Reproductive technologies and the risk of birth defects.

BACKGROUND: The extent to which birth defects after infertility treatment may be explained by underlying parental factors is uncertain. METHODS: We linked a census of treatment with assisted reproductive technology in South Australia to a registry of births and terminations with a gestation period of at least 20 weeks or a birth weight of at least 400 g and registries of birth defects (including cerebral palsy and terminations for defects at any gestational period). We compared risks of birth defects (diagnosed before a child's fifth birthday) among pregnancies in women who received treatment with assisted reproductive technology, spontaneous pregnancies (i.e., without assisted conception) in women who had a previous birth with assisted conception, pregnancies in women with a record of infertility but no treatment with assisted reproductive technology, and pregnancies in women with no record of infertility. RESULTS: Of the 308,974 births, 6163 resulted from assisted conception. The unadjusted odds ratio for any birth defect in pregnancies involving assisted conception (513 defects, 8.3%) as compared with pregnancies not involving assisted conception (17,546 defects, 5.8%) was 1.47 (95% confidence interval [CI], 1.33 to 1.62); the multivariate-adjusted odds ratio was 1.28 (95% CI, 1.16 to 1.41). The corresponding odds ratios with in vitro fertilization (IVF) (165 birth defects, 7.2%) were 1.26 (95% CI, 1.07 to 1.48) and 1.07 (95% CI, 0.90 to 1.26), and the odds ratios with intracytoplasmic sperm injection (ICSI) (139 defects, 9.9%) were 1.77 (95% CI, 1.47 to 2.12) and 1.57 (95% CI, 1.30 to 1.90). A history of infertility, either with or without assisted conception, was also significantly associated with birth defects. CONCLUSIONS: The increased risk of birth defects associated with IVF was no longer significant after adjustment for parental factors. The risk of birth defects associated with ICSI remained increased after multivariate adjustment, although the possibility of residual confounding cannot be excluded. (Funded by the National Health and Medical Research Council and the Australian Research Council.).

Maternal and neonatal outcomes following induction of labor: a cohort study.

OBJECTIVE: To evaluate maternal and neonatal outcomes associated with birth at term by week of gestational age and also by onset of labor. DESIGN: Cohort study. SETTING: A state-wide perinatal outcome database. POPULATION: 28,626 women with spontaneous onset of labor, induction of labor for recognized indications and induction of labor for non-recognized indications. METHODS: Cohort study utilizing a validated dataset comparing outcomes with type of onset of labor using a log binomial model. MAIN OUTCOME MEASURES: Cesarean section, assisted vaginal birth, important measures of maternal and neonatal morbidity. RESULTS: Induction of labor for non-recognized indications was associated with a significantly increased risk of a range of outcomes, including cesarean section (RR 1.67, 95% CI 1.55-1.80). The lowest risk of adverse maternal and infant outcome occurred with birth between 38 and 39 weeks and with the spontaneous onset of labor. CONCLUSIONS: Induction of labor for non-recognized indications at term is associated with an increased risk of adverse outcomes. Caution is warranted with a liberal policy of induction of labor at term in an otherwise uncomplicated pregnancy.

Maternal and perinatal health outcomes by body mass index category.

AIMS: To determine the effect of increasing maternal body mass index (BMI) during pregnancy on maternal and infant health outcomes. METHODS: The South Australian Pregnancy Outcome Unit's population database, 2008 was accessed to determine pregnancy outcomes according to maternal BMI. Women with a normal BMI (18.5-24.9 kg/m(2) ) formed a reference population, to which women in other BMI categories were compared utilising risk ratios and 95% confidence intervals. RESULTS: Overweight and obese women had an increased risk of gestational diabetes, hypertension and iatrogenic preterm birth. Labour was more likely to be induced, and the risk of caesarean birth was increased. Infants were more likely to require resuscitation at birth and to have birth weight in excess of 4 kg. The risk increased with increasing maternal BMI. CONCLUSIONS: There is a well-documented increased risk of maternal and perinatal health complications for women who are overweight or obese during pregnancy.

Late diagnosis of developmental dysplasia of the hip: an analysis of risk factors.

