Impact of maternal age and maternal somatic characteristics on newborn size

Pregnancies during early adolescence were commonly thought to represent special risks, such as preterm delivery or low‐weight newborns, resulting in increased mortality and morbidity of mother and child. An important biopsychosocial interaction can be assumed. In the present study the impact of maternal age and maternal somatic characteristics such as prepregnancy weight, stature, or pregnancy weight gain on newborn somatometric features (birth weight, birth length, head circumference, and arcomial circumference) using a dataset of 8,011 single term births were analyzed. The offspring of 215 extremely young mothers ages 12–16 years were significantly (P < 0.0001) lighter and smaller in all body dimensions than the offspring of older adolescent mothers, ages 17–19 years, and the offspring of adult gravida, ages 20–29 years, although no increased incidence of low‐weight newborns (<2,500g) could be observed. As expected, the youngest mothers were also significantly smaller and lighter than their older, biologically more mature counterparts, although the relative weight gain during pregnancy was highest in the youngest age group (23.4% vs. 22.9 and 22.1%, respectively). In general, age but also pregnancy weight gain and prepregnancy weight status were significantly associated with pregnancy outcome. Within term births taking place under sufficient psychosocial support, maternal somatic features had an important impact on newborn size. Am. J. Hum. Biol. 15:220–228, 2003. ©2003 Wiley‐Liss, Inc.     

The effects of prenatal care utilization and maternal risk factors on pregnancy outcome between Mexican Americans and non-Hispanic whites.

This study evaluates the effects of prenatal care classification and levels of maternal risk status on pregnancy outcomes in Mexican Americans and non-Hispanic whites in Arizona. All live birth certificates from 1986 and 1987 were reviewed yielding a total population of 101,206 (26,827 Mexican Americans). The adequacy of prenatal care was evaluated based on an index that includes six prenatal care groups. Two levels of maternal risk status (low and high) were defined based on a series of maternal risk factors. Overall, Mexican Americans had a greater proportion of maternal risk factors and a greater proportion of mothers with inadequate or no prenatal care compared with non-Hispanic whites. Prematurity and macrosomia were more prevalent than low birthweight in Mexican Americans. Low-risk status and adequate prenatal care regardless of ethnicity were found to be associated with a lower prevalence of low birthweight and preterm delivery. Whites, however, had a greater variation in the prevalence of low birthweight associated with changes in prenatal care utilization and maternal risk status compared with Mexican Americans. Finally, logistic regression analysis showed an independent effect of prenatal care, maternal risk status, maternal age, and maternal birthplace in predicting the overall low birthweight rate in Mexican Americans. The implications of these results are discussed relative to the usefulness of prenatal care as a health-care intervention in Mexican Americans.     

Intermediate variables as determinants of adverse pregnancy outcome in high-risk inner-city populations.

A probability sample survey of high-risk inner-city women with a live birth in the last 3 years shows that maternal medical risks and health behaviors during pregnancy are important intermediate variables influencing preterm delivery and birthweight. Women who developed two or more medical risks had about three-and-a-half times the risk of preterm delivery and two-and-a-half times the risk of low birthweight compared to those without such risks. Women with prior fetal loss had twofold increase in the risk of preterm delivery and low birthweight. Unintended pregnancy resulted in one-and-a-half to twofold increase in preterm delivery and low birthweight, respectively. Inadequate gestational weight increased the risk of preterm delivery by about 50%. Smoking during pregnancy raised the risk of low birthweight slightly more than one-and-a-half times.     

Enzyme polymorphisms,smoking, and human reproduction. A study of human placental alkaline phosphatase

We investigated the possible effects of placental alkaline phosphatase (PLAP) genotype on the deleterious action of maternal smoke on intrauterine survival and birthweight. PLAP is a highly polymorphic enzyme with several alleles associated with different enzymatic activities. PLAP is produced by the embryo and is found in maternal blood, where it is responsible for the rise of serum alkaline phosphatase during pregnancy. Two hundred and fourteen Caucasian consecutive newborn infants delivered in the Maternity Department of the University of Rome La Sapienza Hospital were studied. Infants from smoking women 28 years or older show a strong decrease of both PLAP*1/*1 and *2/*2 homozygous types and a marked deviation from Hardy‐Weinberg expectation, thus suggesting a different lethal effect of smoke depending on PLAP genotype and maternal age. In infants from smoking mothers there is a decrease of birthweight that is much less evident and statistically not significant in infants carrying the PLAP*1/*1 genotype as compared to other genotypes. The difference between PLAP genotypes concerning birthweight is more marked in women older than 28 years than in younger ones. This suggests that the effects of smoke on birthweight are also dependent on PLAP and maternal age. Am. J. Hum. Biol. 15:781–785, 2003. © 2003 Wiley‐Liss, Inc.     

