Maternal, delivery, and perinatal characteristics associated with cryptorchidism: a population-based case-control study among births in Washington State

BACKGROUND: The etiology of cryptorchidism is largely unknown. To identify maternal, perinatal, and delivery characteristics associated with cryptorchidism at birth, we conducted a population-based case-control study using Washington State birth certificates linked to birth hospitalization records. METHODS: We identified 2,395 cases of cryptorchidism among male infants born in Washington State during 1986-1996, and, for comparison, we randomly selected four controls per case (N = 9,580), frequency-matched by year of birth. RESULTS: Infant characteristics associated with cryptorchidism included low birth weight (OR = 1.5; 95% CI = 1.3-1.8), small size for gestational age (OR = 1.9; 95% CI = 1.6-2.2), and breech presentation (OR = 1.7; 95% CI = 1.4-2.1). In addition to cryptorchidism, cases were more likely to have another type of congenital malformation (OR = 3.7; 95% CI = 3.2-4.2), particularly digestive (OR = 6.8; 95% CI = 3.7-12.7) or genitourinary (OR = 4.1; 95% CI = 3.0-5.6). Maternal and pregnancy characteristics associated with cryptorchidism included nulliparity (OR = 1.2; 95% CI = 1.1-1.3), maternal smoking during pregnancy (OR = 1.2; 95% CI = 1.1-1.4), and the following pregnancy complications: oligohydramnios (OR = 1.8; 95% CI = 1.3-2.6), placental abnormality (OR = 1.3; 95% CI = 1.0-1.8), and pregnancy-induced hypertension (OR = 1.6; 95% CI = 1.4-1.9). Odds ratios were similar when the analysis was restricted to term infants. CONCLUSIONS: These findings suggest that factors affecting fetal growth and development may increase the risk of cryptorchidism.     

Maternal night blindness during pregnancy is associated with low birthweight, morbidity, and poor growth in South India

Maternal night blindness is common during pregnancy in many developing countries. Previous studies have demonstrated important consequences of maternal night blindness during pregnancy on the health of the mother and newborn infant. We compared birthweight, 6-mo infant mortality, morbidity, and growth among infants of women who did and did not report a history of night blindness from a community-based, randomized trial of newborn vitamin A supplementation in south India. Birthweight was measured within 72 h of delivery. Infants were followed until 6 mo of age for mortality and morbidity was assessed at household visits every 2 wk. Anthropometry was assessed at 6 mo of age. A total of 12,829 live-born infants were included, 680 of whom were infants of mothers with night blindness during the index pregnancy. Maternal night blindness was associated with an increased risk of low birthweight in a dose-dependent fashion based on birthweight cut-offs: <2500 g, adjusted relative risk (RR) = 1.13 (95% CI = 1.01, 1.26); <2000 g, adjusted RR = 1.70 (95% CI = 1.27, 2.26); <1500 g, adjusted RR = 3.38 (95% CI = 1.18, 6.33); with an increased risk of diarrhea (adjusted RR = 1.16, 95% CI = 1.03, 1.30), dysentery (adjusted RR = 1.25, 95% CI = 1.03, 1.53), acute respiratory illness (adjusted RR = 1.32, 95% CI = 1.21, 1.44), and poor growth at 6 mo; underweight (adjusted RR = 1.14, 95% CI = 1.02, 1.26), stunting (adjusted RR = 1.19, 95% CI = 1.05, 1.34). Maternal night blindness was not associated with 6-mo infant mortality or wasting at 6 mo. This study demonstrates that there are important consequences to the infant of maternal vitamin A deficiency during pregnancy.     

Chemical hair treatments and adverse pregnancy outcome among Black women in central North Carolina

Several studies suggest that toxic chemicals in hair products may be absorbed through the scalp in sufficient amounts to increase the risks of adverse health effects in women or their infants. This case-control study of 525 Black women from three counties in North Carolina who had delivered a singleton, liveborn infant examined whether exposure to chemicals used in hair straightening and curling increased the odds that the infant was preterm or low birth weight. Cases consisted of 188 preterm and 156 low birth weight births (for 123 women, their infant was both low birth weight and preterm). Controls were 304 women who delivered term and normal birth weight infants. Women who used a chemical hair straightener at any time during pregnancy or within 3 months prior to conception had an adjusted odds ratios (OR) of 0.7 (95% confidence interval (CI) 0.4-1.1) for preterm birth and 0.6 (95% CI 0.4-1.1) for low birth weight. Exposure to chemical curl products was also not associated with preterm delivery (adjusted OR = 0.9, 95% CI 0.5-1.8) or low birth weight (adjusted OR = 1.0, 95% CI 0.5-1.9). Despite this failure to find an association, continued search for risk factors to which Black women are uniquely exposed is warranted.     

