Neonatal morphometry. Relation to obstetric, pediatric, and menstrual estimates of gestational age

Maternal anthropometric characteristics as determinants of birth weight in north-west Nigeria: prospective study

OBJECTIVE

This study was undertaken to determine the sensitivity and specificity of anthropometric measurements in predicting birth weight.

METHODS

This was a prospective study. Interviewer-administered questionnaires were used. Two hundred were used. The weight, height and BMI of the women were measured. Unclothed newborns were weighed immediately after delivery. The data obtained were analyzed using SPSS version 16.0 statistical software. The accuracy of maternal weight, height and body mass index in predicting birth weight was compared using chi-squared test and p < 0.05 was considered statistically significant.

RESULT

The mean maternal age was 28.2 ± 5.7 years. The mean parity was 3 ± 2. The mean gestational age at delivery was 38.5 ± 2 years. The mean actual birth weight was 3.27 ± 0.53 kg. The mean maternal weight was 72.03 ± 11 kg. Maternal weight showed a strong positive correlation with birth weight (r = 0.48) and this was statistically significant (p < 0.001). The mean maternal height was 1.64 ± 0.55 m. The mean maternal BMI was 27.9 ± 4.33. Maternal weight, height and BMI had sensitivities of 50%, 40% and 50% and specificities of 48%, 57.9% and 67.3%, respectively.

CONCLUSION

Maternal weight, height and BMI are not good predictors of birth weight and cannot be recommended for use as screening test in poor resource setting where ultrasound available.

Peripheral insertion of umbilical cord

Numerous studies have addressed the significance of marginal and membranous umbilical cord (UC) insertion. Recent reports suggest that an eccentrically inserted UC may also be important. This case-control study assessed the potential relevance of peripheral insertion of UC (PIUC), defined as <3 cm from the nearest margin. Singleton placentas (n  =  1418) submitted to the pathology department over an 18-month period were analyzed. Each case of PIUC (n  =  119) was matched with a control placenta of the same gestational age. Placentas with marginal or membranous UC and multiple gestations were excluded. The overall prevalence of PIUC was 8.4%, but PIUC frequency was significantly increased in premature births at <28 weeks (21.4%, P < 0.001). There was no association with other adverse pregnancy outcomes. PIUC was associated with decreased placental weight Z-score (-0.69 ± 0.92 versus -0.22 ± 1.3, P  =  0.0056), but not fetal weight Z-score, suggesting increased utilization of placental reserve. PIUC was also associated with relatively elongated placentas (length minus width: 2.6 ± 3.2 versus 1.0 ± 3.1, P  =  0.006). PIUC tended to be more frequent in young primiparous mothers and was significantly less common in women with a history of prior curettage (66% vs 50%, P  =  0.013). These data, together with equivalent rates of prior cesarean section, multiparity, and advanced maternal age, support a primary developmental disorder as opposed to secondary placental migration due to underlying uterine abnormalities ("trophotropism"). Except for a borderline significant association with findings suggestive of maternal malperfusion (P  =  0.078), PIUC was not associated with other placental lesions.

Outcomes of small for gestational age micropremies depending on how young or how small they are

Purpose

The outcomes of small for gestational age (SGA) infants especially in extremely low birth weight infants (ELBWIs) are controversial. This study evaluated the mortality and morbidity of ELBWIs, focusing on whether or not they were also SGA.

Methods

The medical records of 415 ELBWIs (birth weight <1,000 g), who were inborn and admitted to the Samsung Medical Center neonatal intensive care unit from January 2000 to December 2008, were reviewed retrospectively. Mortality and morbidities were compared by body size groups: very SGA (VSGA), birth weight ≤3rd percentile; SGA, 3rd to 10th percentile; and appropriate for gestational age (AGA) infants, >10th percentile for gestational age. For gestational subgroup analysis, groups were divided into infants with gestational age ≤24⁺⁶ weeks (subgroup I), 25⁺⁰ to 26⁺⁶ weeks (subgroup II), and ≥27⁺⁰ weeks (subgroup III).

