Therapeutic amnioinfusion for oligohydramnios during pregnancy (excluding labour) (interventional procedures consultation)
NATIONAL INSTITUTE FOR HEALTH AND CLINICAL EXCELLENCE
Interventional Procedure Consultation Document
Therapeutic amnioinfusion for oligohydramnios during pregnancy (excluding labour)
Oligohydramnios is a condition in which an abnormally low volume of fluid surrounds an unborn baby in the womb. Amnioinfusion involves infusion of fluid by a needle inserted into the womb and the space surrounding the unborn baby, to increase the amount of amniotic fluid.
The National Institute for Health and Clinical Excellence is examining fetal vesico-amniotic shunts and will publish guidance on its safety and efficacy to the NHS in England, Wales and Scotland. The Institute's Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisors, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about therapeutic amnioinfusion for oligohydramnios during pregnancy (excluding labour).
Note that this document is not the Institute's formal guidance on this procedure. The recommendations are provisional and may change after consultation.
The process that the Institute will follow after the consultation period ends is as follows.
For further details, see the Interventional Procedures Programme manual, which is available from the Institute's website (www.nice.org.uk/ipprogrammemanual).
Closing date for comments: 25 July 2006
Note that this document is not the Institute's guidance on this procedure. The recommendations are provisional and may change after consultation.
Current evidence on the safety and efficacy of therapeutic amnioinfusion for oligohydramnios during pregnancy (excluding labour) does not appear adequate for this procedure to be used without special arrangements for consent and for audit or research. Most of the evidence on the procedure relates to preterm premature rupture of membranes, rather than other causes of oligohydramnios.
Clinicians wishing to undertake therapeutic amnioinfusion for oligohydramnios during pregnancy (excluding labour) should take the following actions.
|1.3||Therapeutic amnioinfusion for oligohydramnios during pregnancy should only be performed in centres specialising in invasive fetal medicine and in the context of a multidisciplinary team, which may include a consultant in fetal medicine, a neonatologist, and a specialist midwife.|
|1.4||Further research will be useful. Clinicians are encouraged to enter patients into well-designed randomised controlled trials comparing therapeutic amnioinfusion with no intervention. The Institute may review the procedure upon publication of further evidence.|
|2.1.1||An abnormally low volume of amniotic fluid surrounding the fetus is termed oligohydramnios.|
|2.1.2||Oligohydramnios may be the result of decreased fetal urine production or excretion, or excessive loss of amniotic fluid. Causes of oligohydramnios include premature preterm rupture of amniotic membranes, congenital abnormalities of the fetus's urinary tract, placental insufficiency, twin-to-twin transfusion syndrome, post-maturity (more than 42 weeks' gestation), problems with maternal health, such as high blood pressure, and some medications. Severe oligohydramnios in early pregnancy may lead to the underdevelopment of fetal lung tissue (pulmonary hypoplasia) and limb defects and is associated with poor fetal growth. There is also an increased risk of miscarriage, premature birth and stillbirth.|
|2.1.3||Oligohydramnios is not routinely treated during pregnancy. There is some evidence that maternal hydration can increase the volume of amniotic fluid.|
|2.2||Outline of the procedure|
|2.2.1||Under ultrasound guidance, isotonic fluid, such as normal saline or Ringer's lactate, is infused into the amniotic cavity via a needle inserted through the uterine wall, to restore the normal volume of amniotic fluid. The procedure may be repeated on a regular basis if oligohydramnios recurs (serial amnioinfusion).|
A randomised controlled trial of 34 pregnant women reported a significantly lower incidence of pulmonary hypoplasia among fetuses of pregnancies treated with amnioinfusion compared with the controls - (12% (2/17) versus 53% (9/17); relative risk 0.22; 95% confidence interval 0.05 to 0.87, p < 0.05). A non-randomised comparative study reported a rate of pulmonary hypoplasia among neonates of 23% (6/26) in the treated group compared with 31% (4/13) in the control group (not significantly difference).
|2.3.2||In a randomised controlled trial comparing amnioinfusion with expectant management, neonatal mortality was 6% (1/17) in both the treated group and the control group. A non-randomised controlled study reported neonatal mortality (excluding stillbirths) of 18% (2/11) in the treated group compared with 71% (5/7) in the expectant management group (p = 0.05). In another non-randomised comparative study, mortality within the first week after birth was 23% (6/26) in the treated group compared with 38% (5/13) in the expectant management group (not significantly different). A third non-randomised comparative study reported a survival rate of 73% (8/11) for neonates treated with amnioinfusion and 21% (6/29) for those managed expectantly (p < 0.05). For more details, refer to the sources of evidence (see appendix).|
|2.3.3||The Specialist Advisors stated that key efficacy outcomes include prolongation of gestation, reduced incidence of pulmonary hypoplasia and improved neonatal survival.|
|2.4.1||A non-randomised comparative study including 45 women treated with serial amnioinfusions reported onset of labour shortly after the procedure in one case (2%).|
|2.4.2||One non-randomised comparative study reported spontaneous abortion in 11% (3/28) of women with unruptured membranes and 21% (5/24) of women with ruptured membranes treated with amnioinfusion. A second non-randomised, retrospective case series study reported miscarriage in 12% (2/17) of pregnancies. Four studies reported intrauterine death rates ranging from 0% (0/15) to 14% (4/28) in fetuses of pregnancies treated with amnioinfusion, and from 0% (0/14) to 38% (11/29) in fetuses managed expectantly.|
|2.4.3||Other complications included placental abruption in 0% (0/11) to 25% (3/12) of cases and chorioamnionitis in 0% (0/11) to 32% (8/25) of cases. A study including 12 women treated with amnioinfusion reported that one neonate had a laceration on the leg that required sutures, which was attributed to the procedure. For more details, refer to the sources of evidence (see appendix).|
|2.4.4||The Specialist Advisors listed potential adverse events as including premature labour and delivery, fetal loss, fetal trauma, infection, uterine perforation and premature rupture of membranes.|
|3.1||This guidance requires that clinicians undertaking the procedure make special arrangements for audit. The Institute has identified relevant audit criteria and is developing an audit tool (which is for use at local discretion), which will be available when the guidance is published.|
Chairman, Interventional Procedures Advisory Committee
|Appendix:||Sources of evidence|
The following document, which summarises the evidence, was considered by the Interventional Procedures Advisory Committee when making its provisional recommendations.
Available from: www.nice.org.uk/ip338overview
This page was last updated: 08 February 2011