the incidence of preeclampsia and eclampsia

7/30/2019 The Incidence of Preeclampsia and Eclampsia

1/5

OBSTETRICS

The incidence of preeclampsia and eclampsia and associatedmaternal mortality in Australia from population-linked

datasets: 2000-2008Charlene Thornton, PhD; Hannah Dahlen, PhD; Andrew Korda, FRANZCOG; Annemarie Hennessy, PhD

OBJECTIVE: To determine the incidence of preeclampsia and

eclampsia and associated mortality in Australia between 2000 and

2008.

STUDY DESIGN: Analysis of statutorily collected datasets of singleton

births in New South Wales using International Classification of Disease

coding. Analyzed using cross tabulation, logistic regression, and

means testing, where appropriate.

RESULTS: The overall incidence of preeclampsia was 3.3% with adecrease from 4.6% to 2.3%. The overall rate of eclampsia was 8.6/

10,000 births or 2.6% of preeclampsia cases, with an increase from

2.3% to 4.2%. The relative risk of eclampsia in preeclamptic women in

2008 was 1.9 (95% confidence interval, 1.28e2.92) when compared

with the year 2000. The relative risk of a woman with preeclampsia/

eclampsia dying in the first 12 months following birth compared with

normotensive women is 5.1 (95% confidence interval, 3.07e8.60).

CONCLUSION: Falling rates of preeclampsia have not equated to a

decline in the incidence of eclampsia. An accurate rate of both pre-

eclampsia and eclampsia is vital considering the considerable

contribution that these diseases make to maternal mortality. The

identification and treatment of eclampsia should remain a priority in

the clinical setting.

Key words: eclampsia, incidence, maternal mortality, preeclampsia

Cite this article as: Thornton C, Dahlen H, Korda A, et al. The incidence of preeclampsia and eclampsia and associated maternal mortality in Australia from

population-linked datasets: 2000-2008. Am J Obstet Gynecol 2013;208:476.e1-5.

Reported rates of preeclampsia andeclampsia in developed countriesvary significantly. The preeclampsia rate

is commonly quoted in the literature asbeing anywhere between 5% and 8% of

all pregnancies worldwide, although

more recently lower rates of 2-8% are

being cited.1,2 Geographic variation,

varying definitions of the disease and the

size of data sources used largely accountfor these variations3 although seasonal

variation at birth and time of conceptionhave also been postulated as explana-

tions of rate variations.4

Eclampsia rates also vary significantly

in the literature. In Europe rates of 2-3

cases per 10,000 births are quoted5,6

although rates in developing countriesare between 16-69 per 10,000 births.7

Knight3 quotes 2.7/10,000 births in a

12-month surveillance of all maternityunits in the United Kingdom in

2005/2006, although an earlier surveil-

lance study in the Unitd Kingdom in

19928 resulted in a rate of 4.9/10,000.

Worldwide, 12% of maternal deaths areattributed to eclampsia9 with a case

fatality rate of 3-5% in developing

countries.10 The Australasian Maternity

OutcomesSurveillance System (AMOSS)is currently conducting a surveillance of

eclampsia in Australia in 2011, althoughreporting of cases to AMOSS is voluntary

and results are to date, not available.Effective detection and treatment of

preeclampsia and eclampsia within any

country or health region should at leastbe influenced by clinicians knowledge

of the incidence of the disease within

their area of practice. The aim of thisstudy was to determine the incidence

of both preeclampsia and eclampsia inthe largest populated area of Australia

(which contributes to be over one third

of all Australian births), the variations

over time periods and maternal mortal-

ity subsequent to diagnosis within a12-month period following birth.

MA T E R I A L S A N D METHODS

Data sources

Birth data including maternalage, parity,

delivery type, smoking status, andneonatal outcomes for the period July 1,

2000, till June 30, 2008, of all singleton

births was provided by New South Wales(NSW), Australia, Department of Health

as recorded in the NSW Midwives

Data Collection (MDC). This popula-tion based surveillance system contains

maternal and infant data on all birthsof greater than 400 g birthweight or

20 weeks gestation and covers over one-

third of births that occur in Australia.1

The NSW MDC contains statistics on33% of births that occur in Australia

annually. This dataset (NSW MDC)

was linked to the Admitted Patient

Data Collection (APDC) and the NSWRegistry of Births, Deaths and Marriages

(BDM). The APDC records all admittedpatient services provided by NSW Public

From the, School of Medicine (Drs Thornton,Korda, and Hennessy), and the School ofNursing and Midwifery (Dr Dahlen), University ofWestern Sydney, Sydney, NSW, Australia.