Results

Gestational age was 29⁺²±2⁺⁶ weeks in the VSGA infants (n=49), 27⁺⁵±2⁺² weeks in the SGA infants (n=45), and 25⁺⁴±1⁺⁴ weeks in AGA infants (n=321). Birth weight was 692±186.6 g, 768±132.9 g, and 780±142.5 g in the VSGA, SGA, and AGA groups, respectively. Cesarean section rate and maternal pregnancy-induced hypertension were more common in the VSGA and SGA than in AGA pregnancies. However, chorioamnionitis was more common in the AGA group. The mortalities of the lowest gestational group (subgroup I), and also of the lower gestational group (subgroup I+II) were significantly higher in the VSGA group than the SGA or AGA groups (P=0.020 and P=0.012, respectively). VSGA and SGA infants showed lower incidence in respiratory distress syndrome, ductal ligation, bronchopulmonary dysplasia, intraventricular hemorrhage than AGA group did. However, by multiple logistic regression analysis of each gestational subgroup, the differences were not significant.

Conclusion

Of ELBWIs, extremely SGA in the lower gestational subgroups, had an impact on mortality, which may provide information useful for prenatal counseling.

Multifocal chorangiomatosis

Multifocal chorangiomatosis (MC) is an uncommon villous capillary lesion sharing some features with villous chorangiosis and placental chorangioma. We prospectively identified 53 cases of MC among 5429 consecutively accessioned placentas of >20 weeks gestation over a 10-year period. Two gestational age (GA)-matched controls were selected for each case from the same cohort and a case control analysis of associated clinical and pathologic features was performed. Multifocal chorangiomatosis was seen at all GAs but was most frequent in very preterm placentas (<32 weeks). Avascular villi, villous chorangiosis, and distal villous immaturity were each seen in approximately half of placentas with MC. Other common placental findings included concentric narrowing of fetal villous arterioles, villous edema, and dysmorphic villi. Only one case had an associated placental chorangioma. Maternal factors significantly associated with MC were advanced maternal age, non-African-American ancestry, nonprimigravid status, and >5 previous pregnancies. Infants with placental MC had a significantly increased prevalence of congenital anomalies. Multifocal chorangiomatosis was subcategorized as extensive versus patchy based on the size of the largest focus (> versus < ×2 microscopic field). Fetuses with extensive MC, when compared with patchy MC, were more likely to have congenital anomalies and stillbirth and to be large for GA. Paradoxically, those with patchy MC were more likely to be small for GA. The results of this study suggest that MC may represent an abnormal proliferation of the paravascular capillary net in proximal villi related to fetoplacental developmental anomalies and abnormal fetal blood flow.

Cerebral palsy in term infants: a clinicopathologic analysis of 158 medicolegal case reviews

Our understanding of cerebral palsy (CP) in term infants is hindered by its low incidence and sporadic presentation. Many of these CP cases enter litigation, and a focused review of medicolegal consultations provides an opportunity to better understand the pathogenesis of these cases. In this study complete clinical and pathologic data from 158 cases of CP complicating singleton pregnancies after 36 weeks of gestation were prospectively collected over a 10-year period extending from 1998 to 2008. A hierarchical system was used to separate cases into the following 5 groups: (1) clinical/sentinel events (20%), (2) severe large fetoplacental vascular lesions (34%), (3) placental lesions indicative of chronic placental dysfunction (23%), and (4) placental lesions indicative of subacute/chronic adaptation to hypoxia (15%). The remaining 8% (group 5) of cases were idiopathic. Common to all subgroups was clinical and/or pathologic evidence of umbilical cord obstruction, which was observed in 63% of cases. The following clinical features significantly differed among subgroups. Group 1 had less maternal obesity and more cases involving multicystic encephalopathy. Group 2 had increased oligohydramnios, cerebral edema, nucleated red blood cell counts greater than 10 000/mm(3), hypoglycemia, pulmonary hypertension, and cardiac dysfunction. Group 3 had more preeclampsia and, together with group 2, more infants with a low ponderal index. Group 5 had a higher prevalence of positive family history of neurodevelopmental disorders. In conclusion, infant cases subject to litigation related to CP following term birth can be separated into distinct clinicopathologic subgroups with only a small number lacking either clinical/sentinel events or placental evidence of subacute or chronic in utero stress.

