Janet Horenstein

Selective termination for structural, chromosomal, and mendelian anomalies: International experience

OBJECTIVE Our purpose was to evaluate the outcomes of selective termination for fetal anomalies at 8 centers with the largest known experiences worldwide. STUDY DESIGN Outcomes in 402 cases of selective termination in pregnancies with dizygotic twins from 8 centers in 4 countries were analyzed by year, gestational age at procedure, and indication. Reductions of fetuses were as follows: 2 to 1, n = 345; 3 to 2, 39; >/=4 to 2 or 3, n = 18. Potassium chloride was used in all procedures. RESULTS Selective termination resulted in delivery of a viable infant or infants in >90% of cases. Loss up to 24 weeks occurred in 7.1% of cases in which the final result was a singleton fetus and in 13.0% of cases in which the final result was twins. Loss was 6.6% as a result of structural abnormalities, 7.0% for chromosomal abnormalities, and 10% for mendelian abnormalities (difference not statistically significant). Loss rates for procedures were as follows: 9-12 weeks, 5.4%; 13-18 weeks, 8.7%; 19-24 weeks, 6.8%; and >/=25 weeks, 9.1% (difference not statistically significant). Mean gestational age at delivery was 35.7 weeks. No differences were seen in outcomes by maternal age. The rate of very early premature deliveries has fallen in recent years. There were no known cases of disseminated intravascular coagulation or serious maternal complications. CONCLUSION (1) Selective termination, in the most experienced hands, can be technically performed in all 3 trimesters with good outcomes in >90% of cases. (2) The previously observed increase in second- versus first-trimester losses has diminished. (3) Third-trimester procedures, where legal, can be performed with a good outcome for the surviving fetus.

Efficacy of second-trimester selective termination for fetal abnormalities: International collaborative experience among the world's largest centers

OBJECTIVE Our goal was to develop the most comprehensive database possible to counsel patients about selective termination for fetal abnormalities, because no one center has sufficient data to assess much more than crude loss rates. STUDY DESIGN A total of 183 completed cases of selective termination from 9 centers in 4 countries were combined (169 twins, 11 triplets, 3 quadruplets). Variables included indications, methods, (potassium chloride, exsanguination, air embolus), gestational age at procedure, pregnancies lost (< or = 24 weeks), gestational age at delivery, and neonatal outcome. RESULTS Indications for selective termination were 96 chromosomal, 76 structural, and 11 mendelian. Selective termination was technically successful in 100% of cases. In 23 of 183 (12.6%) miscarriage occurred before 24 weeks; 2 of 37 (5.4%) occurred when the procedure done at < or = 16 weeks and 21 of 146 (14.4%) when it was done thereafter. Air embolization had a higher loss rate: 10 of 24 (41.7%) compared with 13 of 156 (8.3%) by potassium chloride (chi 2 = 117, p < 0.0001). Three cases of selective termination performed in monochorionic pregnancies all resulted in pregnancy loss. Among 183 potentially viable deliveries, 7 occurred before 28 weeks, 19 at 29 to 32 weeks, 41 at 33 to 36 weeks, and 93 at > or = 37 weeks. Gestational age at delivery was not influenced by the technique used or the indication but was negatively correlated with gestational age at the time of selective termination. No coagulopathy or ischemic damage was observed in survivors. There was no maternal morbidity. CONCLUSIONS (1) Selective termination in experienced hands for a dizygotic abnormal twin is safe and effective when done with potassium chloride. A total of 83.8% of viable deliveries occurred after 33 weeks and only 4.3% at 25 to 28 weeks. (2) Gestational age at the procedure correlated positively with loss rate and inversely with gestational age at delivery; this emphasizes the need for early diagnosis in multifetal pregnancies. (3) Coagulopathy tests are probably unnecessary.

