Recurrent uterine rupture after abdominal pregnancy

Uterine rupture can occur at any time throughout gestation. We present a woman with a previous Cesarean section followed by an abdominal pregnancy. In her next pregnancy, complete uterine rupture resulted in an emergency laparotomy. This case is unique in that it gives insight into the variable presentations of uterine rupture and the risks associated with prior Cesarean sections.

Defining the relationship between obstetricians and maternal-fetal medicine specialists

OBJECTIVE

The purpose of this study was to determine how frequently general obstetricians refer pregnant patients to maternal-fetal medicine specialists in the presence of the clinical indications specified as appropriate for referral or consultation by the 1996 statement of the Society of Perinatal Obstetricians.

STUDY DESIGN

A questionnaire was mailed to 400 randomly selected general obstetricians across the United States. The obstetricians were asked how often they refer their high-risk pregnant patients to maternal-fetal medicine specialists in the presence of (1) a need for diagnostic or therapeutic procedures, (2) medical/surgical disorders, (3) healthy gravid women with high-risk fetuses, and (4) conditions that necessitate admission for reasons other than delivery. Response categories for each individual procedure/high-risk condition included "always," "frequently," "infrequently," "never," and "not applicable."

RESULTS

Overall, 55% of the responses indicated referral (always or frequently) to maternal-fetal medicine specialists for procedures or in the presence of high-risk conditions. More than 75% of the obstetricians always or frequently refer to maternal-fetal medicine specialists for most diagnostic/therapeutic procedures and for the following high-risk conditions: acute fatty liver, portal hypertension, pulmonary hypertension, transplantations, fetal hydrops, fetal anomaly/cytogenetic abnormality, fetal supraventricular tachycardia or congenital heart block, isoimmunization, and twin-to-twin transfusion syndrome.

CONCLUSION

Most of the conditions for which >75% of the obstetricians refer to maternal-fetal medicine are rarely seen in practice. Comprehensive ultrasound examination is the only commonly encountered clinical situation that >75% of the general obstetricians refer to maternal-fetal medicine specialists.

Appropriateness of antibiotic use in the postpartum period

OBJECTIVE

To determine the appropriateness of current postpartum antibiotic use in clinical practice.

METHODS

Medical records were reviewed for all patients delivering in a 3-month period who received postpartum antibiotics during the delivery hospitalization. Subjects were excluded if they received a single postpartum antibiotic dose as part of a mitral valve prolapse prophylaxis protocol, or if they received no more than one postpartum antibiotic dose for surgical prophylaxis. Characteristics of postpartum antibiotic use were abstracted.

RESULTS

Two hundred and eleven of 1537 (14%) delivering patients met the inclusion criteria. Seventy-four (35%) delivered vaginally and 137 (65%) delivered by Cesarean section. Postpartum fevers were found in 40 (54%) of vaginal delivery cases and 80 (58%) of women delivering by Cesarean section who received postpartum antibiotics (p = 0.54). For vaginal deliveries there were no differences in the duration of antibiotic use or number of antibiotic doses based on fever status. For Cesarean deliveries, a fever was associated with more antibiotic doses and a longer duration of antibiotic use. Physician justification for antibiotic use was documented in only 116 cases (55%).

CONCLUSIONS

The high proportion of women receiving postpartum antibiotics having no evidence for infection or documented indication for therapy suggests that antibiotics may not be appropriately used in the postpartum period.

Do maternal-fetal medicine practice characteristics influence high-risk referral decisions by general obstetrician-gynecologists?

OBJECTIVE

To determine whether the decision of the general obstetrician-gynecologist to refer high-risk obstetric patients depends on the type of practice of the maternal-fetal medicine (MFM) specialist.

METHODS

A questionnaire was mailed to 935 general obstetrician-gynecologists who were asked whether the MFM specialist's practice characteristics would influence their decision to refer their high-risk obstetric patients. Potential MFM practice components presented in the survey included: MFM, high-risk obstetrics, low-risk obstetrics or general obstetrics and gynecology.

RESULTS

A total of 140 (15%) general obstetrician-gynecologists responded, 110 of whom were practicing obstetrics. Of the practicing responders, 77% stated that they were more likely to refer their high-risk obstetric patients if the MFM specialist practiced only MFM and high-risk obstetrics; 69% were less likely to refer their patients when the MFM specialist, in addition to MFM, practiced general obstetrics; and 75% were less likely to refer their patients when the MFM specialist also practiced general obstetrics and gynecology. The MFM practice setting (university vs. community hospital vs. private practice), as well as the geographic location and years of practice of the respondents, did not influence the general obstetrician-gynecologists' decision to refer their high-risk obstetric patients.