Prenatal and neonatal risk factors for sleep disordered breathing in school-aged children born preterm

OBJECTIVES

Previously published data from the Cleveland Children's Sleep and Health Study demonstrated that preterm infants are especially vulnerable both to sleep disordered breathing (SDB) and its neurocognitive sequelae at age 8 to 11 years. In this analysis, we aimed to identify the components of the neonatal medical history associated with childhood SDB among children born prematurely.

STUDY DESIGN

This analysis focuses on the 383 children in the population-based cohort from the Cleveland Children's Sleep and Health Study who were born <37 weeks gestational age and who had technically acceptable sleep studies performed at ages 8 to 11 years (92% of all preterm children). Logistic regression was used to evaluate the associations between candidate perinatal and neonatal risk factors and the presence of childhood SDB by sleep study.

RESULTS

Twenty-eight preterm children (7.3%) met the definition for SDB at age 8 to 11 years. Having a single mother and mild maternal preeclampsia were strongly associated with SDB in unadjusted and race-adjusted models. Unadjusted analyses also identified xanthine use and cardiopulmonary resuscitation or intubation in the delivery room as potential risk-factors for SDB. We did not find a significant link between traditional markers of severity of neonatal illness-such as gestational age, birth weight, intraventricular hemorrhage, bronchopulmonary dysplasia, or duration of ventilation-and childhood SDB at school age.

CONCLUSIONS

These results represent a first step in identifying prenatal and neonatal characteristics that place preterm infants at higher risk for childhood SDB. The strong association between mild preeclampsia and childhood SDB underscores the importance of research aimed at understanding in utero risk factors for neurorespiratory development.

Elevated circulating fetal nucleated red blood cells and placental pathology in term infants who develop cerebral palsy

An elevated circulating fetal nucleated red blood cell count has long been recognized as an indicator of significant intrauterine stress. However, the nature of the causative events and their timing remain controversial. In this study, subacute and chronic placental lesions known to be associated with neurodisability were used as surrogates for antenatal stress. Mother-infant pairs with complete blood counts within 2 hours of delivery (n = 81) were drawn from a larger database of 152 term infants with cerebral palsy. An elevated nucleated red blood cell count (2.5 x 10(3)/mm(3)) in these infants was associated with a significantly increased prevalence of subacute or chronic placental lesions, whereas clinical findings did not significantly differ. The number of nucleated red blood cells per 10 high-power fields of villous parenchyma was directly correlated with the nucleated red blood cell count, and a threshold of 10 or more nucleated red blood cells predicted a nucleated red blood cell count greater than 2.5 x 10(3)/mm(3). Among individual placental lesions, multiple foci of avascular villi and chronic villitis were significantly associated with an elevated nucleated red blood cell count, whereas meconium-associated vascular necrosis showed a borderline association. Acute chorioamnionitis was the only placental lesion more common in the group without elevated nucleated red blood cell count. The presence of significant placental lesions was associated with an elevated nucleated red blood cell count in infants with or without either acidosis (cord pH <7.0) or birth asphyxia (American College of Obstetrics and Gynecology criteria). Acidosis and birth asphyxia were not significantly related to an elevated nucleated red blood cell count in infants without these placental lesions.

Anthropometric measurements for neonates, 23 to 29 weeks gestation, in the 1990s

Reference data describing weight, length, and head circumference (anthropometric measurements) at birth were published by Lubchenco and Usher before 1970. Few attempts have been made to investigate whether these data are appropriate for today's cohort of preterm neonates. We analysed anthropometric data for neonates born between 23 and 29 weeks' gestation. Reference charts were developed from the measurements obtained from neonatal records, and gestational age, obtained from maternal charts, on 975 neonates delivered at four neonatal centres in Michigan during 1992 and 1997. The analysis was confined to children with gestational age that was consistent or within 7 days by last menstrual period, obstetric examination, ultrasound and neonatal determinations. At 23 to 29 weeks' gestation, ethnicity and multiple births did not have any significant impact on birthweight but girls were lighter. We compared our anthropometric charts with those presently being used at many neonatal centres. In our study, physical measurements at birth of preterm neonates born between 1992 and 1997 were significantly different from those currently used to assess growth status. Furthermore data derived from published studies that utilised birth certificates with gestational age based on last menstrual period seem to overestimate birthweight. For preterm infants, our findings are concordant with recently published values from 18 states of the US. Because of improved survival, gestational age assessment and perinatal care of preterm neonates, development of new reference anthropometric measurements for neonates is overdue. Our Michigan data of 23-29 weeks preterm provides new national reference values, which we recommend for use in US neonatal centres for extremely preterm neonates.

