CRC Handbook of Ultrasound in Obstetrics and Gynecology, Volume II

Asim Kurjak

• Publisher: CRC Press
• Year: 2020
• ISBN:
  9781351366168
• Edition: 1
• Topic: Medicine
• Subtopic: Gynecology, Obstetrics & Midwifery

This practical, two volume handbook provides a critical look at state-of -the-art ultrasound techniques and equipment. It is a comprehensive reference with numerous black/white and color ultrasonograms, tables and graphs. The volumes include extensive literature citations which assist the investigator in finding more in-depth references.This work focuses on the recent remarkable expansion in both diagnostic techniques and clinical applications. It reports findings based on an unusually large patient population over al long time period. It presents the accuracy and limitations of various aspects of ultrasound.

Chapter 1

FETAL ECHOCARDIOGRAPHY

Asim Kurjak and Mladen Miljan

INTRODUCTION

Echocardiography has had a major impact on the health care of the infants and children bom with congenital heart disease (CHD) by providing accurate, noninvasive anatomic and functional information for diagnosis and follow-up. Recent improvements in resolution have resulted in the prenatal diagnoses of various birth defects. Although diagnostic ultrasound has been utilized antenatally in the detection of the anomalies of other organ systems, the cardiovascular system has not been adequately evaluated. Fetal cardiac imaging has been attempted in the past using M mode^1,2 and two-dimensional techniques.^3,4 Use of static B scanners for cardiac imaging is limited because the heart is a moving structure. M mode echocardiography has limited value for fetal echocardiography because it lacks spatial orientation and is very difficult to interpret when the examiner has no information about changing fetal position within the uterus. With the recent development of high-resolution, real-time, cross-sectional scanners, previously unrecognized capabilities in fetal cardiac imaging appear to warrant investigation. During the last decade, a number of papers has been published about ultrasonic assessment of fetal cardiovascular anatomy and function.^{5, 6, 7, 8, 9, 10, 11} Quantitative assessment of growth of particular cardiac structures became possible,^{10,12, 13, 14, 15, 16, 17} as well as antenatal diagnosis of fetal heart rhythm disturbances.^{18, 19, 20, 21, 22, 23, 24, 25, 26} In recent times, new technology has influenced fetal echocardiography, too. The introduction of color Doppler technique enables visualization of intracardiac flow.^{27, 28, 29} This method offers new possibilities for easier and more accurate antenatal detection of congenital heart defects. With this approach, the clinician has the potential of improving overall perinatal survival because, once diagnosed as having CHD or altered cardiac function, the fetus can be optimally managed at a perinatal center equipped to provide maximal antenatal and postnatal care.

HIGH RISK PREGNANCIES FOR CONGENITAL HEART DEFECTS

CONGENITAL HEART DEFECTS AND CHROMOSOMAL ABNORMALITIES

It has been estimated that 0.5% of all live-bom infants have a chromosome abnormality. Although the overall incidence of heart defects among patients with chromosome abnormalities is 30%, involvement of the heart may range from a few to nearly 100% in specific syndromes, with 90% and above in trisomies 13 and 18 and 40 to 50% in trisomy 21.³⁰ Since heart anomalies occur in about 1% of the population in general, the contribution of chromosome abnormalities to the total number of cases with structural heart defects can be considered appreciable.³¹ A number of chromosomal defects are characteristically associated with CHD.³²

The above results show the necessity to perform amniocentesis for chromosome studies in all pregnancies in which a fetal cardiac abnormality has been demonstrated, especially when the cardiac defect per se is considered amenable to surgical treatment and other major structural abnormalities have been ruled out. This will influence both the counseling of the parents and management of pregnancy and delivery.³³

ULLRICH-NOONAN SYNDROME

The Ullrich-Noonan syndrome encompasses features of Turner’s syndrome (such as short stature, characteristic facies, hypertelorism, webbed neck, and shield chest), but in the presence of a normal karyotype. These phenotypic features may not be diagnosable in utero; however, CHD is found in 50 to 55%, with right heart involvement in 80% of these, usually pulmonary valvular or infundibular stenosis.^30,34 Asymmetric left ventricular free wall hypertrophy may be seen and should be amenable to diagnosis in utero if present at the time of examination.³⁵ Tetralogy of Fallot, Ebstein’s anomaly, ventricular septal defects, and total anomalous pulmonary venous return have also been described.^35,36 As the syndrome is transmitted as autosomal dominant, couples at risk may request prenatal diagnostic testing, and fetal echocardiography may be useful.