The influence of maternal cigarette smoking, snuff use and passive smoking on pregnancy outcomes: the Birth To Ten Study

This article describes the patterns and effects of maternal snuff use, cigarette smoking and exposure to environmental tobacco smoke during pregnancy on birthweight and gestational age, in women living in Johannesburg and Soweto in 1990. A cohort of 1593 women with singleton live births provided information about their own and household members' usage of tobacco products during pregnancy. The women completed a questionnaire while attending antenatal services. Data on gestational age and birthweight were obtained from birth records. Women who smoked cigarettes or used snuff during pregnancy accounted for 6.1% and 7.5% of the study population respectively. The mean birthweight of non-tobacco users was 3148 g [95% CI 3123, 3173] and that of the smokers 2982 g [95% CI 2875, 3090], resulting in a significantly lower mean birthweight of 165 g for babies of smoking mothers (P = 0.005). In contrast, women using snuff gave birth to infants with a mean birthweight of 3118 g [95% CI 3043, 3192], which is a non-significant (P = 0.52) decrease (29.4 g) in their infants' birthweights compared with those not using tobacco. A linear regression analysis identified short gestational age, female infant, a mother without hypertension during pregnancy, coloured (mixed racial ancestry), and Asian infants compared with black infants, lower parity, less than 12 years of education and smoking cigarettes as significant predictors of low birthweight, while the use of snuff during pregnancy was not associated with low birthweight. The snuff users, however, had a significant shorter gestational age than the other two groups of women. The birthweight reduction adjusted for possible confounders was 137 g [95% CI 26.6, 247.3 (P = 0.015)] for cigarette smokers and 17.1 g [95% CI -69.5, -102.7, P = 0.69] for snuff users respectively, compared with the birthweight of non-tobacco users. Among women who did not smoke cigarettes or use snuff, exposure to environmental tobacco smoke did not result in significant effects on the birthweight of their infants. In conclusion, infants of cigarette smokers had significantly lower birthweights than those of non-tobacco users or snuff users who are exposed to nicotine during pregnancy. Passive smoking did not affect birthweight significantly in this population.     

No fathers' names: a risk factor for infant mortality in the State of Georgia, USA

Many studies have explored maternal and infant factors as risks for infant mortality, but little attention is given to paternal factors. In Georgia, listing a father's name on the birth certificate is optional for married couples and possible after paternal acknowledgment for unmarried couples. The authors evaluated father's name reporting as a paternity measure and risk for infant mortality. Using the linked 1989-1990 birth and death certificates of singleton Georgia infants to calculate relative risks (RRs), infant mortality rates for 38,943 infants with no father's names listed were compared to rates for 178,100 with father's names listed. Compared with the rate for married women listing names, the death rates were higher for unmarried mothers not listing fathers (relative risk, RR = 2.5; 95% CI 2.3-2.7), unmarried mothers listing fathers (RR = 1.4; 95% CI 1.3-1.6), and married women not listing fathers (RR = 2.3; 95% CI 1.6-3.1). Increased risks remained after stratifying by maternal race, age, adequacy of prenatal care and medical risks; and congenital malformations, birthweight, gestational age, and small-for-gestational age. Using logistic regression to examine for effect modification and to adjust for these factors together, the adjusted relative risks for death varied across different groups without fathers' names, regardless of marital status. For example, it remained statistically higher for infants with no father listed and without effect-modifying conditions such as low birthweight (estimated RR = 2.0; 95% CI 1.6-2.4). Although these findings suggest paternal involvement, as measured by listing fathers' names, is protective against low birthweight and infant mortality, further evaluation is needed.     

