The Journal of Maternal-Fetal & Neonatal Medicine
ISSN: 1476-7058 (Print) 1476-4954 (Online) Journal homepage: http://www.tandfonline.com/loi/ijmf20
Health outcomes of infants born to women with heart valve prostheses: complications of prematurity alone? Claire M. Lawley, Samantha J. Lain, Gemma A. Figtree & Christine L. Roberts To cite this article: Claire M. Lawley, Samantha J. Lain, Gemma A. Figtree & Christine L. Roberts (2014): Health outcomes of infants born to women with heart valve prostheses: complications of prematurity alone?, The Journal of Maternal-Fetal & Neonatal Medicine To link to this article: http://dx.doi.org/10.3109/14767058.2014.995082
Accepted author version posted online: 08 Dec 2014. Published online: 24 Dec 2014. Submit your article to this journal
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Date: 13 November 2015, At: 07:13
http://informahealthcare.com/jmf ISSN: 1476-7058 (print), 1476-4954 (electronic) J Matern Fetal Neonatal Med, Early Online: 1–3 ! 2014 Informa UK Ltd. DOI: 10.3109/14767058.2014.995082
SHORT REPORT
Health outcomes of infants born to women with heart valve prostheses: complications of prematurity alone? Claire M. Lawley1,2, Samantha J. Lain1, Gemma A. Figtree2, and Christine L. Roberts1
Downloaded by [Washington University in St Louis] at 07:13 13 November 2015
1
Clinical Population Perinatal Health Research, Kolling Institute, University of Sydney, Sydney, Australia and 2Department of Cardiology, Royal North Shore Hospital, St Leonards, Australia Abstract
Keywords
The health outcomes of children born to women with heart valve prostheses in New South Wales, Australia, 2000–2011, were examined in a record-linkage population-based study. Eighty-one women delivered 112 infants. One infant was stillborn, two died prior to discharge from hospital. Twenty seven (24.8%) were readmitted to hospital in their first year of life. The average number of readmissions up to age 6 years was 2.7 (95% CI 1.51–3.89) versus population rate of 2.04 (95% CI 2.03–2.05). The children demonstrated an increased risk of adverse event in the first year of life. Reassuringly however, and not previously reported, mortality and health outcomes in the first 6 years of life were not significantly different to the general population.
Cardiovascular diseases, infants, perinatal mortality, pregnancy
Introduction The combination of improvements in cardiac and obstetric care and the delayed age of child bearing has led to an increasing number of women with concurrent cardiac conditions giving birth. This includes women with prosthetic heart valves, both mechanical and bioprosthetic. Those born to these women are known to be at a higher risk of adverse birth and neonatal outcomes. Beyond this, there is little information on their longer-term health outcomes. To date, there has only been one study of 12 children born to women with mechanical heart valves looking at growth and development beyond the neonatal period [1]. This knowledge is essential, particularly when counselling women with prosthetic heart valves contemplating pregnancy. The aim of this study was to describe the health outcomes of children born to women with heart valve prostheses.
