The use of customised versus population-based birthweight standards in predicting perinatal mortality

OBJECTIVE: The objective of this study was to critically examine potential artifacts and biases underlying the use of 'customised' standards of birthweight for gestational age (GA). DESIGN: Population-based cohort study. SETTING: Sweden. POPULATION: A total of 782,303 singletons > or =28 weeks of gestation born in 1992-2001 to Nordic mothers with complete data on birthweight; GA; and maternal age, parity, height, and pre-pregnancy weight. METHODS: We compared perinatal mortality in four groups of infants based on the following classification of small for gestational age (SGA): non-SGA based on either population-based or customised standards (the reference group), SGA based on the population-based standard only, SGA based on the customised standard only, and SGA according to both standards. We used graphical methods to compare GA-specific birthweight cutoffs for SGA using the two standards and also used logistic regression to control for differences in GA and maternal pre-pregnancy body mass index (BMI) in the four groups. MAIN OUTCOME MEASURES: Perinatal mortality, including stillbirth and neonatal death. RESULTS: Customisation led to a large artifactual increase in the proportion of SGA infants born preterm. Adjustment for differences in GA and maternal BMI markedly reduced the excess risk among infants classified as SGA by customised standards only. CONCLUSION: The large increase in perinatal mortality risk among infants classified as SGA based on customised standards is largely an artifact due to inclusion of more preterm births.     

Predictiveness of antenatal umbilical artery Doppler for adverse pregnancy outcome in small-for-gestational-age babies according to customised birthweight centiles: population-based study

Objective  To examine the relationship between smallness at birth and the predictive value of umbilical artery Doppler.
Design  Retrospective cohort.
Setting  Tertiary referral university hospital, Barcelona.
Population  A total of 7645 singleton pregnancies delivered between January 2002 and June 2004.
Methods  The associations with adverse outcome were assessed for small-for-gestational-age (SGA) babies according to customised standards who had normal and abnormal umbilical artery Doppler.
Main outcome measures  Neonatal morbidity and perinatal mortality.
Results  Of the 369 SGA fetuses that had been identified antenatally, 70 (19%) had an abnormal umbilical artery Doppler and the babies from these pregnancies had a higher risk for neonatal morbidity when compared with babies with normal birthweight (OR 3.99, 95% CI 1.04–11.03). However, the remaining 299 (81%) fetuses with normal umbilical artery Doppler also had an elevated risk of neonatal morbidity (OR 2.26, 95% CI 1.04–4.39). Overall, many of the instances of adverse outcome associated with smallness for gestational age were attributable to the group with normal Doppler than to the group with abnormal Doppler.
Conclusion  Normal antenatal umbilical artery Doppler cannot be taken as an indicator of low risk in pregnancies where the fetus is SGA according to customised percentiles.     

Should parity be included in customised fetal weight standards for identifying small-for-gestational-age babies? Results from a French multicentre study

Objective  Parity is one of several parameters used to customise fetal growth norms. However, it is uncertain whether the lower birthweight of babies born to primiparous women reflects physiological or pathological variation. Our aim was to assess the impact of adjusting for parity in identification of small-for-gestational-age (SGA) births.
Design  Comparison of two customised definitions of SGA with and without parity.
Setting  Routinely collected data in five tertiary maternity hospitals in France.
Population  A total of 51 126 singleton births without malformations from 1997 to 2002.
Methods  Characteristics of mothers and babies and adverse pregnancy outcomes for SGA and non-SGA births were compared using customised definitions with and without parity.
Main outcome measures  Neonatal morbidity and mortality.
Results  SGA births among primiparas increased from 14.9 to 18.0% when parity was excluded. Overall rates of SGA rose from 14.4 to 15.0%. Newly defined cases of SGA were babies of primiparas. They had higher rates of admission to a neonatal unit and caesarean section than babies reclassified as non-SGA. Perinatal mortality was 9.1‰ (parity included) and 9.7‰ (parity excluded) and did not differ significantly from babies classified as non-SGA by both standards (5.4‰).
Conclusions  Adjustment for parity markedly decreased the proportion of primiparas diagnosed with SGA babies but did not appear to improve the identification of high-risk babies. Removing parity would simplify the customised definition of SGA and would eliminate the need for the assumption that lower birthweight for primiparous women is normal.     