A neonatal clinical screening program for developmental dysplasia of the hip (DDH) operates in South Australia to diagnose DDH as early as possible. However, some cases of DDH are diagnosed late (>3 months of age). The aims of this study were to identify the specific risk factors for late diagnosis by comparing early diagnosed DDH, late diagnosed DDH, and normal controls in the South Australian population. There were 1945 children with DDH born between 1988 and 2003, of which 67 cases were late diagnosis (3.4%). Maternal characteristics, pregnancy, and delivery details were analyzed, and compared with controls (early diagnosed DDH and the general population). There was a trimodal pattern of age at presentation with a gradual increase in the incidence of late diagnosed DDH over the time period in this study. Birthweight (<2500 g), birth in a rural setting, and early hospital discharge following delivery (<4 days) were significant risk factors for late diagnosed DDH. Breech presentation and delivery by caesarean section were protective for late diagnosed DDH. Risk factors for late diagnosed DDH relate to factors that influence the screening program. A rigorous population-based hip surveillance program is important for early diagnosis of DDH.

Prevalence of neural tube defects in Australia prior to mandatory fortification of bread-making flour with folic acid.

OBJECTIVE: To establish baseline prevalence of neural tube defects (NTDs) prior to mandatory folic acid fortification in Australia. METHOD: Retrospective population based study. Data from the Australian Congenital Anomalies Monitoring System, for 1998-2005 were used to calculate birth prevalence including live/stillbirths of at least 20 weeks gestation or 400 g birthweight. Total prevalence and trends of NTD including terminations of pregnancy (TOPs) before 20 weeks were established using data from South Australia, Victoria and Western Australia because of the incomplete ascertainment in other states. RESULTS: The birth prevalence of NTDs from 1998-2005, was 5/10,000 births. The total prevalence including TOPs was 13/10,000 births. A 26% declining trend in total prevalence was seen from 1992-2005, but the main decline occurred prior to 1998. Women who were Indigenous, socially disadvantaged, young, living in remote areas and had multiple gestations were more likely to give birth to babies with NTDs. CONCLUSION: The prevalence of NTD has been stable since 1998. Reporting of the birth prevalence alone underestimates the actual prevalence of NTD. IMPLICATIONS: From a public health perspective, future monitoring of NTD following implementation of fortification of bread-making flour with folic acid should include a mixed methods approach; reporting birth prevalence on national data and total prevalence on tri-state data.

Planned home and hospital births in South Australia, 1991-2006: differences in outcomes.

OBJECTIVE: To examine differences in outcomes between planned home births, occurring at home or in hospital, and planned hospital births. DESIGN AND SETTING: Population-based study using South Australian perinatal data on all births and perinatal deaths during the period 1991-2006. Analysis included logistic regression adjusted for predictor variables and standardised perinatal mortality ratios. MAIN OUTCOME MEASURES: Perinatal death, intrapartum death, death attributed to intrapartum asphyxia, Apgar score < 7 at 5 minutes, use of specialised neonatal care, operative delivery, perineal injury and postpartum haemorrhage. RESULTS: Planned home births accounted for 0.38% of 300,011 births in South Australia. They had a perinatal mortality rate similar to that for planned hospital births (7.9 v 8.2 per 1000 births), but a sevenfold higher risk of intrapartum death (95% CI, 1.53-35.87) and a 27-fold higher risk of death from intrapartum asphyxia (95% CI, 8.02-88.83). Review of perinatal deaths in the planned home births group identified inappropriate inclusion of women with risk factors for home birth and inadequate fetal surveillance during labour. Low Apgar scores were more frequent among planned home births, and use of specialised neonatal care as well as rates of postpartum haemorrhage and severe perineal tears were lower among planned home births, but these differences were not statistically significant. Planned home births had lower caesarean section and instrumental delivery rates, and a seven times lower episiotomy rate than planned hospital births. CONCLUSIONS: Perinatal safety of home births may be improved substantially by better adherence to risk assessment, timely transfer to hospital when needed, and closer fetal surveillance.

Recurrence risks for trisomies 13, 18, and 21.