Pregnancy outcome among offspring of airline pilots and cabin attendants

OBJECTIVES: This study assessed the occurrence of perinatal death, low birthweight, preterm birth, and birth defects (total, major, neural tube defects, total cleft, cleft palate, hypospadias, and Down syndrome) in the offspring of airline pilots and cabin attendants. METHODS: A cohort of offspring of airline pilots and cabin attendants was established and characterized in terms of parental exposure to cosmic radiation the year before birth or ever. Pregnancy outcome was derived from the Medical Birth Register of Norway. The reference group comprised offspring of parents without occupational exposure to cosmic radiation. RESULTS: No deviant risks were observed for the offspring of male pilots, either for the year preceding birth (N=2,111) or ever (N=2,356). Specific birth outcomes were fewer for the pilots than for the referents (N=1,621,186), except for Down syndrome, which was more frequent [odds ratio (OR) 1.41, 95% confidence interval (95% CI) 0.53-3.76]. For exposure the year preceding birth (N=2,512), the risk of low birthweight was lower for the female cabin attendants than for the referents (adjusted OR 0.83, 95% CI 0.69-1.00), while Down syndrome was more frequent (OR 1.44, 95% CI 0.60-3.47). For exposure ever (N=3346), the risk of low birthweight was lower (OR 0.82, 95% CI 0.70-0.96) for the cabin attendants, while hypospadias (OR 1.18, 95% CI 0.61-3.04) and Down syndrome (OR 1.79, 95% CI 0.03-3.45) were more frequent CONCLUSIONS: In general, offspring of air pilots and cabin attendants do not seem to be at increased risk of adverse pregnancy outcome.     

Maternal smoking, alcohol consumption, and caffeine consumption during pregnancy in relation to a son's risk of persistent cryptorchidism: a prospective study in the Child Health and Development Studies cohort, 1959-1967

The Child Health and Development Studies is a > or =40-year follow-up of 20,754 pregnancies occurring between 1959 and 1967 in California. There were 84 cases of undescended testes at birth persisting to at least age 2 years among 7,574 liveborn sons whose mothers were interviewed in early pregnancy. Cases were matched to three controls on birth year and race. Compared with mothers of controls, mothers of cryptorchid boys consumed more caffeine during pregnancy (odds ratio = 1.4, 95% confidence interval: 1.1, 1.9 for an interquartile range equivalent to three cups of coffee per day) but were not more likely to smoke or drink alcohol when all behaviors were considered together. Other maternal and perinatal risk factors were not significantly associated with persistent cryptorchidism and did not confound the association with caffeine.     

Intrauterine growth retardation and risk of sudden infant death syndrome (SIDS)

The purpose of this study was to assess whether intrauterine growth retardation was associated with an increased risk of sudden infant death syndrome (SIDS). A total of 148 SIDS cases were identified from the Upstate New York (exclusive of New York City) live birth cohort for 1974 (n = 132,948). Dead controls represented all other sudden deaths (n = 114). Live controls were randomly selected and matched to cases on mother's age, race, parity, and residence and infant's birth date (n = 355). Data were collected from vital certificates (response, 97%), medical records (89%), and autopsy reports (100%). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated with the use of logistic regression techniques to control for confounding. With live controls, significant risks were observed for gestations less than 37 weeks (OR = 2.2, CI 1.2-4.1), birth weights less than 2,500 g (OR = 2.5, CI 1.3-5.0) and birth lengths less than or equal to 47.0 cm (OR = 3.4, CI 1.8-6.4). Birth length less than or equal to 47.0 cm was the only significant risk factor observed when dead controls were used (OR = 2.9, CI 1.3-6.8). Risk decreased with increasing gestation and birth size. Postterm infants (greater than or equal to 42 weeks) were at lowest risk (live controls OR = 0.9, CI 0.5-1.6; dead controls OR = 0.6, CI 0.3-1.1). When gestational age was controlled for, SIDS infants were found to have reductions in both weight and length; this suggests that responsible mechanisms begin early in pregnancy.     