Customised birthweight centiles are useful for identifying small-for-gestational-age babies in women with type 2 diabetes

Background: Customised birthweight centiles identify small-for-gestational-age (SGA) babies at increased risk of morbidity more accurately than population centiles, but they have not been validated in obese populations.
Aims: To compare the rates of SGA by population and customised birthweight centiles in babies of women with type 2 diabetes and examine perinatal outcomes in customised SGA infants.
Methods: Data were from a previous retrospective cohort study detailing pregnancy outcomes in 212 women with type 2 diabetes. Customised and population birthweight centiles were calculated; pregnancy details and neonatal outcomes were compared between groups that delivered infants who were SGA (birthweight < 10th customised centile) and appropriate weight for gestational age (AGA) (birthweight 10–90th customised centile).
Results: Fifteen (7%) babies were SGA by population centiles and 32 (15%) by customised centiles. Two babies of Indian women were reclassified from SGA to AGA by customised centiles. Nineteen babies were reclassified from AGA to SGA by customised centiles; of these, 15 (79%) were born to Polynesian women, five (26%) were born less than 32 weeks and two (11%) were stillborn. Customised SGA infants, compared with AGA infants, were more likely to be born preterm (19 (59%) vs 20 (16%), P  < 0.001) and more likely to be stillborn (4 (13%) vs 0 P  = 0.001). After excluding still births, admission to the neonatal unit was also more common (19 of 28 (68%) vs 43 of 127 (34%), P  < 0.001).
Conclusions: In our population more babies were classified as SGA by customised compared with population centiles. These customised SGA babies have high rates of morbidity.     

Application of a customised birthweight standard in the assessment of perinatal outcome in a high risk population

Objective Physiological as well as pathological variables influence birthweight. The aim of the present study was to examine perinatal outcome in relation to birthweight centiles applying a customised birthweight standard.
Methods Two hundred and seventeen babies from high risk pregnancies were evaluated and classified as small or not small for gestational age according to two standards: 1. conventional Dutch birthweight centiles and 2. customised centiles which adjust individually for physiological variables like maternal booking weight, height and ethnic origin.
Results Customisation of the weight standards resulted in identification of an additional group of infants who were small for gestational age, but not by the Dutch standards. These babies were associated with significantly more adverse perinatal events than those who were not small for gestational age as defined by a customised standard.
Conclusions Adjustment of birthweight centiles for physiological variables significantly improves the identification of infants who have failed to reach the expected birthweight and who are at increased risk for adverse perinatal events.     

Preterm and term births of small for gestational age infants: a population-based study of risk factors among nulliparous women

Objective To study risk factors for small for gestational age (SGA) infants by gestational age among nulliparous women and to estimate mortality rates among SGA and appropriate-for-gestational-age (AGA) infants by gestational age.
Design A population-based study from the Swedish Medical Birth Register.
Setting Sweden 1992–1993.
Population Liveborn singleton infants to nulliparous women (   n = 96,662  ).
Main outcome measures Crude and adjusted odds ratios of risk factors for SGA by gestational age. Rates of neonatal and postneonatal mortality.
Results Older maternal age (≥ 30 years) was foremost associated with increased risks of very and moderately preterm SGA (≥ 32 weeks and 33–36 weeks, respectively), but also with term SGA (≥ 37 weeks). Risks of SGA increased with decreasing maternal height at all gestational ages. Smoking increased the risks of moderately preterm and term SGA. Short maternal education increased the risk of preterm SGA and low pre-pregnancy body mass index slightly increased the risk of term SGA. Pre-eclampsia and essential hypertension foremost increased the risk of very preterm SGA (OR = 40.5 and 32.4, respectively) and moderately preterm SGA (OR = 17.4 and 10.6, respectively), but also increased the risk of term SGA. Neonatal and postneonatal mortality rates of SGA infants were substantially influenced by gestational age, and mortality rates were consistently higher among preterm SGA infants compared with AGA infants.
Conclusions Risk factors for SGA and mortality rates among SGA infants vary by gestational age. A subdivision of risk factors by gestational age adds knowledge, particularly about risks of preterm SGA, where the highest rates of mortality were observed.     