Maternal height,pregnancy weight gain,and birthweight

The Institute of Medicine recommends that short women gain less weight during pregnancy than taller women in order to reduce the risk of high birthweight, which can lead to feto-pelvic disproportion. This recommendation, however, is based on clinical judgment rather than on epidemiologic evidence, as few studies have examined the relationships between maternal height, pregnancy weight gain, and infant birthweight. Our objective was to determine whether maternal height is an independent risk factor for infant birthweight and to assess whether maternal height modifies the effect of pregnancy weight gain on infant birthweight. We examined the relationship between maternal height and infant birthweight in a multi-ethnic cohort of 8,870 women with uncomplicated pregnancies who delivered singleton infants at the University of California, San Francisco, 1980–1990. Using multiple linear regression, we modeled the contribution of height and weight gain to birthweight in four different ethnic groups. Increasing maternal height was significantly and positively associated with infant birthweight in White, Black, and Asian women, but not Hispanic women. The relationship between pregnancy weight gain and infant birthweight was not modified by maternal height. Am. J. Hum. Biol. 12:682–687, 2000. © 2000 Wiley-Liss, Inc.     

Prenatal Factors Affecting Perinatal Mortality in Blacks

A study of 222 black mothers who gave birth to low-birth-weight infants in a tertiary care center showed that prenatal care plays a significant role in perinatal outcome; the effect of prenatal care was especially dramatic in the infants weighting less than 1,500 grams. In addition, maternal age is an important factor when less than 17 years. When a teenage pregnancy is associated with a lack of, or irregular, prenatal care, fetal outcome is compromised.     

Adequacy of prenatal care utilization, maternal ethnicity, and infant birthweight in Chicago.

This study examines the extent to which the Adequacy of Prenatal Care Utilization Index explains the racial disparity in infant birthweight. A stratified analysis was performed on all African-American, Mexican-American, and non-Latino white singleton infants born in Chicago, Illinois between 1982 and 1983. This older cohort was chosen to avoid the confounding effect of cocaine associated with its increased local availability after 1985. The adequacy of prenatal care utilization varied by race and place of residence. However, in moderate-income areas (median family annual income of $20,001 to $30,000), the African-American birthweight disadvantage persisted among infants born to mothers who received adequate and adequate-plus prenatal care. Similarly, although race-specific term (gestational age > 37 weeks) low birthweight rates declined as prenatal care usage rose, the position of African Americans relative to Mexican Americans and whites was essentially unchanged. These findings indicate that maternal race or some factor closely related to it affects pregnancy outcome regardless of the adequacy of prenatal care utilization.     

Generations of loss: contemporary perspectives on black infant mortality

The U.S. black infant mortality rate (IMR) remains a significant public health concern. Although improved during the last four decades, the U.S. IMR remains within the lowest tier of IMRs for all industrialized countries, and black American infants remain disproportionately represented in low birthweight (LBW) and infant death statistics. Numerous risk factors have been analyzed for their relative contributions to the U.S. IMR and black-white infant survival health disparities. Those factors include prenatal care quality and access, maternal socioeconomic status (SES), HIV/AIDS status, infections, intrapartum risk factors, existing comorbidities, social support, and nutritional status. However, the role of these and other factors have not fully explained the higher infant mortality risks for black infants. This review will discuss a variety of risk factors that contribute to infant mortality disparities between non-Hispanic black and white infants. Among those factors, the goal will be to review selected topics pertaining to maternal SES, LBW, preterm birth, perinatology advances, birth record data quality, maternal stress, prenatal care adequacy, and physical and substance abuse, and the relationships of those topics to black-white IMR health disparities.     