Methods The study population included all infants born to women with prosthetic heart valves in New South Wales (NSW), Australia, between 1 July 2000 and 21 December 2011. Data were obtained from four routinely collected population data sets: the NSW Perinatal Data Collection (PDC), the NSW Admitted Patient Data Collection (APDC), Register of
Address for correspondence: Dr Claire Lawley, Clinical Population Perinatal Health Research Group, The Kolling Institute, University of Sydney at Royal North Shore Hospital, Sydney, Australia. Tel: +61-2-9462-9790. Fax: +61-2-9462-9058. E-mail: claw2317@ uni.sydney.edu.au
History Received 23 September 2014 Revised 25 November 2014 Accepted 2 December 2014 Published online 24 December 2014
Congenital Conditions (RoCC) and the Register of Births, Deaths and Marriages (RBDM). The PDC is a populationbased surveillance system of all births in NSW at least 20 weeks gestation or 400 g in weight. The APDC is an administrative database of all hospital admissions. The RoCC is a register of congenital conditions diagnosed in infants up to 1 year of age. The RBDM is a record of all deaths occurring in NSW. The four databases were linked by the Centre for Health Record Linkage (CHeReL) using probabilistic linkage. The APDC was used to identify women who had a heart valve prosthesis implanted prior to giving birth and the PDC was used to identify births, as described in a previous study [2]. Gestational age (GA) and small-for-gestational-age (SGA) were identified from the PDC. Deaths included stillbirths, neonatal deaths (up to 28 days), infant deaths (up to age 1 year) and paediatric deaths (age 1–6 years). The Neonatal Adverse Outcome Indicator was used to identify infants born with severe neonatal morbidity [3]. Congenital conditions were identified from the RoCC and/or APDC. Minor anomalies were excluded. Readmissions to hospital after initial discharge home were identified from the APDC for the first year of life, and up to age 6 years or 2011, whichever came first. Frequencies of each study outcome were calculated for infants of mothers with prosthetic heart valves. The rates of outcomes for the whole of NSW were compared from the same data sources. Over 1 million (n ¼ 1 053 822) infants born in NSW from 2000 to 2011 were included as a populationbased comparison group. The rates of outcomes for infants
2
C. M. Lawley et al.
J Matern Fetal Neonatal Med, Early Online: 1–3
This was not significantly different to the population rate, 3.7% (p ¼ 0.32). Of 109 infants that were discharged home, 24.8% (n ¼ 27) were readmitted to hospital at least once in the first year, compared to 18.0% of the NSW population. A higher proportion of readmitted infants born to women with heart valve prostheses were preterm, 41% as compared to the population rate of 11%. When examining readmissions up to age 6 years or to 2011, the proportion of infants born to mothers with heart valve prostheses readmitted at least once was not significantly different to the general population (39.9 versus 36.3%). The average number of readmissions up to age 6 years or 2011 was 2.70 (95% CI 1.51–3.89) for infants of mothers with heart valves, compared to a population rate of 2.04 (95% CI 2.03–2.05). Infants born to women with heart valve prostheses spent an average of 6.89 days (95% CI 0.66–13.11) in hospital up to age 6 years (or 2011), compared to the general population, spending an average of 4.26 days (95% CI 4.22–4.30). Of the 81 hospital admissions of infants born to women with heart valve prostheses after birth prior to the sixth year of life, 34 (41.9%) were for management of an acute respiratory illness, including 15 admissions for bronchiolitis.
born to women with and without a prosthetic heart valve were compared using contingency table analysis. The average number of readmissions per infant and average total number of hospital days (not including the birth admissions) per infant up to age 6 years (or 2011) were calculated. The primary diagnosis of each readmission of infants of women with prosthetic heart valves was examined. The study was approved by the NSW Population and Health Services Research Ethics Committee (Approval No.: 2012/12/430).
Downloaded by [Washington University in St Louis] at 07:13 13 November 2015
Results From 1 July 2000 to 31 December 2011, 81 women with heart valve prostheses delivered 112 infants of at least 20 weeks gestation. The type of maternal heart valve prostheses was known in 52 of the births; 38 bioprosthetic valves and 14 mechanical valves. One infant was stillborn at 26 weeks gestation. Two infants died prior to discharge from hospital during the birth admission. Both had congenital conditions identified and were born preterm, one at 20 weeks gestation and the other at 34 weeks gestation. No deaths were recorded after age 1 year. The overall death rate for infants, up to 1 year of age, born to mothers with heart valves was not significantly different to the population rate (p ¼ 0.13) (Table 1). The rate of preterm birth amongst infants born to mothers with heart valves (18.8%) was 2.6 times greater than the preterm birth rate in NSW during the same period (6.8%) (Table 1). This included 2.7% born extremely preterm (528 weeks) compared to 0.7% of the NSW population. Only 7 of the preterm 21 births followed spontaneous labour. The remaining 14 were the result of induction of labour or pre-labour caesarean section. The proportion of infants born SGA and infants that experienced severe neonatal morbidity were significantly higher for infants born to mothers with heart valve prostheses compared to the rest of the population (p50.0001) (Table 1). As expected, preterm infants were over-represented among those who experience severe neonatal morbidity, both those infants born to women with heart valve prostheses (9/14, 64% of those experiencing severe neonatal morbidity in this group) and the general population (52%). Six (5.3%) infants had a congenital anomaly, two with a congenital cardiac condition.
