Vaginal ultrasound for the practicing clinician. Equipment selection.

This article has essentially been a list of secondary factors for selecting an ultrasound machine. When a clinician narrows his/her choices for a new machine by viewing the image quality and features, the secondary factors in this article also should be studied. By doing so, a number of traps will be avoided and complaints from staff will be decreased. All sonographers and staff should have input to machine selection because all may have an impact on office operations. By anticipating problems before they occur, the selection of a new ultrasound machine becomes a smooth, well defined operation.

Successful management of viable cervical pregnancy by local injection of methotrexate guided by transvaginal ultrasonography.

We evaluated the feasibility of transvaginal methotrexate injection of viable cervical pregnancies to avoid complications of the "classic" surgical procedures in use and to preserve future fertility. Five viable cervical pregnancies, at 6 to 8 weeks, were treated. In three patients a spring-loaded automated puncture device and in two a manually operated simple needle guide mated to and guided by a transvaginal ultrasonography probe were used with 21-gauge needles. The puncture and injection treatment was successful and without complications in all five cases presented. This procedure may become a useful alternative to other, more radical or complex surgical approaches.

Multifetal pregnancy reduction by transvaginal puncture: evaluation of the technique used in 134 cases.

OBJECTIVE: This report reviews multifetal pregnancy reductions performed transvaginally and tests the feasibility and associated pregnancy loss rates with this technique. STUDY DESIGN: One hundred thirty-four consecutive multifetal pregnancy reductions were analyzed regarding different aspects of total pregnancy losses and complications. The first 40 manually performed were compared with the last 94 procedures performed with an automated puncture device and a thin needle. The losses were also analyzed as a comparison of the reduction of the lower-lying with the higher-lying fetuses located in relation to the internal os. RESULTS: A total uncorrected total pregnancy loss rate of 12.6% and a corrected loss rate of 10.6% was observed. Of the 112 pregnancies in which the lower-lying fetus was reduced, 11 losses were seen. The loss rate in the group reducing the upper fetus was three of 22. The manual versus the puncture device groups showed the same loss rate (10%); however, the manual group had a larger number of subchorionic hematomas after the procedure. CONCLUSIONS: The data are indicative of a very low maternal complication rate (infection) and an acceptable loss rate of the entire pregnancy. The loss rates compare favorable with those for multifetal pregnancy reduction performed transabdominally.

First-trimester fetal biometry using transvaginal sonography.

First-trimester fetal biometry using transvaginal sonography is now feasible and desirable due to improved imaging and probe maneuverability. A study of 144 early normal pregnancies with precise dates is presented. Regression models were constructed for the crown-rump length, biparietal diameter, head circumference and abdominal circumference. Error analysis of the technique and calculations was performed. First-trimester fetal biometry may be used for obtaining precise estimates of gestational age and may help to detect early fetal maldevelopment resulting in abnormal growth.

High-frequency transvaginal sonographic examination for the potential malformation assessment of the 9-week to 14-week fetus.

A study was undertaken to evaluate the ability of the high-frequency transvaginal scanning method to consistently image first- and early second-trimester fetal structures, such as body contours, long bones, fingers, face, palate, feet, toes, and the four-chamber view. Ninety-seven low-risk pregnancies were scanned from 9 weeks to 14 menstrual weeks inclusive. Accurate dating was ascertained. The results showed that consistent detection of the respective structures was achieved at the following menstrual ages: sagittal contours at 9 weeks to 10 weeks, long bones at 10 weeks to 11 weeks, fingers at 12 weeks, face and palate at 12 weeks, feet and toes at 13 weeks, and the four-chamber view at 14 weeks. The organs and structures examined could be detected at 9 weeks to 14 weeks inclusive. An increasing number of structure were detected consistently with the increasing menstrual age. The study supports the possibility of searching for specific malformations at or after the menstrual ages mentioned, or performing a more comprehensive malformation evaluation after 13 weeks.

Puncture procedures utilizing transvaginal ultrasonic guidance.

The introduction of transvaginal sonography has enabled the use of this scanning method for guided puncture procedures. A total of 102 puncture procedures are described: 63 fetal reductions, eight punctures of ectopic pregnancies, 19 drainages of pelvic contents, seven punctures of ovarian cysts, four diagnostic culdocenteses and one injection of a cervical pregnancy. Every procedure is discussed in detail. There was only one procedure-related complication. The advantages of the ultrasound-guided vaginal puncture procedure are its performance under real-time imaging, a low complication rate, a better pregnancy outcome when considering the reduction of multifetal gestations, and, most importantly, the fact that abdominal surgery can be avoided in several cases.

Ultrasonographic evaluation of uteroplacental blood flow patterns of abnormally located and adherent placentas.