Risk factors for early infant mortality in Sarlahi district, Nepal

OBJECTIVES: Early infant mortality has not declined as rapidly as child mortality in many countries. Identification of risk factors for early infant mortality may help inform the design of intervention strategies. METHODS: Over the period 1994-97, 15,469 live-born, singleton infants in rural Nepal were followed to 24 weeks of age to identify risk factors for mortality within 0-7 days, 8-28 days, and 4-24 weeks after the birth. FINDINGS: In multivariate models, maternal and paternal education reduced mortality between 4 and 24 weeks only: odds ratios (OR) 0.28 (95% confidence interval (CI) = 0.12-0.66) and 0.63 (95% CI = 0.44-0.88), respectively. Miscarriage in the previous pregnancy predicted mortality in the first week of life (OR = 1.98, 95% CI = 1.37-2.87), whereas prior child deaths increased the risk of post-neonatal death (OR = 1.85, 95% CI 1.24-2.75). A larger maternal mid-upper arm circumference reduced the risk of infant death during the first week of life (OR = 0.88, 95% CI = 0.81-0.95). Infants of women who did not receive any tetanus vaccinations during pregnancy or who had severe illness during the third trimester were more likely to die in the neonatal period. Maternal mortality was strongly associated with infant mortality (OR = 6.43, 95% CI = 2.35-17.56 at 0-7 days; OR = 11.73, 95% CI = 3.82-36.00 at 8-28 days; and OR = 51.68, 95% CI = 20.26-131.80 at 4-24 weeks). CONCLUSION: Risk factors for early infant mortality varied with the age of the infant. Factors amenable to intervention included efforts aimed at maternal morbidity and mortality and increased arm circumference during pregnancy.     

Antecedents of macrosomia.

Antecedents of high birthweight (macrosomia) were studied using the state birth certificates of White singleton infants born in three large metropolitan counties of Washington State from 1984 to 1986. Cases consisted of 2082 live-born macrosomic infants, defined by a birthweight of over 4.5 kg. A random sample of 4440 live births with birthweights of 2.5-4.0 kg was selected as a comparison group. Estimates for the independent risks associated with gestational and established diabetes, male sex, parity, duration of gestation, maternal smoking during pregnancy, maternal age, and median income of maternal residential area were obtained and combined in a single logistic model. Maternal smoking was associated with a decreased risk of macrosomia (OR 0.4, 95% CI 0.3-0.5). Established diabetes (OR 6.4, 95% CI 2.7-15.4), gestational diabetes (OR 3.2, 95% CI 2.1-5.1) and male sex of the infant (OR 2.4, 95% CI 2.2-2.7) were associated with an increased risk. Increasing parity was related to an increasing risk from para one (OR 1.4, 95% 1.2-1.6) to para six and greater (OR 3.3, 95% CI 1.5-7.4). Increasing duration of gestation was associated with an increasing risk from 33-36 weeks (OR 0.8, 95% CI 0.5-1.2) to 43-45 weeks (OR 3.3, 95% CI 2.5-4.2). Maternal age, median income of maternal area of residence, and maternal marital status were not significantly associated with macrosomia.     

Antecedents of macrosomia

Summary. Antecedents of high birthweight (macrosomia) were studied using the state birth certificates of White singleton infants born in three large metropolitan counties of Washington State from 1984 to 1986. Cases consisted of 2082 live-born macrosomic infants, defined by a birthweight of over 4.5 kg. A random sample of 4440 live births with birthweights of 2.5-4.0kg was selected as a comparison group. Estimates for the independent risks associated with gestational and established diabetes, male sex, parity, duration of gestation, maternal smoking during pregnancy, maternal age, and median income of maternal residential area were obtained and combined in a single logistic model. Maternal smoking was associated with a decreased risk of macrosomia (OR 0.4, 95% CI 0.3-0.5). Established diabetes (OR 6.4, 95% CI 2.7–15.4), gestational diabetes (OR 3.2, 95% CI 2.1–5.1) and male sex of the infant (OR 2.4, 95% CI 2.2-2.7) were associated with an increased risk. Increasing parity was related to an increasing risk from para one (OR 1.4, 95% 1.2-1.6) to para six and greater (OR 3.3, 95% CI 1.5–7.4). Increasing duration of gestation was associated with an increasing risk from 33–36 weeks (OR 0.8, 95% CI 0.5-1.2) to 43–45 weeks (OR 3.3, 95% CI 2.5-4.2). Maternal age, median income of maternal area of residence, and maternal marital status were not significantly associated with macrosomia.     