Birthweights in sickle cell trait pregnancies

Objectives  Available evidence on the effect of sickle cell trait (SCT) on birthweight is conflicting, not gestational age specific, and does not account for maternal and infant factors. The objectives of this study are to determine the contemporary mean birthweight, mean customised birthweight centile, and to analyse the risk of small-for-gestational-age (SGA) and large-for-gestational-age (LGA) babies in SCT pregnancies.
Design  Large retrospective cohort study.
Setting  London hospital.
Population  Singleton pregnancies between 24 and 42 completed weeks delivered between 2000 and 2005 in parturient with body mass index between 18.0 and 35.0 kg/m².
Methods  All qualifying pregnancies were identified on Terra Nova Healthware. Birthweight centiles of these cases were computed with Gardosi customised bulk centile calculator using collected data on maternal height, weight, ethnicity and parity, and the infant's gender, gestational age and birthweight. Birthweight and birthweight centiles of SCT and pregnancies with no haemoglobinopathy (control) were compared. Statistical analysis was performed using Stata version 9.2.
Main outcome measures  Birthweight and birthweight centiles.
Results  Five hundred and five SCT and 16 320 controls were analysed. The mean birthweight of SCT pregnancies was 3223 g, 57 g lower than controls ( P = 0.024). However, its mean birthweight centile was 49.0% similar to that of controls' 47.5% ( P = 0.320). There is an apparent risk of LGA babies in SCT pregnancies, but logistic regression analysis suggests that the odds are related to being an older non-white parturient and a male infant rather than SCT status.
Conclusions  SCT is not a risk factor for SGA or LGA infants.     

Fetal growth restriction and other risk factors for stillbirth in a New Zealand setting

BACKGROUND: Stillbirth affects almost 1% of pregnant women in the Western world but is still not a research priority. AIMS: To assess in a cohort of stillbirths: the demographic risk factors, the prevalence of small for gestational age (SGA) by customised and population centiles, and the classification of death using the Perinatal Society of Australia and New Zealand Perinatal Death Classification (PSANZ-PDC). METHODS: The study population comprised 437 stillborn babies (born from 1993 to 2000 at National Women's Hospital, Auckland, New Zealand) and their mothers. The referent population for demographic factors was live births n=69 173. RESULTS: After multivariable analysis, risk factors for stillbirths were: Indian (odds ratio (OR) 1.85, 95%CI (1.18, 2.91)), or Pacific Islander (OR 1.65, 95%CI (1.27, 2.14)); smoking (OR 1.33, 95%CI (0.99, 1.79)) or unknown smoking status (OR 2.87, 95%CI (2.30, 3.58)); nulliparity (OR 1.42, 95%CI (1.10, 1.83)), and para 2 (OR 1.36, 95%CI (1.01, 1.83)). One hundred and twenty-nine (46%) stillbirths born>or=24 weeks (n=278) were SGA by customised, and 94 (34%) by population centiles. Customised SGA was more common in preterm versus term stillbirths (101 of 198 (51%) vs 28 of 80 (35%), respectively, P=0.02) but rates of population SGA did not differ (72 of 198 (36%) vs 22 of 80 (28%) P=0.16). 'Spontaneous preterm' was the most common cause of stillbirth at <28 weeks and 'unexplained' at >or=28 weeks using PSANZ-PDC classification. CONCLUSIONS: This study again emphasises the importance of suboptimal fetal growth as an important risk factor for stillbirth. Customised centiles identified more stillborn babies as SGA than population centiles especially preterm.     

