First-Trimester Ultrasound: A Comprehensive Guide

Foreword
Preface
Contents
Contributors
1: Ultrasound in the First Trimester: How to Keep It Safe
	Bioeffects of Ultrasound
		Thermal Effects
		Non-thermal Effects
	The Output Display Standard (OSD)
	Ultrasound and the Ovum
	Ultrasound in Early Gestation
	Fetal Susceptibility to External Insults
	Is Doppler Different and Can It Have Detrimental Effects on the Fetus in the First Trimester?
	Acoustic Output
	3D/4D Ultrasound
	Shear Wave Elastography
	How to Limit Fetal Exposure and Safety Statements
	Conclusions
	References
2: How to Optimize the Ultrasound Image
	Introduction
	Choosing the Best Tools
	A Systematic Approach
	Basic Knobology
	Transducer Selection and the Impact of Frequency
	Depth
	Sector Width
	Gain (Brightness)
		Overall Gain
		Time Gain Compensation (TGC)
	Focus (Focal Zone)
	Dynamic Range
	Tissue Harmonic Imaging (THI)
	Three-Dimensional Imaging
	Additional Knobs/Buttons
	References
3: Ultrasound and Infertility
	Baseline Evaluation
		Uterus
		Ovaries
		Adnexa
		Miscellaneous
	Advanced Ultrasound Techniques and Reproductive Pathology
	Contrast Infusion Sonography for Uterine Cavity Assessment and Tubal Patency Assessment
	Follicular Monitoring Ultrasounds
	Ultrasound in ART Procedures (Oocyte Retrieval and Embryo Transfer)
	Conclusion
	References
4: Maternal Co-morbidities and First Trimester Ultrasound Examination
	Introduction
	Maternal Co-morbidities
	Pregestational Diabetes
	Obesity
	Maternal Conditions Associated with Congenital Heart Defects
	Maternal Vascular Disease
	Conclusion
	References
5: First Trimester Embryology: An Overview
	Introduction
	Signaling Pathways Identified for Embryologic Development
		Development of the Bilaminar Embryo (Weeks 1–2)
		Embryonic Weeks 3–4
			Formation of the Neural Tube
			Formation of the Fetal Brain
		Embryonic Weeks 5–8
			Development of the Embryonic Cavities and Diaphragm
			Development of the Fetal Face
			Development of the Respiratory System
			Development of the Gastrointestinal Tract
			Development of the Urogenital System
	Highlights of Cardiac Development
		Early Cardiac Development
		Cardiac Septae Formation and Valvular Development
			Atrioventricular (AV) Septum
			Atrial Septum
			Ventricular Septum
			Aorticopulmonary (AP) Septum
		Development of the Lymphatic System
	Summary
	References
6: Elements of Teratology
	Definition
	Perception of Teratogenic Risk
	Teratogens
		Drugs in Pregnancy
			Alcohol
			Aminopterin
			Benzodiazepines
			Carbamazepine
			Carbon Monoxide Poisoning
			Cocaine
			Corticosteroids
			Diethylstilbestrol (DES)
			Lithium
			Methotrexate
			Methyl Mercury, Mercury Sulfide
			Misoprostol
			Mycophenolate Mofetil (CellCept)
			Polychlorinated Biphenyls
			Penicillamine
			Phenobarbital
			Phenytoin
			Systemic Retinoids
			Thalidomide
			Valproic Acid
			Warfarin
		Infections
			Cytomegalovirus
			Parvovirus B19
			Rubella
			Toxoplasma gondii
			Treponema pallidum
			Varicella
			Zika
			COVID-19
		Physical Factors
			Ionizing Radiation
			Non-ionizing Radiation
			Ultrasound Waves
	Summary
	References
7: First-Trimester Ultrasound: Practice Guidelines
	Equipment
	Safety
	Indications and Timing of First-Trimester Ultrasound
	Content of the Examination
		Assessment of Viability
		Pregnancy Location
		Fetal Number
		Measurements and Determination of Gestational Age
		Assessment of Fetal Anatomy
		Fetal Aneuploidy Assessment
		Other Intrauterine and Extrauterine Structures
		First-Trimester Screening for Pre-Eclampsia
	Documentation
	Training Guidelines
	Quality Assurance
	Cleaning and Preparing Transducers
	Teaching Points
	References
8: Normal First Trimester of Pregnancy
	Introduction
	Gestational Sac
		Measurement of the Gestational Sac
		Mean Sac Diameter and Viability
		Gestational Sac Appearance and β-hCG in Early Pregnancy
	Yolk Sac
	Embryo
	Embryonic and Fetal Cardiac Activity
	Multiple Gestations and Chorionicity
	Heterotopic Pregnancy
	Early Pregnancy Dating
	Thresholds for Assessing Viability
	Nuchal Translucency Evaluation
