Normal values for amniotic fluid index during uncomplicated twin pregnancy.

OBJECTIVE: To establish the gestational age trends of amniotic fluid index (AFI) in uncomplicated twin pregnancies. METHODS: Amniotic fluid index was measured in uncomplicated twin pregnancies seen between 1985 and 1993 and meeting the following criteria: 1) no maternal medical or obstetric complications, 2) normal growth of both twins by serial ultrasound, and 3) normal amniotic fluid volume by ultrasound. Amniotic fluid index was measured by adding the deepest vertical pockets in four quadrants, defined by the umbilicus and linea nigra. The relation between gestational age and AFI was evaluated using linear regression analysis. RESULTS: Two hundred eighty-two sets of twins were considered uncomplicated; 1101 AFI measurements were performed on these pregnancies between 25.5 and 40.5 weeks' gestation. Percentile values for AFI were determined according to gestational age. The regression equation relating the median AFI to gestational age was: AFI = 19.4 - 0.12 x gestational age (P = .03). The R2 value was 0.04. CONCLUSION: Gestational age trends in normative AFI measurements for twin pregnancies have been established. Their use will facilitate a more reproducible, quantitative diagnosis of oligohydramnios in twins, compared with subjective, qualitative approaches to amniotic fluid volume assessment.

Doppler velocimetry in pregnancy.

Since the late 1970s, Doppler velocimetry has been investigated extensively for use in obstetrics. Initially, this technique showed promise for the management of certain complications of pregnancy; this promise has yet to be fulfilled. Doppler velocimetry of either the uterine or umbilical vessels, which showed some merit in selecting growth-retarded fetuses at particular risk, has neither become a screening tool for intrauterine growth retardation nor proven clinically successful in improving fetal outcome. Likewise, its use for other complications of pregnancy (eg, postdate pregnancy, twin pregnancy, and diabetes) has not led to improved pregnancy outcome. More recently this technique has been used to study other vascular beds. Changes in the Doppler characteristics of these vascular beds may demonstrate the fetal response to its environment. These investigations provide the potential for a better understanding of fetal physiology; however, it has yet to be shown by prospective evaluation that their application results in improved pregnancy outcome. This review defines the uses and limitations of Doppler ultrasound in current obstetric practice.

Intrapartum obstetric emergencies.

Shoulder dystocia, uterine inversion, and prolapse of the umbilical cord are three uncommon complications of the intrapartum period. These complications share several common characteristics in that they are rare, difficult to predict, and can result in significant morbidity and mortality. This article describes the etiology, predisposing factors, and methods of management of these complications.

Critical review of articles regarding pregnancy exposures in popular magazines.

To determine the scope of teratogen information available to the public through the media, a survey of 15 popular magazines was conducted. All 1985 issues of the selected magazines were reviewed for articles addressing pregnancy exposure concerns, yielding 56 articles from 10 magazines. The remaining 5 publications provided no pertinent articles. Two health professionals, both experienced teratology counselors, independently rated each article for accuracy of content and quality of presentation based on standardized evaluation criteria. The findings were compared and agreement for all criteria in each article was reached by the 2 reviewers. Regarding the quality of the information in the 56 articles, 31 (55.4%) were scored as misleading or inaccurate. On examination of overall presentation, 26 (46.4%) were rated as alarming and 8 (14.3%) presented a false sense of security; 22 (39.3%) provided a balanced presentation. A review of the types of articles rated revealed 19 (33.9%) general overviews of pregnancy issues, 18 (32.1%) news stories, 17 (30.4%) question-and-answer columns, and 2 (3.6%) feature stories. Of the reviewed papers, 7 (12.5%) included a citation from which the primary data could be obtained and only 14 of the articles (25%) suggested that the reader contact her/his healthcare provider regarding the issues. We conclude that the information available in popular magazines regarding exposures in pregnancy is frequently misleading, alarming, and unsupported by the scientific literature.

Evaluation of a perinatal autopsy protocol: influence of the Prenatal Diagnosis Conference Team.

This study was designed to evaluate changes in the perinatal autopsy following the adoption of a new autopsy protocol. The University of Utah Medical Center has a Prenatal Diagnosis Conference Team composed of obstetricians, pediatricians, geneticists, and other health care professionals. These individuals are involved in the care of patients whose pregnancies are at risk for congenital malformations. An autopsy protocol was designed to increase the interaction of the pathologist with the Prenatal Diagnosis Conference Team in the evaluation of perinatal death. Two years, 1982 and 1987, before and after the protocol was implemented, were selected for retrospective review. The autopsies in 1987 made more specific diagnoses compared with those in 1982. Additional congenital anomalies were diagnosed, and increased numbers of patients were found to have well-described congenital disorders. The number of attempted postnatal autopsy chromosome studies increased and more chromosomal abnormalities were detected. The final autopsy diagnoses made in 1987 have provided more information to the physician for genetic or other patient counseling. After the protocol was adopted, increased numbers of cases were referred to the Medical Center for evaluation at autopsy. More of those who came to autopsy had been evaluated during life by members of the Prenatal Diagnosis Conference Team. Premortem sonograms had been done at an earlier gestational age and a greater number of anomalies were detected. Fewer of the fetuses had intrauterine death and more had pregnancy terminated by induction of labor. The gestational age at delivery declined.

