SOGC Clinical Practice Guideline
No. 347-Obstetric Management at Borderline Viability

https://doi.org/10.1016/j.jogc.2017.03.108Get rights and content

Abstract

Objective

The primary objective of this guideline was to develop consensus statements to guide clinical practice and recommendations for obstetric management of a pregnancy at borderline viability, currently defined as prior to 25+6 weeks.

Intended Users

Clinicians involved in the obstetric management of women whose fetus is at the borderline of viability.

Target Population

Women presenting for possible birth at borderline viability.

Evidence

This document presents a summary of the literature and a general consensus on the management of pregnancies at borderline viability, including maternal transfer and consultation, administration of antenatal corticosteroids and magnesium sulfate, fetal heart rate monitoring, and considerations in mode of delivery. Medline, EMBASE, and Cochrane databases were searched using the following keywords: extreme prematurity, borderline viability, preterm, pregnancy, antenatal corticosteroids, mode of delivery. The results were then studied, and relevant articles were reviewed. The references of the reviewed studies were also searched, as were documents citing pertinent studies. The evidence was then presented at a consensus meeting, and statements were developed.

Validation Methods

The content and recommendations were developed by the consensus group from the fields of Maternal-Fetal Medicine, Neonatology, Perinatal Nursing, Patient Advocacy, and Ethics. The quality of evidence was rated using criteria described in the Grading of Recommendations Assessment, Development and Evaluation methodology framework (reference 1). The Board of the Society of Obstetricians and Gynaecologists of Canada approved the final draft for publication.

Methods

The quality of evidence was rated using the criteria described in the Grading of Recommendations, Assessment, Development, and Evaluation methodology framework. The interpretation of strong and weak recommendations is described later. The Summary of Findings is available upon request.

Benefits, Harms, and Costs

A multidisciplinary approach should be used in counselling women and families at borderline viability. The impact of obstetric interventions in the improvement of neonatal outcomes is suggested in the literature, and if active resuscitation is intended, then active obstetric interventions should be considered.

Guideline Update

Evidence will be reviewed 5 years after publication to decide whether all or part of the guideline should be updated. However, if important new evidence is published prior to the 5-year cycle, the review process may be accelerated for a more rapid update of some recommendations.

Sponsors

This guideline was developed with resources funded by the Society of Obstetricians and Gynaecologists of Canada and the Women and Babies Program at Sunnybrook Health Sciences Centre.

Recommendations

  • 1.

    Women facing decisions regarding obstetric and neonatal management at extremely preterm gestations should be counselled by an expert multidisciplinary team. Neonatal survival data vary globally, and national and local data are important elements of counselling. The data should be interpreted with the understanding that perinatal management has a role to play in these results (Weak, Moderate).

  • 2.

    Whenever possible, women at periviable gestations should be offered transfer to a level 3 centre. If a clear, informed decision has been reached not to provide the infant with intensive care if delivered, and if specialized comfort care can be provided at the referring centre, the transfer may not be necessary. Decision to transfer should factor in gestational age, estimated fetal weight, and parental preferences. Practitioners should be educated about the management options for extreme prematurity and should have the option to call specialist practitioners for advice in managing these cases. Care providers should acknowledge the difficulty and disruption associated with transfer and should prepare women and their families for the process and potential outcomes (Strong, Moderate).

  • 3.

    First trimester ultrasound should be offered in all pregnancies, especially when risk factors for preterm birth are present. The value of ultrasound-measured estimated fetal weight in decision-making around obstetric interventions requires study (Strong, Low).

  • 4.

    In the periviable periods, antenatal corticosteroids should be administered after careful consideration of the likelihood of delivery and the resuscitation wishes of the family. If delivery is expected within 7 days, and if full resuscitation is planned, a single course of antenatal corticosteroids should be administered to women (Strong, Moderate).

  • 5.

    A rescue dose of corticosteroid, when the initial course of corticosteroid was given before 25 weeks, should not currently be recommended because benefit or harm of such additional dose is not proven. Further study is required (Strong, Moderate).

  • 6.

    Magnesium sulfate for neuroprotection should be given after careful consideration of the likelihood of delivery and the benefits of treatment. If delivery is expected imminently, and if full resuscitation is planned, magnesium sulfate should be administered in the extreme preterm population in accordance with local protocols and the existing SOGC guideline (Strong, Moderate).

  • 7.

    Other than for maternal indications, routine Caesarean delivery in the extreme preterm population should be avoided (Strong, High). In cases of fetal malpresentation or other obstetric indications, the limitations of evidence should be discussed and a multidisciplinary approach should be used to come to a decision that considers both maternal and fetal outcome when active neonatal management is planned (Strong, Moderate).

