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.     

The value of customised centiles in assessing perinatal mortality risk associated with parity and maternal size

Objective  We wanted to compare customised and population standards for defining smallness for gestational age (SGA) in the assessment of perinatal mortality risk associated with parity and maternal size.
Design  Population-based cohort study.
Setting  Sweden.
Population  Swedish Birth Registry database 1992–1995 with 354 205 complete records.
Method  Coefficients were derived and applied to determine SGA by the fully customised method, or by adjustment for fetal sex only, and using the same fetal weight standard.
Main outcome measure  Perinatal deaths and rates of small for gestational age (SGA) babies within subgroups stratified by parity, body mass index (BMI) and maternal size within the BMI range of 20.0–24.9.
Results  Perinatal mortality rates (PMR) had a U-shaped distribution in parity groups, increased proportionately with maternal BMI, and had no association with maternal size within the normal BMI range. For each of these subgroups, SGA rates determined by the customised method showed strong association with the PMR. In contrast, SGA based on uncustomised, population-based centiles had poor correlation with perinatal mortality. The increased perinatal mortality risk in pregnancies of obese mothers was associated with an increased risk of SGA using customised centiles, and a decreased risk of SGA using population-based centiles.
Conclusion  The use of customised centiles to determine SGA improves the identification of pregnancies which are at increased risk of perinatal death.     

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.     

Pregnancy-induced hypertension and infant mortality: Roles of birthweight centiles and gestational age

OBJECTIVE: To assess the effect of pregnancy-induced hypertension (PIH) on infant mortality in different birthweight centiles (small for gestational age [SGA], appropriate for gestational age [AGA], and large for gestational age [LGA]) and gestational ages (early preterm, late preterm, and full term). DESIGN: Retrospective cohort study. SETTING: Linked birth and infant death data set of USA between 1995 and 2000. POPULATION: A total of 17 464 560 eligible liveborn singleton births delivered after 20th gestational week. METHODS: Multivariate logistic regression models were applied to evaluate the association between PIH and infant mortality, with adjustment of potential confounders stratified by birthweight centiles and gestational age. MAIN OUTCOME MEASURE: Infant death (0-364 days) and its three components: early neonatal death (0-6 days), late neonatal death (7-27 days), and postneonatal death (28-364 days). RESULTS: PIH was associated with decreased risks of infant mortality, early neonatal mortality, and late neonatal mortality in both preterm and term SGA births, and PIH was associated with lower postneonatal mortality in preterm SGA births. PIH was associated with decreased risks of infant mortality, early neonatal mortality, late neonatal mortality and postneonatal mortality in preterm AGA births. Decreased risk of infant mortality and early neonatal mortality was associated with PIH in early preterm LGA births. CONCLUSIONS: The association between PIH and infant mortality varies depending on different birthweight centiles, gestational age, and age at death. PIH is associated with a decreased risk of infant mortality in SGA births, preterm AGA births, and early preterm LGA births.     

Development of a customised birthweight standard for ethnic Chinese subjects

A model to establish customised birthweight standards for the Chinese population was developed, using data from a cohort of 1564 Chinese women with normal singleton pregnancies. Multiple regression analysis was performed using maternal height, weight, parity, gestation at delivery and fetal sex as independent (predictor) variables. From this, a customised ideal birthweight for each baby can be estimated, and the normality of the actual birthweight can be evaluated according to this, rather than from population standards. The results of this study show that birthweights are strongly influenced by maternal characteristics, confirming conclusions from similar studies in other ethnic populations. The overall mean birthweight at 280 days of gestation was 3252 g, which was smaller than that of the Caucasian population. Birthweight increased with maternal height (5.1 g/cm), maternal booking weight (10.2 g/kg) and gestation at delivery (18.3 g/day from 280 days). Babies from women who had two previous deliveries weighed 145.2 g more than the nulliparous. Male babies were 84.8 g heavier than females. Adjustment using these results produces a customised ideal birthweight for each baby. When compared with population based standards, customised birthweight standards identified significantly fewer small for gestational age (SGA - birthweight below 10th centile, McNemar Chi square = 19.1, p < 0.01) and fewer large for gestational age (LGA - birthweight above 90th centile, McNemar Chi square = 23.7, p < 0.01) cases.     

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.     