Intrapartum management of twin gestation.

The intrapartum management of the patient with a multiple gestation should begin in the antenatal period. With the present widespread use of ultrasound, the number of multiple gestations diagnosed early in pregnancy has now increased, permitting determination of placentation and monitoring of fetal growth. When a patient with a twin gestation presents in labor, ultrasound should be used to establish fetal presentation and size. The fetal well-being should be evaluated with fetal heart monitoring, and assessment of potential maternal complications, such as anemia, hypertension, and polyhydramnios, should be accomplished. With more than two fetuses, cesarean delivery is recommended. The principal controversy in intrapartum management of twin gestation relates to the planned route of delivery, particularly because this consideration is influenced by malpresentation and prematurity. There is general agreement favoring vaginal delivery for vertex-vertex twin pairs. With dual fetal heart rate monitoring and appropriate delivery room preparation for emergency cesarean section, recent evidence supports planned vaginal delivery of the mature nonvertex second twin. Elective cesarean section for the nonvertex second twin estimated as weighing less than 1800 gm is advised.

Intrauterine manometry: technique and application to fetal pathology.

A technique is described for measuring pressure within the amniotic cavity and within fetal vessels and/or body compartments. Two saline-filled catheters were connected at one end to needles inserted during indicated invasive procedures and at the other to silicon strain gauge transducers. In 36 pregnancies with normal liquor volume, stable intra-amniotic pressure (IAP, range 1-14 mmHg) increased with gestation (r = 0.48, p less than 0.01). In pregnancies complicated by severe oligohydramnios, IAP was less than or equal to 1 mm Hg and rose to normal levels with saline amnioinfusion. Raised IAP (range 17-26 mm Hg), found in pregnancies with gross polyhydramnios, fell with drainage of amniotic fluid. Subtraction manometry was used to determine supra-amniotic pressure within the intervillus space, umbilical vein, umbilical artery, abdominal and thoracic cavities, and the urinary tract in normal and/or pathological fetuses. Low intravesical and intrapelvicalyceal pressures (median 6.5, range 2-10 mm Hg) were noted in fetuses with obstructive uropathies. Intrauterine subtraction manometry appears to be a useful tool in the understanding of fetal pathophysiology and may be of clinical benefit in the therapeutic drainage and infusion of amniotic fluid and in the assessment of certain fetal disease states.

Neodymium:yttrium-aluminum-garnet laser occlusion of rhesus placental vasculature via fetoscopy.

We tested the feasibility of photocoagulating placental vascular communications with a fetoscopically delivered neodymium:yttrium-aluminum-garnet laser in 12 pregnant monkeys in the second trimester. The technique was successful in eight cases. One ended in spontaneous labor 2 weeks after occlusion and one stillbirth occurred at term. Six live fetuses were delivered at term, with all treated vessels demonstrating occlusion. There was minimal placental damage at the laser impact sites, and no fetal abnormalities were detected. Long-term occlusion of placental vasculature can be accomplished by fetoscopically delivered laser energy.

When to perform the next intra-uterine transfusion in patients with Rh allo-immunization: combined intravascular and intraperitoneal transfusion allows longer intervals.

Data from 99 intra-uterine transfusions performed in 30 patients (31 fetuses) with Rh allo-immunization have been reviewed. Mean gestational age at the first transfusion was 23.6 weeks and mean fetal haematocrit 19.8%. The number of procedures was on average 3.2 per fetus. Survival rate was 84%. Fifty-nine intravascular transfusions were combined with intraperitoneal transfusions. Combined intravascular and intraperitoneal transfusions, when compared to intravascular transfusions alone, achieved a significantly longer interval between transfusions and also maintained a higher fetal haematocrit at the subsequent transfusion. Mean fall in fetal haematocrit was 0.98% per day with a wide range. There was a general tendency towards a less marked fall during the second interval between transfusions than in the first with the exception of those cases in which the percentage of fetal red cells at the start of the second transfusion was increased compared to that which was found at the end of the first, i.e., when fetal erythropoiesis was not suppressed.

Consequences of fetomaternal haemorrhage after intrauterine transfusion.

Fetomaternal haemorrhage was studied after 68 consecutive fetal intravascular transfusions performed in 20 patients with Rh isoimmunisation. alpha Fetoprotein concentration was assayed in maternal blood taken before, and immediately after each transfusion and three and 24 hours later. An increase of 50% or more in the concentration in any of the samples after transfusion was considered to indicate fetomaternal haemorrhage. Fetal alpha fetoprotein concentration in blood sampled before transfusion was also assayed and the amount of fetomaternal haemorrhage calculated. Fetomaternal haemorrhage occurred in 21 of 32 patients with an anterior placenta and in six of 36 with a posterior or fundal placenta. The mean estimated volume of haemorrhage was 2.4 ml, which was on average equal to 3.1% of the total fetoplacental blood volume. When the volume of fetomaternal haemorrhage at the first transfusion was greater than 1 ml there was a greater increase in maternal Rh (D) antibody titres and a greater fall in fetal packed cell volume. Sampling of fetal blood should not be routinely done early in patients with Rh isoimmunisation, and intrauterine transfusion should be delayed as long as possible. Sampling sites other than the placental cord insertion reduces the risk of fetomaternal haemorrhage.