Discussion This study provides new information on the health outcomes of children, up to age 6 years, born to women with heart valve prostheses. It suggests that the impact of this condition is borne predominantly during the neonatal period and diminishes during the first year of life. Prematurity is known to greatly impact health status during this time. Reassuringly, the overall death rate and proportion of infants readmitted to hospital up to the age of 6 years is not significantly different to the population rate. Previous works exploring the outcomes of neonates born to women with cardiovascular disease have reported similarly high rates of prematurity, both in the setting of maternal acquired and congenital heart disease [4,5]. A number of the preterm births in this study resulted from preterm induction of labour and preterm pre-labour caesarean section, potentially due to the need to control maternal anticoagulation in the setting of mechanical heart valves or due to concerns about
Table 1. Childhood health outcomes.
Outcome Mortality up to age 1 year GA (weeks) 20–27 28–33 34–36 37–38 39–41 42+ SGA 510th percentile Severe neonatal morbidity Congenital anomaly Hospital readmissions At least one readmission up to age 1 year At least one readmission up to age 6 years or to 2011 GA: Gestational age, SGA: Small for gestational age.
Children of women with heart valve prostheses (n) N ¼ 112 (%)
All children born NSW 2001–2011 N ¼ 1 053 822 (%)
p value
3 (2.7)
1.1
0.13
(2.7) (5.4) (10.7) (35.7) (42.9) (2.7) (20.5) (12.7) (5.3)
0.7 1.6 5.0 22.5 68.7 1.5 9.9 4.8 3.7
50.0001
27 (24.8) 44 (39.3)
17.8 36.3
0.08 0.55
3 6 12 40 48 3 23 14 6
50.0001 50.0001 0.32
Infants of women with heart valve prostheses
Downloaded by [Washington University in St Louis] at 07:13 13 November 2015
DOI: 10.3109/14767058.2014.995082
intrauterine growth restriction. The high incidence of SGA babies has been noted by other groups examining outcomes of the neonates of women with cardiovascular disease [6,7]. Both SGA and preterm birth are known to increase risk of hospital readmission in the first year of life. Preterm infants have been found to have an altered health trajectory, potentially persisting into adolescence [8]. There is a notably greater incidence of severe respiratory illnesses in these individuals in early childhood, accounting for the high number of hospital admissions for management of acute respiratory compromise [8,9]. A recent prospective Dutch cohort study found that infants born between 32 and 36 weeks GA had twice the hospital admissions caused by respiratory problems in the first year of life as those born at term (6 versus 3%; p50.001) [10]. Despite a number of the mothers suffering from cardiac disease, there were only two infants in this cohort identified with congenital heart disease. Also, although women with mechanical heart valve prostheses may have continued a potentially teratogenic anticoagulant regimen during pregnancy, there was no significant difference in the incidence of congenital anomalies when compared to the general population. The strengths of this study include the duration of followup of the infants, qualifying previously unknown outcomes. The validity of the data used is also well established. Limitations include the lack of detailed clinical information available in routinely collected data, such as the aetiology of maternal cardiovascular disease, complete documentation of heart valve prosthesis type and maternal medications, such as teratogenic anticoagulants.
Conclusion Children born to women with heart valve prostheses are at an increased risk of an adverse event in the first year of life, when prematurity is known to have a larger impact on health status. Reassuringly, their mortality in the first year of life and longer health outcomes are not significantly different to the general population.
3
Declaration of interest The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article. This work was supported by Australian National Health and Medical Research Council (NHMRC) (APP1001066) and Australian Heart Foundation grants. C.L.R. is supported by a NHMRC Senior Research Fellowship (APP1021025) and G.A.F. is co-funded by a NHMRC Career Development Fellowship (APP1062262) and a Heart Foundation (Australia) Future Leader Fellowship. The funding agencies listed had no role in study design, data collection and analysis, decision to publish or preparation of the article.
