISUOG has published guidance on the use of Doppler ultrasound at the 11 to 13+6-week fetal ultrasound examination 1. When performing Doppler imaging, the displayed thermal index (TI) should be  1.0 and exposure time should be kept as short as possible, usually no longer than 5-10 min and not exceeding 60 min 1. It is not the intention of these Guidelines to define clinical indications, specify proper timing of Doppler examination in pregnancy or discuss how to interpret findings or the use of Doppler in fetal echocardiography. The aim is to describe pulsed Doppler ultrasound and its different modalities: spectral Doppler, color flow mapping and power Doppler, which are commonly used to study the maternal-fetal circulation. We do not describe the continuous wave Doppler technique, because this is not usually applied in obstetric imaging; however, in cases in which the fetus has a condition leading to very high-velocity blood flow (e.g. aortic stenosis or tricuspid regurgitation) it might be helpful in order to define clearly the maximum velocities by avoiding aliasing.
The techniques and practices described in these Guidelines have been selected to minimize measurement errors and improve reproducibility. They may not be applicable in certain specific clinical conditions or for research protocols.
"{Chamberlain} emphasized that the transducer should not be angled but when possible should follow the contour of the uterus" Another way to think of the modernized description is as follows:
Find the largest pocket free of cord and fetal body parts If that pocket can fit a 2 x 1 cm rectangle whose long axis is approximately at right angles to the uterine wall, then the amniotic fluid assessment is considered normal If the pocket is so big, that there is fluid/space around an 8 x 1 cm rectangle (oriented as above), then the amniotic fluid assessment is considered to be polyhydramnios
There are different methods to assess the largest pocket of fluid which vary from a single vertical or perpendicular measurement to a two dimensional product of the pocket (Magann, 1994) The terms used are also varied, and unfortunately, are used interchangeably, adding to the confusion when assessing the literature For example, Chamberlain's reference has been described using the following terms: Single deepest pocket (Magann, 2004), Maximum vertical pocket (Williams, 1993), Maximum pool depth (Nwosu, 1994) and Single deepest vertical pocket (Moses, 2004) In his recent (2015) article, Sande uses the terms "single deepest vertical pool" or "maximum vertical pocket", but this is described as the "ultrasound probe being held vertical to the uterine contour onto the abdomen and parallel to the maternal sagittal plane" This does not appear to match the Chamberlain definition, particularly since the minimum width of the pocket is not included Maternal position is not described For this guideline, it was felt that using the term "single deepest pocket" (SDP) was the one most often ascribed to Chamberlain and removes the word "vertical", which suggests that the ultrasound plane has to be vertical, or perpendicular to the floor, which is not used in Chamberlain's description

# Origin of definitions of fluid abnormalities
This was based on Chamberlain's original definitions, and randomised trials used in the Cochrane meta-analysis The reference ranges are from Magann (2000) (whose group contributed three of the RCTs to the above mentioned Cochrane meta-analysis) and the normal distributions published in that paper, suggest the simple definitions proposed are reasonable to define normal from abnormal

# POLICY OBJECTIVE
The objective of this policy is to achieve:  consistency in approach across health authorities to fetal sex determination by ultrasound and disclosure of fetal sex information to patients;  alignment with the College of Physicians and Surgeons of British Columbia's Guideline on Disclosure of Fetal Sex; and,  alignment with Canadian clinical practice guidelines.
This policy applies to obstetrical ultrasound services provided by the regional health authorities and the Provincial Health Services Authority.
- At the time of a routine full fetal anatomical assessment, a reasonable attempt will be made by the practitioner performing the ultrasound assessment to assess fetal genitalia within the allotted exam time.
Antepartum and Intrapartum Consensus Guideline /

# SOGC CLINICAL PRACTICE GUIDELINE

# Fetal Health Surveillance: Antepartum and Intrapartum Consensus Guideline Abstract
Objective: This guideline provides new recommendations pertaining to the application and documentation of fetal surveillance in the antepartum and intrapartum period that will decrease the incidence of birth asphyxia while maintaining the lowest possible rate of obstetrical intervention. Pregnancies with and without risk factors for adverse perinatal outcomes are considered. This guideline presents an alternative classification system for antenatal fetal non-stress testing and intrapartum electronic fetal surveillance to what has been used previously. This guideline is intended for use by all health professionals who provide antepartum and intrapartum care in Canada.
Options: Consideration has been given to all methods of fetal surveillance currently available in Canada.
Outcomes: Short-and long-term outcomes that may indicate the presence of birth asphyxia were considered. The associated rates of operative and other labour interventions were also considered.
Evidence: A comprehensive review of randomized controlled trials published between January 1996 and March 2007 was undertaken, and MEDLINE and the Cochrane Database were used to search the literature for all new studies on fetal surveillance both antepartum and intrapartum. The level of evidence has been determined using the criteria and classifications of the Canadian Task Force on Preventive Health Care (Table 1).