Assessment of gestational age and neuromaturation

Neuromaturation is the functional development of the central nervous system (CNS). It is by its very nature a dynamic process, a continuous interaction between the genome and first the intrauterine environment, then the extrauterine environment. Understanding neuromaturation and being able to measure it is fundamental to infant neurodevelopmental assessment. Fetal and preterm neuromaturation has become easier to observe with the advent of prenatal ultrasonography and neonatal intensive care units. A number of measures of degree of fetal maturation have been developed and used to estimate gestational age (GA) at birth. The most reliable measures of GA are prenatal measures, especially from the first trimester. Postnatal GA measurements tend to be least accurate at the extremes of gestation, that is, in extremely preterm and post-term infants. Observations of measures of neuromaturation in infants born to mothers with pregnancy complications, including intrauterine growth restriction, multiple gestation, and chronic hypertension, have led to the discovery that stressed pregnancies may accelerate fetal pulmonary and CNS maturation. This acceleration of neuromaturation does not occur before 30 weeks' gestation and has a cost with respect to cognitive limitations manifested in childhood. The ability to measure fetal and preterm neuromaturation provides an assessment of neurodevelopmental progress that can be used to reassure parents or identify at risk infants who would benefit from limited comprehensive follow-up and early intervention services. In addition, measures of neuromaturation have the potential to provide insight into mechanisms of CNS injury and recovery, much-needed early feedback in intervention or treatment trials and a measure of early CNS function for research into the relationships between CNS structure and function.

Severe fetal placental vascular lesions in term infants with neurologic impairment

OBJECTIVE

This study tests the hypothesis that placental disease can identify antepartum processes that either progress into the intrapartum period or predispose to intrapartum brain injury.

STUDY DESIGN

Lesions that affect large fetal vessels were compared in the placentas of 125 neurologically impaired term infants who were the focus of clinical negligence litigation and 250 consecutive singleton deliveries of >/=36 weeks of gestation.

RESULTS

One or more of 4 severe placental fetal vascular lesions (fetal thrombotic vasculopathy, chronic villitis with obliterative fetal vasculopathy, chorioamnionitis with severe fetal vasculitis, and meconium-associated fetal vascular necrosis) were found in 51% of index cases versus 10% of the comparison group ( P <.0001). Prevalence of these lesions in the 64 infants with cerebral palsy was 52% ( P <.0001).

CONCLUSION

Severe fetal placental vascular lesions are correlated highly with neurologic impairment and cerebral palsy. Their nature, duration, and anatomic location make them strong candidates for the antepartum processes that place fetuses at risk for brain injury during the intrapartum period.

Clinical and pathological umbilical cord abnormalities in fetal thrombotic vasculopathy

Although inherited fetal coagulation disorders may lead to fetal thrombotic vasculopathy (FTV) in occasional cases, several studies have failed to show a significant association between these 2 entities. This study tests the hypothesis that vascular stasis related to chronic umbilical cord obstruction might be a contributing factor. The study population consisted of 125 neurologically impaired term infants who were the focus of clinical negligence litigation. FTV, as defined by an average of >15 villi per slide exhibiting either a complete lack of blood vessels or villous stromal karyorrhexis, was found in the placentas of 23 cases. Clinical umbilical cord entanglement (ie, true knots or cord loops around the neck or body parts at delivery) was significantly more common in cases with FTV (61% vs 24% in cases without FTV; P = 0.0009). Potentially obstructive pathological abnormalities of the umbilical cord (marginal/ membranous insertion, decreased Wharton's jelly, maximum cord diameter <8 mm, or hypercoiling) were also more frequent in this group (30% vs 9% without FTV; P = 0.0055). Overall, 16 of 23 placentas with FTV had either clinical or pathological cord abnormalities. This study, with careful documentation of cord status at delivery and on the delivered placenta, is the first to report that clinical cord entanglement and pathological cord abnormalities are significantly increased in placentas with FTV.