Transvaginal ultrasonography was used to evaluate antepartum bleeding in a group of 76 patients at varying gestational ages with suspected placenta previa. The clinical outcome of 16 patients with persistent placenta previa was documented. Nine of the 16 patients had placental lacunar blood flow. Two of the nine patients were lost to follow-up. At cesarean section the seven patients with lacunar flow had a higher incidence of blood loss, transfusion requirements, abnormally implanted placenta, and cesarean hysterectomy than the six patients in whom no lacunar flow patterns were seen (p = 0.002). The finding of these flow patterns with abnormally located placentas suggests the anticipation of significant blood loss and probable extension of operative procedures to stop the blood loss.

The discriminatory zone of beta-hCG for vaginal probes.

Recent developments in both laboratory measurements and ultrasound technology have revolutionized the management of early pregnancy. The discriminatory zone concept is a direct result of these developments. By correlating the serum beta-hCG values to the size of an intrauterine gestational sac, a value can be chosen that corresponds to the threshold of visualization of the sac. If the beta-hCG is above this value, a sac must be seen, and if it is not, aggressive steps should be taken to determine whether the pregnancy is abnormal or ectopic. The discriminatory zone may vary among institutions due to different equipment and assays. Thus, its value should be calculated individually at each institution. A proper discriminatory zone and a management protocol such as the one above can eliminate much of the uncertainty in the management of suspected ectopic and early pregnancies.

Sonoembryology: an organ-oriented approach using a high-frequency vaginal probe.

First trimester gestations of 95 patients were studied by high-frequency transvaginal sonography, which permits the imaging of organs shortly after their development. This new technique has great potential for clinical implementation in such cases as accurate gestational dating and malformation workup.

Placenta previa--is the traditional diagnostic approach satisfactory?

The accuracy of the diagnosis of placenta previa using transvaginal sonography (TVS) was compared to that of the traditional transabdominal sonography (TAS). Seventy seven women were scanned by both methods and each sonographic diagnosis was compared to the placental location at delivery. TVS was superior to TAS in diagnosing placenta previa and invariably correct in ruling it out. TVS (and TAS) failed to predict the placental location at delivery only in women diagnosed as having marginal placenta previa prior to 35 weeks gestation. The use of the vaginal probe significantly improved the accuracy of the diagnosis of placenta previa.

First-trimester midgut herniation: a high-frequency transvaginal sonographic study.

The application of high-frequency transvaginal sonography offers new opportunities in scanning for malformations during the first trimester of pregnancy. Scanning of the anterior abdominal wall and the umbilical cord insertion at this gestational age is feasible. A cross-sectional study of 61 embryos-fetuses from 7 to 12 weeks of gestation was performed to observe the physiologic midgut hernia. This herniation was detected in 64% of the cases at 8 weeks, in 100% during weeks 9 and 10, and in 25% at 11 weeks' gestation. None of the fetuses studied at 12 weeks had a midgut herniation. Vaginal sonography of the well-dated fetus at 12 weeks can confirm the final development of the anterior abdominal wall.

Dating the early pregnancy by sequential appearance of embryonic structures.

A total of 97 transvaginal scans were performed from 4 to 12 weeks' gestation in normal and accurately dated gestations. The sequential appearance of six structures were examined: (1) the gestational sac only was present during week 4; (2) the yolk sac appeared in week 5; (3) the fetal pole with detectable heart motion was first seen in week 6; (4) the single unpartitioned ventricle in the brain marked week 7; (5) the falx cerebri appeared during week 9; and (6) the appearance and the disappearance of the physiologic midgut herniation were seen in week 8 and week 11, respectively. Inasmuch as the time in gestation at which these structures appear characterizes the gestational age more than any measurement at this age, we propose a practical method to determine the correct gestational age in early first-trimester pregnancy.

The use of transvaginal ultrasonography in the diagnosis of ectopic pregnancy.

Despite advances in diagnosis made by the introduction of serum beta-subunit of human chorionic gonadotropin determinations and transabdominal ultrasonography, ectopic gestations still present a major diagnostic challenge. The increased resolution of the transvaginally introduced high-frequency ultrasound transducer probes seems to solve this diagnostic problem. In this study 145 patients were referred for ultrasonographic workup because of a suspected ectopic gestation. In 38 patients a diagnosis could be made with classical transabdominal scanning. One hundred seventeen patients required additional transvaginal scanning with a 5.0 and a 6.5 MHz probe. In 98 patients a diagnosis was made during the first transvaginal scan; nine patients were rescanned within 3 days for the final diagnosis. In 56 patients, ectopic pregnancy was successfully ruled out by transvaginal scanning. Thirty-nine ectopic pregnancies were diagnosed. Only one false-positive identification was made. The sensitivity of diagnosing ectopic pregnancy by high-frequency transvaginal sonography was 100%; the specificity was 98.2%. The positive predictive value of this method was 98%, and the negative predictive value was 100%. The rate of the beating fetal heart was seen in the tube (23%). The high number of unruptured tubal pregnancies in this series (66%) suggests the possibility of an early diagnosis that may have therapeutic implications. The use of higher-frequency transvaginal transducer probes improves the diagnosis of the ectopic gestation.