Cryptorchidism and maternal alcohol consumption during pregnancy

BACKGROUND: Prenatal exposure to alcohol can adversely affect the fetus. We investigated the association between maternal alcohol consumption during pregnancy and cryptorchidism (undescended testis) among newborn boys. METHODS: We examined 2,496 boys in a prospective Danish-Finnish birth cohort study for cryptorchidism at birth (cryptorchid/healthy: 128/2,368) and at 3 months of age (33/2,215). Quantitative information on alcohol consumption (average weekly consumption of wine, beer, and spirits and number of binge episodes), smoking, and caffeine intake was obtained by questionnaire and/or interview once during the third trimester of pregnancy, before the outcome of the pregnancy was known. For a subgroup (n = 465), information on alcohol consumption was obtained twice during pregnancy by interviews. RESULTS: We investigated maternal alcohol consumption both as a continuous variable and categorized. The odds for cryptorchidism increased with increasing weekly alcohol consumption. After adjustment for confounders (country, smoking, caffeine intake, binge episodes, social class, maternal age, parity, maturity, and birth weight) the odds remained significant for women with a weekly consumption of five or more alcoholic drinks (odds ratio = 3.10; 95% confidence interval, 1.05-9.10). CONCLUSIONS: Regular alcohol intake during pregnancy appears to increase the risk of congenital cryptorchidism in boys. The mechanisms for this association are unknown. Counseling of pregnant women with regard to alcohol consumption should also consider this new finding.     

孕前体质指数及孕期增重对新生儿出生体重影响的前瞻性队列研究

  目的   分析孕妇孕前体质指数(body mass index, BMI)及孕期增重(gestational weight gain, GWG)与新生儿出生体重的关联性, 并探究孕妇孕前及孕中体重动态变化对新生儿低出生体重(low birth weight, LBW)及巨大儿的影响。   方法   收集中国孕产妇队列·协和纳入的孕早期孕妇孕前体重, 并随访至分娩后, 收集分娩前体重及新生儿出生结局。将孕妇孕前BMI分为低体重组、正常体重组及超重/肥胖组, 将GWG分为适宜、不足及过多组。采用多因素多分类(多项)Logistic回归分析模型探讨孕前BMI及GWG与新生儿出生体重的关系。   结果   孕前BMI及GWG与子代出生体重相关(均有P < 0.05)。孕前超重/肥胖(OR=2.339, 95% CI:1.674~2.282, P < 0.001)、GWG过多(OR=1.398, 95% CI:1.188~1.978, P=0.048)显示为巨大儿的危险因素, GWG不足(OR=1.479, 95% CI:1.461~1.679, P=0.035)显示为LBW的危险因素, GWG过多会降低LBW的发生风险(OR=0.428, 95% CI:0.225~0.817, P=0.010)。低BMI-GWG不足(OR=1.335, 95% CI:1.048~2.319, P=0.048)是LBW的危险因素; 正常BMI-GWG过多(OR=1.088, 95% CI:1.016~1.675, P=0.038)和超重/肥胖-GWG过多(OR=1.498, 95% CI:1.244~2.017, P=0.046)是巨大儿的危险因素。   结论   孕前BMI及GWG是影响新生儿出生体重的重要因素, 提示女性应合理控制孕前及孕中体重变化。     

先天性泌尿生殖系统结构畸形危险因素的研究

目的：探讨有关因素在先天性泌尿生系统结构畸形发病中的作用。方法：采用成组匹配的病列对照研究方法。对95例患先天性泌尿生殖系统 的围产儿和160例对照围产儿及其父母的情况进行调查。采用非条件logistic回归模型进行多因素分析,计算OR值及OR的95％可信限。结果：先天性泌尿生殖系统结构畸形多发生于男性围产儿（性别成比为74．7％,X^2＝74．863,P＝0．001）,多元逐步回归分析表明：母亲孕早、中期感冒（OR＝7．034,95％CI＝3．488－14．187）、低出生体重（OR＝4．075,95％CI＝1．774－9．362）、孕次≥2（OR＝3．133,95％CI＝1．514－6．483）及母亲孕前职业性接触有害化学物质（OR＝10．496,95％CI＝1．053－104．651）为先天性泌尿生殖系统结构畸形的危险因素,结论：胎儿男性别,母亲孕早、中期感冒、低出生体重,母亲孕次≥2及孕前职业性接触有害化学物质与胎儿发生先天性泌尿生系统畸形有关联。     

What do women know about the risks of delayed childbearing?