CONCLUSION

General obstetrician-gynecologists are more likely to refer high-risk obstetric patients if the MFM specialist practiced only MFM and high-risk obstetrics.

The bloodless blood knot

Just as it is difficult to describe adequately the exhilaration one feels when using a fly rod to land a trout caught from a mountain stream, there is also a tremendous amount of satisfaction in the successful completion of an obstetric operation. Until recently, we were woefully ignorant of how fly fishing expertise could benefit pregnancy. We report with great pride an instance in which fly fishing knot skill was essential to successful placement of a cervical cerclage for a woman with an incompetent cervix.

Prenatal sonographic diagnosis of uterine rupture following open fetal surgery

BACKGROUND

Reported cases of uterine rupture diagnosed by ultrasound have shown fetal membranes ballooning through uterine rupture sites, or adjacent areas of hemorrhage.

CASE

A 27-year-old gravida 3, para 2 had open fetal surgery to repair a fetal myelomeningocele at 28 weeks' gestation. Her postoperative course was complicated by threatened preterm labor and anhydramnios. At 33 weeks' gestation, with maternal symptoms of bowel obstruction, ultrasound showed a fetal leg and section of umbilical cord protruding through the uterine wall.

CONCLUSION

Even in the presence of anhydramnios, uterine wall rupture was identified, because ultrasound evaluation of the uterine wall showed prolapsed fetal parts and umbilical cord. Persistent anhydramnios after open fetal surgery should prompt a search for uterine rupture.

First and second trimester sonography: an American perspective

In the United States, first-and second-trimester ultrasonography is most commonly used for gestational dating, detection of fetal aneuploidy, identification of early fetal intrauterine growth restriction (IUGR), and assessment for cervical incompetence. Crown-rump length (CRL) between 7 and 12 weeks is the most accurate parameter for first-trimester dating. In the second trimester, the biparietal diameter, head circumference, transverse cerebellar diameter (TCD), abdominal circumference, femur length, and other long bones, such as tibia and humerus, are useful. The TCD appears to be particularly useful because of its relative sparing in IUGR. Ultrasound can aid in the detection of fetal aneuploidy by identifying structural anomalies or abnormal fetal biometry in the first and second trimester. Numerous structural abnormalities are suggestive of aneuploidy. Cystic hygroma and nuchal translucency appear to be most significant first-trimester markers for fetal aneuploidy. Second-trimester estimated fetal weight (FFW) curves have been developed and are useful in the early detection of IUGR. Second-trimester FFW curves are useful for the detection of trisomy 18 (sensitivity 60%) but not for trisomy 21 (sensitivity 8-12%). Fetal biometry of long bones is also useful in identifying fetuses at risk for aneuploidy. Identification of a second-trimester fetus with either humerus or femur shorter than expected places the fetus at risk for aneuploidy. The sensitivity of short long bone in detection of fetal aneuploidy is approximately 30%, with false positive rates < 5%. Nuchal fold thickness > 6 mm in the second trimester is also used for identifying aneuploid fetuses. The overall sensitivity for the detection of Down's syndrome in fetuses with increased nuchal fold thickness is approximately 34% and the false positive rate is 1.5%. We have developed a model by using an ultrasound examination to adjust the mid-trimester risk for trisomy 21 by combining maternal age or triple screen risk assessment (unconjugated estriol, alpha fetoprotein, and human chorionic gonadotropin) and ultrasound. Using this model, the risk for Down's syndrome is found to be increased with identification of abnormal biometry or anomalies, or decreased with a normal genetic ultrasound examination. Another important application is the use of abdominal and transvaginal ultrasound in the second trimester in pregnancies at risk for premature cervical dilatation, premature delivery, and cervical incompetence. We have found transfundal pressure to be useful in the diagnosis of otherwise clinically inapparent premature cervical dilatation and cervical incompetence.

Prenatal sonographic diagnosis of mid shaft hypospadias

We report the prenatal diagnosis of mid shaft hypospadias and describe the sonographic features of fetal hypospadias including an abnormal urethral canal, ventral curvature of the distal penis, extension of the penile glans beyond the prepuce, and fetal micturation in a plane perpendicular to the penile shaft. An accurate family history is an essential part of the evaluation of the milder degrees of fetal hypospadias.