Influence of prepregnant body mass and weight gain for gestation on spontaneous preterm delivery and duration of gestation during adolescent pregnancy

We examined the influence of two measures of maternal nutritional status: prepregnant body mass (kilograms/meter²) and Weight gain during pregnancy (adjusted for duration of gestation) on spontaneous preterm delivery (<37 completed Weeks' gestation) and duration of gestation, as well as on low birthweight (<2,500 grams) and small-for-gestational-age (SGA) in pregnant adolescents. Inadequate Weight gain for gestation increased the risk of spontaneous preterm delivery when prematurity was reckoned by the obstetric estimate (Adjusted Odds Ratio, AOR = 1.75 95% CI 1.22–2.50) or from the mother's LMP (AOR = 1.49 95% CI 1.10–2.02). In linear models, gestation duration was significantly reduced, by more than half a week, when reckoned from eiter estimate of gestation. However, the association between preterm birth or gestation duration and prepregnancy body mass was not consistent and depended on the method of estimating gestation. Low birthweight and SGA were each significantly associated with inadequate weight gain during pregnancy as well as with prepregnant body mass. These results suggest that current maternal nutritional status, as measured by weight gain during pregnancy, may influence preterm delivery and gestation duration. The inconsistent results obtained with prepregnancy body mass may reflect a size bias inherent in the obstetric estimate of gestation, rather than effects of prepregnant maternal nutritional status on gestation.     

Attachment,autonomy, and multifinality in adolescent internalizing and risky behavioral symptoms

A diathesis-stress interaction model is used to describe multifinality in adolescent internalizing and risky behavioral outcomes. Problematic behavior associated with adolescent insecure preoccupation (a diathesis) was expected to interact with the level of maternal autonomous discourse (a stressor) to predict specific adolescent outcomes. Assessments of adolescent preoccupied attachment organization, observations of maternal displays of autonomy in mother-adolescent interactions, and adolescent reports of internalizing symptoms and risky behaviors were obtained at age 16. As predicted, maternal autonomy in the mother-adolescent relationship helped to explain multifinality in dysfunctional symptoms among preoccupied adolescents. Adolescent preoccupation was more strongly linked to internalizing behavior when mothers demonstrated low levels of autonomy in interactions with their adolescents and more strongly linked to risky behavior when mothers displayed extremely high levels of autonomy. Implications for autonomy processes in increasing our understanding of how adolescent insecure-preoccupation relates to profiles of specific problems during adolescence are discussed as is the importance of exploring the role of attachment in different contexts.     

The effects of maternal risk factors during pregnancy on the onset of sleep difficulties in infants at 3 months old

Sleep problems in young children are among the most common concerns reported to paediatricians. Sleep is thought to have important regulatory functions, and sleep difficulties in early childhood are linked to several psychosocial and physiological problems. Moreover, several prenatal factors have been found to influence infants’ sleep. Among them, most of the studies have been focused on maternal prenatal depression and/or anxiety as potential risk factors for sleep problems in childhood, whereas other relevant psychological factors during pregnancy have not received as much attention. Therefore, we aimed to examine the effect of several psychiatric maternal risk factors during pregnancy (i.e. symptoms of anxiety, depression, insomnia, alcohol use, seasonality, attention deficit and hyperactivity disorder and/or stressful life events) on the onset of some sleep problems related to sleep quality and sleep practices in 3‐month‐old infants. We examined 1,221 cases from a population‐based birth cohort, with subjective measures during pregnancy in mothers, and at 3 months after birth in the infants. The findings showed that all the maternal risk factors during pregnancy, except for symptoms of alcoholism and sleepiness, were related to sleep difficulties in infants. Interestingly, attention deficit and hyperactivity disorder symptomatology in mothers during pregnancy was the only variable that predicted more than two sleeping difficulties (i.e. long sleep‐onset latency, co‐sleeping with parents and irregular sleeping routines) at 3 months old. Our results highlight the relevance of maternal risk factors during pregnancy, and not only prenatal depression and/or anxiety, as variables to be considered when examining sleep difficulties in infants.     

