Hydramnios: ultrasound diagnosis and its impact on perinatal management and pregnancy outcome

Approach for Oxygenation of the Newborn with Airway Obstruction Due to a Cervical Mass

Large congenital cervical neck masses present major difficulties in management of the neonatal airway at delivery and in the perinatal period. With ultrasound, these lesions can be predicted prenatally. An airway treatment plan can then be formulated and modified in relation to the airway presentation at birth. We describe a case of a massive cervical-mediastinal teratoma and our management plan. Preparation involved a multidisciplinary approach including endoscopy to secure the airway while the neonate remained on fetal circulation and an extracorporeal membrane oxygenation system was available. Once the infant's condition was stable, a cervical approach with resection of the massive teratoma with mediastinal dissection without sternotomy was successful. A differential diagnosis of cervical neck masses and review of cervical teratomas is presented.

Preterm premature rupture of membranes and abruptio placentae: is there an association between these pregnancy complications?

OBJECTIVE

Our purpose was to determine whether the incidence of abruptio placentae is increased in pregnancies with preterm premature rupture of membranes and to assess whether certain clinical risk factors in this group predispose them to have abruptio placentae.

STUDY DESIGN

A retrospective cohort study over a 2.5-year period was performed. The study group consisted of 756 singleton pregnancies between 20 and 36 weeks' gestation complicated by preterm premature rupture of membranes and managed expectantly. The control group consisted of 11,240 pregnancies not complicated by preterm premature rupture of membranes and delivered during the same time period. The incidence of abruptio placentae was compared between the two groups. The study group of patients with preterm premature rupture of membranes was further subdivided into cases with (n = 38) and without abruptio placentae (n = 718) and compared. Clinical factors such as admission amniotic fluid index, history of bleeding before or after rupture of membranes, incidence of intrapartum fetal distress, and low 5-minute Apgar scores (< 6), latency-to-delivery interval, gestational age and weight at delivery, and incidence of amnionitis and endometritis were compared.

RESULTS

The incidence of abruptio placentae in the study group (38/756, 5%) was significantly higher than that in the control group (97/11, 240, 0.9%) (p < 0.001, odds ratio = confidence interval). Comparison of cases with preterm premature rupture of membranes with and without abruptio placentae demonstrated both groups to have a similar gestational age at delivery, birth weight, latency-to-delivery interval, amniotic fluid index, and infectious morbidity. The group with abruptio placentae had a significantly higher incidence of bleeding before rupture of membranes (six of 38, 15% vs eight of 718, 1%; p < 0.005) and of intrapartum fetal distress (18/38, 46% vs 49/718, 7%; p < 0.0009).

CONCLUSIONS

Pregnancies complicated by preterm premature rupture of membranes that are managed expectantly are at significant risk for abruptio placentae. Preterm premature rupture of membranes in such cases is more often preceded by bleeding. These abruptions may predispose the patient to intrapartum fetal distress.

Amniotic fluid volume: fluid dynamics and measurement technique

Evaluation of amniotic fluid volume is an important aspect of obstetrical ultrasound. Several methods are currently used to describe amniotic fluid volumes. The most common are the subjective assessment of fluid and the semiquantitative methods. The reproducibility of these methods is excellent in experienced hands. Because of the multiple methods used to assess fluid, both oligohydramnios and polyhydramnios have numerous definitions. Regardless of which definition is used, it is clear that both of these entities are associated with a variety of fetal and maternal conditions. Abnormal amniotic fluid volume may be the only or earliest sonographic sign of an obstetrical problem. Therefore, it is important that sonologists are familiar with amniotic fluid volume assessment. Although subjective and semiquantitative techniques may produce similar results, a numerical scale is no substitute for experience and training. One should be able to recognize lesser degrees of fluid abnormality and be able to assess the trend of amniotic fluid volume in serial examinations.

Fetal malformations associated with chronic polyhydramnios in singleton pregnancies

Forty-one congenital malformations were found in 28 newborns in a group of 197 cases of chronic polyhydramnios in singleton pregnancies. Of these, a total of 61% (17/28) was antenatally diagnosed ultrasonically. Nine newborns (4.5%) had malformations of the central nervous system (CNS), 9 (4.5%) cardiovascular malformations, 8 (4.1%) musculoskeletal anomalies, 7 (3.6%) malformations of the urinary and reproductive system, 4 (2%) respiratory system anomalies and 3 (1.6%) anomalies of the gastrointestinal system. Chromosomal abnormalities were found in three cases. As the association of polyhydramnios with fetal congenital anomalies is quite high (14.2% in our series), it is imperative to make a major effort to antenatally detect as many cases as possible. This means that in the case of hydramnios the following are required: ultrasound examination by an expert, echo ultrasonography when no other abnormalities are detected, and maybe even a chromosomal analysis.

Study of 156 cases of polyhydramnios and congenital malformations in a series of 118,265 consecutive births

Polyhydramnios associated with congenital anomalies was studied over nine years in 118,265 consecutive pregnancies. The prevalence of this association was 1.32% (156 cases). A case-control study allowed the examination of genetic and environmental factors for the origin of polyhydramnios associated with congenital malformations. Diagnosis of polyhydramnios associated with congenital malformations was performed prenatally in 41% of the cases; 16% of the infants were stillborn. Fifty-five percent of the cases had more than one malformation, 13.4% of them had a chromosomal aberration, and 32% had multiple malformations that do not constitute a syndrome. There was an increase of consanguinity in the parents of our patients. The incidence of polyhydramnios and congenital anomalies in first-degree relatives was 3.8%, and first-degree relatives had more malformations than the controls had (8.3% vs 3.2%). Our study demonstrated the low capacity of a general prenatal screening program because the diagnosis of malformations associated with polyhydramnios was made in only 41% of the cases and only six of 21 chromosomal abnormalities were diagnosed prenatally. We recommend the use of fetal chromosome analysis and careful ultrasonographic examination in every pregnancy complicated by polyhydramnios.

Genetic implications of idiopathic hydramnios

The antenatal diagnosis of hydramnios requires a careful search for associated underlying maternal or fetal conditions. Even in pregnancies associated with idiopathic hydramnios in which no underlying condition can be identified, a high perinatal mortality rate exists. Although trisomy 18 has been seen in pregnancies with hydramnios and growth retardation, the association with specific chromosomal disorders and idiopathic hydramnios has not been well defined. A review of pregnancies complicated by hydramnios was undertaken; 99 cases with complete pregnancy and delivery information were identified. Fifty-nine pregnancies were complicated by idiopathic hydramnios, and except for the hydramnios, sonographic evaluation was normal. Delivery information revealed one infant with trisomy 18 and eight infants with structural anomalies not appreciated antenatally. Of the undiagnosed malformations, 25% are frequently associated with trisomy 21. We recommend fetal chromosomal analysis as an adjunct to the evaluation of pregnancies complicated by idiopathic hydramnios.