Determining a strategy to reduce smoking in pregnancy.

BACKGROUND: Further efforts, informed by current data, are needed to reduce smoking during pregnancy. AIMS: To describe trends in smoking during pregnancy and identify regions most likely to benefit from targeted smoking cessation interventions, in New South Wales (NSW), Australia. MATERIALS AND METHODS: All women who gave birth in NSW between 1994 and 2016 were included. Smoking status was identified from the Perinatal Data Collection. For births between 2012 and 2016, women were grouped into Local Health District (LHD) of residence, and smoking rates calculated. The impacts of a hypothetical smoking cessation intervention in four LHDs with (i) high smoking rates and (ii) high numbers of smokers, were compared. RESULTS: The overall smoking rate during pregnancy decreased from 22.1% in 1994 to 8.3% in 2016. [Correction added on 13 August 2020, after first online publication: the overall smoking rate during pregnancy in 1994 has been corrected from 14.5% to 22.1%.]. The decrease was lowest among women living in the most socioeconomically disadvantaged areas (41%) and highest among those living in the most advantaged areas (83%). Between 2012 and 2016, over half the women who smoked during pregnancy lived in one of four LHDs. Only 1% of women reporting smoking during pregnancy resided in the LHD with the highest smoking rate (34.7%). A simulated intervention targeting only four regions showed greater effect on the statewide smoking rate when targeting LHDs with high numbers of smokers rather than high smoking rates. CONCLUSIONS: Despite decreases in rates of smoking during pregnancy, there was evidence of geographic clustering of smokers. The greatest reduction in overall smoking may come from interventions targeting the four LHDs with the highest number of smokers.

Benefits of not smoking during pregnancy for Australian Aboriginal and Torres Strait Islander women and their babies: a retrospective cohort study using linked data.

OBJECTIVES: To provide evidence for targeted smoking cessation policy, the aim of this study was to compare pregnancy outcomes of Aboriginal mothers who reported not smoking during pregnancy with Aboriginal mothers who reported smoking during pregnancy. DESIGN: Population based retrospective cohort study using linked data. SETTING: New South Wales, the most populous Australian state. POPULATION: 18 154 singleton babies born to 13 477 Aboriginal mothers between 2010 and 2014 were identified from routinely collected New South Wales datasets. Aboriginality was determined from birth records and from four linked datasets through an Enhanced Reporting of Aboriginality algorithm. EXPOSURE: Not smoking at any time during pregnancy. MAIN OUTCOME MEASURES: Unadjusted and adjusted relative risks (aRR) and 95% CIs from modified Poisson regression were used to examine associations between not smoking during pregnancy and maternal and perinatal outcomes including severe morbidity, inter-hospital transfer, perinatal death, preterm birth and small-for-gestational age. Population attributable fractions (PAFs) were calculated using adjusted relative risks. RESULTS: Compared with babies born to mothers who smoked during pregnancy, babies born to non-smoking mothers had a lower risk of all adverse perinatal outcomes including perinatal death (aRR=0.58, 95% CI 0.44 to 0.76), preterm birth (aRR=0.58, 95% CI 0.53 to 0.64) and small-for-gestational age (aRR=0.35, 95% CI 0.32 to 0.39). PAFs (%) were 27% for perinatal death, 26% for preterm birth and 48% for small-for-gestational-age. Compared with women who smoked during pregnancy (n=8919), those who did not smoke (n=9235) had a lower risk of being transferred to another hospital (aRR=0.76, 95% CI 0.66 to 0.89). CONCLUSIONS: Babies born to women who did not smoke during pregnancy had a lower risk of adverse perinatal outcomes. Rates of adverse outcomes among Aboriginal non-smokers were similar to those among the general population. These results quantify the proportion of adverse perinatal outcomes due to smoking and highlight why effective smoking cessation programme are urgently required for this population.

Appendicectomy during pregnancy and the risk of preterm birth: A population data linkage study.

