Predicting Adverse Outcomes in Women with Severe Pre-eclampsia
Introduction
The reason pre-eclampsia matters so much to maternity care providers is that adverse maternal and perinatal events cluster around the diagnosis of proteinuric gestational hypertension. While this is true, most pre-eclampsia is mild and evanescent, resolving rapidly postpartum. Therefore, every effort must be made to identify those women at greatest personal risk, and those bearing fetuses at greatest risk. Once identified, these women can be offered closer surveillance and lower thresholds for the use of effective interventions, such as delivery and the use of MgSO4. Conversely, as delivery remote from term can increase perinatal risks1 and as liberal MgSO4 use is frequently associated with maternal morbidity,2 it may be as important to identify those women who have “mild” disease and bear little personal and/or fetal actuarial risk. For women with “mild” disease at presentation, expectant management remote from term or nonuse of MgSO4 would be appropriate.
It is also increasingly apparent that, other than the presence of a placenta, there is no single root cause for the maternal syndrome of pre-eclampsia across the spectrum of severity.3 The maternal syndrome appears to be triggered variably through a multihit process, where genetic predisposition, pre-existing renal disease or metabolic syndrome, chronic infectious and inflammatory states, and fetal growth potential (eg, macrosomia, multiple pregnancy) exist. These factors all modulate the maternal response to a placenta that may, or may not, be adequately formed during the first half of pregnancy where the interaction between maternal innate immune surveillance and invading cytotrophoblast plays a central role. Poor placentation appears to be most important in early onset pre-eclampsia (<34 weeks' gestation at onset), with other maternal and fetal factors acting as modifiers, whereas, at term, factors other than the adequacy of placentation appear to contribute more strongly.3
Whatever the inciting cause or causes, the result appears to be a complex soup of cellular, subcellular, and suspended components. Derived from the maternal (eg, activated leukocytes) and fetal (eg, trophoblast debris) compartments that exit the intervillous space of the placenta, this complex soup interacts primarily with the systemic maternal endothelium.3
The outcome of these complex interactions is a maternal syndrome of hypertension, glomerular endotheliosis and proteinuria, and systemic inflammation that we term pre-eclampsia—in a minority of cases this syndrome is severe and potentially life-threatening.
This article confines its focus to the prediction of severe and potentially life-threatening adverse outcomes in women, and, too a smaller extent, their fetuses, with suspected or confirmed pre-eclampsia, and not to the prediction of the diagnosis of pre-eclampsia during the first and/or second trimesters.
Section snippets
Current Classification and Evaluation of Pre-Eclampsia
Guidelines for the diagnosis, classification, and management of pre-eclampsia have been produced by the Canadian Hypertension Society (CHS; 1997),4 the U.S. National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy (NHBPEP; 2000),5 the Australasian Society for the Study of Hypertension in Pregnancy (2000),6 and the Society of Obstetricians and Gynaecologists of Canada (2008).3
These publications classify pre-eclampsia as being either mild or severe. Mild
The PIERS Program of Research
The PIERS program of research was initiated to develop an evidence-based framework by which clinicians can better define the maternal risks associated with the diagnosis of pre-eclampsia and the other hypertensive disorders of pregnancy. The ultimate goal is to develop and promulgate a clinical PIERS score that will not only guide clinical practice, especially as it relates to decisions around expectant management, but also have utility in selecting women for, and describing outcomes in,
Management of Pre-Eclampsia Pregnancies
Currently, management of pre-eclampsia is guided primarily by clinical impression rather than by evidence-based criteria of disease severity. The definitive treatment for pre-eclampsia is always delivery for the mother, but this is not always the best option for the fetus. Evidence from randomized controlled trials (RCTs) has shown that, remote from term, pregnancy prolongation by expectant therapy (delaying delivery until compelled by either maternal or fetal condition) decreases serious
Predictors of Adverse Outcomes Associated with Pre-Eclampsia—The Role for National Guidelines
At present, it is extremely difficult to identify which mothers with pre-eclampsia are at increased risk of developing adverse maternal complications, and this risk cannot be graded. Hypertension and proteinuria are commonly recognized risk factors for adverse maternal or perinatal outcome in pre-eclampsia pregnancies, and, as such, are often used to differentiate between “mild” and “severe” disease.3, 4, 5, 6, 16 Both heavy proteinuria and severe maternal hypertension are listed as “adverse
Single Site Experience
Through the PIERS project design of using primarily a continuous quality improvement approach, we chose to assess the incidence of combined adverse maternal and perinatal outcomes in women with pre-eclampsia before and after introducing standardized assessment and surveillance at BC Women's Hospital and Health Centre.18
This study was a preintervention (retrospective) compared with a postintervention (prospective) cohort comparison in a single-tertiary, perinatal unit that included women
References (30)
- et al.