Customized birthweight centiles predict SGA pregnancies with perinatal morbidity

OBJECTIVES: To determine the following: (1) the proportion of babies reclassified as small or appropriately grown using customized and population centiles; and (2) the relative risks of perinatal morbidity, including abnormal umbilical Doppler studies, in babies classified as small for gestational age (SGA) and appropriate for gestational age (non-SGA) using the two centile calculations. DESIGN: Cohort study in SGA and general hospital populations. SETTING: National Women's Hospital, Auckland, NZ. POPULATION: A cohort of SGA pregnancies (n= 374) and a general obstetric population (n= 12,879). METHODS: Pregnancy outcomes were compared between 'non-SGA both' (> or =10th% by population and customized centiles) and those who were 'SGA both' (<10th% by population and customized centiles), 'SGA customized only' (SGA by customized but non-SGA by population centiles) and 'SGA population only' (SGA by population but non-SGA by customized centiles). MAIN OUTCOME MEASURES: Maternal and newborn morbidity and perinatal death. RESULTS: In the SGA cohort 271 (72%) babies were 'SGA both', 27 (7%) were 'SGA customized only', 32 (9%) were 'population SGA only' and 44 (12%) were 'non-SGA both'. In the general obstetric population 863 (6.7%) babies were 'SGA both', 445 (3.5%) were 'customized SGA only', 285 (2.2%) were 'population SGA only' and 11,286 (88%) were 'non-SGA both'. Perinatal death and newborn morbidity including nursery admission and long hospital stay were increased and comparable between 'SGA both' and 'customized SGA only' in both study populations. Newborn morbidity was low and comparable between 'population SGA only' and 'non-SGA both'. No perinatal deaths occurred in 'population SGA only' babies. Abnormal Doppler studies were more common in 'SGA both' or 'customized SGA only' but not in 'population SGA only' groups compared with 'non-SGA both'. CONCLUSIONS: Customized birthweight centiles identified small babies at risk of morbidity and mortality. Use of customized centiles is likely to detect more babies at risk of perinatal morbidity and mortality than would be detected by population centiles.     

Relationship between customised birthweight centiles and neonatal anthropometric features of growth restriction

Objective To determine the relationship between customised birthweight centiles (adjusted for maternal and fetal physiological variables) and neonatal anthropometric features of intrauterine growth restriction (IUGR).
Design Observational study.
Population Two-hundred and seventy women with low risk pregnancies participating in a cohort study of serial ultrasound biometry.
Methods Customised birthweight centiles were calculated following adjustment for maternal weight, height and ethnic origin, gestational age at delivery, birth order, and sex of the infant. Three separate neonatal anthropometric measures were used to define IUGR: subscapular or triceps skinfold thickness  <10th  centile; ponderal index  <25th  centile; and mid-arm circumference to occipito-frontal circumference ratio (MAC/OFC) <−1 standard deviation (SD). Relationship of the centiles to these outcomes was evaluated using likelihood ratios (LR) and kappa statistic. These approaches allowed us to examine the strength of the association: an LR of 5–10 would be expected to generate moderate changes in the pre-test probability of IUGR, whereas a kappa value of 0.2–0.4 would reflect fair agreement between customised birthweight centiles and neonatal anthropometric measures.
Results Customised birthweight centile of 10 or less had the following LR values for the various anthropometric criteria for IUGR: 5.1 (95% CI 3–8.5) for low skinfold thickness; 4.3 (95% CI 2.5–7.1) for low ponderal index; and 3.9 (95% CI 2–6.6) for low MAC/OFC ratio. The kappa values were: 0.4 (95% CI 0.26–0.51) for low skinfold thickness; 0.33 (95% CI 0.21–0.46) for low ponderal index; and 0.13 (95% CI 0–0.26) for low MAC/OFC ratio.
Conclusion In a low risk population, customised birthweight centiles can only be moderately useful in the identification of neonates with low skinfold thickness and low ponderal index.     