References 1. Jiang L, Yang F, Li YB, et al. Preliminary observation on the impact of pregnant women taking warfarin after mechanical valve replacement on children’s physical and mental development. Chinese J Evid Based Med 2012;12:516–19. 2. Lawley CM, Algert CS, Ford JB, et al. Heart valve prostheses in pregnancy: outcomes for women and their infants. J Am Heart Assoc 2014;3:e000953. 3. Lain SJ, Algert CS, Nassar N, et al. Incidence of severe adverse neonatal outcomes: use of a composite indicator in a population cohort. Matern Child Health J 2011;16:600–8. 4. Sillesen M, Hjortdal V, Vejlstrup N, Sorensen K. Pregnancy with prosthetic heart valves - 30 years’ nationwide experience in Denmark. Eur J Cardio-Thorac Surg 2011;40:448–54. 5. Thanajiraprapa T, Phupong V. Pregnancy complications in women with heart disease. J Matern Fetal Neonatal Med 2010;23:1200–4. 6. Pieper PG, Balci A, Aarnoudse JG, et al. Uteroplacental blood flow, cardiac function, and pregnancy outcome in women with congenital heart disease. Circulation 2013;128:2478–87. 7. Sadler L, McCowan L, White H, et al. Pregnancy outcomes and cardiac complications in women with mechanical, bioprosthetic and homograft valves. BJOG 2000;107:245–53. 8. Saigal S, Doyle LW. An overview of mortality and sequelae of preterm birth from infancy to adulthood. Lancet 2008;371:261–9. 9. Pramana IA, Latzin P, Schlapbach LJ, et al. Respiratory symptoms in preterm infants: burden of disease in the first year of life. Eur J Med Res 2011;16:223–30. 10. Vrijlandt EJ, Kerstjens JM, Duiverman EJ, et al. Moderately preterm children have more respiratory problems during their first 5 years of life than children born full term. Am J Respir Crit Care Med 2013;187:1234–40.
ISSN: 1476-7058 (Print) 1476-4954 (Online) Journal homepage: http://www.tandfonline.com/loi/ijmf20
Health outcomes of infants born to women with heart valve prostheses: complications of prematurity alone? Claire M. Lawley, Samantha J. Lain, Gemma A. Figtree & Christine L. Roberts To cite this article: Claire M. Lawley, Samantha J. Lain, Gemma A. Figtree & Christine L. Roberts (2014): Health outcomes of infants born to women with heart valve prostheses: complications of prematurity alone?, The Journal of Maternal-Fetal & Neonatal Medicine To link to this article: http://dx.doi.org/10.3109/14767058.2014.995082
Accepted author version posted online: 08 Dec 2014. Published online: 24 Dec 2014. Submit your article to this journal
Article views: 14
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ijmf20 Download by: [Washington University in St Louis]
Date: 13 November 2015, At: 07:13
http://informahealthcare.com/jmf ISSN: 1476-7058 (print), 1476-4954 (electronic) J Matern Fetal Neonatal Med, Early Online: 1–3 ! 2014 Informa UK Ltd. DOI: 10.3109/14767058.2014.995082
SHORT REPORT
Health outcomes of infants born to women with heart valve prostheses: complications of prematurity alone? Claire M. Lawley1,2, Samantha J. Lain1, Gemma A. Figtree2, and Christine L. Roberts1
Downloaded by [Washington University in St Louis] at 07:13 13 November 2015
1
Clinical Population Perinatal Health Research, Kolling Institute, University of Sydney, Sydney, Australia and 2Department of Cardiology, Royal North Shore Hospital, St Leonards, Australia Abstract
Keywords
The health outcomes of children born to women with heart valve prostheses in New South Wales, Australia, 2000–2011, were examined in a record-linkage population-based study. Eighty-one women delivered 112 infants. One infant was stillborn, two died prior to discharge from hospital. Twenty seven (24.8%) were readmitted to hospital in their first year of life. The average number of readmissions up to age 6 years was 2.7 (95% CI 1.51–3.89) versus population rate of 2.04 (95% CI 2.03–2.05). The children demonstrated an increased risk of adverse event in the first year of life. Reassuringly however, and not previously reported, mortality and health outcomes in the first 6 years of life were not significantly different to the general population.