The objective was to establish whether the risk of trisomies 13, 18, and 21 (Patau, Edwards, and Down syndrome, respectively) in a subsequent pregnancy is raised for women who have had a previous pregnancy with trisomy 13, 18, or 21. Birth defect register data were used to investigate this issue. Pregnancy data from three Australian population-based birth defect registers contained 5,906 women with a previous trisomy 13, 18, or 21 pregnancy in whom there were 3,713 subsequent pregnancies, 75 of which were trisomic. Relative risk of subsequent trisomy at 15 weeks gestation was estimated by comparing the observed number of subsequent trisomies with the expected number of subsequent trisomies based on maternal age-related risk. There was evidence of increased risk of the same trisomy subsequent to a previous pregnancy with trisomy 13 or 18 (RR = 3.8 (1.5, 7.9)), the increase in risk being greater for women aged under 35 at the previous trisomic pregnancy (RR = 7.8 (2.1, 20.2)). There was also evidence of increased risk of trisomy 21 subsequent to previous trisomy 21 (RR = 2.2 (1.6, 2.9)), again higher in women under 35 at previous affected pregnancy (RR = 3.5 (2.1, 5.5)). There was a suggestion that the risk of a different trisomy subsequent to trisomy 21 may also be increased (RR = 1.4 (0.7, 2.5)). In conclusion, women who have had a previous trisomic pregnancy, particularly those under 35 years of age at the time, appear to be at an increased risk of future pregnancies being trisomic.

Genetic susceptibility to viral exposure may increase the risk of cerebral palsy.

AIM: Cytokine polymorphisms may alter the fetal inflammatory response, increasing susceptibility to cerebral palsy (CP). This study investigates associations between selected inflammatory mediator and cytokine gene polymorphisms (Toll-like receptor-4 (TLR-4) Asp299Gly, interleukin-6 G-174C and interleukin-4 C-589T) and CP from 443 CP infants and 883 control infants. Results were correlated with viral nucleic acids in the same samples. RESULTS: At all gestational ages (GA), TLR-4 was associated with a decreased risk of developing CP (homozygous/heterozygous odds ratio (OR) 0.70, 95% confidence interval (CI) 0.50-0.98) and interleukin (IL)-6 was associated with an increased risk of developing hemiplegia (OR 1.38, 95% CI 1.05-1.83). For infants born 32-36 weeks GA, there was a tenfold increase in the risk of quadriplegic CP with homozygous/heterozygous IL-6 (OR 10.42, 95% CI 1.34-80.82). Viral exposure in combination with IL-4 in preterm infants was associated with a fourfold increased risk of quadriplegia (homozygous/heterozygous OR 4.25, 95% CI 1.21-14.95). In very preterm infants, the absence of detectable viral exposure in combination with IL-4 decreased the risk of developing CP (homozygous/heterozygous OR 0.31, 95% CI 0.13-0.76). CONCLUSION: Polymorphisms in TLR-4 may be associated with a decreased risk of CP. Polymorphisms in IL-6 or IL-4 may act as susceptibility genes, in the presence of viral exposure, for the development of hemiplegic and quadriplegic CP. These associations require confirmation but they suggest a hypothesis for CP causation due to double jeopardy from neurotropic viral exposure and genetic susceptibility to infection.

Previous abortion and risk of pre-term birth: a population study.

OBJECTIVE: This population study was undertaken to determine whether previous abortion is an independent risk factor for pre-term birth and to calculate population-attributable risks for risk factors. METHODS: All South Australian first singleton births in 1998-2003 (n = 42 269) were included in a multivariable logistic regression analysis, comparing pre-term births with term births. RESULTS: Risk factors for pre-term birth were found to be: being indigenous, single, a smoker [adjusted odds ratio (AOR) 1.28, 95% confidence interval 1.17-1.41], age 40 years or older, reproductive technology assistance, threatened miscarriage, antepartum haemorrhage, urinary tract infection, pregnancy hypertension and suspected intra-uterine growth restriction. A previous spontaneous abortion was of borderline statistical significance, whereas a previous induced abortion (AOR 1.25, 1.13-1.40) was an independent risk factor. A dose-response relationship was found with increasing number of previous spontaneous or induced abortions. Population-attributable risks were highest for pregnancy hypertension (12.4%) and antepartum haemorrhage (9.2%). Smoking and previous induced abortion had risks of 4.7% and 2.7%, respectively. Among indigenous women, 51% of whom smoked, 16.4% of pre-term birth could be attributed to smoking. CONCLUSIONS: A previous induced abortion and smoking during pregnancy (particularly among indigenous women) are preventable risk factors for pre-term birth. Their population-attributable risks are likely to be under-estimates from under-reporting.

Folate awareness and the prevalence of neural tube defects in South Australia, 1966-2007.