BACKGROUND: Women aged 35 and older account for an increasing proportion of births and are at increased risk of pregnancy complications and poor infant outcomes. The objectives of the study were: 1) to determine what women know about delayed childbearing, including pregnancy complications and outcomes associated with low birthweight (LBW, < 2500 grams), preterm delivery (< 37 weeks) and multiple birth, and 2) to assess the characteristics of women with limited knowledge of risks. METHODS: A computer-assisted telephone interview survey was conducted with 1,044 randomly selected women who delivered their first live-born infant, between July 2002 and September 2003, in two urban centres, Calgary and Edmonton, in Alberta, Canada. RESULTS: The proportion of women aware of specific childbearing risks associated with advanced maternal age were as follows: conception difficulties (85.3%), multiple birth (24.0%), caesarean section (18.8%), preterm delivery (21.8%), and LBW (11.2%). Knowledge of specific developmental and health-related risks of suboptimal infant outcomes ranged between 18.0% and 46.5%. Logistic regression revealed that limited knowledge of maternal age-related pregnancy risks were associated with unplanned pregnancy (OR, 1.48; 95% CI, 1.03-2.14), smoking (OR, 1.83; 95% CI, 1.29-2.60) and non-use of fertility treatment (OR, 2.15; 95% CI, 1.44-3.19). Characteristics associated with limited knowledge of the risks associated with suboptimal birth outcomes were: age 35-39 years (OR, 2.98; 95% CI, 1.35-6.58), less than post-graduate education (< or = high school OR, 2.14; 95% CI, 1.20-3.82), and not currently enrolled as a student (OR, 1.75; 95% CI, 1.02-3.00). CONCLUSIONS: Many women are generally unaware of the potential consequences of delayed childbearing. There are missed opportunities in preconception counselling and education, which should be addressed to allow for more informed decision-making about family planning.     

Effect of smoking and alcohol use during pregnancy on the occurrence of low birthweight in a farming region in South Africa

The aim of this case-control study was to determine the risk factors for low birthweight in a farming region in South Africa, with particular attention to maternal alcohol use and smoking, both independently and in combination. Data collection was via structured postpartum interviews and review of antenatal and delivery records. The study setting was a regional referral hospital in a farming region. The study subjects were 200 infants with birthweight < 2500 g (cases) and 200 unmatched control infants of normal weight born during the same period as the cases. The outcome measure was low birthweight, i.e. infant birthweight <2500 g. Results showed the contribution of term low birthweight (as a measure of intrauterine growth retardation) to the total low-birthweight incidence was almost 50%, indicating a substantial intrauterine growth retardation component in this population. Sociodemographic factors were not as predictive of low birthweight in this predominantly low income population. Smoking (adjusted OR 2.67, [95% CI 1.69, 4.20]) was the strongest life style-related predictor of low birthweight. The alcohol low-birthweight relationship was not significant when adjusted for smoking status (crude OR 2.15, [95% CI 1.37, 3.39]; adjusted OR 1.32, [95% CI 0.80, 2.20]). However, there appeared to be an interaction with combined use of these two substances during pregnancy that increased the risk of low birthweight (adjusted OR increased to 4.24, [95% CI 1.01, 17.76]. It is clear that life style factors such as smoking and drinking are contributing to the occurrence of low birthweight in the target region. A comprehensive health promotion programme needs to be implemented as an integral part of antenatal and family planning services, to reduce smoking and drinking by women in this community.     

Prenatal and intrapartum events and sudden infant death syndrome

The purpose of this study was to evaluate specific pregnancy and labour and delivery events that may increase the risk of sudden infant death syndrome (SIDS). A matched case-control study was conducted in five counties in southern California, using California death certificate records. The sample consisted of 239 Caucasian, African-American, Hispanic and Asian mothers of SIDS infants and 239 mothers of control infants matched on sex, race, birth hospital and date of birth. Mothers participated in a detailed telephone interview and provided access to obstetric and paediatric records. More case than control mothers reported a family history of anaemia (OR=2.12, P < 0.001). Placental abruptions were strongly associated with SIDS (unadjusted OR=7.94, [95% CI 1.34,47.12]). There was an increased risk of SIDS death associated with maternal anaemia during pregnancy (OR=2.51, [95% CI 1.25,5.03]), while simultaneously adjusting for maternal smoking during pregnancy, maternal years of education and age, parity, infant birthweight, gestational age, medical conditions at birth, infant sleep position and post-natal smoking. Interactions of anaemia and prenatal smoking as well as anaemia and post-natal smoking were not statistically significant. There were no other statistically significant differences between case and control mothers for pregnancy conditions, labour and delivery events (e.g. caesarean sections, anaesthesia, forceps) or newborn complications (e.g. nuchal cord, meconium aspiration). Anaemia and placental abruptions were significantly associated with an increased risk of SIDS; both are circumstances in which a fetus may become hypoxic, thereby compromising the subsequent growth, development and ultimate survival of the infant.     