Cardiovascular diseases, infants, perinatal mortality, pregnancy
Introduction The combination of improvements in cardiac and obstetric care and the delayed age of child bearing has led to an increasing number of women with concurrent cardiac conditions giving birth. This includes women with prosthetic heart valves, both mechanical and bioprosthetic. Those born to these women are known to be at a higher risk of adverse birth and neonatal outcomes. Beyond this, there is little information on their longer-term health outcomes. To date, there has only been one study of 12 children born to women with mechanical heart valves looking at growth and development beyond the neonatal period [1]. This knowledge is essential, particularly when counselling women with prosthetic heart valves contemplating pregnancy. The aim of this study was to describe the health outcomes of children born to women with heart valve prostheses.
Methods The study population included all infants born to women with prosthetic heart valves in New South Wales (NSW), Australia, between 1 July 2000 and 21 December 2011. Data were obtained from four routinely collected population data sets: the NSW Perinatal Data Collection (PDC), the NSW Admitted Patient Data Collection (APDC), Register of
Address for correspondence: Dr Claire Lawley, Clinical Population Perinatal Health Research Group, The Kolling Institute, University of Sydney at Royal North Shore Hospital, Sydney, Australia. Tel: +61-2-9462-9790. Fax: +61-2-9462-9058. E-mail: claw2317@ uni.sydney.edu.au
History Received 23 September 2014 Revised 25 November 2014 Accepted 2 December 2014 Published online 24 December 2014
Congenital Conditions (RoCC) and the Register of Births, Deaths and Marriages (RBDM). The PDC is a populationbased surveillance system of all births in NSW at least 20 weeks gestation or 400 g in weight. The APDC is an administrative database of all hospital admissions. The RoCC is a register of congenital conditions diagnosed in infants up to 1 year of age. The RBDM is a record of all deaths occurring in NSW. The four databases were linked by the Centre for Health Record Linkage (CHeReL) using probabilistic linkage. The APDC was used to identify women who had a heart valve prosthesis implanted prior to giving birth and the PDC was used to identify births, as described in a previous study [2]. Gestational age (GA) and small-for-gestational-age (SGA) were identified from the PDC. Deaths included stillbirths, neonatal deaths (up to 28 days), infant deaths (up to age 1 year) and paediatric deaths (age 1–6 years). The Neonatal Adverse Outcome Indicator was used to identify infants born with severe neonatal morbidity [3]. Congenital conditions were identified from the RoCC and/or APDC. Minor anomalies were excluded. Readmissions to hospital after initial discharge home were identified from the APDC for the first year of life, and up to age 6 years or 2011, whichever came first. Frequencies of each study outcome were calculated for infants of mothers with prosthetic heart valves. The rates of outcomes for the whole of NSW were compared from the same data sources. Over 1 million (n ¼ 1 053 822) infants born in NSW from 2000 to 2011 were included as a populationbased comparison group. The rates of outcomes for infants
2
C. M. Lawley et al.
J Matern Fetal Neonatal Med, Early Online: 1–3
This was not significantly different to the population rate, 3.7% (p ¼ 0.32). Of 109 infants that were discharged home, 24.8% (n ¼ 27) were readmitted to hospital at least once in the first year, compared to 18.0% of the NSW population. A higher proportion of readmitted infants born to women with heart valve prostheses were preterm, 41% as compared to the population rate of 11%. When examining readmissions up to age 6 years or to 2011, the proportion of infants born to mothers with heart valve prostheses readmitted at least once was not significantly different to the general population (39.9 versus 36.3%). The average number of readmissions up to age 6 years or 2011 was 2.70 (95% CI 1.51–3.89) for infants of mothers with heart valves, compared to a population rate of 2.04 (95% CI 2.03–2.05). Infants born to women with heart valve prostheses spent an average of 6.89 days (95% CI 0.66–13.11) in hospital up to age 6 years (or 2011), compared to the general population, spending an average of 4.26 days (95% CI 4.22–4.30). Of the 81 hospital admissions of infants born to women with heart valve prostheses after birth prior to the sixth year of life, 34 (41.9%) were for management of an acute respiratory illness, including 15 admissions for bronchiolitis.