OBJECTIVES: To ascertain changes in: women's knowledge of the role of folic acid in the prevention of neural tube defects (NTDs); intake of folic acid among pregnant women; and prevalence of NTDs in South Australia. DESIGN, SETTING AND PARTICIPANTS: Computer-assisted telephone interviews of South Australian households from 1994 to 2007 over a period encompassing a statewide folate promotion campaign (1994-1995), continuing folate promotion, as well as the introduction of voluntary folate fortification of foods (1996); ascertainment of the total prevalence of NTDs from births and terminations of pregnancy from 1966 to 2007. MAIN OUTCOME MEASURES: Changes in women's knowledge of the role of folic acid in the prevention of NTDs; changes in the prevalence of NTDs. RESULTS: From 1994 to 2006 and 2007, knowledge about the role of folic acid increased from 25% to 77% (P < 0.001) and knowledge that folic acid needs to be taken in the periconceptional period increased from 12% to 39% (P < 0.001). The proportion of pregnant women who increased their periconceptional intake of folate rose from 61% in 1998 to 81% in 2006 and 2007 (P < 0.001), with significant increases in the consumption of fortified cereals (from 15% to 29%) and folic acid tablets (from 37% to 64%). The total prevalence of NTDs fell from 2.06 per 1000 births in 1986-1990 to 1.23 per 1000 births in 2002-2007 (relative risk, 0.60; 95% CI, 0.48-0.74; P < 0.001). CONCLUSIONS: Folate promotion and voluntary fortification of certain foods with folic acid were associated with increased awareness of the role of periconceptional folic acid, increased folate consumption and a reduction in the prevalence of NTDs in South Australia by 40% (95% CI, 26%-52%).

Risk factors for placental abruption in a socio-economically disadvantaged region.

OBJECTIVE: This study was undertaken in order to determine the risk factors for pregnancies complicated by placental abruption in a socio-economically disadvantaged region in metropolitan Adelaide. METHODS: This was a retrospective case-control study including all singleton pregnancies resulting in placental abruption between 2001 and 2005. RESULTS: The overall incidence of placental abruption was 1.0%; the overall perinatal mortality among the births with abruption was 13%. Univariate analyses showed the following significant risk factors for placental abruption: preterm pre-labor rupture of the membranes (PRE-PROM; odds ratio (OR) 4.79, 95% confidence interval (CI) 1.52-15.08), non-compliance with antenatal care (OR 2.93, 95% CI 1.06-8.90), severe intrauterine growth restriction (IUGR), and elevated homocysteine levels (OR 45.55, 95% CI 7.05-458.93). Severe IUGR was significantly more common in the abruption group compared with the control group (p = 0.032). In the multivariate analysis, PRE-PROM remained a significant independent risk factor for placental abruption. Marijuana use, domestic violence, and mental health problems were more common (borderline significance) in the abruption group. Smoking and preeclampsia were not found to be associated with placental abruption in this study. CONCLUSIONS: In this high-risk population, PRE-PROM and elevated homocysteine levels appear to represent the major risk factors for placental abruption.

Trends in state/population-based Down syndrome screening and invasive prenatal testing with the introduction of first-trimester combined Down syndrome screening, South Australia, 1995-2005.

OBJECTIVE: The purpose of this study was to review trends in the us of maternal serum Down syndrome screening and invasive prenatal testing before and after the introduction of a state-based first-trimester combined Down syndrome screening program. STUDY DESIGN: A retrospective population-based study was performed on first- and second-trimester Down syndrome screening, invasive prenatal testing, and prenatal detection of Down syndrome from 1995 to 2005 in South Australia with data from state-based registers. Chi-square tests were used to evaluate trends. RESULTS: There was a significant decrease in the use of second-trimester Down syndrome maternal serum screening (from 75% in 1995 to 25% in 2005; P < .001) and a corresponding significant increase in first-trimester combined screening (from 0.8% in 2000 to 49% in 2005; P < .001). The proportion of all confinements that involved invasive prenatal testing fell (from 9.3% in 1995 to 7.6% in 2005; P < .001). There was a significant decrease in the number of invasive prenatal tests that were needed to detect 1 Down syndrome fetus (from 86 tests in 1995 to 40 tests in 2005; P < .001), with no significant change in the proportion of Down syndrome cases that were detected prenatally. CONCLUSION: The introduction and increased use of first-trimester combined Down syndrome screening has been associated with more efficient use of invasive prenatal testing in South Australia and has maintained a high level of overall prenatal detection.

Risks of adverse outcomes in the next birth after a first cesarean delivery.

