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Elasticity Imaging in Obstetrics

Introduction Palpation, the technique by which clinicians evaluate a patient by touch, has been fundamental to medical practice for thousands of years. Information about tissue stiffness can provide diagnostic information about the presence or status of disease, or about structural or microstructural changes in tissue because of physiologic and pathologic processes. Quantification of this type of information, however, did not emerge until the past two decades,…

Ultrasound Physics for the Clinician

Introduction Since its introduction to the medical community in the 1950s, ultrasound (US) has become a widespread imaging modality because of its portability, nonionizing energy, and relatively low cost. This chapter reviews basic physics concepts behind the formation of an US image, emphasizing conventional B-mode imaging. Other approaches, including US-based elasticity assessment, Doppler, and three-dimensional imaging, as well as magnetic resonance imaging, are discussed in other…

Congenital Syphilis

Introduction A number of maternal perinatal infections result in congenital malformations. Traditionally these diseases were delineated by the acronym TORCH ( t oxoplasmosis, o ther, r ubella, c ytomegalovirus, and h erpes simplex virus). Syphilis has dominated the “other” category, although several other infections have increased over time, including coxsackievirus, human immunodeficiency virus (HIV), parvovirus B19, and varicella zoster virus. Syphilis is the quintessential bacterial infection…

Parvovirus B19 Infection During Pregnancy

Introduction Parvovirus B19 infection during pregnancy is rare, but potentially dangerous. In susceptible mothers, transplacental transmission of parvovirus B19 is possible. If acquired in utero , parvovirus B19 infection can lead to severe fetal anemia and myocarditis. In some instances, the infection may result in fetal death in the second or third trimester. Although in utero fetal infection is usually self-limited, severe cases are treated with…

Congenital Zika Virus Syndrome

Introduction Every few years the threat of a “new” infectious disease becomes the center of world attention, producing waves of fear and even mass panic. Until now, at least in the beginning, these diseases affected only adult populations. Although, since the Yap island epidemic in 2007, Zika virus (ZIKAV) was known to be able to produce epidemics, it remained unknown for the general population at large…

Cytomegalovirus, Rubella, Toxoplasmosis, Herpes Simplex Virus, and Varicella

Cytomegalovirus Sonya S. Abdel-Razeq Introduction The acronym TORCH refers to a group of organisms associated with congenital infections: t oxoplasmosis, o ther (congenital syphilis and viruses), r ubella, c ytomegalovirus (CMV), and h erpes simplex virus (HSV). The approximate number of cases per year in the United States of these infections is listed in Table 165.1 . In the United States, CMV is the most common fetal…

Diagnostic Procedures in Multiples

Introduction The number of multiple pregnancies has exponentially increased in the last several decades mainly as a result of women delaying childbearing until they are of advanced maternal age and the expanded use of assisted reproductive techniques. The risk of chromosomal abnormalities increases with advancing maternal age; however, it has also been reported that there is an increased risk of structural and genetic abnormalities in twins…

Twin Reversed Arterial Perfusion Sequence

Introduction Twin reversed arterial perfusion (TRAP) sequence is a rare complication specific to monochorionic twin pregnancies. As a result of early vascular disruption occurring during embryogenesis, a dysmorphic acardiac twin receives circulatory support from a pump twin via aberrant placental arterioarterial anastomoses. Because the acardiac twin is entirely dependent on perfusion from the pump twin, the pump twin is at risk of hemodynamic compromise. Originally described…

Twin-Twin Transfusion Syndrome

Introduction Twin-twin transfusion syndrome (TTTS) is a serious condition that can complicate twin pregnancies with monochorionic diamniotic (MCDA) placentation. MCDA twin pregnancies should be monitored for TTTS with serial ultrasound (US) scans beginning in the second trimester. Early-stage TTTS can be managed conservatively, but because of the unpredictable risks of disease progression and intrauterine fetal demise, prenatal testing and delivery before term should be considered. Limited…

Dichorionic Diamniotic Twin Gestations

Introduction Twin pregnancies account for more than 3% of live births in the United States. Determination of chorionicity and amnionicity is essential in the clinical management of multiple gestations. Although dichorionic twin gestations are not associated with as many fetal complications as monochorionic gestations, all twin pregnancies, whether dichorionic or monochorionic, have an increased risk of adverse pregnancy outcomes compared with singletons. Ultrasound (US) plays a…