Received Nov. 12, 2012; revised Jan. 5, 2013;accepted Feb. 25, 2013.

The authors report no conflict of interest.

Reprints: Charlene Thornton, PhD, University ofWestern Sydney, School of Medicine, LockedBag 1797, Penrith South DC NSW,

Australia 1797. [email protected].

0002-9378/$36.00

2013 Mosby, Inc. All rights reserved.

http://dx.doi.org/10.1016/j.ajog.2013.02.042

476.e1 American Journal of Obstetrics &Gynecology JUNE 2013

Research www.AJOG.org
mailto:[email protected]://dx.doi.org/10.1016/j.ajog.2013.02.042http://dx.doi.org/10.1016/j.ajog.2013.02.042mailto:[email protected]


2/5

Hospitals, Public Psychiatric Hospitals,Public Multi-Purpose Services, Private

Hospitals, and Private Day Procedures

Centres. The BDM is a record of allbirths, deaths and marriages that occur

in NSW. The incidence of preeclampsia

and the incidence and timing of event inrelation to birth of eclampsia was pro-

vided by the APDC using the Interna-tional Classification of Diseases Coding

(ICD-10-Australian Modification) that

has been in use in the Australian settingsince 1998. The codes O14.0, O14.1,

O14.2, and O14.9 were used to identify

the cases of preeclampsia and are thosethat refer to new onset proteinuric

hypertension. The codes O15.0, O15.1,O15.2, and O15.9 were used to identify

the cases of eclampsia and the timingof the seizure in relation to the deliveryof the infant. Cause of death was ob-

tained from ICD-10 codes as recorded

on the death certificate and located in theBDM registry. Linkage of the datasets

was conducted by the New South WalesCentre for Health Record Linkage

(CHeReL). Probabilistic data linkage

techniques were used for these purposesand deidentified datasets were provided

for analysis. Probabilistic record linkage

software works by assigning a

linkageweight to pairs of records. For example,

records that match perfectly or nearlyperfectly on first name, surname, date of

birth, and address have a high linkage

weight, and records that match only ondate of birth have a low linkage weight. If

the linkage weight is high it is likely that

the records truly match, and if the link-age weight is low it is likely that the

records are not truly a match. Thistechnique has been shown to have a false

positive rate of 0.3% of records.

11

Ethicalapproval was obtained from the NSW

Population and Health Services ResearchEthics Committee, protocol no. 2010/

12/291.

Subjects

The MDC dataset for this period con-

tains the antenatal, birth, and postnatal

details on 691,738 births during this

period. The APDC contains >1.7million admissions for the same women

occurring after the index pregnancy. TheBDM registry contains death data on 97

women who died within 12 months

following delivery.

Data analysis

Incidence and demographic data wascalculated. Contingency table analyses,

Student t tests and analyses of variance(ANOVA) were used to examine differ-

ences between the pregnancies coded as

preeclamptic/eclamptic and those not.Binary logistic regression modelling

was also undertaken. Significance was

determined


3/5

The unadjusted RR of a seizure occur-

ring in all women postnatally following a

birth via caesarean section compared

with a vaginal birth was 2.9 (95% CI,

2.14e

3.99. An analysis of the time frombirth to seizure was undertaken anddisplayed in Figure 2. The majority of

women experienced eclampsia on theday of birth (53%). Median time for

eclampsia was zero days (day of birth),

range, 0e55 days. When the cases that

occurred following the day of birth were

examined, the median day of postnatal

seizure occurrence was day 4 (range,1e55).

Maternal characteristics and neonatal

outcomes are described in Table 2. Thistable demonstrates that women with

eclampsia were younger, more likely tobe primiparous, delivered at earlier ges-tations, and their infants suffered higher

neonatal mortality.The seasonal variation of eclampsia

was explored and when examined in

relationship to the number of births thatoccurred within each season, there was

no statistical difference in the incidence

of eclampsia based on season of seizureoccurrence (c2, P .35).

