J Hirsch

Fetal cystic adenomatoid malformation: Prenatal diagnosis and natural history

We studied the natural history and pathophysiology of congenital cystic adenomatoid malformation (CCAM) detected prenatally by ultrasound in twelve fetuses. Two types of fetal CCAM can be distinguished by gross anatomy, ultrasound findings, and prognosis. Microcystic lesions are usually associated with fetal hydrops and have a poor prognosis (five cases with one survivor). Antenatal diagnosis, maternal transport, and immediate thoracotomy after birth allowed the first reported survival of a newborn with a large microcystic CCAM. Macrocystic lesions are not usually associated with hydrops and have a favorable prognosis (five of seven survived). We conclude that fetuses with hydrops are at high risk for fetal or neonatal demise without intervention. Fetuses with CCAM but without hydrops have a good chance for survival with maternal transport, planned delivery, and immediate neonatal resuscitation and surgery.

The “stuck twin” phenomenon: Ultrasonographic findings, pregnancy outcome, and management with serial amniocenteses

Abstract Thirteen consecutive twin pregnancies affected by the “stuck twin” phenomenon were reviewed to determine the potential benefit of serial amniocenteses. The fetal survival rate for the eight pregnancies that underwent serial amniocenteses was 69% (11 of 16 fetuses). This is significantly improved compared with a fetal survival rate of 20% among the five preceding pregnancies managed without serial amniocenteses at the same institution (p = 0.01). It is also markedly improved compared with a combined fetal survival rate of 16% among 48 previously reported pregnancies with the stuck twin phenomenon managed without serial amniocenteses (p

Meckel-Gruber syndrome : importance of prenatal diagnosis

Prenatal sonographic findings are reported in six fetuses with the Meckel‐Gruber syndrome to illustrate the variety of sonographic findings associated with this disorder and to emphasize the importance of prenatal sonography in helping to establish the correct diagnosis. All six fetuses demonstrated evidence of renal cystic dysplasia. In five cases the kidneys were large and echogenic, demonstrating small discrete cysts in the range of 2 to 5 mm. The remaining fetus demonstrated unilateral renal cystic dysplasia and contralateral renal agenesis. Oligohydramnios was noted in all cases and was evident as early as 14 weeks. An occipital cephalocele was demonstrated on sonography in each case although the size and contents of the cephalocele varied significantly. Two fetuses, both in the same family, also demonstrated a cystic mass in the posterior fossa and partial absence of the cerebellum consistent with a Dandy‐Walker variant or cerebellar hypoplasia. The concurrence of marked oligohydramnios and bilateral severe renal anomalies should initiate a search for anomalies of the central nervous system indicative of the Meckel‐Gruber syndrome. Recurrence of Meckel‐Gruber syndrome may be evaluated as soon as 14 weeks, but it may not be reliably excluded until 20 weeks.

Significance of a single umbilical artery in fetuses with central nervous system malformations.

To determine whether the presence of a single umbilical artery (SUA) is useful information for evaluating fetuses with known central nervous system (CNS) malformations, the present study reviewed 107 consecutive cases of fetal CNS malformations (hydrocephalus, meningomyelocele, Dandy‐Walker malformation, and holoprosencephaly) identified by prenatal sonography. Of the 107 fetuses studied, 20 (18%) had a SUA noted at the time of delivery or autopsy and 87 (81.3%) had two umbilical arteries. Of the 20 fetuses with a SUA, six were prospectively recognized on sonography, six were identified retrospectively, and eight could not be evaluated due to oligohydramnios or technical factors. All 20 fetuses with a SUA had extra‐CNS anomalies and 8 of 15 (53%) fetuses tested had chromosomal abnormalities. These rates were significantly higher (P less than .05) than observed in 87 fetuses with two umbilical arteries who had extra‐CNS anomalies in 35 cases (39%) and chromosomal abnormalities in 11 of 45 (24%) cases tested. We conclude that identification of a SUA in combination with a CNS anomaly should suggest the presence of additional extra‐CNS anomalies and is an indication for chromosomal analysis.

Translabial ultrasound of the third-trimester uterine cervix. Correlation with digital examination.