Twin deliveries and place of birth in NSW 2001–2005

Background:  Twin pregnancies have an elevated risk of adverse outcomes, particularly preterm twins.
Aims:  Describe the distribution of twin deliveries by hospital level, the associated perinatal and maternal morbidity, and determine predictors of perinatal morbidity and urgent transfer to a neonatal intensive care unit.
Methods:  Longitudinally linked New South Wales delivery and hospital records for the years 2001–2005 were used to identify perinatal and maternal morbidity/mortality in twin pregnancies. Regression analysis was used to examine predictive factors, including birth hospital volume.
Results:  At ≤ 32 weeks, 88.1% of twins were delivered in tertiary referral hospitals. By 34–35 weeks, only 39.7% of twins were delivered in tertiary units. Gestational age was the primary predictor of perinatal morbidity/mortality. Perinatal morbidity/mortality and maternal morbidity were lowest for deliveries at 38 weeks. There was no evidence that planned caesarean section at ≤ 38 weeks was protective against perinatal morbidity/mortality. There was an increased risk of perinatal morbidity/mortality (odds ratio (OR) = 2.22) for twins delivered at 33–35 weeks gestation at hospitals with < 500 deliveries per annum, and an increased risk of urgent neonatal transfer (OR = 2.06). Twin pairs for whom there was a ≥ 20% discordance in birthweight had an increased risk of morbidity/mortality at 36–38 weeks (OR = 1.79).
Conclusions:  Both infant and maternal morbidity increase from 39 weeks gestation. Delivery of twins before 36 weeks at smaller hospitals (< 500 deliveries per annum) should be avoided. A twin pregnancy where there is a ≥ 20% difference in estimated fetal weights should be considered for referral to a tertiary obstetric unit.     

Maternal sleep deprivation is a risk factor for small for gestational age: A cohort study

Aims: To determine trimester-specific risk factors for small-for-gestational-age (SGA) infants.
Methods: A population-based prospective cohort study was conducted in Sri Lanka from May 2001 to April 2002. Pregnant women were recruited on or before 16 weeks of gestation and followed up until delivery. The sample size was 690. Trimester-specific exposure status and potential confounding factors were gathered on average at 12th, 28th and 36th weeks of gestation. SGA was assessed using customised birth centile charts. Multiple logistic regression was applied, and the results were expressed as odds ratios (OR) and 95% confidence intervals (95%CI).
Results: The risk factors for SGA less than 5th centile were shift work and exposure to physical and chemical hazards during 2nd and 3rd trimesters (OR 4.20, 95%CI 1.10–16.0), sleeping for less than or equal to 8 h during 2nd or 3rd or both trimesters (OR 2.23, 95%CI 1.08–4.59), walking for less than or equal to 2.5 h per day (OR 2.66, 95%CI 1.12–6.31) and alcohol consumption during the 3rd trimester (OR 14.5, 95%CI 2.23–94.7). Poor weekly gestational weight gain was significantly associated with both SGA < 10th and < 5th centiles. None of the other factors became significant for SGA < 10th centile.
Conclusions: Risk factors for SGA less than 5th centile were sleep deprivation and shift work and exposure to physical and chemical hazards during 2nd and 3rd trimesters, less walking hours and alcohol consumption during 3rd trimester. Poor weekly gestational weight gain may be considered as a predictor of delivering an SGA infant.     

Adverse perinatal outcome and maternal risk factors in population versus customized defined SGA babies

Objective.?The purpose of this study was to compare population and customized-based birth weight centiles in their association with perinatal outcome and maternal risk factors, in nulliparous Caucasian women in a socio-economic disadvantaged region.

