早孕期超声筛查双胎妊娠的价值

目的 探讨超声在早孕期（孕11~13⁺⁶周）双胎妊娠筛查中的价值。方法 选取接受早孕期超声筛查的196名双胎孕妇,判断其绒毛膜性及羊膜性,测量胎儿头臀长及颈项透明层（NT）厚度,系统检查胎儿结构,检查胎儿是否存在结构畸形,并随访妊娠结局。结果 196名双胎孕妇中,双绒毛膜囊双羊膜囊（DCDA）双胎149名,单绒毛膜囊双羊膜囊（MCDA）双胎43名,单绒毛膜囊单羊膜囊（MCMA）双胎4名。超声筛查共发现36名孕妇存在异常胎儿,包括DCDA双胎30名,MCDA双胎4名,MCMA双胎2名。DCDA双胎中异常胎儿30胎,均为双胎之一异常,其中1胎为多发畸形（脊柱及双下肢发育异常）,1胎可见颈部水囊瘤,25胎停止发育,3胎NT增厚。MCDA共检出异常胎儿6胎,1胎双胎之一为无心畸胎;1胎双胎之一颈部水囊瘤形成;双胎中1胎胚胎停育,另1胎颈部水囊瘤形成;双胎均停止发育。MCMA双胎中,1胎双胎之一脑膜脑膨出,另2胎为胸腹连体双胎。结论 早孕期超声检查对于确定绒毛膜性和羊膜性双胎以及筛查胎儿严重结构畸形和双胎特有并发症具有重要临床意义。     

The contribution of transvaginal ultrasound in the diagnosis of acute appendicitis: an observational study.

OBJECTIVE: To assess the contribution of transvaginal and transabdominal sonography in the diagnosis of acute appendicitis. METHODS: The study group included female patients in whom acute appendicitis was diagnosed preoperatively by ultrasound and confirmed by histology. Each patient was examined by transabdominal (TAS) and transvaginal (TVS) sonography. The contribution of both approaches to the diagnosis of acute appendicitis was assessed. RESULTS: Acute appendicitis was diagnosed sonographically in 38 women. In all of them the diagnosis was confirmed histologically. All patients had both TAS and TVS. In 16 (42%) patients the inflamed appendix was detected by both approaches, in 13 (34%) only by the transabdominal route and in nine (24%) only transvaginally. Thus, TAS detected only 76% of the cases and TVS added 24%. CONCLUSION: The use of TVS in conjunction with TAS seems to improve the detection rate of acute appendicitis.     

Quantitative ultrasound at the hand phalanges in pregnancy: a longitudinal study

In the prospective study, 48 females in normal pregnancy were evaluated to determine if the presence of disturbances of maternal bone and mineral status is related to fetal and newborn growth. The aim of the study was to estimate mean and individual changes in maternal skeletal and laboratory variables during pregnancy and their correlations with fetal and newborn sizes. Maternal bone and mineral status was assessed in first, second and third trimester by quantitative ultrasound (US), or QUS, at the hand phalanges (Ad-SoS [m/s]) performed by DBM Sonic 1200 (IGEA, Carpi, Italy) and laboratory investigations were collected (serum total calcium, total alkaline phosphatase and phosphate). The hypothesis that fetus growth and sizes of the newborn may have an influence on bone and mineral status in pregnancy was tested by the correlation of ultrasonographic fetal measurements and newborn sizes with changes in maternal QUS and biochemical data. Ad-SoS decreased significantly (p < 0.00001) and alkaline phosphatase increased significantly in second and third trimester of pregnancy (p < 0.01). A decrease in Ad-SoS greater than least significant change (LSC) was observed in 22 females (46%) during pregnancy. Changes in alkaline phosphatase correlated significantly with changes in Ad-SoS (r = -0.31, p < 0.05). Fetal ultrasonographic measurements (femur length and biparietal diameter) correlated significantly with changes in alkaline phosphatase (r ranged 0.31 to 0.56, p < 0.05). No significant correlations were observed between fetal ultrasonographic measurements (femur length and biparietal diameter) and newborn size with changes in Ad-SoS. In conclusion, the study revealed considerable changes in maternal bone and mineral status in normal pregnancy.     

First-trimester, three-dimensional transvaginal ultrasound volumetry in normal pregnancies and spontaneous miscarriages.