This prospective blinded study compared translabial ultrasound (TLU) and digital palpation of the cervix among women whose cervix could not be visualized adequately or at all with transabdominal ultrasound during the third trimester of pregnancy. The cervical canal and internal cervical os were adequately visualized during 109 of 113 TLUs (96%). The TLU was well tolerated by the patients; only two patients refused the TLU pending discussion of the technique with their obstetrician. Among 43 examinations of patients without clinical cervical effacement, TLU showed a cervical length of 2.5 to 4.2 cm (mean, 2.9 cm). An excellent correlation (R = 0.90) was noted between cervical length on TLU and percentage of cervical effacement on digital examination. The correlation between amount of cervical dilatation on TLU and on digital examination was not high (R = 0.58). We conclude that the measurements of cervical length on TLU correlate well with the amount of cervical effacement on digital examination and that TLU provides a rapid and well‐tolerated alternative technique to visualize the third‐trimester uterine cervix.

Prenatal sonographic findings of Down syndrome: Review of 94 cases

Prenatal ultrasound findings were reviewed in 94 consecutive fetuses with proved Down syndrome (trisomy 21) during a 6-year period at a single institution. One or more abnormalities were found in 31 fetuses (33%), including two of 11 fetuses seen before 14 weeks, 17 of 68 fetuses seen between 14-24 weeks, and 12 of 15 fetuses seen after 24 weeks. Major anomalies detected included cardiac defects (five), duodenal atresia (four), cystic hygromas (four), omphalocele (two), hydrops (two), and hydrothorax (one). Nuchal thickening was observed in five fetuses, including four of 25 second-trimester fetuses evaluated prospectively during the last 2 years of the study. Mild cerebral ventricular dilatation (three) and hyperechogenic bowel (five) are new findings that have not been generally associated with Down syndrome. A variety of prenatal sonographic abnormalities may be associated with Down syndrome, and the frequency of detecting most abnormalities increases with menstrual age. Anomalies more frequently detected before 20 weeks include cystic hygromas, nuchal thickening, and hyperechogenic bowel. Awareness of the sonographic findings associated with Down syndrome should result in improved detection of this disorder.

The ‘stuck twin’ phenomenon: Ultrasonographic findings, pregnancy outcome, and management with serial amniocenteses

Thirteen consecutive twin pregnancies affected by the stuck twin phenomenon were reviewed to determine the potential benefit of serial amniocenteses. The fetal survival rate for the eight pregnancies that underwent serial amniocenteses was 69% (11 of 16 fetuses). This is significantly improved compared with a fetal survival rate of 20% among the five preceding pregnancies managed without serial amniocenteses at the same institution (p = 0.01). It is also markedly improved compared with a combined fetal survival rate of 16% among 48 previously reported pregnancies with the stuck twin phenomenon managed without serial amniocenteses (p less than 0.0001). Survival correlated with the absence of concomitant pregnancy complications (i.e., maternal hypertension or intractable labor) and with the absence of severe fetal structural abnormalities. Procedural complications occurred in three of eight pregnancies (37.5%) managed with serial amniocenteses and was attributed as a cause of fetal death in one case. Two of 11 survivors (18%) had complications after serial amniocenteses including brain infarction and renal tubular necrosis. Serial amniocenteses may significantly improve the survival rate of twin gestations affected by the stuck twin phenomenon but may be associated with complications among survivors.

Abnormalities of Fetal Cranial Contour in Sonographic Detection of Spina Bifida: Evaluation of the “Lemon” Sign

Previous reports have shown that visualization of the lemon sign on fetal cranial sonograms may indicate the presence of spina bifida before 24 weeks. To further characterize this sign and determine whether other factors might be associated with it, the authors retrospectively (n = 31) and prospectively (n = 19) evaluated 50 fetuses with spina bifida. The lemon sign was noted in 32 (64%), including 24 of 27 (89%) fetuses evaluated before 24 weeks. The presence of both ventricular dilatation, found in 41 (82%) of the fetuses, and a lemon sign correctly predicted spina bifida in all but one case. The location of the spinal defect and other anomalies were not associated with the lemon sign. The lemon sign is an important indicator of spina bifida, particularly in high-risk pregnancies, and should improve sonographic detection of spina bifida before 24 weeks.