Systematic review of pleural-amniotic shunt insertion vs. conservative management in isolated bilateral fetal hydrothorax without hydrops

  • Elaine CarsonEmail author
  • Priscilla Devaseelan
  • Stephen Ong
Open Access
Review Article



In the management of bilateral fetal hydrothorax where the fetus is non-hydropic and apparently otherwise normal, we wished to determine if pleural-amniotic shunt insertion was better than conservative management in terms of mortality.


A systematic review was conducted between 1992 and 2017. Data extracted was inspected for heterogeneity. Where there was comparative data available, the odds ratio (OR) and confidence interval (CI) were calculated.


Seven studies were included in this systematic review. There was a paucity of comparative data where only 2 studies (28 cases) allowed for direct comparison. Within the limitations of the study, there was no difference between shunt insertion vs. conservative management in terms of stillbirth or miscarriage (OR = 1.00, 95% CI 0.12–8.34, heterogeneity I2 = 0%, p = 1.00).


There is insufficient data available to determine whether the outcome is improved by pleural-amniotic shunt insertion compared with conservative management in cases of bilateral fetal hydrothorax where the fetus is non-hydropic and otherwise normal.


Fetal therapy Hydrothorax Pleural effusion Shunt Thoracoamniotic shunting 


In a pregnancy complicated by a fetus with primary bilateral hydrothorax with no other identifiable anomaly, the decision for pleural-amniotic shunt insertion or conservative management can be a therapeutic dilemma. Most clinicians faced with this clinical situation would consider shunt insertion in the presence of hydrops on the grounds that conservative management would likely result in fetal demise. If, however, the fetus was not hydropic, many clinicians would adopt a conservative approach while others would offer shunt insertion.

Given that pleural-amniotic shunt insertion is not without risk, with a procedure-related loss rate of about 1%, this question merits investigation. In this paper, we propose to study pregnancy where the fetus has primary bilateral hydrothorax with no other anomaly and is not hydropic. We wished to perform a systematic review of shunt insertion vs. conservative management in these cases.

Materials and methods

This systematic review was based on a protocol developed using widely recommended methods for the systematic review of observational studies [10, 12, 21, 23; Henderson et al. 2009]. The study was registered with the PROSPERO database (registration number CRD42017060485;

Search strategy

The search strategy involved searching the bibliographic databases MEDLINE and EMBASE, the Cochrane library and Web of Science between March 1992 and March 2017 inclusive, and followed the PRISMA guidelines [14]. The search terms used were “fetus, fetal, foetus, and foetal in combination with hydrothorax, chylothorax, pleural effusion, thoracoamniotic shunt, and shunting. A combination of MeSH and text words was used. All relevant abstracts were reviewed and where the abstract met the pre-defined selection criteria, the full article was retrieved and reviewed. No language restriction was applied. Experts in the area were consulted to ensure the review encompassed all relevant papers.

Study selection

Selection criteria were the following:
  • Population—Pregnancies with non-hydropic fetuses with primary bilateral fetal hydrothorax managed with thoracoamniotic shunting or conservative management.

  • Outcome—intrauterine demise (stillbirth or miscarriage), neonatal death.

  • Study design—Prospective and retrospective studies including case series involving more than 5 cases.

Quality assessment and data extraction

One reviewer (EC) extracted the data from all the papers meeting the selection criteria. This was checked by another reviewer (SO). The studies were assessed for quality using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement criteria [23] and the following criteria were derived from the checklist [18]:
  • Data collection—Prospective data was considered ideal; retrospective collection was considered second best.

  • Description of population—A well-defined sample at a uniform early stage with clear documentation of gestation at diagnosis, gestation at intervention, and delivery was considered ideal.

  • Prognostic factors considered: Clear documentation of other anomalies was considered ideal.

  • Objective outcome—Clear documentation of intrauterine demise or neonatal death was considered ideal.

  • Outcome ascertainment—Greater than 90% follow-up of the original study population was considered ideal, less than 90% was considered second best.