OBJECTIVE: To estimate the risks of cesarean first birth, compared with vaginal first birth, for adverse obstetric and perinatal outcomes in the second birth. METHODS: Population-based retrospective cohort study of all singleton, second births in the South Australian perinatal data collection 1998 to 2003 comparing outcomes for 8,725 women who underwent a cesarean delivery for their first birth with 27,313 women who underwent a vaginal first birth. Predictor variables include age, indigenous status, smoking, pregnancy interval, medical and obstetric complications, gestation, patient type, hospital category, and history of ectopic pregnancy, miscarriage, stillbirth or termination of pregnancy. RESULTS: The cesarean delivery cohort had increased risks for malpresentation (odds ratio [OR] 1.84, 95% confidence interval [CI] 1.65-2.06), placenta previa (OR 1.66, 95% CI 1.30-2.11), antepartum hemorrhage (OR 1.23, 95% CI 1.08-1.41), placenta accreta (OR 18.79, 95% CI 2.28-864.6), prolonged labor (OR 5.89, 95% CI 3.91-8.89), emergency cesarean (relative risk 9.37, 95% CI 8.98-9.76) and uterine rupture (OR 84.42, 95% CI 14.64-infinity), preterm birth (OR 1.17, 95% CI 1.04-1.31), low birth weight (OR 1.30, 95% CI 1.14-1.48), small for gestational age (OR 1.12, 95% CI 1.02-1.23), stillbirth (OR 1.56, 95% CI 1.04-2.32), and unexplained stillbirth (OR 2.34, 95% CI 1.26-4.37). The range of the number of primary cesarean deliveries needed to harm included 134 for one additional preterm birth, up to 1,536 for one additional placenta accreta. CONCLUSION: Cesarean delivery is associated with increased risks for adverse obstetric and perinatal outcomes in the subsequent birth. However, some risks may be due to confounding factors related to the indication for the first cesarean. LEVEL OF EVIDENCE: II.

Associations between inherited thrombophilias, gestational age, and cerebral palsy.

OBJECTIVE: This study was undertaken to investigate associations between inherited thrombophilic polymorphisms and cerebral palsy (CP) in a large case-control study. STUDY DESIGN: This is a population-based case-control study. Genomic DNA from newborn screening cards of 443 white CP cases and 883 white controls was tested for factor V Leiden (FVL, G1691A), prothrombin gene mutation (PGM, G20210A), and methylenetetrahydrofolate reductase (MTHFR) C677T and MTHFR A1298C. RESULTS: MTHFR C677T was associated with an increased risk of developing any CP (32-36 weeks' gestation, homozygous odds ratio [OR] 2.55, 95% CI 1.12-5.74; heterozygous OR 1.91, 95% CI 1.01-3.66). MTHFR C677T was also associated with diplegia at both less than 32 weeks' gestation (homozygous OR 2.76, 95% CI 1.21-6.12) and all gestations (heterozygous OR 1.58 95%, CI 1.02-2.45). For children less than 32 weeks, FVL homozygosity may be associated with an increase in the risk of developing quadriplegia (OR 9.12, 95% CI 0.86-53.71). MTHFR A1298C (heterozygous) was associated with a reduced risk of diplegia developing at 32 to 36 weeks' gestation (OR 0.16, 95% CI 0.02-0.70). There were no associations between any type of CP and thrombophilia for children born 37 weeks or greater. Heterozygous PGM and homozygous MTHFR C677T combined were associated with quadriplegia at all gestational ages (OR 5.33, 95% CI 1.06-23.25). CONCLUSION: MTHFR C677T approximately doubles the risk of CP in preterm infants. A combination of homozygous MTHFR C677T and heterozygous PGM increases the risk of quadriplegia 5-fold at all gestational ages.

Maternal diabetes and congenital anomalies in South Australia 1986-2000: a population-based cohort study.