Methods.?We analyzed perinatal outcomes in births of 302 Caucasian women of which 155 were small for gestational age (SGA) and 147 were appropriate for gestational age (AGA). Out of the overall study group, two cohort studies were designed. One was classified by population centiles as either SGA (n= 133) or AGA (n?= 169) and the other was classified by customized centiles as either SGA (n?= 131) or AGA (n?= 172). Maternal risk factors and operative delivery rates for fetal distress, Apgar scores, need for resuscitation and neonatal nursery care given, were determined for both customized and population-based SGA babies.

Results.?The customized SGA only group showed more mental health problems and special nursery in comparison with the AGA group. The population SGA only group had more smoking and mental health problems than the AGA group, but no differences on neonatal outcome measures.

Conclusion.?Use of customized centiles does identify an additional group neonates with a significantly higher need for special nursery admission in a homogeneous ethnic Caucasian group.     

Perinatal outcome of pregnancies complicated with extreme birth weights at term

Objective: The objective of this study is to investigate whether an abnormal birthweight at term, either small for gestational age (SGA,??95th centile for gestational age), is a risk factor for perinatal complications as compared with birthweight appropriate for gestational age (AGA).

Methods: A population-based retrospective cohort analysis of all singleton pregnancies delivered between 1991 and 2014 at Soroka Medical Center. Congenital malformations and multiple pregnancies were excluded. A multivariable generalized estimating equation regression model was used to control for maternal clusters and other confounders.

Results: During the study period, 228,242 births met the inclusion criteria, of them 91% were AGA (n?=?207,652), 4.7% SGA, and 4.3% LGA. SGA significantly increased the risk for perinatal mortality (aOR 5.6, 95%CI 4.5–6.8) and low 5-min Apgar scores (aOR 2.2, 95%CI 2.0–2.4), while LGA did not. SGA and LGA were both significant risk factors for cesarean delivery. LGA was significantly associated with shoulder dystocia and post-partum hemorrhage (aOR =13.6, 95%CI 10.9–17.0, and aOR 1.7, 95%CI 1.2–2.6, respectively).

Conclusions: Extreme birthweights at term are significantly associated with adverse maternal and neonatal outcomes. As opposed to SGA, LGA is not independently associated with perinatal mortality.     

Fetal growth restriction and other factors associated with neonatal death in New Zealand

BACKGROUND: There are few studies of risk factors for neonatal death in Australia or New Zealand. AIMS: To assess in a cohort of neonatal deaths (i) the demographic and clinical risk factors; (ii) the relationship between low weight for gestation using population and customised centiles; and (iii) the cause of death by the Perinatal Society of Australia and New Zealand Perinatal and Neonatal death classifications. METHODS: A retrospective study of 410 babies who died, in the neonatal period, at National Women's Hospital, between 1993 and 2000. Demographic and clinical data were compared with that from a referent population of live births with neonatal deaths removed (n=68 905). RESULTS: The overall neonatal death rate was 5.9 per 1000 live births and after exclusion of congenital abnormalities was 3.9 per 1000 live births. Infants of Maori women had increased risk compared to European (adjusted odds ration (AOR) 1.52; 95% CI 1.06, 2.18), as did those born to primipara (AOR 1.52; 95% CI 1.10, 2.11), mothers with >or=1 previous low-birthweight baby (AOR 2.97; 95% CI 1.99, 4.44), >or=1 miscarriage (AOR 1.35; 95% CI 1.00, 1.81), and an index multiple pregnancy (AOR 10.51; 95% CI 8.04, 13.76). Infants of Chinese mothers had decreased risk (AOR 0.42; 95% CI 0.18, 0.96). Fifty (34%) babies were small for gestational age by customised and 26 (17%) by population centiles. The most common classification of neonatal death was congenital abnormality (34.6%), followed by extreme prematurity (34.1%). CONCLUSIONS: This study emphasises the importance of suboptimal fetal growth as an important risk factor for neonatal death especially when customised centiles are used.     