Data synthesis

The extracted data were tabulated to allow qualitative inspection for clinical and methodological heterogeneity. The data were not weighted according to the quality of the paper. For comparison of dichotomous outcomes between groups, the odds ratio (OR) and standard errors were calculated for the association in each study. The heterogeneity of estimates was explored graphically using forest plots and formally tested using χ2 tests. A combined proportion was calculated using the random effects models on the log odds scale. Data from individual studies were pooled [6]. The analysis of odds ratios was conducted using Review Manger 5 [1].


Identification of the literature

The electronic search of bibliographical databases yielded 335 citations, of which 15 were considered potentially relevant [3, 4, 5, 7, 8, 9, 11, 13, 15, 16, 17, 19, 20, 22, 24]. Examination of the full manuscripts revealed that 8 did not meet the selection criteria. Thus, a total of 7 primary studies [4, 7, 9, 11, 16, 20, 22] were selected for review (Fig. 1; Table 1). All studies were retrospective observational studies.
Fig. 1

Prisma flow diagram demonstrating study selection

Table 1

Clinical details of the 7 studies included in the systematic review


Number of patients

Number of non-hydropic fetuses with normal karyotype

Number underwent shunting

Average gestation at shunting

Average gestation at delivery

Antenatal care protocolized

Outcome survival

Duration of follow-up


Bianchi [4]








> 5 weeks

Respiratory distress syndrome, infection, mechanical ventilation, cerebral palsy, postnatal pleurodesis

Estroff [9]





Not reported



3 years

Respiratory distress syndrome, chest drain

Ba-Da Jeong [11]





Not reported



0.3–183 months

Pulmonary hypoplasia, preterm labor, premature rupture of membranes, hydrops, pulmonary hypertension, pulmonary hemorrhage, disseminated intravascular coagulopathy, recurrent pneumonia, restrictive lung disease, asthma

Derderian [7]








Not reported

Postnatal fluid drainage, shunt dislodgement, preterm labor

Pellegrinelli [16]





Not reported

Not reported


Not reported

Premature rupture of membranes, mirror syndrome, disseminated intravascular coagulopathy from bleeding trocar site









28 days

PPROM, catheter displacement, mirror syn, polyhydramnios









Range 8 weeks–2 years

Chest drain, removal of stuck shunt

Study characteristics and quality

The quality assessment of included studies is demonstrated in Figs. 2 and 3. The gestational age at diagnosis was reported in 43% of studies. Gestation at shunt insertion was reported in 72% of studies.
Fig. 2

Quality assessment of studies in the systematic review using clinically important criteria

Fig. 3

Quality assessment of studies in the systematic review (STROBE criteria)

Survival rates following shunt insertion vs. conservative management

Only 2 of the 7 selected studies had direct comparative data of conservative management vs. pleural-amniotic shunting (Fig. 4).
Fig. 4

Comparison of shunt insertion versus conservative management. Meta-analysis of the outcomes of stillbirth or miscarriage

There was a paucity of comparative data where only 2 studies (28 cases) allowed for direct comparison. Within the limitations of the study, there was no difference between shunt insertion vs. conservative management in terms of stillbirth or miscarriage (OR = 1.00, 95% CI 0.12–8.34, heterogeneity I2 = 0%, p = 1.00).


This systematic review did not provide sufficient evidence for or against pleural-amniotic shunting in cases of bilateral hydrothorax where the fetus is non-hydropic and apparently otherwise normal. The number of cases was too small to reach a meaningful conclusion.

The strength of this review is that it employed an exhaustive research strategy. This way, we were able to collate evidence for a condition that is imprecisely assessed in individual studies. In addition, the quality of these studies was assessed.

A major weakness of this systematic review is that all the papers evaluated were retrospective in nature and the overall number of cases was very small.