Intravenous immunoglobulin treatment of pregnant patients with recurrent pregnancy loss caused by antiphospholipid antibodies and Rh immunization.

A patient with antiphospholipid antibodies and nine consecutive fetal deaths and a severely Rh-immunized woman with one previous live birth and seven fetal/neonatal deaths achieved live births after antepartum administration of intravenous immunoglobulin. This agent shows promise as a new treatment for patients with previous repetitive fetal deaths from immunologic causes.

Changes in fetal acid base status during intravascular transfusion.

Umbilical venous pH, PCO2, PO2, and base excess was measured immediately before and after 72 intravascular transfusions in 34 fetuses with erythroblastosis fetalis. In 67 uncomplicated transfusions, infused adult blood led to a mean (95% confidence intervals) fall in pH (0.037, CI 0.029 to 0.044) and base excess (2.03, CI 1.61 to 2.45) and a mean rise in PCO2 (0.24 kPa, CI 0.13 to 0.35). These changes correlated significantly with the increase in fetal haemoglobin and packed cell volume. Five transfusions were associated with complications within six hours: intrauterine death in two, fetal-distress necessitating delivery in two, and preterm labour in one. Two had pre-existing acidosis, whereas two of the three with normal blood gas and acid base measurements before transfusion had acute changes that were outside the normal ranges that had been established in uncomplicated transfusions.

Other causes of fetal death.

Although perinatal mortality rates have fallen considerably in the past several decades, the fetal component of this statistic has not decreased as rapidly as the neonatal portion. Syphilis, a significant cause of fetal death at the beginning of this century, has been eliminated and other conditions such as erythroblastosis fetalis and diabetes mellitus have been markedly reduced. It is clear, however, that minimum fetal mortality has not been achieved. Potentially salvagable fetuses still die from the effects of maternal hypertension, intrauterine growth retardation, and post-maturity. Widespread application of current knowledge and techniques would save some of these fetuses; others will only be saved with an increased understanding of pathological processes and their treatment. In the meantime, it is imperative that those involved in obstetrical care follow the sound principles of accurate determination of gestation age, identification of patients at risk for fetal death, meticulous care of associated medical conditions, and careful attention to the progress of pregnancy.

A new postpartum syndrome associated with antiphospholipid antibodies.

Three women with antiphospholipid antibodies and a postpartum syndrome of pleuropulmonary disease, fever, and cardiac manifestations are presented. Each patient had either lupus anticoagulant or anticardiolipin antibodies or both, but did not have antinuclear antibodies or fulfill the criteria for the diagnosis of systemic lupus erythematosus. No infection or embolus was detected that could explain the pulmonary findings. All three patients had electrocardiographic abnormalities, and one patient developed a cardiomyopathy with extensive immunoglobulin G (IgG), IgM, IgA, and C3 deposition in the myocardium. In addition to the reported association between antiphospholipid antibodies and fetal loss, fetal growth retardation, and preeclampsia, we suggest that patients with antiphospholipid antibodies are at risk for a previously unreported and serious autoimmune postpartum syndrome.

Maternal-fetal pH difference and fetal scalp pH as predictors of neonatal outcome.

The purpose of this study was to determine if interpretation of fetal scalp pH values would be enhanced by concurrent measurement of maternal venous pH. The last fetal capillary pH obtained before delivery was compared with simultaneous maternal-fetal pH difference as predictors of neonatal outcome assessed by five-minute Apgar scores. Fetal scalp pH and maternal-fetal pH difference were significantly correlated with r = -0.72 (P less than .0001). The acidotic fetuses born to acidotic mothers had low maternal-fetal pH differences, and all were nondepressed at birth. A 33% reduction in false negatives was found using maternal-fetal pH difference instead of scalp pH alone. Errors in interpretation of fetal scalp pH can be reduced by the use of maternal-fetal pH difference.

Obstetric complications associated with the lupus anticoagulant.

We identified eight patients with the lupus anticoagulant (an autoantibody acquired by some patients with systemic lupus erythematosus), by observation of an increased activated partial thromboplastin time and abnormal results on a tissue thromboplastin-inhibition test. The patients had experienced a total of 30 spontaneous abortions and fetal deaths in 31 previous pregnancies (96.8 per cent). During their next pregnancy, the patients were treated with 40 to 50 mg of prednisone per day and 81 mg of aspirin per day. The therapy shortened their activated partial thromboplastin times, produced normal values for tissue thromboplastin inhibition, and reduced the rate of pregnancy loss to 37.5 per cent. However, preeclampsia developed in the five patients who gave birth to live infants, and fetal growth retardation occurred in three cases. The corticosteroid and low-dose aspirin regimen appears to improve perinatal outcome in cases in which the mother has the lupus anticoagulant, but such practices as careful fetal surveillance and preterm delivery when appropriate are also important to successful obstetric management of such cases.