WHO recommendation on routine Doppler ultrasound examination in antenatal care

A health worker uses ultrasound equipment during an antenatal examination on a pregnant woman, Chad

WHO recommendation on routine Doppler ultrasound examination in antenatal care

Recommendation

Routine Doppler ultrasound examination is not recommended for pregnant women to improve maternal and perinatal outcomes.

(Not recommended)

 

Publication history

First published: December 2016

Updated: No update planned

Assessed as up-to-date: December 2016

 

Remarks

  • The GDG noted that the evidence base for the use of Doppler ultrasound of fetal blood vessels in high risk pregnancy is already established.
  • The GDG agreed that the value of a single Doppler ultrasound examination of fetal blood vessels for all pregnant women in the third trimester needs rigorous evaluation, particularly in LMIC settings. Future trials should be designed to evaluate the effect of a single Doppler ultrasound on preventable perinatal deaths.

 

Background

Doppler ultrasound technology evaluates umbilical artery (and other fetal arteries) waveforms to assess fetal well-being in the third trimester of pregnancy. It is widely used in high-risk pregnancies to identify fetal compromise and thus reduce perinatal mortality (1, 2). Therefore, it might also be useful when performed as an antenatal intervention to detect fetal compromise and predict complications, particularly IUGR and pre-eclampsia, in apparently healthy pregnancies. Doppler ultrasound is useful for distinguishing between fetuses that are growth-restricted (IUGR) and those that are constitutionally small (SGA) (3). It can be performed as part of a fetal ultrasound examination or separately. The examination quantifies blood flow through the umbilical artery as either a pulsatility index or a resistive index (4). A high resistance to blood flow often indicates an increased risk of IUGR and pre-eclampsia and indicates the need for further investigation.

 

Methods

The ANC recommendations are intended to inform the development of relevant health-care policies and clinical protocols. These recommendations were developed in accordance with the methods described in the WHO handbook for guideline development (5). In summary, the process included: identification of priority questions and outcomes, retrieval of evidence, assessment and synthesis of the evidence, formulation of recommendations, and planning for the implementation, dissemination, impact evaluation and updating of the guideline.

The quality of the scientific evidence underpinning the recommendations was graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) (6) and Confidence in the Evidence from Reviews of Qualitative research (GRADE-CERQual) (7) approaches, for quantitative and qualitative evidence, respectively. Up-to-date systematic reviews were used to prepare evidence profiles for priority questions. The DECIDE (Developing and Evaluating Communication Strategies to support Informed Decisions and Practice based on Evidence) (8) framework, an evidence-to-decision tool that includes intervention effects, values, resources, equity, acceptability and feasibility criteria, was used to guide the formulation and approval of recommendations by the Guideline Development Group (GDG) – an international group of experts assembled for the purpose of developing this guideline – at three Technical Consultations between October 2015 and March 2016.

To ensure that each recommendation is correctly understood and applied in practice, the context of all context-specific recommendations is clearly stated within each recommendation, and the contributing experts provided additional remarks where needed.

In accordance with WHO guideline development standards, these recommendations will be reviewed and updated following the identification of new evidence, with major reviews and updates at least every five years.

Further information on procedures for developing this recommendation are available here.

 

Recommendation question

For this recommendation, we aimed to answer the following question:

  • For pregnant women (P), does routine Doppler ultrasound of fetal blood vessels (I) compared with standard ANC (C) improve maternal and perinatal outcomes (O)?

 

Evidence summary

The evidence on Doppler ultrasound examination was derived from a Cochrane review that included five trials involving 14 624 women in HICs (Australia, France and the United Kingdom) (4). One study evaluated a single Doppler examination at 28–34 weeks of gestation, three studies evaluated multiple Doppler examinations from as early as 18 weeks, and one study evaluated women undergoing single or multiple examinations from 26 to 36 weeks of gestation. Data were evaluated together and separately for single and multiple examinations. Women in the control arms received standard ANC with no (or concealed) Doppler examination.

Maternal outcomes

The available moderate-certainty evidence suggests that antenatal Doppler ultrasound probably makes little or no difference to caesarean section rates (2 trials, 6373 women; RR: 0.98, 95% CI: 0.85–1.13) and assisted vaginal birth (2 trials, 6884 women; RR: 1.04, 95% CI: 0.96–1.12). No other maternal outcomes that were prioritized for the ANC guideline were reported in the trials.

Fetal and neonatal outcomes

Low-certainty evidence suggests that Doppler ultrasound may have little or no effect on perinatal mortality (4 trials, 11 183 women; RR: 0.80, 95% CI: 0.35–1.83). Moderate-certainty evidence indicates that the intervention probably has little or no effect on preterm birth (4 trials, 12 162 women; RR: 1.02, 95% CI: 0.87–1.18).

Additional considerations

Subgroup analyses according to the number of Doppler ultrasound examinations (single or multiple) are largely consistent with the overall findings. However, low-certainty evidence from the single examination subgroup suggests that a single Doppler ultrasound examination might reduce perinatal mortality (1 trial, 3890 women; RR: 0.36, 95% CI: 0.13–0.99).

Resources

The cost of ultrasound equipment, especially portable compact units, has decreased (122), and they are currently available at less than US$ 10 000 (28). Thus, given the cost of equipment, maintenance, supplies (ultrasound gel), replacement batteries, initial and ongoing staff training and supervision, and staffing costs, routine Doppler  ultrasound scans may have considerable resource implications for LMIC settings.