A further weakness of this review is that subtle reasons whereby decision-making may change are not accounted for. For example, a clinician may see a woman with a non-hydropic fetus with bilateral hydrothorax at 20 weeks. He may decide to adopt a conservative approach as the fetus is in a difficult position for shunt insertion. By 24 weeks, the clinical picture may be the same but the fetus could be in a better position for shunt insertion. The clinician may well decide to opt for shunt insertion. Our systematic review would have classified such a case as an intervention. In reality, a period of conservative management followed by shunt insertion took place.

In the original conception of this systematic review, we hoped to study outcome at different gestations, i.e., 20 to 24 weeks, 24 to 28 weeks, 28 to 32 weeks, and 32 to 34 weeks. We were particularly keen to study the outcome at the later gestations, where iatrogenic premature delivery (with its attendant risk of morbidity and mortality) is a possibility. Due to the paucity of our data, we were not able to provide useful information at different gestations.


In cases of bilateral fetal hydrothorax, where the fetus is non-hydropic and otherwise structurally normal, the correct management strategy in terms of pleural-amniotic shunting or conservative management remains unknown.

A multicenter randomized controlled trial is the best way to answer this question but may prove to be an impossible undertaking. Another solution would be for several large units to standardize reporting at the outset and pool their respective results in a large observational study.


In a pregnancy complicated by a fetus with primary hydrothorax and no other identifiable anomaly, we wished to determine whether pleural-amniotic shunt insertion was better than conservative management in terms of mortality. To do this, we conducted a systematic review between 1992 and 2017 and identified seven studies from which we could extract data. There was a paucity of comparative data with only two studies allowing for direct comparison. Within the limitations of the review, there was no difference between shunt insertion vs. conservative management.


