Transabdominal ultrasound is appropriate

Routine transabdominal cervical length screening in mid-pregnancy for the prevention of preterm birth: Is it good enough to use as a screening test?

BACKGROUND

Preterm birth (PTB) is a major pregnancy complication. There is evidence that a short cervical length in mid-pregnancy may predict women at increased risk of PTB.

AIMS

To evaluate the utility of population-based, transabdominal cervical length (TACL) measurement screening in mid-pregnancy for PTB prediction in women.

MATERIALS AND METHODS

A transabdominal approach was initially performed, with a transvaginal (TVCL) approach offered when the TACL was <35 mm, could not be accurately measured, or the pregnancy had risk factors for PTB. TACL was compared to the directly related TVCL, when both were performed at the same assessment. Women with risk factors of PTB were included when they had both TACL and TVCL measurements performed at the same visit.

RESULTS

Data were provided for 9355 singleton pregnancies from 13 participating imaging centres. A transabdominal approach was used in 9006 (96.3%), including 682 (7.3%) TVCL combined with TACL. There were 349 (3.7%) women who had TVCL only. The median TACL was longer (40 mm) than the TVCL (38 mm). In 682 paired TACL and TVCL measurements, TACL <35 mm correctly identified 96.2% of pregnancies with TVCL <25 mm, compared with 65.4% of cases when using a TACL <30 mm. A TVCL <25 mm occurred in 59 (0.6%) women. A TACL <35 mm was associated with birth <37 weeks of gestation in 12.1% of women and birth <32 weeks of gestation in 3.9%.

CONCLUSIONS

Universal TACL is a feasible option for population screening of cervical length in a low-risk population, progressing to TVCL if the TACL is <35 mm or the cervix cannot be transabdominally accurately measured.

Comparison of the application value of transvaginal ultrasound and transabdominal ultrasound in the diagnosis of ectopic pregnancy

BACKGROUND

Ectopic pregnancy (EP) is one of the most common acute abdominal diseases in gynecology. Once the condition of EP is delayed, it may lead to massive hemorrhage, shock, and even death in a short time, seriously threatening the patient’s life. Early diagnosis is the key to preventing and improving the prognosis of EP. Transabdominal ultrasound (TAS) and transvaginal ultrasound (TVS) are the main diagnostic methods for abdominal diseases. The purpose of this study is to explore the application value and effect of TAS and TVS in the diagnosis of EP, hoping to provide more valuable references for the diagnosis of EP.

AIM

To explore the application value of TAS and TVS in the diagnosis of EP and to improve the level of clinical diagnosis.

METHODS

A total of 140 patients with EP admitted to our hospital from July 2018 to July 2020 were selected for this study. All patients were divided into two groups according to the examination methods. 63 patients who underwent abdominal ultrasound examination were set as the TAS group, while 77 patients who underwent TVS examination were set as the TVS group. We compared the diagnostic accuracy and misdiagnosis rates between the two types of ultrasound examinations, as well as the postoperative pathological results of the two diagnostic methods for different types of ectopic pregnancies. We also analyzed the sonograms for the presence of mixed ectopic masses, adnexal masses, ectopic gestational sacs, the presence or absence of visible embryo and fetal heart in the ectopic sac shadow, and the detection of fluid in the rectal fossa of the uterus, such as the adnexal area, yolk sac, and embryo, etc. In addition, the diagnosis time, days of gestational sac appearance, operation time, endometrial thickness, and blood flow resistance index were compared as well.

RESULTS

After performing both types of ultrasound examinations in 140 patients with EP, we found that the diagnostic accuracy of TVS was significantly higher than that of TAS, and the misdiagnosis rate was significantly lower than that of TAS. The differences were statistically significant (P < 0.05). In addition, the detection rate of TVS was better than that of TAS for the presence of mixed masses, adnexal masses, ectopic gestational sacs, the presence or absence of visible embryo and fetal heart in the shadow of the ectopic sac, and sonograms such as the adnexal area, yolk sac, and embryo, etc. The coincidence rate of its postoperative pathological examination results was significantly higher than those of TAS. The diagnosis time and the days of gestational sac appearance by TVS were significantly shorter than that by TAS, and the operation time was earlier than that by TAS. What’s more, the detection rates of the endometrial thickness £ 1.5 mm and blood flow resistance £ 0.5 were significantly higher in TVS diagnosis of EP than in TAS. All differences were statistically significant (P < 0.05).

CONCLUSION

Compared with TAS, TVS has the advantages of high detection accuracy and good sonogram performance.

Guideline No. 401: Sonographic Cervical Length in Singleton Pregnancies: Techniques and Clinical Applications

OBJECTIVES

• To assess the association between sonography-derived cervical length measurement and preterm birth. • To describe the various techniques to measure cervical length using sonography. • To review the natural history of the short cervix. • To review the clinical uses, predictive ability, and utility of sonography-measured short cervix.

OUTCOMES

Reduction in rates of prematurity and/or better identification of those at risk, as well as possible prevention of unnecessary interventions.

INTENDED USERS

Clinicians involved in the obstetrical management or cervical imaging of patients at increased risk of a short cervix.

TARGET POPULATION

Women at increased risk of a short cervix or at risk of preterm birth.

EVIDENCE

Literature published up to June 2019 was retrieved through searches of PubMed and the Cochrane Library using appropriate controlled vocabulary and key words (preterm labour, ultrasound, cervix, cervical insufficiency, transvaginal, transperineal, cervical length, fibronectin). Results were restricted to general and systematic reviews, randomized controlled trials, controlled clinical trials, and observational studies. There were no date or language restrictions. Grey (unpublished) literature was identified through searching the websites of health technology assessment agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The evidence and this guideline were reviewed by the Diagnostic Imaging Committee of the Society of Obstetricians and Gynaecologists of Canada, and the recommendations were made and graded according to the rankings of the Canadian Task Force on Preventive Health Care (Online Appendix Table A1).

BENEFITS, HARMS, COSTS

Preterm birth is a leading cause of perinatal morbidity and mortality. Use of the sonographic technique reviewed in this guideline may help identify women at risk of preterm birth and, in some circumstances, lead to interventions that may reduce the rate of preterm birth. SUMMARY STATEMENTS (CANADIAN TASK FORCE ON PREVENTIVE HEALTH CARE GRADING IN PARENTHESES): RECOMMENDATIONS (CANADIAN TASK FORCE ON PREVENTIVE HEALTH CARE GRADING IN PARENTHESES).