		Criteria for NT Measurement
		Significance of Elevated NT Measurement
		Assessment of the Nasal Bone During the NT Evaluation
		Significance of Absent Nasal Bone
	Screening for Neural Tube Defects at the Time of the NT Evaluation
	Normal First Trimester Anatomical Assessment
		Fetal Brain in the First Trimester
		Face
		Thorax
		Fetal Heart in the First Trimester
		Fetal Kidneys and Urinary Tract System in the First Trimester
		Fetal Gastrointestinal Tract in the First Trimester
		Abdominal Wall and Umbilical Cord
		Fetal Skeleton in the First Trimester
		Assessment of Fetal Genitalia in the First Trimester
			Assessment of Spine
			Role of Three-Dimensional (3D) and Four-Dimensional (4D) Ultrasound
	Conclusion
	References
9: Screening for Fetal Chromosome Abnormalities
	Introduction
	Biochemical and Ultrasound Screening for Aneuploidy
		Historical Approaches
		Second Trimester Maternal Serum Biochemical Screening
		First-Trimester Maternal Serum Biochemical Screening
		First Trimester Ultrasound Markers for Chromosome and Genetic Anomalies
		Integrated and Sequential Screening
		Cell Free DNA Screening for Aneuploidy
		Aneuploidy Screening in Multiple Gestations
		Current Status of Aneuploidy Screening
		Nuchal Translucency Ultrasound in the Era of Cell Free DNA Screening
	Future Applications of Cell Free DNA Testing
	Summary
	References
10: Threshold, Discriminatory Zone, and “The New Rules”
	Introduction
	Threshold Value
	Discriminatory Value
	The “New Rules” Regarding Early Pregnancy Failure
	Conclusion
	References
11: Fetal Biometry in Early Pregnancy
	Introduction
	Biometry
		Gestational Sac
		Yolk Sac
		Crown-Rump Length
		Nuchal Translucency
		Nasal Bone
	Other Biometric Measurements
	Conclusion
	References
12: The Fetal Heart in Early Pregnancy
	Introduction
	Basic Description of Cardiac Development
	Why Do We Have to Scan the Fetal Heart Early in Pregnancy?
	Operator Experience and Route of Ultrasound Examination
	When Is the Optimal Time to Perform Early Fetal Cardiac Evaluation?
	Practical Recommendations
	What Constitutes a Cardiac Scan in the First Trimester?
		Color Doppler
	Alternatives for an Early Cardiac Scan
	Including the 3-VV, 3-VTV, and Outflow Tracts in the Fetal Cardiac Evaluation in the First Trimester of Pregnancy
	Indirect Markers for Early Fetal Cardiac Evaluation
		Nuchal Translucency and Ductus Venosus
		Tricuspid Regurgitation
		Cardiac Axis
		Aberrant Right Subclavian Artery (ARSA)
		Heart-to-Chest Ratio
	Detection of Cardiac Anomalies in All Fetuses Undergoing First Trimester Ultrasound
	High-Risk Population
	Complementary Ultrasound Techniques
		4D-Spatio-Temporal Imaging Correlation (STIC)
	Evaluation of the Cardiac Function in Early Pregnancy
	Precautions When Evaluating Fetuses at 11 to 13+6 Weeks?
	Safety
	Teaching Points
	References
13: Doppler Sonography in Early Pregnancy
	Introduction
	Doppler Sonography of the Ductus Venosus
		Anatomy and Hemodynamics
		Doppler Imaging Technique for the Ductus Venosus
		Ductus Venosus Doppler Waveforms
		Factors Affecting the Ductus Venosus Waveform
		Ductus Venosus Doppler in First-Trimester Aneuploidy Screen
		Ductus Venosus Doppler Screening for Congenital Heart Disease
	Doppler Investigation of Tricuspid Flow in the First Trimester
		Doppler Insonation Technique
		Tricuspid Flow Pattern
		Tricuspid Regurgitation
		Tricuspid Doppler Screening for Aneuploidy and Congenital Heart Disease
		Biophysical, Biochemical, and Molecular Screening in Early Pregnancy
	Doppler Ultrasound Imaging of the Uterine Artery in the First Trimester
		Doppler Imaging Technique for the Uterine Artery
		Uterine Artery Doppler Waveform
		Clinical Applications of the Uterine Artery Doppler
	Doppler of the Placental Implantation Site for Early Detection of Placental Accreta Spectrum
		Doppler Imaging Technique
			First Trimester Ultrasound Markers
	References
14: Three-Dimensional Ultrasound: A Role in Early Pregnancy?
	Introduction
	Instrumentation
	Ideal Gestational Age to Perform the Exam
	What Can Be Confidently Imaged?