OBJECTIVE: The aim of this study was to perform three-dimensional ultrasound volumetry of intrauterine contents in cases of normal and failed pregnancies and correlate these with conventional two-dimensional measurements. METHODS: This was a cross-sectional observational study. Three-dimensional volumetric data were collected from a total of 111 patients with first-trimester singleton pregnancies together with conventional two-dimensional measurements. A single investigator performed all ultrasound scans and volume measurements. RESULTS: Among 111 participants, 30 had an ongoing pregnancy and 81 had a miscarriage (anembryonic pregnancy 30, missed miscarriage 30, and incomplete miscarriage 21). There were no significant differences in age, parity, or gestational age between groups. A positive linear correlation was demonstrable between the crown-rump length and gestational sac volume in normal pregnancies (r = 0.962) and between gestational sac volume and gestational age, but the correlation was weaker in cases of missed miscarriage (r = 0.561). The volume of the retained products of conception as measured by three-dimensional ultrasound volumetry in cases of incomplete miscarriage also showed a strong linear correlation (r = 0.938) to their maximum anterior-posterior diameter. There was an exponential correlation between the mean gestational sac diameter and gestational sac volume and the crown-rump length and embryonic volume in cases of both normal and failed pregnancies. The mean gestational sac diameter:crown-rump length ratio (P = 0.008) and gestational sac volume:embryonic volume ratio (P = 0.023) in missed miscarriages were significantly higher than those in ongoing pregnancies. CONCLUSION: Three-dimensional ultrasound volumetry of intrauterine contents in normal and failed pregnancies correlates well with conventional two-dimensional measurements. Volumetric assessment does not seem to improve the diagnosis of miscarriage. However, its potential to predict pregnancies that will fail and determine the appropriate management regime for individual patients merits further research.     

Patterns of normal change in cervical length and width during pregnancy in nulliparous women: a prospective, longitudinal ultrasound study.

OBJECTIVES: To determine what constitutes normal changes in the uterine cervix visible at transvaginal ultrasound examination from 24 gestational weeks until delivery in nulliparous women delivering at term. DESIGN: Cervical length and width were measured using transvaginal ultrasound, and the inner cervical os was assessed as being closed or open every 2 weeks from gestational week 24 until delivery in 19 healthy nulliparae delivering at term. RESULTS: In all but one woman cervical length decreased, and in all but one woman cervical width increased, with advancing gestation. Three patterns of change in cervical length were observed: a continuous decrease ( n = 10), an accelerated shortening rate after approximately 30 gestational weeks ( n = 5), or a sudden drop in length between the last two examinations ( n = 3). The median rate of decrease in cervical length was 1 (range, 0.6-1.9) mm/week for women with continuous shortening of the cervix. For women with accelerated shortening the corresponding figure was 2.2 (range, 1.8-2.7) mm/week after the start of accelerated shortening. Two patterns of increase in cervical width (cervical broadening) were noted: a continuous increase ( n = 12), or an accelerated broadening rate from around 32 weeks ( n = 6). The median rate of increase in cervical width was 0.8 (range, 0.3-2.0) mm/week for women with continuous broadening of the cervix. For women with accelerated broadening rate the corresponding figure was 1.7 (range, 1.0-6.4) mm/week after the start of increased broadening rate. Opening of the internal cervical os was observed at least once in eight of the 19 women (42%) and was first observed at 30 gestational weeks. Dynamic changes (i.e. opening and closing of the inner cervical os during examination) were seen in six women (32%) and were first detected at 31 gestational weeks. CONCLUSIONS: There are different patterns of normal change in cervical length and width during pregnancy in nulliparous women. This must be taken into account if repeated ultrasound examinations of the cervix during pregnancy are used to identify nulliparae at increased risk of preterm delivery.     

Three-dimensional multiplanar transvaginal ultrasound of the cervix in pregnancy.

OBJECTIVES: To develop a standard technique for using three-dimensional ultrasound (3D US) to study and evaluate the cervix in pregnant women at high risk for premature delivery, comparing the findings on 3D US with those on conventional two-dimensional ultrasound (2D US). STUDY DESIGN: Twenty-one pregnant women at high risk for premature delivery had a total of 37 transvaginal 2D and 3D US examinations of the cervix between 11 and 32 weeks' gestation. A 3D US vaginal probe (5.0-8.0 MHz, Voluson 530D, Medison, Pleasanton, CA, USA) was used. Measurements made from the 2D and 3D US were compared. RESULTS: Of the 37 cervical length measurements in 3D US sagittal plane, seven were shorter and three were longer than on 2D US (varying by 5-15 mm) indicating that the true mid-sagittal plane was not obtained in ten (27%) of the 37 2D US examinations. Of 21 examinations showing funneling, funneling was seen on both 2D and 3D US in 15, but was seen only on 3D US in six. There was a significant (P < 0.05) difference between funnel width as measured in the coronal 3D plane versus 2D US, as well as between funnel width in the coronal 3D US plane versus sagittal 3D US plane (P < 0.05). The cerclage was seen in its entirety in nine of 10 examinations; the 3D US axial plane was most valuable for imaging the cerclage. CONCLUSIONS: 3D US appears to offer a more complete assessment of the cervix than 2D US. Multiplanar correlation shows that the standard 2D US sagittal view may under- or over-estimate cervical length. Our preliminary data suggest that 3D US has the potential to improve our understanding of cervical morphology.     