Safety of birth centre care: perinatal mortality over a 10-year period

Objective   To study perinatal mortality in women booked for birth centre care during pregnancy.
Design   Retrospective cohort study.
Setting   In-hospital birth centre and standard maternity care in Stockholm.
Population   Two thousand and five hundred and thirty-four women (3256 pregnancies) admitted to an in-hospital birth centre over 10 years (1989–2000) and 126,818 women (180,380 pregnancies) who gave birth in standard care during the same period and who met the same medical inclusion criteria as in the birth centre. Multiple pregnancies were excluded.
Methods   Data were collected from the Swedish Medical Birth Register. Information on all cases of perinatal death in the birth centre group was retrieved from the medical records.
Main outcome measure   Perinatal mortality.
Results   No statistically significant difference in the overall perinatal mortality rate was observed between the birth centre group and the standard care group (odds ratio [OR] 1.5, 95% CI 0.9–2.4), but infants of primiparas were at greater risk (OR 2.2, 95% CI 1.3–3.9). Infants of multiparas tended to be at lower risk, but this difference was not statistically significant (OR 0.7, 95% CI 0.3–1.9). These figures were adjusted for maternal age and gestation in multiple regression analyses.
Conclusion   Birth centre care may be less safe for infants of first-time mothers.     

Trends in prevalence and outcomes of pregnancy in women with pre-existing type I and type II diabetes

Objective  To describe recent trends in prevalence, outcomes and indicators of care for women with pre-existing type I or type II diabetes.
Design  Regional population-based survey.
Setting  All maternity units in the North of England.
Population  A total of 1258 pregnancies in women with pre-existing diabetes delivered between 1996 and 2004.
Methods  Data from the Northern Diabetic Pregnancy Survey. Outcome of pregnancy cross-validated with the Northern Congenital Abnormality Survey and the Northern Perinatal Mortality Survey.
Main outcome measures  Perinatal mortality, congenital anomaly and total adverse perinatal outcome (perinatal mortality and live births with congenital anomaly).
Results  The prevalence of pregestational diabetes increased from 3.1 per 1000 births in 1996–98 to 4.7 per 1000 in 2002–04 (test for linear trend, P < 0.0001), driven mainly by a sharp increase in type II diabetes. Perinatal mortality declined from 48 per 1000 births in 1996–98 to 23 per 1000 in 2002–04 ( P = 0.064). There was a significant reduction in total adverse perinatal outcome rate ( P = 0.0194) from 142 per 1000 in 1996–98 to 86 per 1000 in 2002–04. There were substantial improvements in indicators of care before and during pregnancy and in glycaemic control throughout pregnancy, but indicators of preconceptual care, such as use of folic acid, remained disappointing.
Conclusion  We observed improvements in pregnancy care and outcomes for women with diabetes in a region with an established audit and feedback cycle. There remains considerable scope for further improvement, particularly in periconceptual glycaemic control. The rising prevalence of type II diabetes presents a challenge to further improvement.     

In utero tobacco exposure: The effects of heavy and very heavy smoking on the rate of SGA infants in the Federal State of Saarland,Germany

Objective

To assess the effects of heavy and very heavy smoking on the rate of small for gestational age (SGA) infants, and to assess socio-economic and regional differences in smoking patterns in pregnant women in Germany.

Study design

The Neonatal and Perinatal database of the federal state of Saarland, Germany was used to perform a population-based analysis of preterm (>32 weeks of gestation) and term (>36 weeks of gestation) newborns in 2004–2006. The rate of SGA babies dependent on the amount of tobacco exposure among self-identified smokers and non-smokers were assessed, and distinct maternal risk factors for smoking were evaluated. Our data were compared with the German National Perinatal database.