	Sonoembryology
		4 to 5 Weeks
		5 to 6 Weeks
		6 to 7 Weeks
		7 to 8 Weeks
		8 to 9 Weeks
		9 to 10 Weeks
	Congenital Anomalies That May Be Diagnosed During the Embryonic Period
		Body-Stalk Anomaly
		Fetal Edema in Early Pregnancy
		Acrania-Exencephaly-Anencephaly Sequence
		Holoprosencephaly
		Early Pleural Effusion
	Additional Potential Benefits of 3D US During Early Pregnancy
		Chorionic Bump
		Determination of Chorionicity and Amnionicity in Multiple Pregnancies
	Anomalies Diagnosable During the 11–14 Weeks Scan
		Central Nervous System
			Sagittal View
			Axial Views
			Acrania–Exencephaly–Anencephaly Sequence
			Holoprosencephaly
			Open Spinal Dysraphism (Spina Bifida)
			Cervical Spina Bifida
		Face
			Cleft Lip and Palate
			Low-Set Ear in Early Fetuses Examined at 11–14 Weeks
			Micrognathia
		Heart
		Thorax and Abdomen
		Urinary Tract
			Patent Urachus with Bladder Prolapse
	Conclusion
	References
15: Multiple Gestations: Multiple Headaches
	Introduction
	Embryology
	Diagnosis
	Placentation
		Diagnosis of Chorionicity and Amnionicity
	Complications
		Vanishing Twin
		Growth Restriction and Differential Growth
		Discordance for Genetic/Structural Anomaly
		Complete Hydatidiform Mole and Coexisting Fetus
	Complications Specific for MC Twins
		Twin-to-Twin Transfusion Syndrome (TTTS)
		Twin Anemia Polycythemia Syndrome (TAPS)
		Twin Reversed Arterial Perfusion (TRAP) Syndrome
		Conjoined Twins
		Cord Entanglement
	Screening for Genetic and Morphologic Abnormalities
	Maternal Complications
	Higher Order Multiple Gestations
	Invasive Diagnostic/Therapeutic Procedures in Twins
	References
16: First-Trimester Ultrasound: Early Pregnancy Failure
	Introduction
	Definitions
	Risk Factors for Failure
	Chemical Evidence of Pregnancy Failure
	Ultrasound Characteristics of Early Pregnancy
	Imaging of the Early Pregnancy
	Ultrasound Evidence of Pregnancy Failure
		Gestational Sac
			Location
			Appearance
			Size/Growth
		Prognosis of a Gestational Sac
		Amnion
		Placenta/Chorionic Frondosum
			Vaginal Bleeding
			Hematoma
			Chorionic Bump
			Vascular Pattern
		Yolk Sac
			Appearance
		Embryo
			Embryonic Motion
			Location
			Appearance
			Size/Growth Rate
			Anatomy
			Embryonic Heart Rate
		Retained Products of Conception
			Ultrasound Evaluation
			Color Doppler Imaging
		Recurrent Pregnancy Loss
	Summary
	References
17: Ectopic Pregnancy and Pregnancy of Unknown Location (PUL)
	Introduction
	Pregnancy of Unknown Location
	Human Chorionic Gonadotropin (hCG) Dynamics
	Threshold and Discriminatory Levels of hCG
		Threshold Level
		Discriminatory Level
	Endometrial Findings in Ectopic Pregnancy
		Endometrial Thickness
		Intrauterine Fluid
	Adnexal Findings in Ectopic Pregnancy
	Workup for Ectopic Pregnancy
	An Argument for Ultrasound First, Tubal Rupture Below the Threshold Level
	Spontaneous Resolution of Pregnancy
	Unusual Ectopic Pregnancies
		Heterotopic Pregnancy
		Interstitial Pregnancy
		Cornual Pregnancy
		Angular Pregnancies
		Ovarian Pregnancy
		Abdominal Pregnancy
		Cervical Pregnancy
		Cesarean Scar Pregnancies
	Summary
	References
18: Cesarean Scar Pregnancy: A Baby Placenta Accreta
	Introduction/Terminology
	Background
	What Is a Cesarean Scar Pregnancy?
	Incidence/Risk Factor
	Pathogenesis of CSP
	Diagnosis of Cesarean Scar Pregnancy
	Differential Diagnosis of CSP
	The Connection Between CSP and PAS
	PAS in the First Trimester?
	Counseling Patients with a First-Trimester CSP
	Management of Cesarean Scar Pregnancy
	Treatment Options Available for CSP
	Summary and Conclusion
	References
19: The First-Trimester Fetal Head and Brain
	Introduction
	What Normal and/or Abnormal Fetal Structures Can Be Reliability Detected at This Gestational Age?