Equity

RCT evidence on maternal and perinatal effects of Doppler ultrasound examination is currently derived from HICs and high-quality research is needed on this intervention in LMICs to determine whether, by improving detection of pregnancy complications, it can reduce perinatal mortality and improve health equity.

Acceptability

Qualitative evidence shows that women generally appreciate the knowledge and  information they can acquire from health-care providers and that they are willing to be screened and tested for a variety of conditions, provided the information and procedures are explained properly and delivered in a caring and culturally sensitive manner (high confidence in the evidence) (8). Evidence also shows that, in some LMICs, the lack of modern technology (like ultrasound equipment) at ANC facilities discourages some women from attending (high confidence in the evidence) (8). Qualitative evidence from health-care providers shows that they generally want to provide screening and testing procedures, but sometimes don’t feel suitably trained to do so (high confidence in the evidence) (9). This suggests that they might welcome Doppler ultrasound scans to identify potential risk factors, if appropriately trained and supported.

Feasibility

Feasibility challenges of Doppler ultrasound scans in LMICs include equipment procurement and staff training, ensuring a power supply (via a power point or rechargeable batteries) and secure storage, regular equipment maintenance, maintaining adequate and continual supplies of ultrasound gel, and ongoing technical support and supervision.

 

Further information and considerations related to this recommendation can be found in the WHO guidelines, available at:

http://apps.who.int/iris/bitstream/10665/250796/8/9789241549912-websupplement-eng.pdf?ua=1

 

 

Implementation considerations

  • The successful introduction of evidence-based policies related to antenatal care into national programmes and health care services depends on well-planned and participatory consensus-driven processes of adaptation and implementation. These processes may include the development or revision of national guidelines or protocols based on this recommendation.
  • The recommendation should be adapted into locally-appropriate documents and tools that are able to meet the specific needs of each country and health service. Modifications to the recommendation, where necessary, should be justified in an explicit and transparent manner.
  • An enabling environment should be created for the use of this recommendation, including changes in the behaviour of health care practitioners to enable the use of evidence-based practices.
  • Local professional societies may play important roles in this process and an all-inclusive and participatory process should be encouraged.
  • Antenatal care models with a minimum of eight contacts are recommended to reduce perinatal mortality and improve women’s experience of care. Taking this as a foundation, the GDG reviewed how ANC should be delivered in terms of both the timing and content of each of the ANC contacts, and arrived at a new model – the 2016 WHO ANC model – which replaces the previous four-visit focused ANC (FANC) model. For the purpose of developing this new ANC model, the ANC recommendations were mapped to the eight contacts based on the evidence supporting each recommendation and the optimal timing of delivery of the recommended interventions to achieve maximal impact.

 

Research implications

The GDG did not identify any priority question related to this recommendation

 

Related links

WHO recommendations on antenatal care for a positive pregnancy experience

(2016) - full document and evidence tables

Managing Complications in Pregnancy and Childbirth: A guide for midwives and doctors

Pregnancy, Childbirth, Postpartum and Newborn Care: A guide for essential practice

WHO Programmes: Sexual and Reproductive Health

Maternal Health

 

 

References

  1. Maulik D, Mundy D, Heitmann E, Maulik D. Evidence-based approach to umbilical artery Doppler fetal surveillance in highrisk pregnancies: an update. Clin Obstet Gynecol. 2010;53(4):869–78. doi:10.1097/ GRF.0b013e3181fbb5f5.
  2. Alfirevic Z, Stampalija T, Gyte GML. Fetal and umbilical Doppler ultrasound in high-risk pregnancies. Cochrane Database Syst Rev. 2013;(11):CD007529.
  3. Soothill PW, Ajayi RA, Campbell S, Nicolaides KH. Prediction of morbidity in small and normally grown fetuses by fetal heart rate variability, biophysical profile score and umbilical artery Doppler studies. Brit J Obstet Gynaecol. 1993;100:742–5.
  4. Alfirevic Z, Stampalija T, Medley N. Fetal and umbilical Doppler ultrasound in normal pregnancy. Cochrane Database Syst Rev. 2015;(4):CD001450.
  5. WHO handbook for guideline development, 2nd edition. Geneva: World Health Organization; 2014 (http://www.who.int/kms/handbook_2nd_ ed.pdf, accessed 6 October 2016).
  6. GRADE [website]. The GRADE Working Group; 2016 (http://gradeworkinggroup.org/, accessed 27 October 2016).
  7. GRADE-CERQual [website]. The GRADECERQual Project Group; 2016 (https://cerqual. org/, accessed 27 October 2016).
  8. The DECIDE Project; 2016 (http://www.decide-collaboration.eu/, accessed 27 October 2016).
  9. Downe S, Finlayson K, Tunçalp Ö, Gülmezoglu AM. Factors that influence the use of routine antenatal services by pregnant women: a qualitative evidence synthesis. Cochrane Database Syst Rev. 2016;(10):CD012392
  10. State of inequality: reproductive, maternal, newborn and child health. Geneva: World Health Organization; 2015 (http://www.who.int/gho/ health_equity/report_2015/en/, accessed 29 September 2016).

 

Citation: WHO Reproductive Health Library. WHO recommendation on routine Doppler ultrasound in pregnancy. (December 2016). The WHO Reproductive Health Library; Geneva: World Health Organization.