Of all cause maternal deaths that

occurred within the 12-month periodfollowing delivery (n 97), 18% (n

17) had experienced preeclampsia. Of

the 30 early deaths (within 42 days ofbirth) attributed to medical causes

(nonviolent deaths), 17% (n 5) hadexperienced preeclampsia. The recorded

reason (with n 1 for each cause):

surgical misadventure, multiorgan fail-ure, intracranial hemorrhage, ruptured

uterus, and aortic dissection. This

equates to a RR for women with pre-

eclampsia/eclampsia dying in the first12 months following birth when com-

pared with normotensive women of5.1 (95% CI, 3.07e8.60). The NeonatalMortality Rate for infants of women

with eclampsia was 22.3/1000 and 10.7/1000 for infants of women with pre-

eclampsia compared with 7.9/1000 for

the normotensive cohort.

COMMENT

This paper reports a mean preeclampsia

rate of 3.3% of all singleton pregnanciesover an 8-year period and eclampsia in

this setting has an incidence of 8.6/10,000 births. Thesefigures are similarto

the world pooled estimate of 3.4%10 and

comparable with that seen in Norway.12

The discrepancy in rates of pre-

eclampsia between developed and devel-

oping countries and between developingcountries is because of a number of fac-

tors including the significant variation inthe quality and accessibility of care and

the variations in reporting methods and

standards. The size of the dataset from

which rates are calculated greatly infl

u-ence the reliability of the data and for

this reason, population-based datasetssuch as this which rely on standardized

coding and are validated for reliabilityare optimal for calculating disease inci-

dence. The issue around consensus of

diagnostic features is also contentiouswhen defining preeclampsia. This paper

used the research definition as estab-

lished by Redman and Jefferies13 of

pregnancy onset proteinuric hyperten-

sion in comparison to the defi

nitionsfound within the SOMANZ guidelines14

that include nonproteinuric variationsof preeclampsia, although it has been

reported that in 77% of cases, women

with preeclampsia diagnosed under moreinclusive definitions do have proteinuria

as a diagnostic factor.15

The declining rate of preeclampsia

over the study period (4.6% to 2.4% ofall births) is of great interest. Potential

reasons for this could be an improve-

ment in the early identifi

cation ofcases over time with the initiation of

TABLE 1

Occurrence of seizure

When seizureoccurred

Percent ofall episodes

Antenatally 25.1%

During labor 44.1%

Postnatally 26.3%

Not specified to venue 4.5%

Thornton. Incidence of preeclampsia and eclampsiain Australia 2000-2008. Am J Obstet Gynecol 2013 .

FIGURE 2

Time between birth and occurrence of eclampsia as a percentage of all

cases occurring during delivery or postnatally

Thornton. Incidence of preeclampsia and eclampsia in Australia 2000-2008. Am J Obstet Gynecol 2013.

Research Obstetrics www.AJOG.org



4/5

medication at earlier gestations tomaintain blood pressure control at

acceptable limits or the shift away from

blood pressure management from theinpatient to the outpatient setting with

a subsequent decrease in the likelihood

of a preeclampsia diagnosis beingrecorded on the birth admission. It could

also be postulated that women withmilder forms of disease are now less

prevalent or are being omitted from the

coding systems because of an increase inmore women with more severe disease

manifestations. Earlier treatments could

also have resulted in more womenreceiving a diagnosis of gestational

hypertension rather than preeclampsia.It could also be postulated that in-

creasing rates of induced labors andelective caesarean sections, and associ-ated birth at earlier mean gestations,16

are resulting in a fall in preeclampsiacases because of a reduction in the

period required for women to developand display disease manifestations, prac-

tices that effectively reduce the occur-

rence of cases that would have presentedin postdate pregnancies.

The 4.2% eclampsia rate (expressed as

a percentage of preeclampsia cases) at

the end of the study period was higherthan that reported in the greater major-ity of developed countries10 with the

relative risk for women with pre-eclampsia suffering an eclamptic seizure

almost doubling between the years 2000

to 2008. This increase reflects global

trends reported by the World HealthOrganization, with an increase from

0.1% to 0.8% of live births affected byeclampsia in developing countries over a

10-year reporting period.10 In our study,

this equated to an overall eclampsia rateover the 8-year period of 8.6/10,000

births with no change between 2000and 2008. This finding is in contrast

with falling eclampsia rates reported

in both Canada (12.4 to 5.9/10,000births between 2003 and 2009)17 and theUnited States (6.34 to 4.80/10,000