Transvaginal salpingocentesis: a new technique for treating ectopic pregnancy.

Transvaginal sonography is an important tool for diagnosing ectopic pregnancy. In this report the transvaginal passage of a needle, with sonographic guidance, into a tubal gestational sac with a live fetus is demonstrated. We injected potassium chloride solution to arrest cardiac activity, terminating the ectopic pregnancy without surgical intervention. The new therapeutic use of transvaginal sonography is an important addition to the treatment of this prevalent disease.

Effect of amniotic membrane rupture on length of labor.

Between January 1, 1979, and December 21, 1982, 2564 medically and obstetrically normal patients, admitted to the hospital with intact amniotic membranes during the latent phase of labor, were matched for spontaneous or artificial rupture of the membranes at similar cervical dilations. Spontaneous rupture of the membranes occurred earlier and was more likely in the latent phase of labor than was artificial rupture of membranes, which tended to occur nearer to or in the active phase of labor, and at lower pelvic stations. When matched by cervical dilation, spontaneous membrane rupture was associated with more rapid cervical dilation. Stepwise regression analysis confirmed that membrane rupture had a significant but small effect on labor length and rate of cervical dilation. Pelvic station and maternal parity had a smaller association with labor length than did membrane rupture. Cervical dilation at the time of membrane rupture appeared to be the most important factor associated with the length of labor.

Transition from latent to active labor.

The transition from the latent to the active phase of labor, as defined by Friedman, was studied in all noncomplicated patients over a four-year period. Mothers studied were in spontaneous labor with a singleton fetus in the vertex position with intact membranes at admission. The independent variables were the parity and vaginal examination data, and the dependent variable was the rate of cervical dilation. The transition from latent to active labor was recorded and stratified by the cervical dilation where it occurred in a sample population consisting of 1060 nulliparous and 639 primiparous or multiparous women. There were no differences between nulliparous and multiparous patients. Less than 50% of labors became active by the time the cervixes had reached 4-cm dilation. By 5 cm, 74% of labors were active. However, when protracted and arrested labors were eliminated, 60% of the patients had reached the latent-active transition by 4 cm and 89% by 5 cm. We concluded that once a normal patient has reached 5 cm, she should be in the active phase of labor. If not, there is a high probability of labor dystocia.

Comparison of biparietal diameter and femur length in the third trimester: effects of gestational age and variation in fetal growth.

A multiple regression-based statistical model capable of quantitatively comparing two or more sonographic parameters for the effects of gestational age, variation in fetal growth and error in sonographic measurement is presented and then used to compare the biparietal diameter and femur length as estimators of gestational age in late pregnancy. A total of 311 patients were studied between 24 and 42 weeks' gestation. Variation in fetal growth was expressed as the birth weight percentile for gestational age. Biparietal diameter and femur length correlated equally well with gestational age. However, the biparietal diameter was more than twice as sensitive as the femur length to variation in fetal growth. Femur length had a larger error associated with its measurement. These results suggest that the biparietal diameter and femur length in late pregnancy are equal estimators of gestational age; that the femur length is a more stable estimator of gestational age when fetal growth deviates from normal; and that the femur length is technically more difficult to obtain.

Latent phase of labor in normal patients: a reassessment.

The vaginal examination data (dilation, station, and time) were examined from 2845 consecutive uncomplicated patients who were admitted in early labor to Cleveland Metropolitan General Hospital between January 1, 1979 and December 31, 1982, using data from the computer database of the Perinatal Clinical Research Center. The length of the latent phase of labor was calculated in 2479 of these patients to form the study group. Individual effects of parity and the cervical dilation on the length of the latent phase of labor resembled Friedman's results from 20 years ago. Furthermore, the average and prolonged lengths of the latent phase confirmed that labors have not changed appreciably in 20 years. However, multivariable analysis and standard stepwise regression on all of the vaginal examination data revealed that the largest influence on the length of latent labor was the admitting cervical dilation. Parity had only a small effect when cervical dilation was controlled. Thus, a multiparous patient may progress as slowly as a primiparous patient if they both are admitted with a low cervical dilation.

Major gynecologic and obstetric surgery in Jehovah's Witnesses.

A retrospective study of 165 Jehovah's Witnesses and 164 Jehovah's Witnesses and 164 control patients compared the morbidity and mortality associated with major obstetric and gynecologic surgery in the 2 groups. There were no deaths and few complications in either group. There were few differences in preoperative and postoperative hemoglobin values. Medicolegal implications of performing major surgery without blood transfusions are discussed. The study adds evidence that major operative procedures can be carried out on Jehovah's Witness patients without blood transfusions or blood products.