Prediction of preterm delivery in twin pregnancy: a prospective, observational study of cervical length and fetal fibronectin testing.

OBJECTIVE: To evaluate prospectively cervical length measurements and fetal fibronectin detection as predictors of spontaneous preterm delivery in an unselected population of twin pregnancies. METHODS: Transvaginal ultrasound assessments of cervical length were performed serially at 18, 24, 28 and 32 weeks' gestation. Receiver-operating characteristic curves were generated at each time point to determine the optimal cut-off for cervical length and rate of change in cervical length in the prediction of preterm delivery (< 35 weeks). A bedside assay for the detection of fetal fibronectin in the maternal vaginal secretions was performed prior to cervical length measurements from 24 weeks. Likelihood ratios (LRs) were used to assess the performance of each test. RESULTS: The spontaneous preterm delivery rate was 16.5% in 91 studied twin pregnancies. A cervical length /= 2.5 mm per week between 18 and 28 weeks' gestation also predicted preterm delivery (LR+ 10.8, sensitivity 16.7%). There was no relationship between the detection of fetal fibronectin and preterm delivery. CONCLUSIONS: This study confirms the value of transvaginal ultrasound assessment of cervical length as a predictor of preterm delivery in twin pregnancies. However, the poor sensitivity of this test makes it unsuitable as a single predictor of preterm delivery. Fetal fibronectin testing does not identify twin pregnancies destined to deliver prematurely.     

Diagnosis of twin reversed arterial perfusion sequence in the first trimester by transvaginal color Doppler ultrasound.

A case of twin reversed arterial perfusion (TRAP) sequence was diagnosed at 12 weeks' gestation using transvaginal color Doppler ultrasound, which demonstrated the presence of retrograde perfusion in the umbilical artery of the abnormal twin. Ultrasound imaging showed a monochorionic-diamniotic twin pregnancy with an inappropriately grown second twin, the morphological evaluation of which revealed an abnormal cephalic pole with acrania, diffuse subcutaneous edema and the presence of cardiac activity in an abnormal heart with a single chamber.     

A longitudinal study of cholinesterase changes in pregnancy

Serum cholinesterase activity was measured at intervals before, during, and after 44 pregnancies in 43 women. Three patterns of change were seen: (a) A decline in activity after conception, with no return towards pre-conception values before delivery (20 pregnancies). (b) A decline in activity accompanied by a partial or complete return to pre-conception values before delivery (19 pregnancies). (c) Either no discernible decline or increased activity during gestation (five pregnancies). We saw no association between these patterns and either the sex of the child, parity, smoking history, or alcohol intake. However, the continuous decrease in cholinesterase activity occurred in the youngest group of women, a decrease followed by an increase in the intermediate age group, and no decrease at all in the oldest group. Although not all the age-related differences quite reached statistical significance, these findings suggest that the patterns of change may be determined by some aspect of maternal physical maturity.     

Genetic amniocentesis in twin pregnancies: results of a multicenter study of 529 cases.

To evaluate the risk of abortion after genetic amniocentesis in twin pregnancies, a retrospective study of 15 centers was performed. The spontaneous abortion rate up to 20 completed weeks of gestation was 2.3%; the abortion rate up to 28 completed weeks, as defined by WHO, was 3.7%. The abortion rate could not be correlated either with the number of needle insertions or with the type of marker dye used. There was also no correlation between the abortion rate and the gestational age at which amniocentesis was performed. A significant association was shown between congenital intestinal obstructions and the application of methylene blue intra-amniotically as a marker dye. Considering the increased natural loss rate in multiple gestations, amniocentesis in twin pregnancies seems to be a safe and reliable technique.     

Doppler flow velocity waveforms in the fetal ductus arteriosus during the first half of pregnancy: a reproducibility study.

Reproducibility of flow velocity waveform measurement in the fetal ductus arteriosus was studied in 52 normal pregnancies between 11 and 25 weeks of gestation. The flow velocity parameters studied were the peak systolic velocity, mean velocity, end-diastolic velocity, flow velocity integral and acceleration time. In each woman two consecutive measurements were performed with a time delay of 15 min. An acceptable reproducibility was achieved for all flow velocity parameters, except for the acceleration time and end-diastolic velocity.     