delivery hospitalizations between 1998

and 2008).18 The latter study did reportan increase in postpartum eclampsia

from 1.76 to 2.8 cases/10,000 delivery

hospitalization during the same period.These results would also support the

argument that the incidence of pre-

eclampsia and eclampsia are not posi-tively correlated and that identificationof impending eclampsia and treatment

variations differ significantly between

obstetric units and countries.Vigilance and the use of magnesium

sulphate (MgSO4) have well been iden-

tified as the most effective tools to

prevent eclampsia,19 although the useof MgSO4 has come under considerable

criticism because of a perceived toxicity

associated with its use.20-22 In Australia

there has not been any adverse drugreactions from MgSO4 reported tothe Australian Government Therapeutic

Goods Administration.23 In contrast, theInstitute of Safe Medication Practices22

in the US maintains a database of

incidents relating to MgSO4 of whichthere are more than 50 cases, some of

which resulted in maternal death or

persistent vegetative state involving theuse of MgSO4 diluted in intravenous

fluids.

There are both short- and potentiallong-term sequelae of having experi-

enced an eclamptic seizure. A study thatfollowed women 6-24 months after

they experienced an eclamptic seizure24

reported that 10% of women reportedpersistent amnesia, 22% reported loss ofmemory, 11% experienced visual dis-

turbances, and 10% had ongoing head-

aches. Long-term consequences may

include structural changes to the whitematter of the brain, with lesions seen

in 40% of women and loss of cerebraltissue in 25% of women 6 weeks

postpartum.25-27 So although there was

no mortality associated with eclampsiaduring this study, eclampsia does cause

significant long-term morbidity. Mag-

nesium sulphate usage differed signifi-cantly between obstetric units in New

South Wales15 from 2.4%-18.0% of allwomen with preeclampsia. Worldwide

the use of MgSO4 also varies greatly.

Seasonal variation found in this studywas in contrast with those found in

earlier work where the incidence of

eclampsia is greatest when in seasons

when the temperature is lowest.

4,5

There could be a number of reasons forthis including the statistical power ob-

tained from a dataset of this size or therelative narrow range of temperature

experienced within the state of NSW

over a 12-month period (32F variationbetween mean winter and summer

temperatures).

In this study, almost 17% (n 5) ofdirect maternal deaths were in women

who had preeclampsia. This figure

refl

ects what occurs worldwide, with10-15% of direct maternal deaths attri-

buted to preeclampsia in both developedand developing countries.2,28 Neonatal

mortality rates of 22.3/1000 for infants

born to mothers with eclampsia in thisstudy compares favorably with rates of

60/1000 in other developed countries.6

This study used ICD-10-AM coding

with a narrow definition of preeclampsiaand a collection period encompassing

691,738 births providing robust data

concerning the epidemiology of pre-eclampsia in Australia. The methodology

TABLE 2

Details of women with and without eclampsia

VariableEclampsian[ 529

Preeclampsiawithout eclampsian[ 22,298

Nonhypertensiven[ 668,911 Pvalue

Agea 28.7 (6.31) 29.5 (5.86) 30.2 (5.58) < .001

Primiparousb 73.2% 45.0% 41.6% < .001

Smoked during pregnancyb 13.9% 8.2% 14.8% < .001

Gestation at deliverya 37.6 (3.27) 37.9 (2.84) 39.1 (2.06) < .01

Vaginal birthb 49.8% 40.5% 73.8% < .001

Neonatal mortality rateb 22.3/1000 10.7/1000 7.9/1000 < .001

a Mean, standard deviation, and ANOVA; b c2 analysis.

Thornton. Incidence of preeclampsia and eclampsia in Australia 2000-2008. Am J Obstet Gynecol 2013.

www.AJOG.org Obstetrics Research

JUNE 2013 American Journal of Obstetrics &Gynecology 476.e4


5/5

used in the work is of course only asreliable as the datasets sourced. The use

of data linkage methodology has been

validated previously with a false-positiverate of 0.03% of cases.11 Data linkage has

improved the ascertainment of cases in

other studies concerning maternal mor-tality, with reports of up to 55% in-

creases in case identification using thismethodology.29 The risk with all large

routinely collected datasets is that

more complex medical complications ofpregnancy are more likely to be incor-

rectly coded, as supported by validation

studies undertaken30-32 but previous

work using population datasets to iden-tify preeclampsia cases reported speci-

ficities >99%.33 This has to be balanced

in comparison to smaller datasets, whichalthough may have greater accuracy of

diagnosis, are more likely to report

Type II errors and are less likely to actu-ally represent what is occurring on a

population level. This study also does notinclude data on multiple pregnancies,

which are affected more frequently by

preeclampsia and may increase overallrates of disease.

