Fetal bladder sagittal length: a simple monitor to assess normal and enlarged fetal bladder size, and forecast clinical outcome.

PURPOSE: We examined if the parameter of fetal bladder sagittal length (FBSL) could serve as a monitor of normative and enlarged fetal bladder size. MATERIALS AND METHODS: There were 76 consecutive cases examined between 1984 and 2000 that included measurement of fetal bladder size as FBSL and postnatal urological followup. Fetal images used to assess normal bladder size were derived from cases in which the bladder was normal on prenatal imaging and postnatal testing. An enlarged bladder was categorized as being greater than the 95% CI for a given gestational age (GA). The presence and extent of renal pelvic dilatation were also noted and correlated with FBSL. RESULTS: Measuring normal FBSL in 39 fetuses showed an exponential growth pattern (r = 0.76), which could be represented by the approximate linear formula FBSL = GA in weeks -5 (+/- 95% upper/lower CI = 7). An enlarged bladder was diagnosed in 37 fetuses. A dilated bladder in 9 fetuses, defined as FBSL greater than the 95% upper CI of normal (ie between GA + 2 and GA + 12), showed outcomes of posterior urethral valves, vesicoureteral reflux or a normal outcome. Megacystis in 28 fetuses, defined as FBSL greater than 10 mm larger than that of a dilated bladder (ie greater than GA + 12), showed additional outcomes of megacystis megaureter/vesicoureteral reflux or prune-belly syndrome. A normal outcome was significantly more likely in fetuses with a dilated bladder than in those with megacystis (p < or = 0.05). The incidence of azotemia in those with a dilated bladder or megacystis and pyelectasis was significantly lower than that in those with megacystis with hydronephrosis (p < or = 0.03). CONCLUSIONS: Postnatal diagnosis of fetuses that show an enlarged bladder is predicted based on whether the bladder is enlarged as a dilated bladder or megacystis and if the renal pelvis is enlarged as pyelectasis or hydronephrosis.

Geographic and temporal analysis of folate-sensitive fetal malformations.

OBJECTIVE: To identify potential geographic and temporal clustering of folate-sensitive fetal malformations as a prelude to a targeted preconception curriculum in folic acid supplementation. METHODS: Our comprehensive prenatal anomaly database was queried to select fetal malformations presumed to be sensitive to preconception folate insufficiency. Evidence of geographic clustering was evaluated by distribution of individual cases using zip codes of maternal residence. Potential temporal clustering of anomalies was sought by tabulating the frequency of each anomaly category during 5 consecutive 2-year intervals between 1992 and 2001. RESULTS: Over a 10-year period, approximately 2000 fetal anomalies were identified, of which 400 (20%) were considered potentially folate sensitive. We found geographic clustering of ventral wall defects as well as obstructive uropathy by zip code analysis. Significant increases in the frequencies of cardiac defects (P <.001) and obstructive uropathy (P <.001) were noted during the epoch of this study. A moderate increase in anomaly frequency was also seen in the diagnostic subcategory of gastroschisis, in which 15 of 27 total gastroschisis cases occurred in 2000-2001. CONCLUSIONS: Geographic clustering and temporal trends in anomaly rates were noted in certain folate-sensitive malformation categories. Identification of specific, high-incidence regions may provide an opportunity for targeted interventions designed to supplement the national folic acid campaign.

Antenatal detection of skeletal dysplasias.

OBJECTIVE: To assess the accuracy of the prenatal diagnosis of skeletal dysplasias. METHODS: All antenatally detected anomalies are coded in our ultrasound database, which is linked with a genetics database that includes outcomes. A final diagnosis is sought on the basis of radiographic studies, molecular testing, or both. Our ultrasound and genetics databases were queried for "skeletal dysplasias." All cases were reviewed specifically for the degree of bone shortening and other distinguishing characteristics on antenatal sonography. RESULTS: Thirty-seven cases of skeletal dysplasia were antenatally diagnosed over an 8-year period. Complete follow-up was available in 31 cases. The mean gestational age at diagnosis was 22.7 weeks (range, 14-32.3 weeks). Twenty-one cases were diagnosed before 24 weeks. A final diagnosis was obtained in 80% of cases. The antenatal diagnosis was correct in 20 (65%) of 31 cases. There were 2 false-positive diagnoses. Specific final diagnoses included thanatophoric dysplasia (8), osteogenesis imperfecta (6), Roberts syndrome (2), achondroplasia (3), Ellis-van Creveld syndrome (1), metaphyseal dysplasia (1), spondyloepiphyseal dysplasia (1), distal arthrogryposis (1), caudal regression (1), and glycogen storage disorder (1). The condition was correctly thought to be lethal in 16 of the fetuses on the basis of early severe long bone shortening (13), femur length-abdominal circumference ratio of less than 0.16 (12), hypoplastic thorax (10), marked bowing or fractures (4), short ribs (4), caudal regression (1), and cloverleaf skull (1). The ability to predict lethality was 100%. There were no false-positive findings with respect to lethality. CONCLUSIONS: Accurate antenatal diagnosis of skeletal dysplasias is problematic; in this series, only 20 of 31 cases were correctly diagnosed. However, the antenatal prediction of lethality was highly accurate. The most common predictors of lethal skeletal dysplasias included early and severe shortening of the long bones, femur length-abdominal circumference ratio of less than 0.16, hypoplastic thorax, and certain distinguishing characteristics.