Is conception delay a risk factor for reduced gestation or birthweight?

Previous studies have suggested an association between delays in conception and adverse perinatal outcomes, specifically, low birthweight and preterm birth. We investigated the relationship between conception delay (defined as >6 months to become pregnant) and three perinatal outcomes: low birthweight (LBW; <2500 g), preterm birth (PTB; <37 weeks), and small-for-gestational-age (SGA; <10th percentile weight for given gestational age) using data from the Collaborative Perinatal Project. The study cohort was limited to pregnancies with a known time-to-pregnancy (n = 8465; 15%). Generalised estimating equations were used to estimate odds ratios (OR) and 95% confidence intervals [CI] for risk of adverse perinatal outcomes accounting for the clustering of pregnancy outcomes for women with more than one pregnancy. After adjusting for confounders, all ORs were close to the null (LBW, OR = 1.01; 95% CI = 0.86, 1.20), (PTB, OR = 1.10; 95% CI = 0.95, 1.27), (SGA, OR = 1.06; 95% CI = 0.91, 1.25). Thus, we found no evidence to support an adverse relationship between conception delay and decrements in gestation or birthweight among this select sample of fertile women, even after varying the cut-point for defining conception delay.     

Birth Characteristics Associated With Early Intervention Referral, Evaluation for Eligibility, and Program Eligibility in the First Year of Life

OBJECTIVES: The Individual with Disabilities Education Act mandates Early Intervention (EI) services for infants and toddlers with developmental delay. We assessed the percentage of infants at risk for developmental delay due to characteristics present at birth who were referred to Massachusetts EI within 1 year of birth, evaluated for eligibility, and eligible for services. In addition, we identified birth characteristics that independently predicted 0-1 year program referral, evaluation, and eligibility. METHODS: The Pregnancy to Early Life Longitudinal (PELL) data system linked birth certificate, hospital discharge, and EI program data of 219,037 infants born in Massachusetts, 1998-2000. Multivariate logistic regressions identified independent infant predictors of referral, evaluation, and eligibility. RESULTS: Of 219,037 births, 14,852 (6.8%) were referred to EI within 1 year. Birthweight<1200 g (OR=9.7, 95% CI 3.3-12.9) and birthweight 1200-1499 g (OR=7.4, 95% CI 5.8-9.5) strongly predicted referral. Referral was high (88%) among infants with two or more birth risks. Among referrals, 88% were evaluated for eligibility. The strongest predictor of evaluation was triplet birth (OR=4.3, 95% CI 1.6-11.8). Among infants evaluated, 85% were determined to be eligible. CONCLUSION: EI referral and evaluation are high among infants born at risk for delay in Massachusetts. Some characteristics not included in the state's high-risk definition (e.g. birthweight 1200-1499 g) were identified that predicted referral. Most referrals were eligible for services. Results demonstrate the value to states of using linked population and program data for program evaluation.     

Birth characteristics and brain cancers in young children

BACKGROUND: High birthweight is a potential risk factor for childhood brain tumours, particularly astrocytomas. We investigated several birth characteristics in relationship to brain cancers in young children. METHODS: We obtained 849 invasive central nervous system (CNS) cancer cases, ages 0-4 years, from California's population-based cancer registry for 1988-1997. We matched 746 (88%) of these cases to a California live birth certificate. We randomly selected two control birth certificates for each case, matched on date of birth and gender. We used conditional logistic regression to obtain odds ratios (OR) and 95% CI. The birth characteristics examined included birthweight, gestational age, race, parental age, and parental education. RESULTS: Analysing all CNS tumours combined, we found that children of other racial/ ethnic groups had OR below one compared with non-Hispanic white children. When adjusted for gestational age, race/ethnicity, and mother's place of birth, the OR for high birthweight (>/=4000 g) was 1.05 (95% CI: 0.79-1.38) compared with children with birthweights of 2500-3999 g. For astrocytomas (313 cases), the adjusted OR for high birthweight was 1.40 (95% CI: 0.90-2.18). When parental education was included in the model (available for only a subset of the birth years), the adjusted OR was 1.71 (95% CI: 1.01-2.90). High birthweight did not appear to be a risk factor for primitive neuroectodermal tumours (PNET). CONCLUSIONS: We found high birthweight associated with increased risk of astrocytomas, but not PNET, in young children.