BACKGROUND: Suspected appendicitis is a common non-obstetric indication for emergency abdominal surgery during pregnancy. AIMS: Assess the risk of preterm birth and other maternal and neonatal adverse birth outcomes following appendicectomy during pregnancy. MATERIALS AND METHODS: Population-based data linkage study of women with singleton births in New South Wales, Australia, 2002-2014. Pregnancies with appendicitis and appendicectomy were compared to pregnancies without appendicitis. Crude and adjusted hazard ratios (aHR) with 95% confidence intervals (CI) for preterm birth were estimated. Modified Poisson regression with robust variance was used to estimate crude and adjusted risk ratios (aRR) with 99% CI for other outcomes. RESULTS: Of 1 124 551 eligible pregnancies, 1024 (0.9/1000 pregnancies) had appendicitis and appendicectomy. Of these, 566 (55.3%) had laparoscopic and 458 (44.7%) had open appendicectomy. Appendicectomy at later gestational ages was associated with increasing rates of preterm birth. After adjustment for maternal and pregnancy factors, appendicectomy was associated with increased risk of preterm birth (overall aHR 1.73, 95% CI 1.42-2.09; planned aHR 2.08, 95% CI 1.60-2.72), maternal morbidity (aRR 2.68, 99% CI 1.88-3.83) and neonatal morbidity (aRR 1.42, 99% CI 1.03-1.94). However, there was no difference in perinatal mortality rates. CONCLUSION: Appendicectomy during pregnancy is associated with increased risk of spontaneous and planned preterm birth, maternal and neonatal morbidity. Availability of resources to prevent or manage preterm labour should be considered when appendicectomy is performed at gestational ages of 20 weeks or more.

Antecedents of Abnormally Invasive Placenta in Primiparous Women: Risk Associated With Gynecologic Procedures.

OBJECTIVE: To evaluate the association between prior invasive gynecologic procedures and the risk of subsequent abnormally invasive placenta (ie, placenta accreta, increta, and percreta). METHODS: We conducted a population-based data linkage study including all primiparous women who delivered in New South Wales, Australia, between 2003 and 2012. Data were obtained from linked birth and hospital admissions with a minimum lookback period of 2 years. Prior procedures invasive of the uterus were considered including gynecologic laparoscopy with instrumentation of the uterus; hysteroscopy, including operative hysteroscopy; curettage, including suction curettage and surgical termination; and endometrial ablation. Modified Poisson regression was used to determine the association between the number of prior gynecologic procedures and risk of abnormally invasive placenta. RESULTS: Eight hundred fifty-four cases of abnormally invasive placenta were identified among 380,775 deliveries included in the study (22.4/10,000). In total, 33,296 primiparous women had at least one prior procedure (8.7%). Among women with abnormally invasive placenta, 152 (17.8%) had undergone at least one procedure compared with 33,144 (8.7%) among women without abnormally invasive placenta (P<.01). After adjustment, the relative risk was 1.5 for one procedure (99% CI 1.1-1.9), 2.7 for two procedures (99% CI 1.7-4.4), and 5.1 for three or more procedures (99% CI 2.7-9.6). Abnormally invasive placenta was also positively associated with maternal age, socioeconomic advantage, mother being Australia-born, placenta previa, hypertension, multiple births, use of assisted reproductive technology, and female fetal sex. CONCLUSION: Women with a history of prior invasive gynecologic procedures were more likely to develop abnormally invasive placenta. These insights may be used to inform management of pregnancies in women with a history of gynecologic procedures.

Outcomes of Gallstone Disease during Pregnancy: a Population-based Data Linkage Study.

BACKGROUND: Gallstone disease is a leading indication for non-obstetric abdominal surgery during pregnancy. There are limited whole population data on maternal and neonatal outcomes. This population-based study aims to describe the outcomes of gallstone disease during pregnancy in an Australian setting. METHODS: Linked hospital, birth, and mortality data for all women with singleton pregnancies in New South Wales, Australia, 2001-2012 were analysed. Exposure of interest was gallstone disease (acute biliary pancreatitis, gallstones with/without cholecystitis). Outcomes including preterm birth (spontaneous and planned), readmission, morbidity and mortality (maternal and neonatal) were compared between pregnancies with and without gallstone disease. Adjusted risk ratios (aRRs) and 99% confidence intervals were estimated using modified Poisson regression and adjusted for maternal and pregnancy factors. RESULTS: Among 1 064 089 pregnancies, 1882 (0.18%) had gallstone disease. Of these, 239 (12.7%) had an antepartum cholecystectomy and 1643 (87.3%) were managed conservatively. Of those managed conservatively, 319 (19.0%) had a postpartum cholecystectomy. Gallstone disease was associated with increased risk of preterm birth (aRR 1.3, 99% CI 1.1, 1.6), particularly planned preterm birth (aRR 1.6, 99% CI 1.2, 2.1), maternal morbidity (aRR 1.6, 99% CI 1.1, 2.3), maternal readmission (aRR 4.7, 99% CI 4.2, 5.3), and neonatal morbidity (aRR 1.4, 99% CI 1.1, 1.7). Surgery was associated with decreased risk of maternal readmission (aRR 0.4, 99% CI 0.2, 0.7). CONCLUSIONS: Gallstone disease during pregnancy was associated with adverse maternal and neonatal outcomes. Most women with gallstone disease during pregnancy are managed conservatively. Surgical management was associated with decreased risk of readmission.