The effect of active and passive maternal smoking before and during pregnancy on neonatal weight at birth

IntroductionSmoking during pregnancy is a risk factor for adverse pregnancy outcomes. Data on the correlation between passive maternal smoking and pregnancy outcomes remain limited. We investigated the effect of active smoking and environmental tobacco smoke (ETS) during pregnancy on neonatal birthweight, including the risk for low birthweight (LBW).Material and methodsThe study was conducted between 2010 and 2012. A group of 8625 women were surveyed during postpartum hospitalization. Outcome measures included mean birthweight of newborns. Additionally, odds ratios with confidence intervals were calculated to investigate the risk for LBW in active and passive smoking groups of mothers.ResultsLower birthweight (46 g – 307 g; p < 0.05) and a higher risk for LBW (OR = 1.35, 95% CI: 1.05–1.75; p < 0.05) were observed in all infants born to smoking mothers. A negative effect of ETS in pregnancy on the reduction of mean birthweight was also found. Additionally, we analyzed the cumulative effect of active and passive smoking on neonatal birthweight. A statistically significant reduction in neonatal weight at birth was found in a group of women who smoked actively and passively during pregnancy (130 g; p < 0.05).ConclusionsSmoking is associated with decreased birthweight and in a group of active smoking mothers increased risk for LBW. This effect is dose-dependent and is also present in a group of women who smoked before pregnancy. There is also a cumulative effect of active smoking and ETS causing decreased neonatal birthweight and increased risk for low birthweight.     

Selenium status, pregnancy outcomes, and mother-to-child transmission of HIV-1

BACKGROUND: Among HIV-infected pregnant women, low selenium status may increase risk of mother-to-child transmission (MTCT) of HIV and poor pregnancy outcomes (low birthweight, small for gestational age, preterm birth, and fetal death) through several mechanisms, such as by promoting maternal HIV disease progression, viral shedding in the genital tract, and development of mastitis. However, there is no direct epidemiologic evidence on these relations among HIV-infected pregnant women. OBJECTIVE: To investigate the association between selenium status during pregnancy and pregnancy outcomes, MTCT of HIV, and child mortality. DESIGN: Baseline plasma selenium measurements from HIV-positive pregnant women (n = 670) were obtained between 12-27 weeks of gestation and mother-child pairs were followed prospectively until 24 months after delivery. RESULTS: Low plasma selenium levels were associated with increased risks of fetal death, child death, and HIV transmission through the intrapartum route. Low selenium status was not associated with risks of low birthweight or preterm birth but was associated with an apparently lower risk of small for gestational age. CONCLUSION: Adequate selenium status may be beneficial for some but not all pregnancy outcomes. Further studies are needed to better understand the role of selenium status in pregnancy outcomes, HIV transmission, and child health.     

Maternal and infant serum phenylalanine levels and pregnancy outcome in infants of nonphenylketonuric mothers.

Maternal consumption of casein is associated with excess low birthweight and infant mortality. Genetically normal infants of hyperphenylalaninemic mothers also show excess low birthweight and mortality. To determine whether the phenylalanine in casein could produce a secondary phenylketonuria effect, maternal serum phenylalanine levels were measured in 77 specimens of maternal blood serum drawn during the 15th through 21st weeks of pregnancy and in 55 specimens of cord [correction of cold] blood collected from the same mothers'' infants. Maternal serum phenylalanine levels correlated negatively with infant birthweight in the 41 infants for whom appropriate confounders were known. Infant serum phenylalanine levels did not correlate with birthweight. Neither maternal nor infant serum phenylalanine levels correlated with 1-minute Apgar scores. A negative association was seen between both maternal and infant serum phenylalanine levels and 5-minute Apgar scores when appropriate confounders were controlled.     

