Chronology of neurological manifestations of prenatally diagnosed open neural tube defects.

OBJECTIVE: To evaluate the incidence and chronology of sonographic markers of neurological compromise in prenatally diagnosed neural tube defects. METHODS: We reviewed our ultrasound database from 1988 to 1999 to identify all cases of prenatally diagnosed neural tube defects. All patients received an initial detailed targeted ultrasound evaluation with subsequent evaluations every 4-6 weeks. Cases involving multiple congenital anomalies, aneuploidy, or inadequate follow-up were excluded. Specific ultrasound markers assessed included the presence of ventriculomegaly (> 10 mm) and clubfoot. RESULTS: Forty-seven cases of neural tube defects were identified over the study interval. After exclusions, 42 cases were available for evaluation. The overall incidence of ventriculomegaly and clubfoot in the study cohort was 86% and 38%, respectively. In the 33 patients with initial ultrasound examination performed at < 24 weeks' gestation, 76% (25/33) had evidence of ventriculomegaly and 30% (10/33) and clubfoot. Only 9% (1/11) of the patients managed expectantly developed evidence of ventriculomegaly and 3/11 (27%) developed clubfoot from the time of the initial ultrasound examination to delivery. CONCLUSIONS: Ultrasound markers of neurological compromise are early and frequent findings associated with fetal neural tube defects. Development of ventriculomegaly is an uncommon occurrence later in gestation, while the risk for developing clubfoot appears to increase as gestation progresses.

Ultrasonographic assessment of cervical length in triplet pregnancies.

OBJECTIVE: Our goal was to evaluate the utility of ultrasonographic assessment of cervical length in the management of triplet pregnancies and to compare these measurements with previously reported data for singleton pregnancies. STUDY DESIGN: The maternal records for all triplet pregnancies managed at the Mayo Medical Center from January 1993-January 1998 were reviewed. Cervical length assessment was undertaken at regular intervals during each pregnancy according to an established real-time transperineal ultrasonographic technique. Presence or absence of cervical funneling was noted at the time of the examination. Obstetric management and outcome data were assessed. RESULTS: Thirty-two triplet pregnancies were managed at our institution between January 1993 and January 1998. Average duration of pregnancy (+/-SD) was 32.4 +/- 2.3 weeks. Progressive cervical shortening was noted with advancing gestational age; average cervical lengths (+/-SD) were 42.0 +/- 5.0 mm at 10 weeks, 37.0 +/- 8.0 mm at 20 weeks, 26.0 +/- 10.0 mm at 25 weeks, and 21.0 +/- 7.0 mm at 30 weeks. Comparison of triplet cervical length measurements with reported data from singleton pregnancies revealed a significant difference between the singleton and triplet data, respectively, at both 24 weeks (35.2 +/- 8.3 mm vs 25.0 +/- 8.0 mm, P <.001) and 28 weeks (33.7 +/- 8.5 mm vs 28.0 +/- 11.0 mm, P <.005). Cervical funneling was noted in 3 women with an average of 27 days from onset to delivery. CONCLUSIONS: Ultrasonographic assessment of cervical length is a useful adjuvant in the management of the triplet gestation. Triplet cervical length measurements are significantly different from those reported for gestational age-matched singleton pregnancies. Premature cervical shortening and the presence of cervical funneling are harbingers of premature delivery and should necessitate obstetric intervention.

Fetal renal growth evaluated by prenatal ultrasound examination.

OBJECTIVE: To determine reference ranges for normal fetal renal size in a population of pregnant patients at Mayo Clinic Rochester. DESIGN: Normal fetal kidneys were prospectively analyzed relative to gestational age and to fetal body weight. MATERIAL AND METHODS: In 100 pregnant women, prenatal ultrasound examinations were performed between 18 and 39 weeks of gestation. Fetal renal length and volume were determined by prenatal ultrasonography and compared with gestational age and estimated fetal body weight. Reference ranges as a function of gestational age were obtained for fetal body weight, renal length, renal volume, renal length/ body weight, and renal volume/body weight. Reference ranges as a function of body weight were determined for renal length and renal volume. Polynomial least-squares regression analysis was used to model each of the growth variables (Y) as a function of either gestational age or body weight (X). RESULTS: Graphic representation of these relationships are presented. These graphs include the 2.5, 5.0, 95.0, and 97.5 percentiles and the predicted value of Y from the regression equations. Fetal body weight, renal length, and renal volume increased throughout gestation, and the ratio between fetal renal volume and body weight remained constant. CONCLUSION: These data about normal fetal renal growth relative to gestational age and fetal body weight should help identify fetal abnormalities in renal size or growth patterns.

Urinary tract anomalies detected by prenatal ultrasound examination at Mayo Clinic Rochester.

OBJECTIVE: To determine the frequency of fetal urinary tract anomalies and to characterize the types of such abnormalities detected on ultrasonography and the outcome of affected patients during a 15-year period at our institution. DESIGN: We retrospectively reviewed the findings on maternal prenatal ultrasound examinations and the postnatal medical records of 56 children with urinary tract abnormalities detected by prenatal ultrasound examination at Mayo Clinic Rochester from November 1979 to June 1994. RESULTS: Of the 56 children, 18 (32%) had severe urinary tract anomalies in conjunction with oligohydramnios, pulmonary hypoplasia, and perinatal death (Potter's syndrome). The other 38 infants had various urinary tract abnormalities--most commonly, isolated hydronephrosis and multicystic dysplasia of the kidney. Six of the 38 children had more than one renal abnormality detected prenatally. Reflux was noted in association with prenatally detected urinary tract abnormalities in 4 of 32 newborns (12%) who underwent voiding cystourethrography. In fetuses with normal amniotic fluid volume, the perinatal outcome was good. Children with lower urinary tract obstruction had evidence of more severe renal dysfunction than did those with involvement at more proximal levels. The presence or absence of urinary tract obstruction postnatally could not be determined reliably on the basis of prenatal ultrasound appearance. CONCLUSION: In this study, more than half of all prenatally detected urinary tract abnormalities were isolated hydronephrosis or multicystic dysplasia of the kidney. Postnatal renal function could not be reliably predicted on the basis of prenatal ultrasound findings.