Contribution of changing risk factors to the trend in breech presentation at term.

BACKGROUND: Recent population-wide changes in perinatal risk factors may affect rates of breech presentation at birth, and have implications for the provision of breech services and training in breech management. AIMS: To investigate whether changes in maternal and pregnancy characteristics explain the observed trend in breech presentation at term. MATERIALS AND METHODS: All singleton term (≥37 week) births in New South Wales during 2002-2012 were identified through birth and associated hospital records. Annual rates of breech presentation were determined. Logistic regression modelling was used to predict expected rates of breech presentation and these were compared with observed rates over time. A priori predictors included maternal age, country of birth, parity, smoking during pregnancy, diabetes, pregnancy hypertension, placenta praevia, previous singleton term breech, previous caesarean section, infant sex, gestational age, birthweight and congenital anomalies. Hospital and Medicare data were used to assess concomitant trends in external cephalic version. RESULTS: Among 914 147 singleton term births, 3.1% were breech at delivery. Rates of breech presentation declined from 3.6% in 2002 to 2.7% in 2012 (test for trend P < 0.001), but was predicted to increase from 3.6% in 2002 to 4.3% in 2012 because of increased maternal age, nulliparity, maternal diabetes, history of breech presentation and previous caesarean section. However, use of external cephalic version appears to have increased over time. CONCLUSIONS: Breech presentation at delivery has decreased in New South Wales. Increased use of external cephalic version likely accounts for this decline, as changes in risk factors do not.

Population-Based Study of Sleep Apnea in Pregnancy and Maternal and Infant Outcomes.

STUDY OBJECTIVES: To examine the association between sleep apnea and pregnancy outcomes in a large population-based cohort. METHODS: Population-based cohort study using linked birth and hospital records was conducted in New South Wales, Australia. Participants were all women who gave birth from 2002 to 2012 (n = 636,227). Sleep apnea in the year before pregnancy or during pregnancy was identified from hospital records. Outcomes of interest were gestational diabetes, pregnancy hypertension, planned delivery, caesarean section, preterm birth, perinatal death, 5-minute Apgar score, admission to neonatal intensive care or special care nursery, and infant size for gestational age. Maternal outcomes were identified using a combination of hospital and birth records. Infant outcomes came from the birth record. Modified Poisson regression models were used to examine associations between sleep apnea and each outcome taking into account maternal age, country of birth, socioeconomic disadvantage, smoking, obesity, parity, pre-existing diabetes and hypertension. RESULTS: Sleep apnea was significantly associated with pregnancy hypertension (adjusted RR 1.43; 95% CI 1.18-1.73), planned delivery (1.15; 1.07-1.23), preterm birth (1.50; 1.21-1.84), 5-minute Apgar < 7 (1.60; 1.07-2.38), admission to neonatal intensive care/special care nursery (1.26; 1.11-1.44), large-for-gestational-age infants (1.27; 1.04-1.55) but not with gestational diabetes (1.09; 0.82-1.46), caesarean section (1.06; 0.96-1.17), perinatal death (1.73; 0.92-3.25), or small-for-gestational-age infants (0.81; 0.61-1.08). CONCLUSIONS: Sleep apnea is associated with higher rates of obstetric complications and intervention, as well as preterm delivery. Future research should examine if these are independent of obstetric history.

Variation in and factors associated with timing of low risk, pre-labour repeat caesarean sections in NSW, 2008-2011.

