Tetralogy of Fallet with absent Thyroto/icosis�
Functional cardiac etiology Cardiom 'apathy, myocarditisa Cardiac arrhythmia tnali flutter, atrial fibrillation, supraventricular tachycardia Bradyarrhythmiaa.
Neurological or muscular etiology Arthrogryposis, akinesia sequence Myotonic dystrophy Neoplastic etiology Sacrococcygeal teratomaa Mesoblastic nephromaa aPoses risk for hydrops.
CHAOS = congenital high-airway obstruction sequence; GI = gastrointestinal.
correlate with the amnionic fluid glucose concentration (Dashe, Idiopathic Hydramnios 2000; Spellacy, 1973; Weiss, 1985). Such findings support the his accounts for up to 70 percent of cases of hydramnios and is hypothesis that maternal hyperglycemia causes fetal hyperglythus identified in as many as 1 percent of pregnanciescemia, with resulting fetal osmotic diuresis into the amnionic (Panting-Kemp, 1999; Pri-Paz, 2012; Wiegand, 2016). Idiopathic luid compartment. hat said, rescreening for gestational diahydramnios is rarely identiied during midtrimester sonography betes in pregnancies with hydramnios does not appear to be and is oten an incidental inding later in gestation. he gestabeneicial, provided that the second-trimester glucose tolerance tional age at sonographic detection usually lies between 32 and 35 test result was normal (F rank Wolf, 2017).
weeks (Abele, 2012; Odibo, 2016; Wiegand, 2016). Although it is a diagnosis of exclusion, an underlying fetal abnormality may subsequently become apparent with advancing gestation, particu
Hydramnios is generally deined in multifetal gestations as larly if the degree of hydramnios becomes severe. In the absence a single deepest amnionic luid pocket measuring 8 cm or of an etiology, idiopathic hydramnios is mild in approximately 80 more. It may be further characterized as moderate if the single percent of cases, and resolution is reported in more than a third deepest pocket is at least 10 cm and severe if this pocket is of afected pregnancies (Odibo, 2016; Wiegand, 2016). Mild, at least 12 cm. In a review of nearly 2000 twin gestations, idiopathic hydramnios is most commonly a benign finding, and
Hernandez and colleagues (20i12) identified hydramnios in associated pregnancy outcomes are usually good.
18 percent of both monochorionic and dichorionic pregnancies. As in singletons, severe hydramnios was more strongly associated with fetal abnormalities. In monochorionic gestations, hydramnios of one sac and oligohydramnios of the Unless hydramnios is severe or develops rapidly, maternal other are diagnostic criteria for twin-twin transfusion synsymptoms are infrequent. With chronic hydramnios, luid drome (TTTS), discussed in Chapter 45 (p. 878). Isolated accumulates gradually, and a woman may tolerate excessive hydramnios of one sac also may precede the development abdominal distention with relatively little discomfort. Acute of this syndrome (Chon, 2014). In the absence of TTTS, hydramnios, however, tends to develop earlier in pregnancy. hydramnios does not generally raise pregnancy risks in nonIt may result in preterm labor before 28 weeks or in symptoms anomalous twins (Hernandez, 2012). that become so debilitating as to necessitate intervention.