The incidence of preeclampsia has

altered over the past 2 decades and cur-

rent disease rates need to be used in anyfuture discussion. Comparison of data-sets such as these on an international

stage would provide a statistical basis,

enabling a robust disease profile to beestablished. Considering the role played

by eclampsia in maternal and infant

morbidity and mortality increasing ratesshould be of concern to all clinicians, as

vigilance and prophylaxis are the onlytools to prevent eclampsia. It would

appear that more efficient surveillance

of women with preeclampsia is urgentlyrequired as this will influence treat-

ments, including the timely use of

MgSO4 where required. -

REFERENCES

1. Australian Bureau of Statistics. Births 2010.ABS, Canberra, Australia.2. World Health Organization InternationalCollaborative Study of Hypertensive Disordersof Pregnancy. Geographic variation in the

incidence of hypertension in pregnancy. Am JObstet Gynecol 1988;158:80-3.3. Knight M. Eclampsia in the United Kingdom.BJOG 2005;114:1072-8.4. Rylander A, Lindqvist P. Eclampsia is moreprevalent during the winter season in Sweden.

Acta Obstet Gynecol Scand 2011;1:114-7.5. Subramaniam V. Seasonal variation in the

incidence of preeclampsia and eclampsia intropical climatic conditions. BMC WomensHealth 2007;7:18.6. Kullberg G, Lindeberg S, Hanson U.Eclampsia in Sweden. Hypertens Pregnancy2002;21:13-21.7. Altman D, Carroli G, Duley L, Magpie TrialCollaboration Group. Do women with pre-eclampsia, and their babies, benefit frommagnesium sulphate? The Magpie Trial: arandomised placebo-controlled trial. Lancet2002;359:1877-90.8. Douglas KA,Redman CWG. Eclampsia in theUnited Kingdom. BMJ 1994;309:1395-9.

9. World Health Organisation. The World HealthReport 2005: Make every mother and childcount. Geneva: World Health Organization;2005.10. Dolea C, AbouZahr C. Global burden ofhypertensive disorders of pregnancy in the year2000. Geneva:World Health Organisation; 2003.11. Centre for Health Record Linkage. Qua-lity assurance report. [Internet] 2012. Avail-able at: http://www.cherel.org.au/media/24160/qa_report_2012.pdf. Accessed Oct. 22, 2012.12. Klungsoyr K, Morken NH, Irgens L,

Vollset SE, Skjaerven R. Secular trends in theepidemiology of pre-eclampsia throughout 40years in Norway: prevalence, risk factors andperinatal survival. Paed Perinat Epi 2012;26:190-8.13. Redman CWG, Jefferies M. Revised defini-tionof pre-eclampsia. Lancet1988;8589:809-15.14. Lowe SA, Brown MA, Dekker G, et al.Guidelines for the management of hypertensivedisorders of pregnancy [Internet] 2008. Avail-able at: http://www.somanz.org/pdfs/somanz_guidelines_2008.pdf. Accessed June 26, 2012.15. Thornton C. Benchmarking the hyper-tensive disorders of pregnancy [PhD thesis].Sydney, NSW: University of Western Sydney;2011.16. Mealing NM, Roberts CL, Ford JB,

Simpson JM, Morris JM. Trends in induction oflabour, 1998-2007: a population-based study.