OBJECTIVE: To explore variation in public hospital rates of early (37-38 weeks gestation) prelabour repeat caesarean section among low-risk women at and beyond term in New South Wales (NSW) between 2008 and 2011. IMPORTANCE OF THE STUDY: A NSW Ministry of Health policy directive for public hospitals (PD2007_024), 'Maternity - timing of elective or pre-labour caesarean section', requires that low-risk elective or prelabour caesarean section does not occur before 39 completed weeks gestation. However, compliance with this policy has not been evaluated. STUDY TYPE: Population-based record linkage study Methods: Linked birth and hospital data for low-risk, prelabour repeat caesarean sections in NSW in 2008-2011 were analysed using multilevel regression modelling. Rates were adjusted for casemix and hospital factors. Low-risk pregnancies were defined as singleton live births at 37-42 weeks gestation among women without medical or obstetric complications and where the indication for caesarean section was 'elective repeat caesarean section'. RESULTS: In 2008-2011, there were 15 163 prelabour repeat caesarean sections among low-risk women in NSW. Overall, 34.7% of low-risk prelabour repeat caesarean sections occurred before 39 weeks gestation. Adjusted NSW public hospital rates of early (37-38 weeks gestation) low-risk prelabour repeat caesarean section varied widely (16.3-67.5%). Adjusting for casemix factors actually increased the between-hospital variation by 4.3%; adjusting for hospital factors reduced variation by 20.0%. Smoking, private healthcare, assisted reproductive technology use, higher parity, a noncaesarean uterine scar and delivering in a hospital with CPAP (continuous positive airway pressure) facilities were associated with higher odds of early delivery, although infants that were small for gestational age were associated with lower odds. Hospitals with higher rates of low-risk deliveries and higher propensity for vaginal birth after caesarean section had lower odds of early delivery. CONCLUSIONS: The findings suggest generally poor compliance with the policy directive that prelabour caesarean does not occur before 39 weeks gestation, with adjusted compliance rates ranging from 32.5% to 83.7%. Large between-hospital variation after adjustment suggests that nonmedical factors are related to timing of low-risk prelabour repeat caesarean sections. Further strategies are needed to improve adherence to this evidence based policy.

Intravenous iron: barriers and facilitators to its use at nine maternity hospitals in New South Wales, Australia.

BACKGROUND: Anaemia in pregnancy is mostly due to iron deficiency, and the use of intravenous (IV) iron is gaining acceptance as a treatment option. Recently released obstetric transfusion guidelines recommend IV iron for obstetric patients in certain situations, including when oral formulations are poorly tolerated, unlikely to be well absorbed, or when rapid restoration of iron stores is required. AIMS: To identify barriers and facilitators to the use of IV iron in pregnancy among nine maternity hospitals in New South Wales, Australia. MATERIALS & METHODS: A qualitative research study was undertaken using semi-structured interviews. Nine maternity units were chosen to cover a range of clinical settings and obstetric blood transfusion rates. Interviews were conducted with haematologists, obstetricians and midwives, and included questions about the use of IV iron in each institution. Interviews were transcribed and coded, and NVivo software was used to develop themes. RESULTS: A total of 125 interviews were conducted: 61 with doctors. The use of IV iron differed between hospitals and individual doctors. There were hospital/pharmaceutical, clinician and patient factors which acted as either barriers or facilitators to the use of IV iron. Where perceived barriers outweighed facilitators in a particular hospital, doctors were less likely to use IV iron. DISCUSSION: The use of IV iron, as perceived by doctors, differed across hospitals. There are some potentially modifiable barriers to the use of IV iron that may need to be addressed for IV iron to be available to obstetric patients not tolerating oral formulations or requiring rapid restoration of iron stores.

Red cell and platelet transfusions in neonates: a population-based study.

OBJECTIVES: This study aimed to describe the use of red cells, platelets and exchange transfusions among all neonates in a population cohort, to examine trends in transfusion over time and to determine transfusion rates in at-risk neonates. DESIGN: Linked population-based birth and hospital data from New South Wales (NSW), Australia, were used to determine rates of blood product transfusion in the first 28 days of life. The study included all live births ≥23 weeks' gestation in NSW between 2001 and 2011. RESULTS: Between 2001 and 2011, 5326 of 989 491 live born neonates received a red cell, platelet or exchange transfusion (5.4/1000 births). Transfusion rates were 4.8 per 1000 for red cells, 1.3 per 1000 for platelets and 0.3 per 1000 for exchange transfusion. Overall transfusion rate remained constant from 2001 to 2011 (p=0.27). Among transfused neonates, 60% were <32 weeks' gestation (n=3210, 331/1000 births), 40% were ≥32 weeks' gestation (n= 2116, 2/1000 births) and 7% received transfusions in a hospital without a neonatal intensive care unit (NICU). Factors other than prematurity associated with higher transfusion rates were prior in utero transfusion (631/1000), congenital anomaly requiring surgery (440/1000) and haemolytic disorder (106/1000). CONCLUSIONS: In this population-based study, preterm neonates had a higher rate of transfusion than term neonates; however, 40% of those who received a transfusion were born ≥32 weeks' gestation and 7% were transfused in hospitals without an NICU. These findings need to be considered by transfusion services and personnel developing neonatal transfusion guidelines.

