Placental pathophysiology of the twin oligohydramnios-polyhydramnios sequence and the twin-twin transfusion syndrome.

Currently accepted sonographic criteria for antenatal diagnosis of twin-twin transfusion (TTT) syndrome include a monochorionic placenta with same-sex twins, marked growth discordance, and oligohydramnios of the growth-retarded twin with coexistent polyhydramnios of the larger twin. Our previous report of nine women fulfilling these criteria, examined using sequential funipuncture of both fetuses, demonstrated inter-twin blood transfusion in only four cases (44 per cent). It was proposed that traditional sonographic criteria actually describe a heterogeneous group of disorders more appropriately described as the twin oligohydramnios-polydramnios sequence (TOPS). True TTT is a subset of this population, the antenatal diagnosis of which requires specific demonstration of transfusion from one fetus (donor) to the other (recipient). In this report, antenatal placental evaluation has been correlated using duplex pulsed-wave Doppler analysis of arterial blood flow velocity with postpartum gross and histopathologic evaluation of the placenta, with special attention to microvasculature. There was a higher incidence of resistance to blood flow, abnormal umbilical cord insertion, and diminished placental microvasculature associated with oligohydramnic growth-retarded (donor) twins when compared with polyhydramnic (recipient) twins. Based on these observations, it is proposed that TTT and TOPS represent asymmetric placental insufficiency resulting from aberrant placentation.

Prenatal findings in Brachmann-de Lange syndrome.

Brachmann-de Lange syndrome is a congenital disorder of uncertain cause characterized by severe mental retardation, small stature, microbrachycephaly, hirsutism, limb deformities, and characteristic facies. Although more than 300 neonatal cases have been reported, a lack of specific fetal markers has precluded successful antepartum diagnosis. We describe a case of Brachmann-de Lange syndrome identified at 15 weeks' gestation by a low maternal serum alpha-fetoprotein (MSAFP) value. Sonography revealed a fetus with a posterior nuchal cystic hygroma and early-onset symmetrical intrauterine growth retardation (IUGR). The fetal karyotype was 46,XX, but the infant fulfilled the phenotypic criteria of the Brachmann-de Lange syndrome at delivery. The triad of an abnormally low MSAFP value, early-onset symmetrical IUGR, and characteristic ultrasound findings during the second trimester of pregnancy may define adequate criteria for prenatal diagnosis of Brachmann-de Lange syndrome.

Fetal acoustic stimulation as a possible adjunct to diagnostic obstetric ultrasound: a preliminary report.

Unfavorable fetal position during diagnostic obstetric ultrasound can interfere with visualization of certain structures, leading to prolonged or repeated examination. Fetal acoustic stimulation induces a fetal startle reflex and an increase in fetal movements. This report describes our experience with fetal acoustic stimulation to prompt fetal movement in an effort to improve fetal visualization. At gestational ages of 28 weeks or more a 94.1% success rate was noted, in 30 seconds or less in 70.6% of the cases. We conclude that fetal acoustic stimulation may be a valuable adjunct to diagnostic obstetric ultrasound.

Pregnancy associated with Friedreich ataxia.

The pregnancy of a woman with Friedreich ataxia was complicated by the onset of preterm labor and preeclampsia. Administration of magnesium sulfate (MgSO4.7H2O) in the usual intravenous dosage resulted in the dramatic development of profound motor weakness and respiratory distress. Magnesium acts to antagonize the action of acetylcholine at the motor end plate of the neuromuscular junction and may operate synergistically with underlying neuromuscular disorders. Therefore, the use of magnesium sulfate in patients with Friedreich ataxia and other similar neurodegenerative diseases is contraindicated.

Congenital chyloperitoneum as a cause of isolated fetal ascites.

Isolated fetal ascites is an unusual prenatal finding and must be differentiated from immune and nonimmune hydrops. This entity is most commonly associated with gastrointestinal and genitourinary anomalies. Fetal chyloperitoneum, however, should be considered as a possible cause. Pulmonary hypoplasia and abdominal dystocia during attempted vaginal delivery are potential complications. We present a case of isolated fetal ascites due to congenital chyloperitoneum.

Doppler umbilical artery velocimetry in pregnancy complicated by insulin-dependent diabetes mellitus.