Squamous cells in the maternal pulmonary circulation

Identification of squamous cells in the maternal pulmonary arterial circulation, either at autopsy or in blood aspirated from a pulmonary artery catheter, is currently regarded as pathognomonic for amniotic fluid embolism. Sixteen pregnant women underwent pulmonary arterial catheterization for a variety of medical indications. Examination of the buffy coat fraction of the distal lumen aspirate resulted in the identification of squamous cells in all cases. Squamous cells were similarly identified in control specimens from 17 nonpregnant patients; however, the difference in cell count between the pregnant and nonpregnant patients was significant. Such cells presumably reflect, in part, bloodstream contamination from sites of venous access. Reliable differentiation of adult from fetal squamous cells is not possible; however, the significant increase in cell count documented in pregnant patients suggests a possible fetal origin for some squamous cells detected during pregnancy. The detection of squamous cells in the pulmonary arterial circulation of pregnant women is not pathognomonic for amniotic fluid embolism. In a critically ill obstetric patient, such a finding should not deter the clinician from a thorough search for other causes of hemodynamic instability.

Qualitative assessment of maternal uterine and fetal umbilical artery blood flow and resistance in laboring patients by Doppler velocimetry

The purpose of this study is to evaluate the effect of uterine contractions during labor on both the uterine and the umbilical circulations. Twenty-seven patients in active labor were studied by continuous-wave Doppler velocimetry. Umbilical, left uterine, and right uterine arterial waveforms were obtained before, during, and after peak uterine contractions, and the ratio of maximum systolic and minimum diastolic velocities was calculated. Fifteen patients showed absent flow in end diastole on the uterine artery waveform and had significantly higher intra-amniotic pressures (64.5 +/- 3.5 mm Hg) during the peak amplitude of the uterine contraction compared with the 12 patients with maintained end diastolic flow (46.5 +/- 2.6 mm Hg; p less than 0.05). During the peak amplitude of the uterine contractions the 12 patients maintaining end-diastolic flow had significantly higher systolic/diastolic ratios in the uterine artery (6.5 +/- 1.5) compared with either before or after a contraction (2.1 +/- 0.15 and 2.0 +/- 0.2, respectively; p less than 0.05). Also, these 12 patients showed a linear relationship between the systolic/diastolic ratio and the intrauterine pressure. However, no differences were observed in the umbilical artery systolic/diastolic ratios before, during, or after a contraction in the intensity range studied. On the contrary, during contractions an increase in uterine artery resistance occurs with decreased or absent end-diastolic flow, which bears an inverse linear relationship to the intensity of the contraction. This suggests that during uterine contractions the human fetus continues to have uninterrupted fetoplacental blood flow, whereas the degree of interruption or reduction in uteroplacental blood flow is dependent on the intensity of uterine contraction.

Fetal echocardiography: VII. Doppler color flow mapping: A new technique for the diagnosis of congenital heart disease

One of the difficulties for the fetal sonographer is the complete elucidation of structural defects of the cardiovascular system that are associated with intracardiac or great vessel flow disturbances. With the recent introduction of Doppler color flow mapping, in which blood flow is displayed in color superimposed on a real-time image, it has been impossible to identify flow disturbances in the pediatric and adult patient. This study was undertaken to determine whether Doppler color flow mapping could be used in the fetus to identify normal and abnormal cardiovascular anatomy. Thirty-five normal and high-risk fetuses were examined between 16 and 40 weeks of gestation. Doppler color flow mapping identified normal and abnormal anatomy (ventricular septal defect, atrial septal defect, endocardial fibroelastosis, dysplastic pulmonary valve, and tricuspid regurgitation). It appears that Doppler color flow mapping will add a new dimension to fetal cardiovascular imaging.

Labor and delivery in the presence of mitral stenosis: central hemodynamic observations.

During a 1-year period, eight patients with New York Heart Association Class III or IV mitral stenosis were studied throughout the peripartum period with a pulmonary artery catheter. All patients were delivered vaginally. Intrapartum management was based upon cautious diuresis for preload optimization and heart rate control with propranolol. A mean increase in pulmonary capillary wedge pressure of 10 mm Hg was observed in the immediate postpartum period. Only two patients demonstrated a significant increase in cardiac output during this same time period. Central venous pressure correlated poorly with pulmonary capillary wedge pressure in seven of eight patients. Neonatal outcome was uniformly excellent. With the management approach described, no patient exhibited deterioration of cardiopulmonary status during the peripartum period.