Incidence and outcomes of pregnancy-associated melanoma in New South Wales 1994-2008.

BACKGROUND: There is controversy about the interaction between melanoma and pregnancy. There is a lack of Australian data on pregnancy outcomes associated with melanoma in pregnancy, despite Australia having the highest incidence of melanoma in the world. AIMS: Describe trends, maternal characteristics and pregnancy outcomes associated with pregnancy-associated melanoma in New South Wales. MATERIALS AND METHODS: Population-based cohort study of all births (n = 1 309 501) of at least 20-week gestation or 400 g birthweight in New South Wales, 1994-2008. Logistic regression was used to analyse the association between melanoma in pregnancy and adverse birth outcomes. RESULTS: 577 pregnancy-associated melanomas were identified, including 195 diagnosed during pregnancy and 382 diagnosed within 12 months postpartum. The crude incidence of pregnancy-associated melanoma increased from 37.1 per 100 000 maternities in 1994 to 51.84 per 100 000 maternities in 2008. Adjusting for maternal age accounted for the trend in pregnancy-associated melanoma. Melanomas diagnosed in pregnancy were thicker (median = 0.75 mm) than melanomas diagnosed postpartum (median = 0.60 mm) (P = 0.002). Pregnancy-associated melanoma was associated with the increased risk of large-for-gestational-age infant but not preterm birth, planned birth, caesarean section or stillbirth. Parity was inversely associated with pregnancy-associated melanoma, as women with three or more previous pregnancies had 0.59 times the odds of pregnancy-associated melanoma compared to nulliparous women (95% CI 0.42-0.84, P = 0.003). CONCLUSIONS: The incidence of pregnancy-associated melanoma has increased with increasing maternal age. The observation of thicker melanomas in pregnancy and increased risk of large-for-gestational-age infants may suggest a role for growth-related pregnancy factors in pregnancy-associated melanoma.

Rate of spontaneous onset of labour before planned repeat caesarean section at term.

BACKGROUND: Guidelines recommend that, in the absence of compelling medical indications (low risk) elective caesarean section should occur after 38 completed weeks gestation. However, implementation of these guidelines will mean some women go into labour before the planned date resulting in an intrapartum caesarean section. The aim of this study was to determine the rate at which low-risk women planned for repeat caesarean section go into spontaneous labour before 39 weeks. METHODS: We conducted a population-based cohort study of women who were planned to have an elective repeat caesarean section (ERCS) at 39-41 weeks gestation in New South Wales Australia, 2007-2010. Labour, delivery and health outcome information was obtained from linked birth and hospital records for the entire population. Women with no pre-existing medical or pregnancy complications were categorized as 'low risk'. The rate of spontaneous labour before 39 weeks was determined and variation in the rate for subgroups of women was examined using univariate and multivariate analysis. RESULTS: Of 32,934 women who had ERCS as the reported indication for caesarean section, 17,314 (52.6%) were categorised as 'low-risk'. Of these women, 1,473 (8.5% or 1 in 12) had spontaneous labour or prelabour rupture of the membranes before 39 weeks resulting in an intrapartum caesarean section. However the risk of labour <39 weeks varied depending on previous delivery history: 25% (1 in 4) for those with spontaneous preterm labour in a prior pregnancy; 15% (1 in 7) for women with a prior planned preterm birth (by labour induction or prelabour caesarean) and 6% (1 in 17) among those who had only previously had a planned caesarean section at term. Smoking in pregnancy was also associated with spontaneous labour. Women with spontaneous labour prior to a planned CS in the index pregnancy were at increased risk of out-of-hours delivery, and maternal and neonatal morbidity. CONCLUSIONS: These findings allow clinicians to more accurately determine the likelihood that a planned caesarean section may become an intrapartum caesarean section, and to advise their patients accordingly.