Variation in childhood asthma among former preterm infants

OBJECTIVES

The role of in utero and perinatal exposures in modifying asthma risk among children born prematurely was assessed. Study design Former preterm children (n=251) were identified from a birth cohort. Examinations, including lung function testing, were performed at ages 8 to 11 years. Perinatal exposures were ascertained from neonatal medical records.

RESULTS

Univariate predictors of asthma included male gender, African American ethnicity, maternal asthma, and birth weight. Asthmatics were less likely to have been small for gestational age (SGA) than nonasthmatics (12.4% vs 22.7%, P=.04) and had more neonatal pulmonary disease. After adjusting for maternal asthma and demographic factors, asthma was associated with chronic lung disease of infancy, neonatal mechanical ventilation and corticosteroid use, and a higher childhood body mass index. Children who were septic postbirth and girls who were SGA were less likely to have asthma (OR for sepsis, 0.2; 95% CI, 0.1-0.6; OR for girls who were SGA compared with girls who were not SGA, 0.05; CI, 0.01-0.34).

CONCLUSIONS

Among premature children, female SGA status and neonatal sepsis appear protective relative to the development of childhood asthma. Differential susceptibility to asthma among preterm children may relate to exposures that operate in the in utero and early postnatal environment to accelerate lung development, alter innate immunity, or both.

Asthma During Pregnancy

OBJECTIVE

To determine neonatal and maternal outcomes stratified by asthma severity during pregnancy by using the 1993 National Asthma Education Program Working Group on Asthma and Pregnancy definitions of asthma severity. The primary hypothesis was that moderate or severe asthmatics would have an increased incidence of delivery at <32 weeks of gestation compared with nonasthmatic controls.

METHODS

This was a multicenter, prospective, observational cohort study conducted over 4 years at 16 university hospital centers. Asthma severity was defined according to the National Asthma Education Program Working Group on Asthma and Pregnancy classification and modified to include medication requirements. This study had 80% power to detect a 2- to 3-fold increase in delivery less than 32 weeks of gestation among the cohort with the moderate or severe asthma compared with controls. Secondary outcome measures included obstetrical and neonatal outcomes.

RESULTS

The final analysis included 881 nonasthmatic controls, 873 with mild asthma, 814 with moderate, and 52 with severe asthma. There were no significant differences in the rates of preterm delivery less than 32 weeks (moderate or severe 3.0%, mild 3.4%, controls 3.3%; P =.873) or less than 37 weeks of gestation. There were no significant differences for neonatal outcomes except discharge diagnosis of neonatal sepsis among the mild group compared with controls, adjusted odds ratio 2.9, 95% confidence interval 1.2, 6.8. There were no significant differences for maternal complications except for an increase in overall cesarean delivery rate among the moderate-or-severe group compared with controls (adjusted odds ratio 1.4, 95% confidence interval 1.1, 1.8).

CONCLUSION

Asthma was not associated with a significant increase in preterm delivery or other adverse perinatal outcomes other than a discharge diagnosis of neonatal sepsis. Cesarean delivery rate was increased among the cohort with moderate or severe asthma.

LEVEL OF EVIDENCE

II-2

Placental and other perinatal risk factors for chronic lung disease in very low birth weight infants