  • 8.

    Intrapartum continuous fetal monitoring should be used when active neonatal management in planned. Interpretation parameters should be used cautiously by those experienced in the care of preterm and extremely preterm gestations (Weak, Low).

  • 9.

    Delayed cord clamping in the extreme preterm population is recommended. When this is not feasible, cord milking should be considered (Strong, Moderate).

Introduction

This document reflects emerging clinical and scientific advances on the date issued and is subject to change. The information should not be construed as dictating an exclusive course of treatment or procedure to be followed. Local institutions can dictate amendments to these opinions. They should be well-documented if modified at the local level. None of these contents may be reproduced in any form without prior written permission of the publisher.

Women have the right and responsibility to make informed decisions about their care in partnership with their health care providers. To facilitate informed choice, women should be provided with information and support that are evidence based, culturally appropriate, and tailored to their needs. The values, beliefs, and individual needs of each woman and her family should be sought and the final decision about the care and treatment options chosen by the woman should be respected.

As technology and medical interventions have evolved, the lower limits of GA at which newborns are considered viable have shifted. With increased provision of active resuscitative measures to infants born at lower GAs, obstetric interventions remain a key component in ensuring that these very fragile infants have the best chance of intact survival. The borderline of viability is classically defined as the period between 22+0 and 25+6 weeks. Most centres will advocate for active intervention beyond 25+0 weeks, and few will offer active intervention at 22+0 weeks. The period of ambiguity of intervention is greatest prior to and including 24+6 weeks. The lower limit of viability is constantly changing. The role of active obstetric intervention in the outcome of the neonates at borderline viability requires increased discussion and research. This document aims at providing guidance for these difficult cases.

According to Canadian data from level 3 centres, neonates at 23+0 to 24+6 weeks constitute about 2% of admissions to NICUs. In the 2015 annual report of the Canadian Neonatal Network,1 75% and 94% of 23-week and 24-week neonates, respectively, received active management. This was an increase from 2013,2 when 46% and 67% of the 23-week and 24-week neonates, respectively, received active management. In 2015, the Canadian Neonatal Network reported that 53% of 23-week neonates and 75% of 24-week neonates survived to discharge from the level 3 NICU. It is unclear from these data what obstetric circumstances and interventions preceded the delivery and what impact these circumstances may have had on neonatal survival.

Because of this lack of differentiation in outcomes based on care provision prior to delivery, and because we know that these interventions may confer a survival benefit, the outcome of database findings should be interpreted with caution. Indeed, as more obstetric interventions are offered, an increase in survival has been seen in database studies examining outcomes in this population.3 At present, there is a paucity of research on outcomes of infants born after mothers received active obstetric management. The impact of administration of ACS for enhanced lung maturity, MgS04 for neuroprotection, and mode of delivery on survival on the long-term outcomes of the neonate at borderline viability remains unanswered in the current literature, and although the gaps are being filled by ongoing research, guidelines are necessary to help direct clinical care during this time of rapid change.

The intention of this guideline is to help practitioners in counselling families to make an informed decision about obstetric management relating to the planned resuscitation of their child and to allow clinicians to optimize this management to allow for the best maternal and neonatal outcome when active management is offered and full resuscitation is intended. The present survival of an infant born prior to 23+0 weeks is uncommon but is increasing as more interventions are offered.1, 2 It should be noted that the lower limit of 23+0 weeks discussed in this guideline may change as technology and interventions evolve. Ultimately, decisions around management in the periviable stage should be made through discussions between families and their care providers.

The guidance provided in this document should be used in conjunction with that of pediatric and neonatal expert groups. A full multidisciplinary team, including maternal-fetal medicine specialists, obstetricians, neonatologists, perinatal nursing, midwifery, and family practice, should be involved in the counselling of women and families making decisions about their potential extremely preterm birth. The development of local guidelines may facilitate this informed consent process.4

Section snippets

Methods

A group of Canadian perinatal experts from the fields of Maternal-Fetal Medicine, Neonatology, Perinatal Nursing, Patient Advocacy, and Ethics met to discuss the obstetric management of pregnancies at borderline viability. The meeting was funded by Sunnybrook Health Sciences Women and Babies Program and supported by SOGC.

The intention was to develop a consensus statement to help guide clinical management and further investigative research in this important area. Similar documents have been

Transfer to Obstetric Centre With a Level 3 NICU

All obstetric providers may encounter women who are unexpectedly faced with a possible delivery before 25 weeks' GA. A consistent local management protocol and counselling regarding management options should be available to all providers to help support women and families until transfer to a level 3 centre can be facilitated, if appropriate.