Are pregnancy outcomes associated with risk factor reporting in routinely collected perinatal data?

AIM: To assess reporting characteristics of commonly dichotomised pregnancy outcomes (e.g. preterm/term birth); and to investigate whether behaviours (e.g. smoking), medical conditions (e.g. diabetes) or interventions (e.g. induction) were reported differently by pregnancy outcomes. METHODS: Further analysis of a previous validation study was undertaken, in which 1680 perinatal records were compared with data extracted from medical records. Continuous and polytomous variables were dichotomised, and risk factor reporting was assessed within the dichotomised outcome groups. Agreement, kappa, sensitivity and positive predictive value calculations were undertaken. RESULTS: Gestational age, birthweight, Apgar scores, perineal trauma, regional analgesia and baby discharge status (live birth/stillbirth) were reported with high accuracy and reliability when dichotomised (kappa values 0.95-1.00, sensitivities 94.7-100.0%). Although not statistically significant, there were trends for hypertension, infant resuscitation and instrumental birth to be more accurately reported among births with adverse outcomes. In contrast, smoking ascertainment tended to be poorer among preterm births and when babies were <2500 g. CONCLUSION: Dichotomising variables collected as continuous or polytomous variables in birth data results in accurate and well ascertained data items. There is no evidence of systematic differential reporting of risk factors.

Are babies getting bigger? An analysis of birthweight trends in New South Wales, 1990-2005.

OBJECTIVE: To determine whether the proportion of babies born large for gestational age (LGA) in New South Wales has increased, and to identify possible reasons for any increase. DESIGN AND SETTING: Population-based study using data obtained from the NSW Midwives Data Collection, a legislated surveillance system of all births in NSW. PARTICIPANTS: All 1 273 924 live-born singletons delivered at term (> or = 37 complete weeks' gestation) in NSW from 1990 to 2005. MAIN OUTCOME MEASURES: LGA, defined as > 90th centile for sex and gestational age using 1991-1994 Australian centile charts; maternal factors associated with LGA were assessed using logistic regression. RESULTS: The proportion of babies born LGA increased from 9.2% to 10.8% (18% increase) for male infants and from 9.1% to 11.0% (21% increase) for female infants. The mean birthweight increased by 23 g for boys and 25 g for girls over the study period. Increasing maternal age, higher rates of gestational diabetes and a decline in smoking contributed significantly to these increases, but did not fully explain them. CONCLUSIONS: There is an increasing trend in the proportion of babies born LGA, which is only partly attributable to decreasing maternal smoking, increasing maternal age and increasing gestational diabetes.

Using hospital discharge data for determining neonatal morbidity and mortality: a validation study.

BACKGROUND: Despite widespread use of neonatal hospital discharge data, there are few published reports on the accuracy of population health data with neonatal diagnostic or procedure codes. The aim of this study was to assess the accuracy of using routinely collected hospital discharge data in identifying neonatal morbidity during the birth admission compared with data from a statewide audit of selected neonatal intensive care (NICU) admissions. METHODS: Validation study of population-based linked hospital discharge/birth data against neonatal intensive care audit data from New South Wales, Australia for 2,432 babies admitted to NICUs, 1994-1996. Sensitivity, specificity and positive predictive values (PPV) with exact binomial confidence intervals were calculated for 12 diagnoses and 6 procedures. RESULTS: Sensitivities ranged from 37.0% for drainage of an air leak to 97.7% for very low birthweight, specificities all exceeded 85% and PPVs ranged from 70.9% to 100%. In-hospital mortality, low birthweight (< or =1500 g), retinopathy of prematurity, respiratory distress syndrome, meconium aspiration, pneumonia, pulmonary hypertension, selected major anomalies, any mechanical ventilation (including CPAP), major surgery and surgery for patent ductus arteriosus or necrotizing enterocolitis were accurately identified with PPVs over 92%. Transient tachypnea of the newborn and drainage of an air leak had the lowest PPVs, 70.9% and 83.6% respectively. CONCLUSION: Although under-ascertained, routinely collected hospital discharge data had high PPVs for most validated items and would be suitable for risk factor analyses of neonatal morbidity. Procedures tended to be more accurately recorded than diagnoses.