Fetal macrosomia

Birthweight has increased in the last century partly attributed to increasing maternal obesity and prevalence of gestational diabetes. Although changes in mean birthweight reflect the trends and demography of the population, increased risk of adverse outcomes occurs at the extremes of the distribution (i.e. in small and large infants). The aim of this review is to provide better understanding of definition, epidemiology, prediction and management of large infants. Many definitions of large infants, or fetal overgrowth, have been described in the literature, including macrosomia (weight above 4 kg) or large for gestational age (LGA) (weight above the 90^th centile by population, customized or international charts). However, no single definition is currently universally accepted. Irrespective of definition, fetal overgrowth is associated with increased risk of adverse perinatal outcomes, including need for caesarean delivery, postpartum haemorrhage, severe perineal tears, low Apgar score, admission to neonatal intensive care unit, and severe neonatal morbidity and perinatal mortality. Major risk factors for LGA are maternal obesity, diabetes and increased gestational weight gain but these are not highly predictive of LGA. Efforts to prevent fetal overgrowth have had limited success, helping to justify the current focus on improving management once a large infant is identified by ultrasound. Induction of labour for the large for gestational age fetus at term is a promising strategy but ongoing studies will help inform timing of induction and target population. The Royal College of Obstetricians and Gynaecologists (RCOG) suggests elective caesarean section should be considered when the estimated fetal weight is above 4.5 kg in women with diabetes. Although caesarean section should not be recommended below this threshold, the ruling Montgomery v Lanarkshire Health Board [2015] has emphazised our duty to provide clear and comprehensive information during antenatal care.     

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.     

Term birthweight centiles for babies from New Zealand's main ethnic groups

BACKGROUND: There are significant differences in mean birthweights between New Zealand's main ethnic groups. Birthweight centiles developed predominantly from babies of European ethnicity may therefore not be appropriate to classify babies from other ethnic groups. AIMS: To develop ethnic specific birthweight centiles for New Zealand babies delivered at term (>37 weeks). METHODS: Births from the National Women's Hospital database from 1993 to 2000 who also had scan data at <24 weeks comprised the study population (n = 10 292). Multiple pregnancies, fetal abnormalities, stillbirths and preterm births were excluded. For six ethnic groupings, born at gestational weeks from 38 to 41, sex specific centiles were generated and smoothed. RESULTS: Birthweight centiles were constructed from 5203 European, 801 Maori, 825 Samoan, 577 Tongan, 1058 Chinese, 433 Indian and 1395 other ethnic group births. Mean birthweights by ethnic group were: European 3521 g, Maori 3467 g, Samoan 3691 g, Tongan 3791 g, Chinese 3418 g, Indian 3192 g and other 3466 g. Tongan and Samoan babies were significantly heavier and Indian babies were significantly lighter than babies from all other ethnic groups (P < 0.001 for all comparisons). Overall Maori babies were approximately 50 g lighter than European babies but this difference was not statistically significant (P = 0.08), whereas Chinese babies were significantly lighter with a mean birthweight 100 g less than European (P < 0.001). CONCLUSIONS: These ethnic specific centile charts are likely to identify term babies with inappropriate growth better than population centiles generated predominantly from one ethnic group.     

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.     

The association between customised small for gestational age infants and pre-eclampsia or gestational hypertension varies with gestation at delivery

OBJECTIVES: (1) To describe the association between small for gestational age (SGA) infants and pre-eclampsia (PE) and gestational hypertension (GH) and (2) to determine how this association changes with gestational age at delivery using customised centiles to classify infants as SGA. DESIGN: A retrospective observational study. SETTING: National Women's Hospital, a Tertiary Referral Centre in Auckland, New Zealand. POPULATION: A total of 17 855 nulliparous women delivering between 1992 and 1999. METHODS: A comparison of the number of women with a customised SGA infant, PE and GH according to gestational age at delivery. MAIN OUTCOME MEASURES: The incidence of SGA infants (defined as birthweight <10th customised centile), PE and GH at <34, 34-36(+6) and > or =37 weeks. RESULTS: A total of 1847 (10.3%) infants were SGA, 520 (2.9%) women had PE and 1361 (7.6%) had GH. SGA, PE and GH all occurred more commonly with increasing gestation at delivery with 85%, 62% and 90% of cases delivered at term. In women delivering SGA infants, coexisting PE was more likely to occur among those delivered preterm than at term (38.6% at <34 weeks [relative risk, RR 10.2 95%CI 7.3-14.4], 22.4% at 34-36(+6) weeks [RR 6.0 95%CI 4.1-8.6] and 3.8% at > or =37 weeks [OR 1.0]). Women with preterm PE were more likely to have a SGA infant than women with term PE (57.1% at <34 weeks [RR 3.1 95%CI 2.3-4.2], 31.7% at 34-36(+6) weeks [RR 1.7 95%CI 1.2-2.5]) and 18.3% at > or =37 weeks [OR 1.0]). There was a similar association between GH and SGA infants as gestation advanced (57.6% at <34 weeks [RR 4.8 95%CI 3.4-6.6], 30.5% at 34-36(+6) weeks [RR 2.5 95%CI 1.8-3.5] and 12.1% > or =37 weeks [OR 1.0]). CONCLUSIONS: SGA infants and PE are more likely to coexist in preterm births compared with term births. This is likely to reflect the degree of placental involvement in each disease process.     