Serious perinatal complications of non-proteinuric hypertension: An international, multicenter, retrospective cohort study
J Obstet Gynaecol Can
(2003) - et al.
Pregnancy-related mortality from preeclampsia and eclampsia
Obstet Gynecol
(2001) - et al.
The prediction of adverse maternal outcomes in preeclampsia
J Obstet Gynaecol Can
(2004) - et al.
Early risk assessment of severe preeclampsia: Admission battery of symptoms and laboratory tests to predict likelihood of subsequent significant maternal morbidity
Am J Obstet Gynecol
(1999) - et al.
Higher mortality rates among inborn infants admitted to neonatal intensive care units at night
J Pediatr
(2003) - et al.
Fortnightly review: Management of hypertension in pregnancy
BMJ
(1999) - et al.
Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate?The magpie trial: A randomised placebo-controlled trial
Lancet
(2002) - et al.
SOGC guidelines: Diagnosis, evaluation and management of the hypertensive disorders of pregnancy
J Obstet Gynaecol Can
(2008) - et al.
Report of the Canadian Hypertension Society Consensus ConferenceDefinitions, evaluation and classification of hypertensive disorders in pregnancy
CMAJ
(1997) Report of the National High Blood Pressure Education Program Working Group on High Blood Pressure in pregnancy
Am J Obstet Gynecol
(2000)
The detection, investigation and management of hypertension in pregnancy: Full consensus statement
Aust NZ J Obstet Gynaecol
A survey of Canadian practitioners regarding diagnosis and evaluation of the hypertensive disorders of pregnancy
Hypertens Pregnancy
The control of hypertension in pregnancy study pilot trial
Br J Obstet Gynaecol
Eclampsia in the United Kingdom
BMJ
Activated protein C in normal human pregnancy and pregnancies complicated by severe preeclampsia: A therapeutic opportunity?
Crit Care Med
Cited by (53)
Prediction of adverse neonatal outcome at admission for early-onset preeclampsia with severe features
2023, Pregnancy HypertensionPregnancy: Pre-eclampsia and diet
2023, Encyclopedia of Human Nutrition: Volume 1-4, Fourth EditionDevelopment and validation of risk prediction models for adverse maternal and neonatal outcomes in severe preeclampsia in a low-resource setting, Mpilo Central Hospital, Bulawayo, Zimbabwe
2021, Pregnancy HypertensionCitation Excerpt :The outcomes of interest for this research were a composite adverse maternal outcome and a composite adverse neonatal outcome as in the fullPIERS and miniPIERS studies to facilitate comparison [7,8]. The composite adverse maternal outcome was defined as one or more serious complication of major organ morbidity in renal, hepatic, cardiac, respiratory, cerebral and haematological systems, pulmonary oedema, ventilator support, renal dialysis, transfusion of any blood product, abruption placenta, antepartum haemorrhage and postpartum haemorrhage (blood loss of > 500 ml after a vaginal birth or > 1000 ml after a caesarean section) within 48 h of admission to 7 days post-delivery [11,12,22]. The composite adverse neonatal outcome was defined as one or more of perinatal mortality, 5 min Apgar score < 7, respiratory distress syndrome and admission to neonatal intensive unit [14,15].
The predictive value of signs and symptoms in predicting adverse maternal and perinatal outcomes in severe preeclampsia in a low-resource setting, findings from a cross-sectional study at Mpilo Central Hospital, Bulawayo, Zimbabwe
2020, Pregnancy HypertensionCitation Excerpt :Thus, efforts are urgently needed to reduce maternal and perinatal mortality and morbidity from preeclampsia and hypertensive disorders in Sub-Saharan Africa. Severe preeclampsia is usually defined once there is high blood pressure (i.e. ≥160–170/100–110 mmHg), heavy proteinuria of >3–5 g/24 h, and/or the occurrence of symptoms, such as headache or visual disturbances [9]. Appearance of symptoms in preeclampsia could herald adverse consequences for both maternal, fetal and neonatal health.