The question of maternal transfer has important resource and policy implications.

Beyond the proven benefits of place of birth of the newborn, such as

GA AND EFW

The discussion about intervention at periviability is limited by accurate GA prediction. Other than in pregnancies conceived using IVF, accurate first trimester dating of pregnancies remains a challenge. Decisions to intervene for fetal benefit are largely made on the basis of prediction of survival, which in turn are based largely on GA.

The SOGC recommends accurate dating of all pregnancies.11 It is believed that the crown-rump length measured at the earliest stage of the pregnancy, after 7

Administration of ACS

ACS are a mainstay in the management of threatened spontaneous or iatrogenic preterm delivery. Initial evidence supports their use in the prevention of respiratory and extrapulmonary neonatal complications when administered to women after 25+0 weeks' gestation.16, 17 This recommendation has since been extrapolated to the 24-week population, and administration at this stage is generally the standard of care across Canada. Neonatologists caring for very preterm infants recognize that the

MgS04 for Neuroprotection

The benefits of MgS04 for the prevention of cerebral palsy in infants with birth weight under 1500 g were initially shown in a case-control study published 2 decades ago.31 Since then, RCTs and meta-analyses have supported the use of MgS04 for neuroprotection in preterm deliveries.32, 33 The SOGC recommends administration in the case of imminent birth at less than 31+6 weeks' GA.34

The extremely preterm gestations comprised only a small portion of the infants enrolled in the sentinel studies

Mode of Delivery

Although debate exists about a neonatal benefit of Caesarean delivery, there is little question about the increased maternal risks, especially at early gestations. In the 23- to 24+6–week period, there is little differentiation of a developed lower segment, and classical or high transverse uterine incisions are usually required.

A retrospective cohort of women who underwent periviable Caesarean deliveries showed that their subsequent pregnancies had a higher rate of uterine rupture compared with

Intrapartum Fetal Monitoring

EFM is an important component of intrapartum care in complex pregnancies. The purpose of EFM in periviable gestations is two-fold:

  • 1.

    To alert obstetricians to possible signs of fetal compromise in labour in cases in which surgical intervention would be considered to expedite delivery. It should be recognized that survival figures for extremely preterm infants are likely to be reduced in the presence of acidemia but unlikely to be completely recoverable by Caesarean delivery. Furthermore, our

Delayed Cord Clamping, Cord Milking, and Delivery Room Temperature

Delayed cord clamping has been adopted as an intervention to help minimize blood transfusion and improve outcomes in preterm births. Several studies and meta-analyses have shown improvement in short-term outcomes, significantly lower rates of blood transfusion, and trends towards decreased rates of IVH and sepsis in infants who underwent delayed cord clamping or cord milking.50, 51 Studies reporting benefit with delayed cord clamping report protocols ranging from 20 to 180 seconds of delay.52,

Discussion

A multidisciplinary team plan should be in place when women present at risk for delivery prior to 25 weeks. Accurate pregnancy dating is important to appropriately counsel regarding maternal, fetal, and newborn management options and to develop the optimal obstetric management plan, with the family's wishes taken into account.

Practitioners should acknowledge uncertainty around our knowledge of best practices and the limitations in the evidence available. We should also be aware of our inherent

Acknowledgements

This guideline was developed with resources funded by the Society of Obstetricians and Gynaecologists of Canada and the Women and Babies Program at Sunnybrook Health Sciences Centre.

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    This Clinical Practice Guideline was prepared by the Obstetrical Management at Borderline Viability Working Group; reviewed by the Maternal-Fetal Medicine, Clinical Practice-Obstetrics, Diagnostic Imaging and Guideline Management and Oversight committees; and approved by the Board of The Society of Obstetricians and Gynaecologists of Canada.

    Disclosure statements have been received from all authors.

    Working Group members: Keith Barrington, MB, Montréal, QC; Jennifer Blake, MD, Ottawa, ON; Donna Brown, MN, Toronto, ON; Joan Crane, MD, St. John’s, NL; Ann Jefferies, MD, Toronto, ON; Shoo K. Lee, PhD, Toronto, ON; Kellie E. Murphy, MD, Toronto, ON; Renato Natale, MD, London, ON; Eugene Ng, MD, Toronto, ON; Kirsten M. Niles, MD, PhD, Toronto, ON; Nan Okun, MD, Toronto, ON; Kate Robson, MEd, Toronto, ON; Anne Simmonds, RN, PhD, Toronto, ON; Amanda Skoll, MD, Vancouver, BC.

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