The mean peak systolic to end-diastolic (S/D) umbilical artery ratio was measured in 291 Doppler studies performed during pregnancy in 35 insulin-dependent diabetic women. A normal decline was observed in the umbilical artery S/D ratio, from 4.2 +/- 0.21 at 18 weeks to 2.18 +/- 0.22 at 38 weeks. There was no significant correlation between mean third-trimester S/D and either glycosylated hemoglobin (r = 0.25) or mean blood glucose levels (r = 0.15). Fetuses of women with vascular disease (class F/R or chronic hypertension) had a mean third-trimester S/D of 3.0 or higher in five of ten cases, compared with three of 25 in patients with uncomplicated diabetes (P less than .03). Mean second- and third-trimester S/D ratios differed significantly in patients with and without vascular disease: 4.34 +/- 0.7 and 3.2 +/- 0.65 versus 3.72 +/- 0.42 and 2.55 +/- 0.32, respectively (P less than .03). Two of three women without vascular disease who demonstrated an elevated mean S/D ratio developed preeclampsia and delivered appropriate for gestational age infants. In women with vascular disease, four of five with an abnormal mean third-trimester umbilical artery S/D ratio were delivered of growth-retarded infants, whereas all five with normal umbilical artery S/D ratios had appropriate for gestational age infants. In three of the abnormal cases, elevated S/D ratios were present in the second trimester before ultrasound documentation of fetal growth retardation.(ABSTRACT TRUNCATED AT 250 WORDS)

Diabetes mellitus and Graves' disease in pregnancy complicated by maternal allergies to antithyroid medication.

The pregnancy of a women with diabetes mellitus was complicated by Graves' disease and maternal allergies to propylthiouracil and methimazole. Preparations for surgical removal of the thyroid gland were being made until pregnancy intervened. Several well-documented mechanisms of hyperthyroidism, including increased intestinal absorption of glucose, decreased insulin responsiveness, and increased glucose production may exacerbate glucose intolerance; the daily insulin requirement of this patient rose 80% from her pregestational dosage. When large doses of propranolol failed to control her thyrotoxic symptoms and led to severe, recurrent hypoglycemic episodes, subtotal thyroidectomy was performed. A 42% decrease in insulin requirements was observed postoperatively, with return to the euthyroid state. A propensity for symptomatic postoperative hypoglycemia should be anticipated in diabetic patients undergoing thyroidectomy.

A model for in utero endoscopic treatment of myelomeningocele.

An animal model for intrauterine surgical treatment of myelomeningocele is described using sheep. We report the technical feasibility of endoscopic intrauterine skin graft placement over surgically induced defects, including over exposed spinal cord. These grafts exclude amniotic fluid from the underlying lesion and provide a matrix for fetal skin growth below the graft. The potential for human application is discussed.

The umbilical artery Doppler ultrasonographic gradient: confirmation, cause, and comparison of continuous-wave and duplex ultrasonographic pulsed-wave measurements.

The umbilical artery Doppler ultrasonographic gradient has been described, and the need for site-specific nomograms has been pointed out. However, controversy still exists about the cause of this phenomenon and the optimal site for obtaining umbilical artery Doppler ultrasonographic measurements. Cross-sectional measurements of umbilical artery flow velocity waveform (FVW) systolic/diastolic (S/D) ratios were therefore made in 35 gravid women during the second or third trimester of pregnancy with both duplex pulsed-wave (PW) and free-standing continuous-wave (CW) Doppler ultrasonographic equipment. Multiple duplex PW Doppler ultrasonographic signals were recorded at the abdominal cord insertion, placental cord insertion, and free cord sites. Multiple CW Doppler FVWs were obtained from four quadrants, in decreasing order of ease of measurement. Repeated-measures analysis of variance demonstrated a statistically significant decrease in mean and median values of the umbilical artery S/D ratio from the abdominal cord insertion site to the placental cord insertion site. The reduction in the value of the S/D ratio as the placental cord insertion site is approached results more from a decrease in the peak systolic maximum velocity envelope than from an increase in diastolic velocities. Moreover, mean and median CW Doppler ultrasonographic values correlate most closely with corresponding PW measurements of the free cord segment. These data confirm the presence of the umbilical artery Doppler ultrasonographic gradient. Decreasing values of the S/D ratio from the fetal abdomen to the placenta are a result of attenuation of the systolic maximum velocity envelope.(ABSTRACT TRUNCATED AT 250 WORDS)

Smoking and buccally administered nicotine. Acute effect on uterine and umbilical artery Doppler flow velocity waveforms.