born to women with and without a prosthetic heart valve were compared using contingency table analysis. The average number of readmissions per infant and average total number of hospital days (not including the birth admissions) per infant up to age 6 years (or 2011) were calculated. The primary diagnosis of each readmission of infants of women with prosthetic heart valves was examined. The study was approved by the NSW Population and Health Services Research Ethics Committee (Approval No.: 2012/12/430).
Downloaded by [Washington University in St Louis] at 07:13 13 November 2015
Results From 1 July 2000 to 31 December 2011, 81 women with heart valve prostheses delivered 112 infants of at least 20 weeks gestation. The type of maternal heart valve prostheses was known in 52 of the births; 38 bioprosthetic valves and 14 mechanical valves. One infant was stillborn at 26 weeks gestation. Two infants died prior to discharge from hospital during the birth admission. Both had congenital conditions identified and were born preterm, one at 20 weeks gestation and the other at 34 weeks gestation. No deaths were recorded after age 1 year. The overall death rate for infants, up to 1 year of age, born to mothers with heart valves was not significantly different to the population rate (p ¼ 0.13) (Table 1). The rate of preterm birth amongst infants born to mothers with heart valves (18.8%) was 2.6 times greater than the preterm birth rate in NSW during the same period (6.8%) (Table 1). This included 2.7% born extremely preterm (528 weeks) compared to 0.7% of the NSW population. Only 7 of the preterm 21 births followed spontaneous labour. The remaining 14 were the result of induction of labour or pre-labour caesarean section. The proportion of infants born SGA and infants that experienced severe neonatal morbidity were significantly higher for infants born to mothers with heart valve prostheses compared to the rest of the population (p50.0001) (Table 1). As expected, preterm infants were over-represented among those who experience severe neonatal morbidity, both those infants born to women with heart valve prostheses (9/14, 64% of those experiencing severe neonatal morbidity in this group) and the general population (52%). Six (5.3%) infants had a congenital anomaly, two with a congenital cardiac condition.
Discussion This study provides new information on the health outcomes of children, up to age 6 years, born to women with heart valve prostheses. It suggests that the impact of this condition is borne predominantly during the neonatal period and diminishes during the first year of life. Prematurity is known to greatly impact health status during this time. Reassuringly, the overall death rate and proportion of infants readmitted to hospital up to the age of 6 years is not significantly different to the population rate. Previous works exploring the outcomes of neonates born to women with cardiovascular disease have reported similarly high rates of prematurity, both in the setting of maternal acquired and congenital heart disease [4,5]. A number of the preterm births in this study resulted from preterm induction of labour and preterm pre-labour caesarean section, potentially due to the need to control maternal anticoagulation in the setting of mechanical heart valves or due to concerns about
Table 1. Childhood health outcomes.
Outcome Mortality up to age 1 year GA (weeks) 20–27 28–33 34–36 37–38 39–41 42+ SGA 510th percentile Severe neonatal morbidity Congenital anomaly Hospital readmissions At least one readmission up to age 1 year At least one readmission up to age 6 years or to 2011 GA: Gestational age, SGA: Small for gestational age.