Results

14,593 paired data sets (peripartum/perinatal) were included in this study. The overall rate of smoking during pregnancy was 11.8% with a high percentage of pregnant women smoking 11–20 cigarettes/day (heavy smoker; 4.0%), and >20 cigarettes/day (very heavy smoker; 0.6%). Self-identified heavy tobacco use signifcantly increased the risk for SGA infants (p < 0.01) in women without uteroplacental insufficiency. Risk factors for smoking included ethnicity (German/Caucasian), socio-economic parameters (single vs. non-single households, status of employment) and age. Smoking pattern and the rate of SGA babies in our cohort differed substantially from the national average.

Conclusions

Although the overall rate of smoking appears comparable to previously published data, heavy and very heavy smoking was high in our cohort. Heavy smoking was disproportionately associated with SGA. Preventative measures and strategies should take into consideration socio-economic risk factors as well as regional differences, and should be targeted at distinct subgroups that are especially prone to smoking during pregnancy.     

Expected day of delivery from ultrasound dating versus last menstrual period--obstetric outcome when dates mismatch

Objective  To analyse the association between fetal size at time of dating ultrasound and risk for preterm delivery and small-for-gestational-age (SGA) birth and to evaluate if timing of ultrasound, that is before 14 weeks of gestation or after 16 weeks affects this association.
Design  Retrospective cohort study.
Setting  Ultrasound departments of Ultragyn, Stockholm, Sweden.
Population  A total of 28 776 singleton pregnancies dated between 1998 and 2004.
Methods  Obstetric outcome was assessed through linkage of the cohort to the Swedish Medical Birth Register.
Main outcome measures  Risks of preterm delivery, low birthweight for gestational age, pre-eclampsia, asphyxia, respiratory distress, instrumental delivery, caesarean section, and postterm birth were calculated for the groups dated early and late.
Results  When the expected date of delivery was postponed after ultrasound dating by 7 days or more, there was an increased risk for preterm delivery and pre-eclampsia in the late dating group (OR 1.49, 95% CI 1.27–1.73 and OR 1.27, 95% CI 1.02–1.60, respectively) but not in the early dating group. In both dating groups, there was an increased risk for SGA birth (OR 1.77, 95% CI 1.13–2.78 and OR 2.09, 95% CI 1.59–2.73, respectively) There was no increased risk for any of the other diagnoses.
Conclusion  Our study gives further support to the notion that intrauterine growth restriction may be present as early as the first trimester. Accordingly, our study also suggests that surveillance of pregnancies with postponed estimated date of delivery may provide means for increased detection of fetal growth restriction.     

Identifying risk factors for premature rupture of membranes in small for gestational age neonates: a population-based study

Objective. To determine the prevalence and risk factors for premature rupture of membranes (PROM) among pregnancies complicated with small for gestational age (SGA) neonates.

Methods. A computerised database was used to identify deliveries of SGA neonates in pregnancies complicated with PROM between the years 1988 and 2002. Pregnancies with PROM and SGA neonates were compared to those with SGA and without PROM. Demographic, obstetric, clinical and labour characteristics were evaluated. Multiple logistic regression analysis was used to determine independent risk factors for PROM in pregnancies complicated by SGA. Statistical analysis was performed with SPSS package.

Results. There were 120 982 deliveries included out of which 6074 (5.99%) presented with appropriate for gestational age (AGA) neonates and PROM. A total of 1077 delivered SGA infants complicated with PROM (5.5%). After adjustment for confounding variables, the following characteristics were significantly associated with PROM and SGA: Jewish ethnicity, parity and cervical incompetence. The following complications were associated with PROM and SGA: arrest of labour, fetal distress, failed induction, cesarean delivery, clinical chorioamnionitis and placenta accreta. No significant differences regarding low Apgar scores and perinatal mortality rates were noted.

Conclusions. The risk of PROM among patients with SGA is lower than in AGA infants. Parity and cervical incompetence are risk factors for PROM among women who delivered SGA neonates. In this population there is a higher rate of arrest of labour, chorioamnionitis, fetal distress and cesarean delivery. Neonatal outcome and perinatal mortality are similar in both groups.