The effects of maternal smoking and buccal nicotine exposure on uterine and umbilical artery blood flow velocity waveforms were studied in 47 healthy women during late pregnancy. Systolic:diastolic ratios of recorded waveforms were calculated before and after each woman smoked one cigarette containing 1.2 mg of nicotine. The same protocol was followed at a subsequent clinic visit, when each woman chewed a piece of nicotine polacrilex containing 2 mg of nicotine. No significant changes could be induced in either nonsmokers or prior smokers, nor were any significant changes measured in the uterine vessels of any patient subgroup. A significant decrease (P less than .01) in umbilical artery diastolic blood flow velocities was measured after smoking in all habitual smokers after chewing nicotine polacrilex and in those who smoked greater than 10 cigarettes per day (P less than .05). All the measured changes returned to baseline levels by 10 minutes after cessation of exposure. Similar changes in the umbilical artery flow velocity waveforms after exposure to a cigarette and nicotine polacrilex implicated nicotine as a probable cause. Failure to observe significant changes except in habitually smoking women suggests a receptor-mediated response. The finding of altered umbilical artery flow velocity waveforms in the absence of demonstrable changes in the uterine vessels indicates a direct toxic effect of maternal nicotine exposure on the fetal cardiovascular system.

Umbilical artery Doppler velocimetry in pregnancies complicated by oligohydramnios.

OBJECTIVE: To determine the role of umbilical artery Doppler velocimetry in the management of oligohydramnios. STUDY DESIGN: In a retrospective chart review covering a two-year period, pregnancies with oligohydramnios evaluated by Doppler velocimetry of the umbilical artery were identified. Those patients with ruptured membranes and complex congenital anomalies were excluded from analysis. In the remainder, various measures of perinatal morbidity, including delivery of a small-for-gestational-age infant, preterm delivery, hyperbilirubinemia, requirement for blood transfusion, and other cardiovascular or pulmonary complications, were correlated with recorded values of the systolic/diastolic (S/D) ratio. RESULTS: Seventy-six subjects were identified for study. Forty-six had normal S/D ratios; 17 (37%) were associated with identifiable perinatal morbidity. When prematurity due to delivery for the sole indication of oligohydramnios was excluded, morbidity occurred in five patients (11%). Conversely, of the 30 patients with abnormal Doppler indices, 80% had an adverse outcome. CONCLUSION: Pregnancies with oligohydramnios and normal umbilical artery Doppler velocimetry were significantly (P < .001) less likely to experience an abnormal perinatal outcome as compared to those with abnormal Doppler indices. An elevated S/D ratio identified an increased risk of an adverse perinatal outcome in women with oligohydramnios. Avoiding intervention in pregnancies with oligohydramnios and normal umbilical artery Doppler velocimetry may decrease iatrogenic morbidity due to prematurity by as much as 26%.

All-fours maneuver for reducing shoulder dystocia during labor.

OBJECTIVE: To report on a large amount of clinical experience with shoulder dystocia managed primarily with the all-fours maneuver. STUDY DESIGN: The all-fours maneuver consists of moving the laboring patient to her hands and knees. Eighty-two consecutive cases of shoulder dystocia managed with this technique were reported to a registry through January 1996. RESULTS: The incidence of shoulder dystocia was 1.8%, and half of the newborns weighed > or = 4,000 g. Sixty-eight women (83%) delivered without the need for any additional maneuvers. The mean diagnosis-to-delivery interval was 2.3 +/- 1.0 (SD) minutes (range, 1-6). No maternal or perinatal mortality occurred. Morbidity was noted in only four deliveries: a single case of postpartum hemorrhage that did not require transfusion (maternal morbidity, 1.2%), one infant with a fractured humerus and three with low Apgar scores (neonatal morbidity, 4.9%). All morbidity occurred in cases with a birth weight > 4,500 g (P = .0009). CONCLUSION: The all-fours maneuver appears to be a rapid, safe and effective technique for reducing shoulder dystocia in laboring women.