ENVIRONMENTAL FACTORS

Both embryonic consideration and epidemiologic evidence support the concept that teratogenic exposure prior to implantation of the fertilized human ovum does lead to malformation. If the teratogenic insult is major, viability is not maintained. Implantation and differentiation must progress to about 14 d of conceptual age before maldevelopment may be produced by teratogens.

It is thought that the most sensitive, vulnerable period for almost all cardiac structures occurs from the 18th to 60th d of embryonic development. Limits are variable in relation to the involved cardiac structure and the teratogenic agent to which fetus has been exposed.

Drugs

A number of drugs have been implicated as the primary cause of various syndromes of congenital malformations often including the heart. Now only of historic interest, thalidomide was primarily known for its association with phocomelia when ingested in the first trimester. If the exposure was between days 20 and 36 after conception, a 5 to 10% incidence of CHD was identified, especially tetralogy of Fallot, truncus arteriosus, and septal defects.³⁷

Alcohol

A number of papers were published concerning the increased frequency of stillbirths, infant mortality and prematurity, decreased birth weight, and retardation of growth and psychomotor development. A fetal alcohol syndrome, consisting of mental retardation, microcephaly, intrauterine growth retardation (IUGR), hypertelorism with other facial abnormalities, and joint anomalies, has usually been seen in women consuming more than 60 ml of absolute alcohol per day, but more moderate alcohol consumption may carry some risk as well.³⁸ CHD has been identified in 25 to 30% of infants with the full syndrome, especially ventricular and atrial septal defects.^37,39,40

Anticonvulsants

Approximately 0.5% of pregnant women have epilepsy; thus, the obstetrician if often faced with women who require anticonvulsants during the period of organogenesis.

In 1968, Meadow reported the increased risk of malformations (particularly cleft lip and palate and CHD) to offspring of epileptic mothers on anticonvulsants. A large number of reports followed, and eventually the data from the collaborative perinatal study were analyzed for the association of diphenylhydantoin, and selected malformations were reported.⁴¹

The questions arises as to whether teratogenicity is caused by the maternal illness itself or by the effect of the drugs given to the mother. Several studies have compared untreated epileptic patients with the general population and found no difference in overall malformation rates.^{42, 43, 44} CHD has been described in 2 to 3% of offspring whose mothers were under the hydantoin treatment, particularly ventricular septal defect, pulmonary stenosis, aortic stenosis, and coarctation of the aorta.³⁷ Trimethadione has been reported to be associated with a high incidence of CHD, with as many as 15 to 30% of exposed fetuses found to have transposition of the great arteries, tetralogy of Fallot, or hypoplastic left heart.^37,45,46

Lithium

Lithium has won increasing acceptance in the treatment of manic-depressive psychoses. In a study of 118 infants whose mothers were under lithium therapy during the pregnancy, 6 of them were found to have congenital heart defects (a 5-fold increase over expectation).⁴⁷ In another study of 143 cases, 11 newborns had a cardiovascular anomaly.⁴⁸ It is interesting that the incidence of Ebstein’s anomaly showed a 400-fold increase in the group of lithium-exposed infants. That leads us to believe that this drug is a potent teratogen in susceptible individuals.⁴⁹

Sex Hormones

Exposure of the fetus to sex steroid hormones as a cause of CHD has been a source of controversy in the literature...

Table of contents

• Cover
• Title Page
• Copyright Page
• Dedication
• Preface
• The Editor
• Advisory Board
• Contributors
• Table of Contents
• Chapter 1 Fetal Echocardiography
• Chapter 2 Invasive Diagnostic Procedures in Obstetrics
• Chapter 3 Fetal Therapy—Approaches and Problems
• Chapter 4 Doppler Ultrasound in the Assessment of Fetal and Maternal Circulation
• Chapter 5 Blood Flow and Behavioral States in the Human Fetus
• Chapter 6 Transvaginal Ultrasonographic Diagnosis in Gynecology and Infertility
• Chapter 7 Tissue Characterization in Obstetrics and Gynecology
• Chapter 8 Endosonography for the Diagnosis of Uterine Malignomas
• Chapter 9 Normal Anatomy of the Female Pelvis and Principles of Ultrasound Diagnosis of Pelvic Pathology
• Chapter 10 Ectopic Pregnancy
• Chapter 11 Ultrasound and Infertility
• Chapter 12 The Role of Ultrasonography in In Vitro Fertilization
• Chapter 13 Transvaginal Color Doppler
• Index