BACKGROUND: This study examined the risk of congenital anomalies in infants born in South Australia to women with maternal diabetes in a population-based cohort study of births over a 15-year period, 1986-2000. Differences in the reporting, recording, and diagnosis of pre-existing diabetes mellitus, gestational diabetes mellitus, and impaired glucose tolerance make comparisons between studies difficult. In order to compare published research, details of research methods and analytic approaches are required to understand the potential confounding, bias, and effect modification that may occur. METHODS: Data on congenital anomalies from the South Australian Birth Defects Register were linked to birth data from the Pregnancy Outcome Statistics Unit of the South Australian Department of Health. This enabled information on congenital anomalies to be linked to pregnancy details, including diabetes status. RESULTS: Between 1986 and 2000, the prevalence of congenital anomalies in the infants of mothers with pre-existing diabetes mellitus, gestational diabetes mellitus, or impaired glucose tolerance was significantly higher than in the total population; relative risk = 2.01 (1.66-2.43) and 1.19 (1.08-1.31), respectively. This increased prevalence was not modified by adjustments for maternal age, ethnicity, or other demographic factors, nor did the rate change over the 15 years of the study period. CONCLUSIONS: The prevalence of congenital anomalies was found to be significantly higher in the infants of mothers with maternal diabetes. Larger population-based studies are needed to determine which anomalies are involved and how their occurrence can be reduced.

The prevalence of inherited thrombophilias in a Caucasian Australian population.

AIMS: To describe the prevalence of four inherited thrombophilias and their combinations for the first time in a large Caucasian Australian population. METHODS: Newborn screening cards of 883 Caucasian babies born in South Australia in 1986-1999 were de-identified and tested for the following inherited thrombophilic polymorphisms: factor V Leiden (G1691A), prothrombin gene mutation (G20210A), methylenetetrahydrofolate reductase gene (MTHFR) C677T and A1298C, as well as compound heterozygosity for the MTHFR polymorphisms. RESULTS: The birth prevalences of heterozygosity and homozygosity for the four thrombophilic polymorphisms were: factor V Leiden 9.5% and 0.7%, prothrombin gene 4.1% and 0.2%, MTHFR C677T 37.3% and 12.4%, and MTHFR A1298C 38.3% and 11.8%, respectively. Compound heterozygosity for MTHFR C677T and A1298C was seen in 16.6% of the population. Overall, 64.2% and 24.5% of the population studied were homozygous and heterozygous, respectively, for at least one of the four polymorphisms studied. CONCLUSION: Inherited thrombophilic polymorphisms are common in the Caucasian Australian population. Knowledge of the background prevalence of these polymorphisms will allow further study of their associations in future disease research.

Estimating Australia's abortion rates 1985-2003.

AIM: To estimate national rates of induced abortion in Australia from 1985 to 2003, using Medicare claim statistics for private patients and hospital morbidity statistics for public patients. DESIGN AND SETTING: Estimates were based on Australian and South Australian data collections relating to abortions. SA hospital morbidity statistics were compared with SA statutory notifications of abortions to estimate the accuracy of these collections. Medicare statistics on abortion procedures performed on private patients in South Australia were then compared with hospital morbidity statistics for private patients. National statistics on abortion derived from Medicare and hospital morbidity statistics were adjusted for inaccuracies found in these sources. MAIN OUTCOME MEASURES: Numbers of induced abortions in Australia for each year from 1985 to 2003; abortion rates per 1000 women aged 15-44 years. RESULTS: Abortion numbers based on Medicare claims by private patients overestimated by 18.7% the number of abortions derived from statutory notifications in South Australia during the period 1988-89 to 1999-00. Hospital morbidity data using principal diagnosis codes relating to medical abortion overestimated statutory notifications by 2.3% (mainly because of readmissions). National statistics were adjusted for these overestimations and for the estimated 14.1% of private patients who would not have submitted Medicare claims (based on surveys of private-clinic patients in New South Wales and Victoria). The estimated Australian abortion rate increased from 17.9 per 1000 women aged 15-44 in 1985 to a peak of 21.9/1000 in 1995, then declined to 19.7/1000 in 2003 (estimated number of abortions, 84,460). CONCLUSION: There are no data currently available for deriving accurate numbers of induced abortions in Australia. Suggestions are made for collection of national statistics.

Substance use during pregnancy: risk factors and obstetric and perinatal outcomes in South Australia.

