Fetology: Diagnosis and Management of the Fetal Patient, Second Edition
Forty years ago it made sense to link obstetrics with gynecology because both dealt exclusively with the care of women, pregnant or not. In the 1960s, research began to focus on the hitherto unexplored world of the developing fetus, and the technological explosion of the mid-1970s made it possible for the first time to visualize the fetus throughout gestation and to monitor its development. Direct and indirect tests of fetal well-being were subsequently developed and led to fetal therapy; the first report of intraperitoneal fetal red-cell transfusion for Rh isoimmunization appeared in 1963.Simultaneously, advances in knowledge about genetics and related technology raised the possibility of genetic evaluation of the fetus. The first report of successful karyotyping of amniocytes appeared in 1966, followed by the first report of genetic amniocentesis in 1970. By the mid-1970s, the fetus had become a full-fledged patient, and obstetrics had become a complicated specialty -- so much so that in 1974 the first board-certification examination was given in the subspecialty of maternal-fetal medicine, in recognition of the tremendous body of knowledge in this area. Obstetricians now care for two patients, the pregnant woman and her fetus, and are expected to diagnose abnormalities accurately and to provide therapy appropriate to both.To provide such services, the obstetrician struggling to keep up with the explosion of information and technology has had to refer to sonography textbooks to confirm the correct interpretation of the ultrasound image, a variety of references in the area of genetics to pull together the constantly changing data regarding the possibility of prenatal genetic diagnosis and the implications of any identified abnormality, and the literature on maternal-fetal medicine and pediatric surgery to keep abreast of the dramatic new fetal therapies currently offered or being investigated.In many centers, the overwrought patient is referred to specialists in radiology, genetics, maternal-fetal medicine, pediatric surgery, and other fields to obtain the comprehensive information and services required for many fetal abnormalities. However, when confronted with a fetal anomaly, even these subspecialists sometimes find it difficult to compile the most recent data, present a balanced and thorough review of the issues in a way that is meaningful to the patient, and provide appropriate therapy.What was desperately needed was a single source of relevant, critically reviewed data, along with therapeutic guidance. Fetology is such a resource. The practitioner who has identified a fetal abnormality can turn to the appropriate chapter in this book and find all the information needed to make the diagnosis, counsel the patient, and provide therapy. Since ultrasonography provides the first and possibly the best opportunity to evaluate the fetus, the topics are organized according to organ system, and the anomalies of each system that are commonly detected by sonography are presented alphabetically. Each chapter is thus devoted to a single anomaly -- for example, encephalocele -- and includes a description of the anomaly, its incidence, the characteristic sonographic findings, the differential diagnoses, the antenatal natural history, the best treatment during pregnancy (including possible fetal therapies), the appropriate treatment of the newborn, the expected long-term outcome, the genetic features of the anomaly, and the risk of recurrence. Each of these sections contains a succinct critical review of the relevant literature and the reasoning behind any recommendations, as well as a frank discussion of the gaps in our knowledge.The three authors of Fetology represent the subspecialties of genetics, pediatric surgery, and maternal-fetal medicine, which probably accounts for the well-balanced approach to each anomaly and the fact that the information in all the subsections of each chapter is equally strong. The authors, all recognized experts in their fields, are the very best type of consultants; they combine an academic approach to the analysis of data and an objective review of controversial areas with knowledge gained firsthand by caring for patients. Thus, the reader learns both what the research says and what these experienced clinicians would do. An added bonus is that the book is written clearly, in one voice, and follows Einstein's dictum that "things should be made as simple as possible, but not any simpler."As an example of the book's approach to anomalies, consider the chapter on choroid-plexus cysts. These cysts are a source of distress among patients and physicians because they can be recognized even by inexperienced sonographers and they occur commonly in both normal and abnormal fetuses. The patient who is referred for the evaluation of such cysts in her fetus is usually tearful and anxious, in large part because of the referring clinician's inability to provide