To clarify the relationship between chorioamnionitis and chronic lung disease (CLD) in very low birth weight (VLBW) infants, we performed a retrospective cohort study of all inborn patients between 1995-1997 with gestational age (GA) less than 32 wk, birth weight less than 1.5 kg, survival to 36 wk adjusted GA, and placentas submitted to pathology (n = 371). Racial distribution as defined by the mother was 40% white/60% nonwhite. Prevalence of CLD, defined as O(2) dependence at 36 wk adjusted GA, was 30%. In a preliminary analysis GA and birth weight for GA (standard deviations from the mean, Z-score), considered together, were inversely related to CLD. After adjustment for GA and Z-score, other risk factors for CLD were white race, acute respiratory distress, pulmonary air leak, patent ductus arteriosus, and septicemia. Two placental lesions were inversely related to CLD: histologic chorioamnionitis and acute atherosis (a placental indicator of preeclampsia). Following multivariate analysis, independent risk factors for CLD were GA (OR, 0.6; 95% CI = 0.5, 0.7), birthweight for GA (OR, 0.4; 95% CI = 0.3, 0.6), white race (OR, 1.9; 95% CI = 1.0, 3.3), patent ductus arteriosus (OR, 2.0; 95% CI = 1.0, 3.5), and pulmonary air leak (OR, 3.0; 95% CI = 1.3, 7.1). Acute atherosis was inversely related to CLD (OR, 0.2; 95% CI = 0.1, 0.8). Chorioamnionitis was stratified by subtype and again no association with CLD was seen in the population as a whole. Finally, chorioamnionitis of all subtypes tended to be increased in white infants and decreased in black infants with CLD. This dichotomy was not explained by differences in death rates, acute respiratory distress, intubation on d 2 of life, or total duration of assisted ventilation. We conclude that while chorioamnionitis was not a risk factor for CLD in our total population, racial differences in its relationship to CLD are worthy of further study.

Correctly identifying the macrosomic fetus: improving ultrasonography-based prediction

OBJECTIVE

Our goal was to improve the accuracy of estimating fetal weights among macrosomic fetuses with the traditional measurements of abdominal circumference, femur length, and head circumference.

STUDY DESIGN

We used 4831 cases without anomalies from an ultrasonography laboratory database with an estimated fetal weight obtained a maximum of 14 days before delivery. Abdominal circumference, femur length, and head circumference were each regressed on birth weight to obtain estimated fetal weight by abdominal circumference, femur length, and head circumference, respectively. We compared the individual variation for estimated fetal weight by abdominal circumference, femur length, and head circumference by calculating a within-subject standard deviation to quantify the level of disparity. We adjusted the estimated fetal weight to the date of delivery and for dependencies on maternal diabetes mellitus, weight, and height. We then weighted cases with birth weight >4500 g and diabetic cases with birth weight >4000 g 20-fold (weighted estimated fetal weight) for the purpose of creating a favorable bias for classifying these cases. The equation of Hadlock et al, with abdominal circumference, femur length, and head circumference, was applied as a benchmark estimated fetal weight.

RESULTS

Of the 4831 newborns, 308 (6.4%) had a birth weight >4000 g, and 56 (1.2%) had a birth weight >4500 g. There were 154 pregnancies complicated by diabetes mellitus; 26 (16.9%) of the resulting infants weighed >4000 g, and 5 (3.2%) weighed >4500 g. At 95% specificity, the weighted estimated fetal weight had a sensitivity of 85.7% at a cut point of 3912 g, compared with a sensitivity of 71.4% at 3604 g by use of the estimated fetal weight of Hadlock et al.

CONCLUSIONS

We were able to improve the accuracy of identifying the macrosomic fetus compared to reliance on the equation by Hadlock et al. A fetus was found to be at significantly increased risk for birth weight >4000 g when the estimated fetal weight based on abdominal circumference is larger than that based on either head circumference or femur length or when there is a large within-subject variance in estimated fetal weight based on abdominal circumference, femur length, and head circumference. We also found that there were significantly different groups of patients whose estimated fetal weights require different equations for better estimates. Even given ultrasonographic measurements, taking into account maternal height, weight, and presence of diabetes mellitus can improve macrosomia detection. Although these findings remain to be optimized and validated, the approach used here appears to yield better predictions than the current "one function fits all" approach.

Racial patterns in the effects of tobacco use on fetal growth

OBJECTIVE

The aim of this study was to characterize the interaction between the effects on fetal growth of maternal smoking and race by means of race-specific growth normograms.

STUDY DESIGN

A case-control study was performed on white and African American mothers who were delivered at 2 hospitals in metropolitan Atlanta between February 1993 and December 1994. The study population consisted of 621 small for gestational age infants and their mothers and 324 appropriate for gestational age infants and their mothers. Face-to-face interviews with mothers and detailed anthropometric measurements of neonates were performed. Relationships among tobacco use, race, and fetal growth were evaluated by means of multiple logistic regression. The chi(2) test of trend was performed to assess a dose-response relationship between smoking and fetal growth.