OBJECTIVE: To determine the prevalence of self-reported substance use during pregnancy in South Australia, the characteristics of substance users, their obstetric outcomes and the perinatal outcomes of their babies. METHODS: Multivariable logistic regression with STATA statistical software was undertaken using the South Australian perinatal data collection 1998-2002. An audit was conducted on every fifth case coded as substance use to identify the actual substances used. RESULTS: Substance use was reported by women in 707 of 89 080 confinements (0.8%). Marijuana (38.9%), methadone (29.9%), amphetamines (14.6%) and heroin (12.5%) were most commonly reported, with polydrug use among 18.8% of the women audited. Substance users were more likely than non-users to be smokers, to have a psychiatric condition, to be single, indigenous, of lower socio-economic status and living in the metropolitan area. The outcome models had poor predictive powers. Substance use was associated with increased risks for placental abruption (OR 2.53) and antepartum haemorrhage from other causes (OR 1.41). The exposed babies had increased risks for preterm birth (OR 2.63), small for gestational age (OR 1.79), congenital abnormalities (1.52), nursery stays longer than 7 days (OR 4.07), stillbirth (OR 2.54) and neonatal death (OR 2.92). CONCLUSIONS: Substance use in pregnancy is associated with increased risks for antepartum haemorrhage and poor perinatal outcomes. However, only a small amount of the variance in outcomes can be explained by the substance use alone. Recent initiatives to improve identification and support of women exposed to adverse health, psychosocial and lifestyle factors will need evaluation.

Hypertension during pregnancy in South Australia, part 1: pregnancy outcomes.

BACKGROUND: There have been conflicting reports about pregnancy outcome in the hypertensive disorders of pregnancy. The present study was undertaken to examine outcomes using a population database. AIMS: To examine for differences in a range of pregnancy outcomes between three different groups of hypertensive women and normotensive women in South Australia. METHODS: Nine pregnancy outcomes were compared for 70,386 singleton pregnancies in the South Australian perinatal data collection in 1998-2001, consisting of 639 women with pre-existing hypertension, 5356 women with pregnancy hypertension, 448 women with superimposed pre-eclampsia and 63 943 normotensive women. Means for the four groups were calculated for birthweight, gestational age, the baby's and mother's length of stay. The groups were also compared for perinatal deaths with an earlier period, 1991-1997. RESULTS: While all three hypertensive groups had high incidences of induction of labour and emergency Caesarean, only pre-existing hypertension and superimposed pre-eclampsia were significantly associated with elective Caesarean section. All hypertensive groups had increased risks for low birthweight and preterm birth and special and neonatal intensive care. Uncomplicated pre-existing hypertension was not associated with small for gestational age infants, but with preterm delivery between 32 and 36 weeks' gestation. Superimposed pre-eclampsia had the worst prognosis for perinatal and maternal morbidity. While pregnancy hypertension held the intermediate position, it was not associated with an increase in perinatal mortality. The perinatal mortality rate for women with hypertensive disorders in 1998-2001 was significantly lower than that of an earlier period and equivalent to that for normotensive women. CONCLUSIONS: Superimposed pre-eclampsia occurs in approximately 40% of pregnancies of women with pre-existing hypertension and has the most severe outcomes. The hypertensive disorders are associated with high levels of morbidity and intervention, but the high perinatal mortality associated with these disorders has fallen significantly.

Hypertension during pregnancy in South Australia, part 2: risk factors for adverse maternal and/or perinatal outcome - results of multivariable analysis.

OBJECTIVE: To identify factors associated with adverse pregnancy outcomes among women with hypertension during pregnancy. DESIGN: A population-based retrospective multivariable analysis using the South Australian perinatal data collection. METHODS: Perinatal data on 70,386 singleton births in 1998-2001 were used in multivariable analyses on three groups: all women combined, all hypertensive women and women with pregnancy hypertension only, in order to identify independent risk factors for requirement for level II/III care, preterm birth, small for gestational age (SGA) birth and maternal length of stay greater than 7 days. RESULTS: The risks for the four morbidities were all increased among women with hypertension compared with normotensive women. Those with pre-existing hypertension had the lowest risk (with odds ratios (OR) 1.26-2.90). Pregnancy hypertension held the intermediate position (OR 1.52-5.70), while superimposed pre-eclampsia was associated with the highest risk (OR 2.00-8.75). Among women with hypertension, Aboriginality, older maternal age, nulliparity and pre-existing or gestational diabetes increased the risk for level II/III nursery care, preterm birth and prolonged hospital stay. Smokers had shorter stays, which may be related to their decreased risk of having a Caesarean section or operative vaginal delivery. Asian women, Aboriginal women, smokers and unemployed women had an increased risk for having an SGA baby, while women with pre-existing or gestational diabetes had a reduced risk. CONCLUSIONS: Among hypertensive pregnant women, nulliparity, older maternal age, Aboriginality, unemployment and diabetes are independent risk factors for one or more major adverse pregnancy outcomes. Smoking does not always worsen the outcome for hypertensive women except for SGA births.