Children of women with heart valve prostheses (n) N ¼ 112 (%)
All children born NSW 2001–2011 N ¼ 1 053 822 (%)
p value
3 (2.7)
1.1
0.13
(2.7) (5.4) (10.7) (35.7) (42.9) (2.7) (20.5) (12.7) (5.3)
0.7 1.6 5.0 22.5 68.7 1.5 9.9 4.8 3.7
50.0001
27 (24.8) 44 (39.3)
17.8 36.3
0.08 0.55
3 6 12 40 48 3 23 14 6
50.0001 50.0001 0.32
Infants of women with heart valve prostheses
Downloaded by [Washington University in St Louis] at 07:13 13 November 2015
DOI: 10.3109/14767058.2014.995082
intrauterine growth restriction. The high incidence of SGA babies has been noted by other groups examining outcomes of the neonates of women with cardiovascular disease [6,7]. Both SGA and preterm birth are known to increase risk of hospital readmission in the first year of life. Preterm infants have been found to have an altered health trajectory, potentially persisting into adolescence [8]. There is a notably greater incidence of severe respiratory illnesses in these individuals in early childhood, accounting for the high number of hospital admissions for management of acute respiratory compromise [8,9]. A recent prospective Dutch cohort study found that infants born between 32 and 36 weeks GA had twice the hospital admissions caused by respiratory problems in the first year of life as those born at term (6 versus 3%; p50.001) [10]. Despite a number of the mothers suffering from cardiac disease, there were only two infants in this cohort identified with congenital heart disease. Also, although women with mechanical heart valve prostheses may have continued a potentially teratogenic anticoagulant regimen during pregnancy, there was no significant difference in the incidence of congenital anomalies when compared to the general population. The strengths of this study include the duration of followup of the infants, qualifying previously unknown outcomes. The validity of the data used is also well established. Limitations include the lack of detailed clinical information available in routinely collected data, such as the aetiology of maternal cardiovascular disease, complete documentation of heart valve prosthesis type and maternal medications, such as teratogenic anticoagulants.
Conclusion Children born to women with heart valve prostheses are at an increased risk of an adverse event in the first year of life, when prematurity is known to have a larger impact on health status. Reassuringly, their mortality in the first year of life and longer health outcomes are not significantly different to the general population.
3
Declaration of interest The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article. This work was supported by Australian National Health and Medical Research Council (NHMRC) (APP1001066) and Australian Heart Foundation grants. C.L.R. is supported by a NHMRC Senior Research Fellowship (APP1021025) and G.A.F. is co-funded by a NHMRC Career Development Fellowship (APP1062262) and a Heart Foundation (Australia) Future Leader Fellowship. The funding agencies listed had no role in study design, data collection and analysis, decision to publish or preparation of the article.
References 1. Jiang L, Yang F, Li YB, et al. Preliminary observation on the impact of pregnant women taking warfarin after mechanical valve replacement on children’s physical and mental development. Chinese J Evid Based Med 2012;12:516–19. 2. Lawley CM, Algert CS, Ford JB, et al. Heart valve prostheses in pregnancy: outcomes for women and their infants. J Am Heart Assoc 2014;3:e000953. 3. Lain SJ, Algert CS, Nassar N, et al. Incidence of severe adverse neonatal outcomes: use of a composite indicator in a population cohort. Matern Child Health J 2011;16:600–8. 4. Sillesen M, Hjortdal V, Vejlstrup N, Sorensen K. Pregnancy with prosthetic heart valves - 30 years’ nationwide experience in Denmark. Eur J Cardio-Thorac Surg 2011;40:448–54. 5. Thanajiraprapa T, Phupong V. Pregnancy complications in women with heart disease. J Matern Fetal Neonatal Med 2010;23:1200–4. 6. Pieper PG, Balci A, Aarnoudse JG, et al. Uteroplacental blood flow, cardiac function, and pregnancy outcome in women with congenital heart disease. Circulation 2013;128:2478–87. 7. Sadler L, McCowan L, White H, et al. Pregnancy outcomes and cardiac complications in women with mechanical, bioprosthetic and homograft valves. BJOG 2000;107:245–53. 8. Saigal S, Doyle LW. An overview of mortality and sequelae of preterm birth from infancy to adulthood. Lancet 2008;371:261–9. 9. Pramana IA, Latzin P, Schlapbach LJ, et al. Respiratory symptoms in preterm infants: burden of disease in the first year of life. Eur J Med Res 2011;16:223–30. 10. Vrijlandt EJ, Kerstjens JM, Duiverman EJ, et al. Moderately preterm children have more respiratory problems during their first 5 years of life than children born full term. Am J Respir Crit Care Med 2013;187:1234–40.