经阴道三维超声冠状切面对子宫角、间质部妊娠的诊断价值

目的：探讨经阴道三维超声冠状切面在诊断子宫角、间质部妊娠中的应用价值。方法：对33例常规经腹部或经阴道超声初步诊断或疑似子宫角、间质部妊娠患者进行经阴道三维超声检查,重点观察冠状切面子宫角、宫角部子宫内膜边缘及其外侧孕囊情况。对全部间质部妊娠患者测量子宫角部子宫内膜边缘与孕囊宫腔侧边缘间距。所有病例术前超声诊断结果均与术后结果（开腹手术、腹腔镜手术或宫腔镜手术）或随访结果（偏心位置的子宫内妊娠患者）相对照。结果：33例患者中,经阴道三维超声冠状切面诊断子宫角妊娠15例,间质部妊娠12例,峡部妊娠1例,偏心位置的子宫内妊娠5例,与手术结果和随访结果对照,除2例峡部妊娠误诊为间质部妊娠外,其余均获得准确诊断。10例经手术确诊为间质部妊娠的患者,冠状切面宫角部子宫内膜边缘与孕囊宫腔侧边缘间距为2~9 mm。结论：经阴道三维超声冠状切面在诊断子宫角妊娠、间质部妊娠和偏心妊娠的诊断中明显优于常规经腹部或经阴道二维超声;冠状切面宫角部子宫内膜边缘与孕囊宫腔侧边缘的间距在诊断子宫间质部妊娠中具有重要意义。     

Ontogeny of fetal renal organic cation excretion: a study with cimetidine and ranitidine during the latter half of gestation in the pregnant ewe

The organic cation cimetidine undergoes renal tubular secretion in the near-term ovine fetus. We investigated the ontogeny of renal tubular secretion of organic cations in the fetus from 80 days of gestation (term = 145). Sixteen sheep were administered both cimetidine and ranitidine in random order by a combination of bolus and i.v. infusion to achieve steady-state plasma concentrations of 1000 to 2000 ng/ml. A further two sheep received cimetidine only. Steady-state plasma concentrations were reached within 2 to 3 hr. Creatinine was used as a marker of glomerular filtration rate. Maternal renal clearance of cimetidine (0.51 +/- 0.18 l/min) and ranitidine (0.54 +/- 0.14 l/min) were not correlated with the period of gestation. Cimetidine/creatinine and ranitidine/creatinine renal clearance ratios were higher than unity being 5.48 +/- 1.91 and 5.65 +/- 1.18, respectively. Fetal creatinine renal clearance increased exponentially with gestational age (r2 = 0.577, P less than .001). Fetal renal clearance of both cimetidine and ranitidine also increased exponentially with gestational age, this trend being more clear-cut for cimetidine (r2 = 0.582, P less than .001) than for ranitidine (r2 = 0.254, P = .046). The rates of increase for cimetidine and ranitidine were similar to that for creatinine (P greater than .05). At 80 days, cimetidine/creatinine and ranitidine/creatinine renal clearance ratios (3.0 and 4.4, respectively) were higher than unity and did not increase further during the remainder of gestation. Therefore, the ovine fetus possesses an efficient tubular secretory pathway for organic cations by 80 days of gestation.(ABSTRACT TRUNCATED AT 250 WORDS)     

A prospective longitudinal study of growth in twin gestations compared with growth in singleton pregnancies. II. The fetal limbs

The assessment of fetal growth is crucial in twin gestations, since the information gained often has an impact on pregnancy management. The measurement of the fetal anatomy by ultrasound enables us to follow the growth and development of the fetus. However, the pattern of fetal growth in twin gestations has not yet been precisely characterized in prospective studies. In this light, we initiated a prospective longitudinal study and sonographically examined 35 patients with twin gestations every 3 weeks from the 15th week until delivery. Multiple biometric parameters were measured, including the femur length, humerus length, ulna length, and tibia length. The results of our study showed that growth of these long bones was not significantly different between twins A and B throughout gestation and that the growth velocity between twins and singletons was not significantly different. The incremental growth, although significantly less in twins than in singletons, was so small that it was judged not to be of clinical importance to warrant the generation of separate nomograms for the evaluation of growth in twin gestations.     

A prospective longitudinal study of growth in twin gestations compared with growth in singleton pregnancies. I. The fetal head

Since the available data on growth in twin gestations have been derived from retrospective cross-sectional studies with varying results, a prospective longitudinal study was initiated to assess fetal head growth in twin gestations as compared to singleton pregnancies. In uncomplicated twin gestations, growth of the fetal head, based on the increment in growth over time and the rate of growth throughout pregnancy, was found not to be significantly different than in singleton pregnancies. In light of these findings, current nomograms derived from measurements obtained in singleton pregnancies remain useful for evaluating fetal head growth in twin gestations.