	Normal Fetal Head-Brain Anatomy
	Pathologies of the First-Trimester Fetal Brain
		Neural Tube Defects
			Exencephaly-Anencephaly Sequence
			Cephalocele
			Open Spina Bifida
		Midline Developmental Anomalies
			Holoprosencephaly
	The Face
		Absent Nasal Bone, Cleft Lip ± Palate, Cataracts, Micrognathia
	Conclusion
	References
20: Fetal Face and Neck
	Introduction
	Orbits
		Hypertelorism
		Hypotelorism (Cyclopia)
		Microphthalmia/Anophthalmia
		Cataracts
	Nose
		Arrhinia
		Proboscis
		Absent Nasal Bone
	Chin and Mouth
		Micrognathia and Retrognathia
		Agnathia
		Macroglossia
		Epignathus
	Lips and Palate
		Orofacial Cleft
			Paramedian Orofacial Cleft
			Median Facial Cleft
	Ears
		External Ear (Pinna/Auricle) Anomalies
			Anotia
			Microtia
			Macrotia (Large Ears)
			Melotia (Low-Set Ears)
			Otocephaly
	Tumors of the Face and Neck
		Frontal Encephalocele
		Cystic Hygroma
		Other Important Neck Masses and Tumors
	References
21: Fetal Gastrointestinal and Abdominal Wall Imaging
	Introduction
	Embryology
	Esophagus
		Esophageal Atresia
	Stomach
		Right-Sided Fetal Stomach
	Bowel, Liver, and Gallbladder
		Echogenic Bowel
		Duodenal Atresia
		Anorectal Atresia
		Abdominal Cysts
	Abdominal Wall
		Physiologic Midgut Herniation (Umbilical Hernia)
		Omphalocele
		Gastroschisis
		Limb-Body Stalk Anomaly
	Conclusion
	References
22: First-Trimester Genitourinary Development and Anomalies
	Introduction
	Fetal Renal Size, Presence, and Location
	Hydronephrosis/Pyelectasis
	Cystic Renal Disease
	Fetal Bladder Abnormalities
	Abnormalities of the Fetal Genitalia
	Genetic Evaluation
	Conclusion
	References
23: Fetal Skeletal Anomalies
	Introduction
	Skeletal Dysplasias
	Arthrogryposis Multiplex Congenita
	Cranial Anomalies
	Spinal Anomalies
	Extremities
		Polydactyly
		Clubfoot
		Limb Reduction Defects
	Summary
	References
24: First-Trimester Ultrasound in Gestational Trophoblastic Disease
	Introduction
	Ultrasound in the Diagnosis of Molar Pregnancy
		Classic Sonographic Findings of Molar Pregnancy
		Ultrasound Diagnosis of Early Molar Pregnancy
		Sensitivity of Ultrasound in Detecting Molar Pregnancy
		Mimics of Molar Pregnancy
		Color Doppler Ultrasound in Diagnosis of Molar Pregnancy
		Uterine Artery Doppler Measurement in Molar Pregnancy and Development of GTN
		Ultrasound in the Diagnosis and Management of Ovarian Theca Lutein Cysts
		Ultrasound in the Diagnosis of Molar Pregnancies with a Coexistent Twin
		Ultrasound in the Evacuation of Molar Pregnancy
	Ultrasound in the Diagnosis and Management of GTN
		Ultrasound to Assess Presence and Volume of Intrauterine Disease
		Ultrasound Evaluation for Postmolar GTN
		Color Doppler in Diagnosis of GTN
	Ultrasound in the Follow-Up of Molar Pregnancy and GTN
		Use in Determining the Need for Surgical Intervention
		Uterine Artery Pulsatile Index as a Predictor of Chemotherapy Resistance in GTN
		GTN-Related Arteriovenous Malformations
	Ultrasound for the Evaluation of Subsequent Pregnancies
	References
25: Invasive Procedures in the First Trimester
	Introduction
		Chorionic Villus Sampling
			Indications
			Multiple Gestations
			Procedure
			Safety
		Complications of Chorionic Villous Sampling
			Bleeding
			Infection
			Rupture of Membranes
		Risk of Fetal Abnormalities Following Chorionic Villous Sampling
		Perinatal Complications
		Long-Term Infant Development
			Accuracy of CVS Cytogenetic Results
			Maternal Cell Contamination (MCC)
			Confined Placental Mosaicism
	Early Amniocentesis
		Post-procedure Amniotic Fluid Leakage
	Fetal Reduction
	Summary
	References
26: Sonography of Pelvic Masses Associated with Early Pregnancy
	Clinical Implications
	Techniques
	Uterine Masses
		Fibroids
	Adnexal Masses
		Corpus Luteum
		Corpus Luteum Cysts
		Hemorrhagic Corpus Luteum Cysts
		Decidualized Endometriomas
		Mature Teratomas
		Ovarian Cancer
	Abdominal Mimickers
	Summary
	References
Index