# SOGC CLINICAL PRACTICE GUIDELINE
This guideline reflects emerging clinical and scientific advances as of the date issued and are subject to change. The information should not be construed as dictating an exclusive course of treatment or procedure to be followed. Local institutions can dictate amendments to these opinions. They should be well documented if modified at the local level. None of these contents may be reproduced in any form without prior written permission of the SOGC. The standards of the Canadian Association of Radiologists (CAR) are not rules, but are guidelines that attempt to define principles of practice that should generally produce radiological care. The physician and medical physicist may modify an existing standard as determined by the individual patient and available resources. Adherence to CAR standards will not assure a successful outcome in every situation. The standards should not be deemed inclusive of all proper methods of care or exclusive of other methods of care reasonably directed to obtaining the same results. The standards are not intended to establish a legal standard of care or conduct, and deviation from a standard does not, in and of itself, indicate or imply that such medical practice is below an acceptable level of care. The ultimate judgment regarding the propriety of any specific procedure or course of conduct must be made by the physician and medical physicist in light of all circumstances presented by the individual situation.

# Content of a Complete Routine Second Trimester Obstetrical Ultrasound Examination and Report Abstract
Objective: To review the benefits of and requirements for a complete second trimester ultrasound and the documentation needed.
Outcomes: A complete second trimester ultrasound provides information about the number of fetuses, the gestational age, the location of the placenta, and fetal and maternal anatomy.
Evidence: In the production of this document, the American Institute of Ultrasound in Medicine's "Practice Guideline for the Performance of Obstetric Ultrasound Examinations," the American College of Obstetricians and Gynecologists' practice bulletin, "Ultrasound in Pregnancy," and the Royal College of Obstetricians and Gynaecologists' Working Party Report, "Ultrasound Screening" were reviewed. PubMed and the Cochrane Database were searched using the words "routine second trimester obstetrical ultrasound."
The evidence was evaluated using the guidelines developed by the Canadian Task Force on Preventive Health Care.
Benefits, Harms, and Costs: A routine complete second trimester ultrasound between 18 and 22 weeks and a complete ultrasound report will provide the best opportunity to diagnose fetal anomalies and to assist in the management of prenatal care. It will also reduce the number of ultrasound examinations done during the second trimester for completion of fetal anatomy survey. The costs are those involved with the performance of obstetrical ultrasound.
Validation: This is a revision of previous guidelines; information from other consensus reviews from medical publications has been used.
The Society of Obstetricians and Gynaecologists of Canada.

# SECOND TRIMESTER ULTRASOUND
A n ultrasound scan performed between 18 and 22 weeks' gestation provides the pregnant woman and her care provider with information about multiple aspects of her pregnancy.  The obstetrical ultrasound will inform them of and/or confirm the number of fetuses present, the gestational age, and the location of the placenta. It will present an opportunity to diagnose congenital anomalies and/or to detect soft markers of aneuploidy and to identify maternal pelvic pathology.
The occurrence of twins undiagnosed at delivery is extremely rare when women have received a second trimester ultrasound, and the likelihood of postdates induction and intrauterine growth restriction significantly decreases. 1 In the last two decades, the infant death rate from congenital www.sogc.org/guidelines/public/162E-CPG-June2005.pdf

# SOGC CLINICAL PRACTICE GUIDELINES

# Fetal Soft Markers in Obstetric Ultrasound
Abstract Objective: To evaluate ultrasound "soft markers" used in fetal genetic screening.
Options: Ultrasound screening at 16 to 20 weeks is one of the most common genetic screening and (or) diagnostic tests used during pregnancy. The practical concern for ultrasound screening is false-positive and false-negative (missed or not present) results. The use and understanding of ultrasound soft markers and their screening relative risks is an important option in the care of pregnant women. Currently, the presence of a "significant" ultrasound marker adds risk to the likelihood of fetal pathology, but the absence of soft markers, except in controlled situations, should not be used to reduce fetal risk.
Outcomes: The use of ultrasound in pregnancy has significant health and economic outcomes for families and the health care system, compared with no ultrasound use. The Society of Obstetricians and Gynaecologists of Canada (SOGC) recommends a single "routine" ultrasound evaluation at 16 to 20 weeks in all pregnancies. Patients need to be counselled about the positive and negative findings that ultrasound may reveal so they are prepared for unexpected pregnancy knowledge and the possibility of further testing options being offered.
Evidence: Committee members were asked to review specific soft marker ultrasound topics after consensus was reached on the most commonly published soft markers. Medline and PubMed databases were searched for peer-reviewed English articles published from 1985 to 2003. Reviews of each soft marker topic were written by committee members with quality of evidence and classification of recommendations. These reviews were then circulated and discussed by the combined committee. Final format for the guideline was completed by the committee chairpersons.
Values: The quality of evidence and classification of recommendations followed discussion and consensus by the combined committees of Diagnostic Imaging and Genetics of the SOGC.
Benefits, Harms, Costs: It is not possible at this time to determine the benefits, harms, and costs of the guideline because this would require health surveillance and research and health resources not presently available; however, these factors need to be evaluated in a prospective approach by provincial and tertiary initiatives. Consideration of these issues is in the options and outcome section of this abstract.
Appendix 17 -SOGC -Fetal Soft Markers in Obstetric Ultrasound