RESULTS

Mothers of small for gestational age neonates were significantly more likely than control mothers to be single (52% versus 40%), to be primiparous (47% versus 37%), to have a low body mass index (26% versus 17%), to have hypertension (22% versus 15%), and to use alcohol (15% versus 9%). Mothers of small for gestational age infants were significantly more likely than control mothers to smoke (26% versus 12%) and to smoke more cigarettes (P <.05). After controlling for potential confounders cigarette smoking in the second trimester was significantly associated with small for gestational age infants in both races (whites <1 pack/d adjusted odds ratio 3.82, 1-2 packs/d adjusted odds ratio 4.86, >2 packs/d crude odds ratio; African Americans <1 pack/d adjusted odds ratio 2. 35, 1-2 packs/d adjusted odds ratio 2.52). The chi(2) test of trend results were consistent with a dose-response relationship between smoking and small for gestational age infants (whites chi(2) = 14.06, P <.0001, African Americans chi(2) = 7.99). Comparison between the 2 races of the adverse effects of smoking on fetal growth showed no significant difference.

CONCLUSION

Self-reported maternal smoking during the second trimester is associated with fetal growth restriction in a dose-response manner. According to race-specific growth normograms no significant difference in the effects of tobacco use on fetal growth was found between white and African American women.

Low-to-moderate gestational alcohol use and intrauterine growth retardation, low birthweight, and preterm delivery

PURPOSE

Heavy drinking during pregnancy is an established risk factor for fetal alcohol syndrome and other adverse perinatal outcomes. However, there is still debate as to the effects of low-to-moderate drinking during pregnancy.

METHODS

This prospective investigation was based on 2714 singleton live births at Yale-New Haven Hospital during 1988-1992. Alcohol drinking during pregnancy was evaluated with respect to intrauterine growth retardation (IUGR), preterm delivery, and low birthweight.

RESULTS

Mild drinking, defined as > 0.10-0.25 oz of absolute alcohol per day, during the first month of pregnancy was associated with a protective effect on IUGR (OR, 0.39; 95% confidence interval (CI), 0.20-0.76). Overall, drinking during month 1 of pregnancy suggested a curvilinear effect on growth retardation, with consumption of > 1.00 oz of absolute alcohol per day showing increased risk. Drinking during month 7 was associated with a uniform increase in the odds of preterm delivery; the ORs were 2.88 (95% CI, 1.64-5.05) for light drinking and 2.96 (95% CI, 1.32-6.67) for mild-to-moderate alcohol consumption.

CONCLUSIONS

Differences in the risk estimates for IUGR and preterm delivery may indicate etiological differences that warrant further investigation of these outcomes and critical periods of exposure. Low birthweight is not a useful neonatal outcome for this exposure because it is a heterogeneous mix of preterm delivery and IUGR. Despite the observed protective effects of mild drinking on IUGR, the increased risk of preterm delivery with alcohol use supports a policy of abstinence during pregnancy.

The effects of poverty on child health and development

Poverty has been shown to negatively influence child health and development along a number of dimensions. For example, poverty-net of a variety of potentially confounding factors-is associated with increased neonatal and postneonatal mortality rates, greater risk of injuries resulting from accidents or physical abuse/neglect, higher risk for asthma, and lower developmental scores in a range of tests at multiple ages. Despite the extensive literature available that addresses the relationship between poverty and child health and development, as yet there is no consensus on how poverty should be operationalized to reflect its dynamic nature. Perhaps more important is the lack of agreement on the set of controls that should be included in the modeling of this relationship in order to determine the "true" or net effect of poverty, independent of its cofactors. In this paper, we suggest a general model that should be adhered to when investigating the effects of poverty on children. We propose a standard set of controls and various measures of poverty that should be incorporated in any study, when possible.

[Fetal growth in premature infants in Haute-Normandie]

BACKGROUND

Fetal growth standards of preterm infants are different from one study to another, especially for extremely preterm babies.

POPULATION AND METHODS

Between 1976 and 1990, a cross-sectional study of the resulting intrauterine growth of premature newborns from Haute-Normandie (France) was conducted by collecting data of the compulsory health certificate set up in the first week after birth. In spite of exclusions, curves for obstetrical terms ranging from 28 to 36 weeks of gestational age were settled. Equivalents of 8,042 birth weights, 7,792 statures, 8,041 head circumferences and 6,737 ponderal index were used.