Antiphosphatidyl serine antibodies are more common in normotensive women with small for gestational age pregnancies

BACKGROUND: Small for gestational age (SGA) babies are more common in women with antiphospholipid antibodies but data are limited about the prevalence of antiphospholipid antibodies in women who have delivered SGA babies. AIM: To determine whether elevated levels of anticardiolipin, antiphosphatidyl serine and/or antibeta2 glycoprotein I antibodies are more common in normotensive women who delivered SGA babies compared with women who delivered appropriate for gestational age babies. METHODS: Case-control study. Cases were normotensive women who delivered an SGA baby (birthweight <10th%) without chromosomal or congenital abnormality. Controls were healthy women who delivered a baby at term with birthweight >10th percentage. RESULTS: A total of 137 women with SGA pregnancies and 290 controls had antiphospholipid antibodies measured. The prevalence of anticardiolipin and antibeta2 glycoprotein I antibodies did not differ between SGA cases and controls. Antiphosphatidyl serine IgG antibodies were more common in women with SGA pregnancies than controls seven (5%) versus five (1.7%), relative risk (RR) 1.84 (1.12-3.03). There was no difference in the prevalence of 'any antiphospholipid antibodies' between SGA 10 (7.2%) and controls 16 (5.6%). There was a trend to more abnormal umbilical Doppler studies in SGA pregnancies with positive antiphospholipid antibodies three (50%) versus 19 (24%), RR 2.9 (0.62-13). CONCLUSIONS: Antiphospholipid antibodies were uncommon in this cohort of SGA pregnancies. Further studies are needed in SGA pregnancies with abnormal umbilical Doppler studies to determine if screening for antiphospholipid antibodies is worthwhile in this severe subgroup.     

A customised birthweight centile calculator developed for a New Zealand population

BACKGROUND: Traditionally, small for gestational age is defined as birthweight <10th percentile using sex-adjusted centile charts. However, this criterion includes constitutional variation due to maternal height, weight, ethnic group and parity. Aims: To develop customised birthweight centiles for a New Zealand population. METHODS: National Women's Hospital database of births from 1993 to 2000 was used to identify eligible women with singleton pregnancies who had data available on the following: scan result for dating at gestation <24 weeks, maternal height and weight at booking, parity and ethnic origin. Multiple regression was used to determine the coefficients applicable to New Zealand. RESULTS: A total of 4707 pregnancies met the inclusion criteria comprising: European 1688 (36.0%), Maori 419 (8.9%) Samoan 506 (10.7%), Tongan 326 (6.9%), Chinese 751 (16.0%), Indian 214 (4.6%) and other 803 (17.1%). Mean term birthweight for an average nulliparous European woman was 3530 g. Babies of Maori and Indian ethnicity were on average 67 g and 150 g lighter, respectively, than European babies. Samoan, Tongan and Chinese babies were 84 g, 124 g and 101 g heavier, respectively. CONCLUSIONS: There are significant differences in birthweight between European and the other major ethnic groups in New Zealand. They relate to maternal physiological variables, for which coefficients have been derived and incorporated into freely available software that enables improved clinical assessment of fetal and neonatal weight.     

The influence of fetal sex on the antenatal diagnosis of small for gestational age

Objective: We evaluated the influence of fetal sex on the antenatal diagnosis and detection of small for gestational age (SGA).