ANZ J Obstet Gynaecol 2009;49:599-605.17. Liu S, Joseph KS, Liston RM. Incidence,risk factors, and associated complications ofeclampsia. Obstet Gynecol 2011;118:987-94.18. Callaghan William M, Creanga Andreea A,Kuklina Elena V. Severe maternal morbidityamong delivery and postpartum hospitalizationsin the United States. Obstet Gynecol 2012;120:1029-36.19. Duley L, Gulmezoglu AM, Henderson-Smart DJ, Chou D. Magnesium sulphate

and other anticonvulsants for women withpre-eclampsia. Cochrane Database SystemRev [Internet] 2005. Available at: http://www.mrw.interscience.wiley.com.cochrane/clsysrev/articles/CD000025/frame.html. Accessed June26, 2012.20. Yeast JD, Halberstadt C, Meyer BA,Cohen GR, Thorp JA. The risk of pulmonary

oedema and colloids osmotic pressure changesduring magnesium sulfate infusion. Am J ObstetGynecol 1993;169:1566-71.21. Benedetti T, Kates R, Williams V. Hemody-namic observations in severe preeclampsiacomplicated by pulmonary oedema. Am JObstet Gynecol 1985;152:330-4.22. Rice SK. Minimizing risk of magnesiumsulfate overdose in obstetrics. Am J MaternChild Health 2006;31:340.23. Australian Government Department ofHealth and Aging. Therapeutic goods adminis-tration Australia [Internet] 2008. Available at:http://www.tga.gov.au. Accessed June 26,

2012.24. Andersgaard A, Herbst A, Johansen M,Borgstrom A, Bille A, Oian P. Follow-upinterviews after eclampsia. Gynecol ObstetInvestig 2009;67:49-52.25. Loureiro R, Leite CC, Kahhale S. Diffusionimaging may predict reversible brain lesionsin eclampsia and severe preeclampsia: initialexperience. Am J Obstet Gynecol 2003;189:1350-5.26. Demirtas O, Gelal F, Vidinli BD. Cranial MRimaging with clinical correlation in preeclampsiaand eclampsia. Diagn Interv Radiol 2005;11:189-94.27. Zeeman G. Neurologic Complications ofpre-eclampsia. Semin Perinat 2009;33:166-72.28. KhanKS, Wojdyla D,Say L. WHOanalysis ofcauses of maternal death: a systematic review.Lancet 2006;367:1066-74.29. Cliffe S, Black D, Bryant J, Sullivan E.Maternal deaths in New South Wales, Australia:a data linkage project. ANZ J Obstet Gynaecol2008;48:255-60.30. Roberts CL, Bell JC, Ford JB, Hadfield RM,

Algert CS, Morris JM. The accuracy of reportingof the hypertensive disorders of pregnancy inpopulation health data. Hypertens Pregnancy2008;27:285-97.31. PymM, TaylorL. Validation study of theNew

South Wales midwives data collection 1990.Public Health Bull Suppl 1993;5-8:1-6.32. Thornton C, Makris A, Ogle R, Hennessy A.Generic obstetric database systems are unreli-able for reporting the hypertensive disorders ofpregnancy. ANZ J Obstet Gynaecol 2004;44:505-9.33. Chen JS, Roberts CL, Simpson JM,Ford JB. Prevalence of pre-eclampsia, preg-nancy hypertension and gestational diabetesin population-based data: impact of differentascertainment methods on outcomes. ANZ JObstet Gynaecol 2012;52:91-5.

Research Obstetrics www.AJOG.org

http://www.cherel.org.au/media/24160/qa_report_2012.pdfhttp://www.cherel.org.au/media/24160/qa_report_2012.pdfhttp://www.somanz.org/pdfs/somanz_guidelines_2008.pdfhttp://www.somanz.org/pdfs/somanz_guidelines_2008.pdfhttp://www.mrw.interscience.wiley.com.cochrane/clsysrev/articles/CD000025/frame.htmlhttp://www.mrw.interscience.wiley.com.cochrane/clsysrev/articles/CD000025/frame.htmlhttp://www.mrw.interscience.wiley.com.cochrane/clsysrev/articles/CD000025/frame.htmlhttp://www.tga.gov.au/http://www.tga.gov.au/http://www.mrw.interscience.wiley.com.cochrane/clsysrev/articles/CD000025/frame.htmlhttp://www.mrw.interscience.wiley.com.cochrane/clsysrev/articles/CD000025/frame.htmlhttp://www.mrw.interscience.wiley.com.cochrane/clsysrev/articles/CD000025/frame.htmlhttp://www.somanz.org/pdfs/somanz_guidelines_2008.pdfhttp://www.somanz.org/pdfs/somanz_guidelines_2008.pdfhttp://www.cherel.org.au/media/24160/qa_report_2012.pdfhttp://www.cherel.org.au/media/24160/qa_report_2012.pdf

the incidence of preeclampsia and eclampsia

Documents