RESULTS

Comparing our results with those published in the literature, we observed short differences for mean or middle values: from less than 170 to more than 180 g for weight, from less than 1 to more than 2.6 cm for stature and from less than 1 to more than 1.9 cm for head circumference.

CONCLUSION

The selected normal lower threshold for each parameter and the varieties of fetal growth inadequacy are under discussion.

Did preterm deliveries continue to decrease in France in the 1980s?

To study the trends in gestational age and birthweight in France, we compared data from three surveys that were based on representative samples of births in 10 French regions and were conducted in 1972, 1981 and 1988-89. Only single livebirths were considered in the analysis. The rate of preterm births decreased from 7.9% in 1972 to 5.8% in 1981 and 4.0% in 1988-89. The corresponding rates of children with a birthweight below 2500 g were 5.4, 4.3 and 4.7%. The mean birthweight of preterm babies born in 1988-89 was lower than the mean birthweight of those born in 1972 and 1981. The reduction in preterm births cannot be attributed to the improved accuracy of gestational age determination, but the general use of ultrasound may have played a major role in the apparent reduction of the mean birthweight of preterm babies.

Trends in an obstetric patient population: an eighteen-year study

OBJECTIVE

Our goal was to evaluate various trends including gestational age, birth weight, and mode of delivery in an inner-city obstetric patient population delivered at a tertiary medical center.

STUDY DESIGN

We used an 18-year computerized perinatal database collected prospectively since 1975 in an inner-city tertiary medical center. More than 63,500 deliveries from 1975 through 1992 were evaluated. Trends in gestational age, birth weight, and mode of delivery were investigated with Cox-Stuart, regression, and other trend analysis methods.

RESULTS

The number of deliveries increased from 2682 in 1975 to 4740 in 1991, an increase of 77%. The median maternal age has increased from 20 years in 1975 to 23 years in 1992 (p < 0.001). Overall, the mean gestational age has declined monotonically from 39.2 +/- 2.84 weeks in 1975 to 38.3 +/- 3.17 weeks in 1992 (p = 0.057). While the median and lower percentiles of birth weight for singleton births have declined, the 75th and higher percentiles of birth weight have increased during 18 years. Overall, the proportion of preterm births (< 37 completed weeks gestational age) has increased from 3.3% in 1975 to 7.8% in 1991 (p < 0.001). During this period the proportion of low-birth-weight infants (< 2,500 gm) increased significantly from 12.7% to 17.3% (p < 0.001). The proportion of cesarean section deliveries for private patients has declined from 37% in 1975 to 25% in 1992 (p = 0.025), while this proportion has increased monotonically for staff patients from 10% to 17% during this period (p < 0.001).

CONCLUSIONS

Considering the large size of the database and diverse background of the study population, we believe that these trends can provide a realistic characterization of an obstetric patient population for a large inner-city urban population.

Gestational age and intrauterine growth retardation among white and black very low birthweight infants: a population-based cohort study

Very low birthweight (VLBW) is a commonly used endpoint in perinatal epidemiology, but the population of VLBW infants comprises a wide range of gestational ages and rates of fetal growth. We used data from a population-based study of all 1072 black and white VLBW liveborn infants born in 29 counties in Georgia between April 1986 and March 1988. Less than 1% of the VLBW infants were > or = 37 weeks gestation; most were 29-32 weeks (26%) or 25 to 28 weeks (40%); 12% were 22 weeks or less. All infants 33 weeks gestation or greater were growth retarded. The population of VLBW infants seems to comprise three groups: approximately 11% very immature infants of 22 weeks or less; the majority of infants, born between 23 and 30 weeks, 90% of which are of normal weight for their gestational age; and a group of less premature, growth-retarded infants from 31 to 36 weeks. We found little or no difference in the distribution of gestational age or the percentage of intrauterine growth rates (IUGR) between black and white infants. In the USA the VLBW rate among black infants is over three times greater than that among white infants and consequently the rates of the three types of VLBW among black infants are likely to be triple those among white infants.