Methods: The cohort consisted of unselected singleton pregnancies, undergoing routine biometry and cerebroplacental ratio (CPR) assessment at 36 weeks. Locally fitted equations for centiles and Z scores were used. “Ultrasound SGA” was defined as estimated fetal weight (EFW)?Results: Among 4112 pregnancies, there were 235 female “ultrasound SGA” fetuses and 177 male; (odds ratios (OR) 1.502 (1.223???1.845)); the detection rate of SGA at birth was 50.6% and 40.9%, respectively (OR 1.479 (0.980???2.228)). In “ultrasound SGA” girls the abdominal circumference growth velocity (ACGV) between 20 and 36 weeks was less frequently in the lowest decile (OR 0.490 (0.320???0.750)), with no differences in CPR.

Conclusions: Females are more commonly diagnosed as SGA; those diagnosed may be at less risk than males.     

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.     

Comparison of customized and cohort-based birthweight standards in identification of growth-restricted infants in GUSTO cohort study

Background: The aim was to evaluate the ability of customized and cohort birthweight standards in discriminating intrauterine growth retardation (IUGR).

Methods: Birthweights (BWs) of GUSTO singleton infants born at gestational age (GA) 35–41 weeks were converted using two standards: (a) GUSTO cohort-based BW centile adjusted for GA and baby gender; (b) customized BW percentile calculator adjusted for maternal height and weight, race, parity, GA and gender. Infants were classified into three groups: (1)?<?10th BW centile by customization– customized-SGA, (2)?<?10th BW centile by GUSTO– GUSTO-SGA; and (3)?>?10th BW centile by both standards – BOTH-non-SGA.

Results: Of the 1011 infant–mother dyads, 68 were customized-SGA and 104 were GUSTO-SGA, with concordance of 61% (n?= 63) for SGA. While 5 (7%) of customized-SGA were not SGA by GUSTO-charts, 41 (39%) of GUSTO-SGA were not SGA by customized-charts. Customized-SGA had significantly the least growth in abdominal circumference (AC) and highest head circumference (HC): AC growth ratio between second and third trimester; and the lowest mean BW, ponderal index and placental weight than other groups.

Conclusion: Customized-SGA standard was a better discriminator of pathologic fetal growth based on AC growth. It improved strength of association with pathology and in our population reduced false positives (41/104?=?39%) in the assessment of SGA.     

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.     

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.     

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.     

Birthweight of IVF children is still a current issue and still related to maternal factors

Research questionDoes fresh embryo transfer after IVF with or without intracytoplasmic sperm injection (ICSI) increase the small for gestational age (SGA) rate, and frozen embryo transfer (FET) after IVF with or without ICSI increase the large for gestational age (LGA) rate versus natural conception?DesignRetrospective comparison of an exposed historical group/cohort involving singletons conceived after fresh embryo transfer and after FET with an unexposed group/cohort involving singletons conceived after a natural conception.ResultsA total of 1961 fresh embryo transfer babies and 366 FET babies were compared with 6981 natural conception babies. The SGA rate in fresh embryo transfer babies was not significantly different to natural conception babies (6.9% versus 6.8%, P = 0.856). This outcome was not influenced by the fresh embryo transfer (adjusted odds ratio [aOR] 1.0; 95% confidence interval [CI] 0.8–1.3), but rather by a low rate of multiparity (aOR 0.5; 95% CI 0.3–0.7), advanced maternal age (aOR 1.1; 95% CI 1.0–1.2), maternal underweight (aOR 1.5; 95% CI 1.1–2.1), maternal smoking or cessation during pregnancy (aOR 1.8; 95% CI 1.4–2.3), pre-existing hypertension (aOR 2.3; 95% CI 1.3–4.1) and pregnancy-induced hypertension (aOR 2.5; 95% CI 1.7–3.7). The LGA rate in FET babies was significantly different from natural conception babies (6.6% versus 3.2%, P = 0.012). This outcome was influenced by the transfer of frozen embryos (aOR 2.2; 95% CI 1.3–3.8) and by a high maternal weight (aOR 1.9; 95% CI 1.1–3.6).ConclusionsMaternal background and obstetric parameters are more likely to influence the SGA rate than fresh embryo transfer conception. FET conception could be associated with an increase in LGA rate.