Intrapartum management of breech presentation

Breech presentation is associated with significantly increased risk of perinatal morbidity and mortality. Most of the morbidity and mortality associated with breech delivery results from cord compression, nuchal arm, and difficulty in the delivery of the aftercoming head. Routine cesarean delivery of term breeches may not be an unreasonable option, according to many physicians. In our view, the best results for vaginal delivery are achieved using strict protocols that select term or near-term frank breeches of normal size and with proper demonstration of pelvic dimensions. Serious consideration for cesarean delivery should be given to all others. If cesarean delivery is chosen for the very low-birth-weight infant, it is important to use a vertical uterine incision and appropriate anesthesia techniques to ensure atraumatic delivery and optimize out-come. ECV is safe and effective for reducing the incidence of breech presentation but will have little, if any, impact on the overall cesarean delivery rate.

A new method for on-screen ultrasonographic determination of fetal cardiac axis

OBJECTIVE

Our purpose was to develop an ultrasonographic method of using multiple electronic calipers for on-screen measurement of fetal cardiac axis.

STUDY DESIGN

Two hundred low-risk patients who were seen for antenatal ultrasonography were studied. Standard biometry, anatomic survey, and echocardiography were performed on all fetuses. By use of a four-chamber view fetal cardiac axis was measured with electronic calipers. A table, derived from a trigonometric formula, was created to convert the caliper measurements to cardiac axis in degrees. The results were compared with a protractor-determined fetal cardiac axis.

RESULTS

All echocardiograms had normal results. Fetal cardiac axis (+/- 2 SD) by the ultrasonographic method was 43 degrees (+/- 16 degrees) versus 43 degrees (+/- 14 degrees) by the protractor method. This difference was not significant.

CONCLUSION

An on-screen method to determine fetal cardiac axis by use of multiple calipers is described. It is comparable to a protractor-measured fetal cardiac axis.

Comparison of humerus length with femur length in fetuses with Down syndrome

A recent report by FitzSimmons et al. demonstrated a greater frequency of upper- versus lower-extremity shortening in autopsies of second-trimester fetuses with trisomy 21. We undertook this study to determine whether this upper-limb shortening could be detected by prenatal ultrasonography in the second trimester and therefore identify fetuses at risk for trisomy 21. A retrospective review of all prenatal sonograms preceding genetic amniocentesis was conducted. Between 1987 and 1990 11 consecutive fetuses between 15 and 22 weeks' gestation with trisomy 21 were identified by genetic amniocentesis. Femur and humerus lengths were plotted on growth curves created from 1470 normal patients between 12 and 26 weeks. Gestational age was confirmed by last menstrual period and biparietal diameter. In fetuses with trisomy 21, seven of 11 humeri were less than 5th percentile, for a sensitivity of 64%, whereas only two of 11 femurs were less than 5th percentile, for a sensitivity of 18%. Biparietal diameter/femur length and biparietal diameter/humerus length ratios were also tested to predict Down syndrome. In only 2 of 11 cases was the biparietal diameter/femur length ratio greater than 95th percentile, whereas the biparietal diameter/humerus length ratio was greater than 95th percentile in 7 of 11. Since all seven were identified by shortened humerus alone, we conclude that humerus length versus gestational age is the simplest and most effective screen. The positive predictive value of an abnormally short humerus length in detecting Down syndrome was 6.8% in our population where the prevalence of Down syndrome was 1 of 173. The present study supports the observations of FitzSimmons et al. that shortened humerus length has a greater sensitivity than femur length in cases of trisomy 21. We conclude that in fetuses at risk for trisomy 21 humerus length should be determined, because it may, if shortened, aid in the prenatal diagnosis.