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


  1. 1.
    (2008) Review Manager (RevMan) 5th edn. The Nordic Cochrane Centre, The Cochrane Collaboration, CopenhagenGoogle Scholar
  2. 2.
    (2009) NHS Centre for Reviews and Dissemination CRD’s guidance for undertaking reviews in health care. In: York UO (ed). YorkGoogle Scholar
  3. 3.
    Bernaschek G, Deutinger J, Hansmann M, Bald R, Holzgreve W, Bollmann R (1994) Feto-amniotic shunting--report of the experience of four European centres. Prenat Diagn 14:821–833CrossRefPubMedGoogle Scholar
  4. 4.
    Bianchi S, Lista G, Castoldi F, Rustico M (2010) Congenital primary hydrothorax: effect of thoracoamniotic shunting on neonatal clinical outcome. J Matern Fetal Neonatal Med 23:1225–1229CrossRefPubMedGoogle Scholar
  5. 5.
    Blaicher W, Hausler M, Gembruch U, Bollmann R, Terinde R, Rempen A, Deutinger J, Bernaschek G (2005) Feto-amniotic shunting -- experience of six centres. Ultraschall Med 26:134–141CrossRefPubMedGoogle Scholar
  6. 6.
    Deeks JJ, Altman DG, Bradburn MJ (2001) Statistical methods for examining heterogeneity and combining results from several studies in meta-analysis. BMJ Books, LondonCrossRefGoogle Scholar
  7. 7.
    Derderian SC, Trivedi S, Farrell J, Keller RL, Rand L, Goldstein R, Feldstein VA, Hirose S, Mackenzie TC (2014) Outcomes of fetal intervention for primary hydrothorax. J Pediatr Surg 49:900–903 discussion 903-4CrossRefPubMedGoogle Scholar
  8. 8.
    Deurloo KL, Devlieger R, Lopriore E, Klumper FJ, Oepkes D (2007) Isolated fetal hydrothorax with hydrops: a systematic review of prenatal treatment options. Prenat Diagn 27:893–899CrossRefPubMedGoogle Scholar
  9. 9.
    Estoff JA, Parad RB, Frigoletto FD Jr, Benacerraf BR (1992) The natural history of isolated fetal hydrothorax. Ultrasound Obstet Gynecol 2:162–165CrossRefPubMedGoogle Scholar
  10. 10.
    Henderson LK, Craig JC, Willis NS, Tovey D, Webster AC (2010) How to write a Cochrane systematic review. Nephrology (Carlton) 15:617–624CrossRefGoogle Scholar
  11. 11.
    Jeong BD, Won HS, Lee MY, Shim JY, Lee PR, Kim A (2015) Perinatal outcomes of fetal pleural effusion following thoracoamniotic shunting. Prenat Diagn 35:1365–1370CrossRefPubMedGoogle Scholar
  12. 12.
    Khan K, Riet GT, Glanville J, Sowden A, Kleijnen J (2000) Undertaking systematic reviews of research on effectiveness. CRD’s guidance for carrying out or commissioning reviews, 2nd edn. NHS Centre for Reviews and Dissemination, University of York, YorkGoogle Scholar
  13. 13.
    Mallmann MR, Geipel A, Bludau M, Matil K, Gottschalk I, Hoopmann M, Muller A, Bachour H, Heydweiller A, Gembruch U, Berg C (2014) Bronchopulmonary sequestration with massive pleural effusion: pleuroamniotic shunting vs intrafetal vascular laser ablation. Ultrasound Obstet Gynecol 44:441–446CrossRefPubMedGoogle Scholar
  14. 14.
    Moher D, Liberati A, Tetzlaff J, Altman DG (2009) Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. J Clin Epidemiol 62:1006–1012CrossRefGoogle Scholar
  15. 15.
    O’brien B, Kesby G, Ogle R, Rieger I, Hyett JA (2015) Treatment of primary fetal hydrothorax with OK-432 (Picibanil): outcome in 14 fetuses and a review of the literature. Fetal Diagn Ther 37:259–266CrossRefPubMedGoogle Scholar
  16. 16.
    Pellegrinelli JM, Kohler A, Kohler M, Weingertner AS, Favre R (2012) Prenatal management and thoracoamniotic shunting in primary fetal pleural effusions: a single centre experience. Prenat Diagn 32:467–471CrossRefPubMedGoogle Scholar
  17. 17.
    Petersen S, Kaur R, Thomas JT, Cincotta R, Gardener G (2013) The outcome of isolated primary fetal hydrothorax: a 10-year review from a tertiary center. Fetal Diagn Ther 34:69–76CrossRefPubMedGoogle Scholar
  18. 18.
    Rennie D (2003) Improving reports of studies of diagnostic tests: the STARD initiative. JAMA 289:89–90CrossRefPubMedGoogle Scholar
  19. 19.
    Rustico MA, Lanna M, Coviello D, Smoleniec J, Nicolini U (2007) Fetal pleural effusion. Prenat Diagn 27:793–799CrossRefPubMedGoogle Scholar
  20. 20.
    Smith RP, Illanes S, Denbow ML, Soothill PW (2005) Outcome of fetal pleural effusions treated by thoracoamniotic shunting. Ultrasound Obstet Gynecol 26:63–66CrossRefPubMedGoogle Scholar
  21. 21.
    Stroup DF, Berlin JA, Morton SC, Olkin I, Williamson GD, Rennie D, Moher D, Becker BJ, Sipe TA, Thacker SB (2000) Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group. JAMA 283:2008–2012Google Scholar
  22. 22.
    Takahashi Y, Kawabata I, Sumie M, Nakata M, Ishii K, Murakoshi T, Katsuragi S, Ikeda T, Saito M, Kawamoto H, Hayashi S, Sago H (2012) Thoracoamniotic shunting for fetal pleural effusions using a double-basket shunt. Prenat Diagn 32:1282–1287CrossRefPubMedGoogle Scholar
  23. 23.
    von Elm E, Altman DG, Egger M, Pocock SJ, Gotzsche PC, Vandenbroucke JP (2007) The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. PLoS Med 4:e296CrossRefGoogle Scholar
  24. 24.
    Yinon Y, Kelly E, Ryan G (2008) Fetal pleural effusions. Best Pract Res Clin Obstet Gynaecol 22:77–96CrossRefPubMedGoogle Scholar

Copyright information

© The Author(s) 2019

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  1. 1.Fetal Medicine departmentRoyal Jubilee Maternity HospitalBelfastUK

Personalised recommendations