Long-term intravenous tocolytic therapy.

Eighteen women required continuous intravenous tocolytic therapy with either ritodrine hydrochloride or magnesium sulfate for greater than 48 hours because of repetitively recurrent preterm labor; these were compared with a similar group of women successfully treated in less than 48 hours in a retrospective, case-controlled study. The mean gestational age at the time of diagnosis was 31 weeks for both groups. Tocolytic selection was similar in both groups, although the dosage per hour was significantly greater with long-term therapy. The mean interval from initiation of therapy until delivery was 41 days in the study group, compared with 39 days among controls (not statistically significant). The mean gestational age at delivery was 36 weeks in both groups. There were no significant difference in various measures of fetal outcome between groups. These data demonstrate that long-term intravenous tocolytic therapy can be a safe and effective means of prolonging gestation in those women who fail to respond to conventional treatment.

Management of shoulder dystocia.

OBJECTIVE: We sought to determine the management of shoulder dystocia currently practiced by physicians in the Middle Tennessee region and the frequency of use of the all-fours (Gaskin) maneuver in clinical practice. METHODS: A questionnaire was developed and sent to physicians in the Middle Tennessee area, asking how they would manage shoulder dystocia in specific practice scenarios. RESULTS: The methods most commonly used to manage shoulder dystocia are episiotomy, the McRoberts maneuver, and suprapubic pressure. Twenty-four percent of practitioners listed more than four options for the management of shoulder dystocia. Only 8% of those surveyed claimed knowledge of and use of the all-fours maneuver. CONCLUSION: Educational programs should be developed to inform practitioners of additional options for the management of shoulder dystocia.

Second-trimester intra-abdominal bowel dilation in fetuses with gastroschisis predicts neonatal bowel atresia.

OBJECTIVE: To determine in fetuses with gastroschisis the association between intra-abdominal bowel dilation in the second trimester and neonatal bowel atresia. METHODS: We reviewed ultrasound and medical records of fetuses with gastroschisis from January 1998 to August 2004. Fetuses with intra-abdominal bowel dilation in the second trimester were identified and followed into the neonatal period. RESULTS: We identified 58 mother-infant pairs showing fetal gastroschisis, with at least one prenatal ultrasound at our hospital and which were delivered there, or were transported there as newborns. Forty-eight of the 58 fetuses had no intra-abdominal bowel dilation and none of these neonates had bowel atresia. Ten of the 58 fetuses had intra-abdominal bowel dilation and all had bowel atresia at birth (P<0.0001). In eight cases in which ultrasound was performed at <25 weeks' gestation, intra-abdominal bowel dilation was already present. CONCLUSION: Intra-abdominal bowel dilation in the second trimester predicts neonatal bowel atresia in fetuses with gastroschisis.

Twin-to-twin transfusion syndrome: a subset of the twin oligohydramnios-polyhydramnios sequence.

OBJECTIVE: Our purpose was to assess the adequacy of currently accepted criteria for the diagnosis of twin-to-twin transfusion syndrome. STUDY DESIGN: Between April 1991 and February 1992 nine consecutive women with twin gestations and ultrasonographic findings of marked growth discordance, coexistent oligohydramnios-polyhydramnios, monochorionic placenta, and same sex of the fetus in the second trimester were evaluated. Mean gestational age at diagnosis was 19 weeks 5 days +/- 5 weeks, and mean growth discordance was 34% +/- 9%. Seven women underwent attempted sequential amniocentesis and cordocentesis at 23 weeks 6 days +/- 2 weeks 4 days to obtain amniotic fluid and cord blood from each fetus. Type O negative, leucocyte-poor, washed adult red blood cells were transfused into the small, oligohydramnic twin during cordocentesis; immediately afterward blood from the polyhydramnic twin was tested with the Kleihauer-Betke stain. RESULTS: The combined procedure was successful in six (86%) of the cases attempted. True twin-to-twin transfusion was confirmed in only four (44%) of those initially identified by ultrasonographic criteria. Hemoglobin difference > 5 g/dl was present in only one of the four cases, and in this case the recipient was anemic. CONCLUSIONS: Currently accepted criteria are insufficient for the diagnosis of true twin-to-twin transfusion. Ultrasonographic findings of marked growth discordance, coexistent oligohydramnios-polyhydramnios, monochorionic placenta, and same sex identify the twin oligohydramnios-polyhydramnios sequence.