Monochorionic Diamniotic Twin Gestations

Introduction Compared with dichorionic twin gestations, monochorionic twin gestations, whether diamniotic or monoamniotic, have an increased risk of adverse pregnancy outcomes. Ultrasound (US) plays a vital role in prenatal determination of chorionicity and in the management of monochorionic diamniotic twin pregnancies. Disease Definition The term monochorionic refers to a multiple gestation with one placental disk (or chorion), and the term diamniotic describes the presence of two…

Monochorionic Monoamniotic Twin Gestations

Introduction In addition to the general risks associated with twin pregnancies and with specific risks of monochorionic gestations, monoamniotic twin gestations face the unique risk of cord entanglement and are at increased risk of fetal demise. Ultrasound (US) plays a vital role in prenatal determination of chorionicity and amnionicity and in the prenatal management of monochorionic monoamniotic twin pregnancies. Disease Definition The term monochorionic refers to…

Chorionicity of Multiple Gestations

Introduction In 2014, the twin birth rate in the United States rose to an all-time high of 33.9 per 1000 live births. Multiple gestations result from either the fertilization of multiple ova or the division of a single fertilized ovum into more than one fetus. The terms monozygotic and dizygotic refer to the number of ova leading to a multifetal gestation. A monozygotic pregnancy results from…

Miller-Dieker Syndrome (17p13.3 Deletion Syndrome)

Introduction Miller-Dieker syndrome (MDS) is a rare, contiguous gene deletion syndrome characterized by type I lissencephaly, facial dysmorphism, seizures, and severe mental retardation. Other associated defects including cardiac malformations, neural tube defects, omphalocele, gastrointestinal anomalies, genitourinary anomalies, and intrauterine growth restriction have also been described in relationship to this syndrome. MDS is caused by a deletion at the chromosome 17p13.3 locus and is thought to represent…

Chromosome 5p Deletion Syndrome (Cri du Chat Syndrome)

Introduction Monosomy for the distal portion of the short arm of chromosome 5 causes 5p deletion syndrome, which is also known by the currently less favored term “cri du chat” syndrome, from the French description of the monotonous high-pitched “cat-like” cry of affected infants. Initially described in 1963 by Lejeune et al., this syndrome is readily detectable by karyotype or with molecular cytogenetic methods, such as chromosomal…

Chromosome 4p Deletion Syndrome (Wolf-Hirschhorn Syndrome)

Introduction First clinically described in 1961 by Hirschhorn and subsequently in 1965 by Wolf, the 4p deletion syndrome, or Wolf-Hirschhorn Syndrome (WHS), is the first example of a classic human chromosomal deletion syndrome. This rare condition, characterized by severe prenatal findings and confirmatory genetic testing, is more limited and consists of isolated case reports and small case series. Although more than 50% of deletions are visible…

22q11.2 Deletion Syndrome

Introduction The 22q11.2 deletion syndrome is the most common human chromosomal microdeletion syndrome and one of the most common syndromes associated with prenatally detected congenital heart defects (CHDs). It has a variable phenotype, with a wide range of associated clinical findings. DiGeorge syndrome, first described in 1965, is its most severe presentation, with primary symptoms of thymus and parathyroid aplasia and severe immunologic abnormalities; CHDs were…

Mosaic Trisomies 8, 9, and 16

Introduction Trisomies can occur with any chromosome, but most often result in spontaneous abortion. For example, trisomy 16 is the most common trisomy in human pregnancies, and the majority of the time results in miscarriage. These severe trisomies are more likely to survive past the first trimester and possibly to birth if they are mosaics, in which the condition of trisomy only affects a portion of…

Turner Syndrome (Monosomy X)

Introduction Turner syndrome (monosomy X) is characterized by complete or partial loss of the second X chromosome in the female, with or without cell line mosaicism. There are three distinct phenotypes: (1) first trimester abortus (98%), (2) second trimester hydrops fetalis (often resulting in fetal demise), and least commonly (3) neonate with a cystic hygroma (thin-walled cyst containing lymphatic fluid). Turner syndrome is the only monosomy…

Trisomy 21

Introduction Trisomy 21 (Down syndrome) is the most common trisomy in live-born infants and in spontaneous abortions. British physician John Langdon Down first described the syndrome in 1866. The chromosomal abnormality was discovered in 1959 by French geneticist Jerome Lejeune, and in 1961, the name Down syndrome was proposed by the editors of The Lancet . Disorder Definition Trisomy 21, also called Down syndrome, results from…