The relationship between umbilical artery Doppler velocimetry and fetal biometry

The relationship between peak-systolic/end-diastolic ratio of the umbilical artery waveform and fetal biometry was studied in 127 uncomplicated pregnancies with established dates between 20 and 40 weeks' gestation. At each ultrasonographic examination fetal biometry included measurement of the biparietal diameter, head circumference, abdominal circumference, and femur length. The peak-systolic/end-diastolic ratio was measured by either a continuous or a pulsed-wave method. There were significant linear negative correlations between all the biometric parameters, as well as between the ultrasonographically estimated fetal weight and peak-systolic/end-diastolic ratio. Of the individual ultrasonographic parameters the femur length (for gestations less than 30 weeks) and the abdominal circumference (for gestations greater than or equal to 30 weeks) were found to be best correlated with the peak-systolic/end-diastolic ratio. Regression curves, including the 10th and the 90th percentile, were developed between each biometric parameter (biparietal diameter, head circumference, abdominal circumference, and femur length), as well as between estimated fetal weight and peak-systolic/end-diastolic ratio. The estimated fetal weight nomogram had the best sensitivity (48%) in predicting intrauterine growth retardation. These nomograms should prove most useful in assessing downstream placental vascular resistance in high-risk patients with unknown dates.

Relationship between fetal biophysical activities and umbilical cord blood gas values

In a prospective study of 62 patients undergoing cesarean section before the onset of labor a fetal biophysical profile assessment was performed within 3 hours before the cesarean section. The presence or absence of the individual fetal biophysical activities (fetal heart rate reactivity, fetal breathing movements, fetal body movements, and fetal tone) were correlated with umbilical cord blood gas and acid-base measurements (artery and vein). Fetuses with nonreactive nonstress test results or the absence of breathing had significantly lower cord artery pH, PO2 bicarbonate, and base excess measurements but not a significantly different PCO2 level as compared with fetuses that had these activities present. Fetuses with the absence of movements or tone had lower pH, PO2 bicarbonate, and base excess levels and higher PCO2 levels as compared with fetuses with the presence of movements or tone, respectively. These blood gas and acid-base differences were observed in both umbilical cord artery and vein. Subsequent analysis of the blood gas and acid-base measurements of the fetuses with compromised biophysical activities revealed that there are different levels of acidemia, hypoxemia, and hypercapnia at which the individual biophysical activities are compromised. These data suggest that the first manifestations of fetal hypoxemia and acidemia are nonreactive nonstress test results and loss of fetal breathing; in advanced acidemia, hypoxemia, and hypercapnia fetal movements and fetal tone are compromised.

The relationship between fetal biophysical assessment, umbilical artery velocimetry, and fetal acidosis

In a prospective study of 62 patients undergoing cesarean delivery before the onset of labor, fetal biophysical assessment and umbilical artery systolic-diastolic ratios (S/Ds) were performed within 3 hours of delivery. There was a significant relationship between the fetal biophysical profile score and cord arterial as well as cord venous pH. However, there was no identifiable relationship between S/D and cord arterial or venous pH. The efficacies of the biophysical components alone (nonstress test [NST] and fetal biophysical profile) and in combination with S/D to predict fetal acidosis were determined. The NST had the best sensitivity (100%) and negative predictive value (100%). The fetal biophysical profile had the best specificity (91%), positive predictive value (62%), and overall efficiency (90%). The S/D had the lowest sensitivity (66%), specificity (42%), positive predictive value (16%), negative predictive value (88%), and overall efficiency (45%). The addition of S/D to the NST or fetal biophysical profile did not improve diagnostic accuracy. These data suggest that the NST should be used as a primary test for the antepartum detection of fetal acidosis, whereas the fetal biophysical profile is a reasonable adjunct test. The umbilical artery S/D, as determined by continuous-wave Doppler velocimetry, has no value as a primary method or an adjunct in the antepartum detection of fetal acidosis.

Calculated risk of chromosomal abnormalities in twin gestations

Genetic counseling concerning the risks of chromosomal abnormalities in twin gestations can be difficult; the risk of amniocentesis is weighed against that of chromosomal abnormalities in either one or both of the twins. Because most twins are dizygotic (each with a risk a priori of aneuploidy), the chance that one of the fetuses is affected is greater than would be expected for a singleton. Only three possibilities would result in either one or both twin's being affected: 1) dizygotic twins with one fetus affected, 2) dizygotic twins with both fetuses affected, and 3) monozygotic twins with both fetuses affected. Using existing tables of estimated risks of chromosomal abnormalities in singleton gestations and mathematically derived formulas, we created tables defining the age-related risks of chromosomal abnormalities in twin gestations. According to these tables, a patient at 33 years of age with a twin gestation has a risk of Down syndrome in at least one of her twins equivalent to that of a 35-year-old with a singleton. Prenatal genetic testing should be considered for women with twins at a younger age than the traditional 35.