Assessment of fetal breathing movements using three different ultrasound modalities.

Twenty-five consecutive women in the third trimester of pregnancy were studied to determine the presence or absence of fetal breathing movements using three different ultrasound imaging techniques. Using real-time B-mode observation of the fetal trunk as the standard, image-directed pulsed wave Doppler insonation of the umbilical vein confirmed the presence of breathing movements with a sensitivity of 100% and the absence of breathing movements with a specificity of 100%. The sensitivity and specificity of color Doppler imaging of the fetal naso- and oropharynx for the presence or absence of fetal breathing movements were 96% and 100%, respectively. In the current study, the detection of fetal breathing movements by three different ultrasound modalities was virtually interchangeable.

Endocardial fibroelastosis: an unusual cause of pulmonary hypertension in pregnancy.

Pulmonary hypertension due to endocardial fibroelastosis is usually diagnosed during infancy and childhood and is almost uniformly lethal when severe. Since females with this disorder rarely reach reproductive age, no cases of successful pregnancy in the presence of this severe cardiopulmonary disease have been reported. A 23-year-old Caucasian primigravida with a history of congenital endocardial fibroelastosis and severe pulmonary hypertension presented at 20 weeks' gestation. Following cardiac catheterization, the pregnancy was managed with bed rest, oral theophylline and digoxin, and low-flow oxygen therapy. After spontaneous onset of labor at 35 weeks, invasive hemodynamic monitoring and epidural anesthesia were initiated. Worsening of maternal pulmonary artery pressures postpartum was relieved by intravenous nitroglycerin infusion. Recent advances in medical care have resulted in more women with endocardial fibroelastosis reaching reproductive age. Successful pregnancy outcome is possible using established techniques of modern obstetric care.

Antenatal ultrasonographic development of ureteroceles. Implications for management.

Ureteroceles associated with a duplex collecting system may lead to obstructive uropathy, the most common genitourinary anomaly of the fetus. Although most frequently presenting as hydronephrosis, damage from obstruction is a progressive process which may even develop into bilateral renal dysfunction. Antenatal intervention for preservation of fetal renal function may be considered, but must be balanced against procedural risks. Therefore, accurate documentation of the progression may be necessary. In these cases, the development of the classic findings of two ureteroceles are documented over a period of several weeks using serial ultrasonographic evaluation. Postnatal evaluation of the infants confirmed the antenatal findings. The importance of serial ultrasonographic evaluation of fetal obstructive uropathies is dramatically illustrated.

Equalization of amniotic fluid volumes after decompression amniocentesis for treatment of the twin oligohydramnios-polyhydramnios sequence.

OBJECTIVE: To measure acute and chronic changes in the placenta and amniotic fluid associated with performance of decompression amniocentesis in pregnancies with the twin oligohydramnios-polyhydramnios sequence (TOPS). METHODS: Amniotic fluid pressures, placental thickness, placental perfusion, and amniotic fluid volumes were measured in each sac of a monochorionic diamniotic twin gestation before and after decompression amniocentesis. Indigo carmine was injected into the polyhydramnic sac after decompression, and fluid from the oligohydramnic sac was sampled after equilibration. Spectrophotometric analysis of amniotic fluid specimens was performed for dye detection. Amniotic fluid volume and placental perfusion studies were repeated 1 week later. RESULTS: Three patients with TOPS were enrolled, and decompression amniocentesis was performed in the midtrimester. After decompression, amniotic fluid volume decreased in the polyhydramnic sac, amniotic fluid pressures decreased in both sacs, placental thickness increased, and umbilical artery Doppler velocimetry was unaffected. The amniotic fluid volume increased acutely in only one oligohydramnic sac after decompression, and ultrasonographic examination, amniotic fluid spectrophotometric analysis, and placental pathologic examination all identified interfetal membrane disruption as the etiology. CONCLUSIONS: Decompression amniocentesis as a treatment for TOPS does not result in acute or chronic changes in the amniotic fluid volume of the oligohydramnic sac in the absence of interfetal membrane disruption.