counseling regarding their significance. The radiologist, obstetrician, or specialist in maternal-fetal medicine who then evaluates the fetus turns to the literature and finds that it is full of case reports and small series accompanied by a wide variety of disparate conclusions about the clinical significance of choroid-plexus cysts and their management. The clinician who turns to Fetology, however, will learn how choroid-plexus cysts form, the history of their prenatal diagnosis, the source of the concern that they indicate fetal trisomy 18, their natural history, and a logical approach to management. The rationale behind the recommendations is provided, including a review of the risk of fetal trisomy 18 in relation to maternal age, an explanation of how to alter this a priori risk with a likelihood ratio (derived from the association of aneuploidy with choroid-plexus cysts) to compute a posterior probability, and a discussion of how to include the presence or absence of other structural abnormalities in the calculation. By the end of this chapter, readers have learned the best approach to the diagnosis and management of fetal choroid-plexus cysts, have reviewed the relevant literature and some valuable statistical principles, and, probably most important, have read such a clear presentation of the issues that they will feel comfortable explaining them to patients.Every chapter contains a wealth of information compiled in a way that most readers will find novel and many interesting tidbits that will be new even to experienced clinicians. The chapter on neural-tube defects, for example, includes the signs and symptoms of hindbrain dysfunction in the neonate with a neural-tube defect and the indications for surgical decompression, along with pearls such as the fact that surgical treatment is complicated by the high frequency of latex allergy in these infants (although this fact is unreferenced). The chapter on nonimmune hydrops includes the most complete differential-diagnosis list I have ever seen. Even the rarest entities, such as hemifacial microsomia and tetrasomy 12p, are presented in the same complete manner. Think of an entity that has caused frustration because it is not fully covered in any of the standard textbooks, and it is here. There are chapters on iniencephaly, agenesis of the corpus callosum, bronchogenic cysts, pentalogy of Cantrell, arthrogryposis, and retinoblastoma, to name just a few. The ultrasound images are excellent, and the other illustrations are very good.My only quibbles are minor and mostly confined to the first two chapters, which provide an overview of prenatal imaging and prenatal diagnostic procedures. These chapters do not present as balanced a view of the topics as that found in the rest of the book, and they contain more declarative but unreferenced statements than the other chapters, but this probably results from the need for brevity. For example, one of these chapters states that amniocentesis is offered when triple-marker screening reveals a risk of Down's syndrome that is higher than 1 in 270, when, actually, different laboratories use different cutoffs -- for example, 1 in 200 or 1 in 365. This variation has been a source of confusion for clinicians and patients and could have been explained here. Some of these statements are outdated. The authors claim, for instance, that percutaneous umbilical-cord sampling is required to determine the fetal blood type, although the fetal Rh type can now be determined by analysis of amniocytes obtained by amniocentesis; the authors also say that percutaneous umbilical-cord sampling at term is required for management of idiopathic thrombocytopenic purpura, although most authorities, including the American College of Obstetricians and Gynecologists, now acknowledge that such sampling is unnecessary. The chapter on anencephaly says that termination should be offered because this condition "carries an increased medical risk to the mother," although no data are provided to support this statement. There are also a few editing errors in these chapters. However, these are minor problems and do not detract from the excellent information in the rest of the book; the reader who needs more information on the topics covered in these introductory chapters can make use of the fine reference list offered in each one.In summary, this is a well-written, easy-to-use reference book that fills a well-defined need. It is interesting enough to read straight through but well organized enough to read a chapter at a time. Those of us who have had the experience of spending hours trying to find the latest diagnostic and therapeutic information on a relatively rare anomaly, only to come up short, will be grateful that this book is on our shelves.Katherine D. Wenstrom, M.D.Copyright &#169; 2001 Massachusetts Medical Society. All rights reserved. The New England Journal of Medicine is a registered trademark of the MMS.--This text refers to an out of print or unavailable edition of this title.