Ultrasonographic estimation of fetal weight in the clinically macrosomic fetus

The purpose of this study is to evaluate models for the prediction of birth weight in fetuses suspected of being macrosomic. A total of 141 patients with standard measurements of the head, abdomen, and femur were studied. Linear regressions were performed with single parameters, squares, and all possible cross products in the generation of models with log (birth weight) and birth weight as dependent variables. These models were then compared with a group of previously published equations. Clinically, all models performed poorly. However, two models were significantly less accurate in the prediction of birth weight (p less than or equal to 0.05). The best results were obtained by equations that used abdominal circumference and femur length measurements. There was no improvement in models that contained log (birth weight) or birth weight as dependent variables or models with complex variables such as squares or cross products of measured parameters. In conclusion, when evaluating patients at risk of macrosomia, the best estimates of fetal weight can be obtained by models that contain abdominal circumference and femur length.

Previous cesarean section: The risks and benefits of oxytocin usage in a trial of labor

Permitting a trial of labor in patients with a previous cesarean birth is rapidly becoming an accepted alternative to routine elective repeat cesarean section. As interest in this approach has grown and the risks associated with a trial of labor have been better defined, the use of oxytocin in these patients emerges as a pertinent issue. Our retrospective experience of oxytocin use in patients undergoing a trial of labor suggested no increased maternal or fetal risk compared to patients who did not receive oxytocin. On the basis of our prior experience, we set out to investigate prospectively the role of oxytocin in 732 patients with prior cesarean section who underwent a trial of labor. During the study period, 289 (40%) patients received oxytocin for either induction (32, 11%) or augmentation (257, 89%) of labor and 443 patients did not receive oxytocin. Successful vaginal delivery was achieved in 200 patients (69%) as opposed to 395 (89%) of the patients who did not receive oxytocin. The incidences of dehiscence in the oxytocin and no oxytocin groups were 3% and 2%, respectively. Further analysis of vaginal and cesarean delivery complications for the two groups were contrasted and no significant differences were found with respect to the incidence of hemorrhage, uterine atony, hysterectomy, or the requirement of transfusions. Neonatal outcome was also comparable for both groups. On the basis of our prospective experience, it appears that the use of oxytocin, when carefully monitored, is a safe and reasonable consideration in the patient undergoing a trial of labor.

Experience with the pulmonary artery catheter in obstetrics and gynecology

Although traditionally the exclusive domain of other medical specialties, pulmonary artery catheterization may be of tremendous benefit to a variety of obstetric and gynecologic patients. Our experience with such invasive hemodynamic monitoring in 72 patients in an obstetrics and gynecology service is presented. In 86% of cases, catheter placement and primary management were carried out by residents in obstetrics and gynecology. Although many of the indications for pulmonary artery catheterization encountered are common to other areas of medicine, certain conditions such as severe preeclampsia or rheumatic heart disease in pregnancy involve pathophysiologic conditions unique to our specialty. On the basis of our experience, recommended indications for pulmonary artery catheterization in obstetric and gynecologic patients are presented. Insertion techniques, complications, and clinical outcome are discussed.

Characteristics of ovarian follicular development in Norplant users

Daily transvaginal ultrasound (US) scanning of the ovaries to assess follicular development and daily blood sampling were performed on 19 Norplant (Leiras, Turku, Finland) subdermal contraceptive implant users who had regular menstrual cycles and on 10 normally cycling women. Three groups were identified in the implant users based on US finding. Six (31.6%) of the implant users had US findings that were consistent with a normal ovulatory pattern. However, their mean peak luteinizing hormone levels and peak midluteal phase progesterone (P) levels were significantly lower than control values. Eleven (57.9%) users had persistent follicles, and 2 users (10.5%) had no follicular development. These data suggest that after 2 to 4 years of use, about one third of Norplant users with regular bleeding patterns may ovulate but most have deficient luteal P levels. In this small study, the presence of persistent follicular enlargement in implant users was common.