The effect of maternal dietary fat on fetal pulmonary maturation in rats

Abstract

In 1966, Singh and Carr noted a characteristic combination of defects in abortuses with XO genotypes. These abortuses were phenotypically female and exhibited generalized edema and large cystic hygromas in the posterior nuchal region. Characteristically abortion had occurred between 123 and 159 days' gestational age (19.5 and 24.7 weeks' menstrual age). Since this original report a number of series have substantiated the pattern of cystic hygroma, generalized edema, failure of ovarian follicular development, and spontaneous abortion of a macerated fetus during the second trimester of pregnancy. When karyotypic analyses have been possible in these fetuses XO monosomy is found. The ultrasonographic characteristics leading to the correct intrauterine diagnosis of this entity should include the following: at least two bilaterally symmetrical echo-free areas in the posterior nuchal region, usually divided by septa; a completely formed cranial vault; and constant location of the masses with respect to the occiput despite fetai motion. The position and presence of septa should weigh against alternative possible diagnoses such as menmgomyelocele and benign cystic teratoma. An intact cranial vault excludes encephalocele. The constant position of the structures with regard to the occiput excludes the possibility of subchorionic placental cyst. Amniotic fluid alpha fetoprotein has been noted to be elevated in association with cystic hygroma. The mechanism of this association is unknown at present and it has been postulated that the elevation is due to the enlarged surface area or the increased interstitial fluid pressure felt to be present in these fetuses. The rather striking size of the cystic area noted at sonography suggests an additional possibility. Unless the borders of u'Ie echo-free areas are noted and the anomaly suspected, the sac may be felt to be a pocket of amniotic fluid and aspirated or punctured. Direct cyst puncture after abortion yielded alpha-fetoprotein levels similar to the high levels found in fetal serum. 2 High prenatal suspi~ion of this diagnosis may also facilitate postnatal diagnosis as samples for karyotype analysis from multiple sources of the fetus and the placenta can be utilized. Although second-trimester fetal death occurred in both cases reported, it is possible that similar findings may be present in gestations which result in viable infants with Turner's syndrome.