Ethnic variation in the size of infant at birth

The impact of ethnicity and other maternal factors (BMI, parity, glucose tolerance, gestational age) on the size of the infant at birth was investigated in a relatively low socioeconomic status, multi-ethnic population at San Francisco General Hospital. A sample of 2,069 infants born to mothers of black, non-Hispanic white, Hispanic, and Chinese descent and whose mothers had received prenatal care at San Francisco General Hospital were studied. Maternal size, pregnancy history, and blood glucose were determined prenatally at 26–28 weeks gestation. Anthropometry was performed on the infant within 72 hours of birth. Black and Chinese infants were the lightest in weight, while Hispanic infants were the heaviest. When correction was made for maternal factors black infants were shown to be significantly (P < .05) lighter in birth weight than non-Hispanic white, Chinese, or Hispanic infants. Black infants were also significantly shorter in birth length and smaller in chest circumference. Chinese infants had significantly (P < .05) greater adiposity, as indicated by the sum of skinfold measurements, than both black and Hispanic infants. These findings are relevant to current practices in neonatal growth categories which are determined solely by birth weight and do not account for variations in body composition. Comparisons with a relatively higher socioeconomic status sample from Kaiser-Permanente Hospital (Oakland) shows a similar prevalence of low birth weight among blacks. These results support other results that ethnicity is a major independent influence on the weight of the newborn.     

A randomized trial of psychosocial support during high-risk pregnancies. The Latin American Network for Perinatal and Reproductive Research.

BACKGROUND. It is often suggested that psychological and social support and health education for women at high risk for delivering a low-birth-weight infant can improve the outcomes of pregnancy, but the evidence is inconclusive. We undertook this prospective trial to evaluate a program of home visits designed to provide psychosocial support during pregnancy. METHODS. At four centers in Latin America, 2235 women at higher-than-average risk for delivering a low-birth-weight infant were recruited before the 20th week of pregnancy. The women were randomly assigned either to an intervention group (n = 1115) that received four to six home visits from a nurse or social worker in addition to routine prenatal care or to a control group (n = 1120) that received only routine prenatal care (with a mean of eight prenatal visits). The principal measures of outcome were low birth weight (< 2500 g), preterm delivery (< 37 weeks of gestation), and specified categories of maternal and neonatal morbidity. RESULTS. The women who received the home visits as well as routine prenatal care had outcomes that differed little from those of the women who received only routine care. The risks of low birth weight (odds ratio for the intervention group as compared with the control group, 0.93; 95 percent confidence interval, 0.68 to 1.28), preterm delivery (odds ratio, 0.88; 95 percent confidence interval, 0.67 to 1.16), and intrauterine growth retardation (odds ratio, 1.08; 95 percent confidence interval, 0.83 to 1.40) were similar in the two groups. There was no evidence that the intervention had any significant effect on the type of delivery, the length of hospital stay, perinatal mortality, or neonatal morbidity in the first 40 days. There was no protective effect of the psychosocial-support program even among the mothers at highest risk. CONCLUSIONS. Interventions designed to provide psychosocial support and health education during high-risk pregnancies are unlikely to improve maternal health or to reduce the incidence of low birth weight among infants.     

Pregnancy outcomes among Whites and Filipinos: A paradoxical birth weight-neonatal mortality relationship

Evidence from the Philippines suggests that, compared to Whites, infants born to Filipino women are more likely to be low birth weight. A paucity of information is available regarding birth outcomes of U.S.-born Filipinos. Using 1979–1987 Hawaii vital record data on single live births to resident mothers, this study compares the maternal characteristics and pregnancy outcomes of White and Filipino mothers, Filipino mothers were significantly more likely to be <18 years of age and single, and have lower educational attainment and less adequate utilization of prenatal care. Significantly higher percentages of very preterm, preterm, very low birth weight, low birth weight, and small for gestational age infants were found for Filipinos. The birth weight-specific neonatal mortality rates for Filipinos compared favorably to Whites except at the high end of the birth weight distribution. After taking into account maternal sociodemographic risk and prenatal care factors in a logistic regression, a significant ethnic difference in low birth weight persisted but was not found for neonatal mortality. These data may suggest that similar neonatal mortality rates among ethnic groups may be possible in the face of persistent birth weight distribution differences and add to the growing evidence that a single standard of low birth weight may be inappropriate as an universal indicator of health status risk in a multi-ethnic population. © 1993 Wiley-Liss, Inc.     

Effect of the interval between pregnancies on perinatal outcomes

BACKGROUND: A short interval between pregnancies has been associated with adverse perinatal outcomes. Whether that association is due to confounding by other risk factors, such as maternal age, socioeconomic status, and reproductive history, is unknown. METHODS: We evaluated the interpregnancy interval in relation to low birth weight, preterm birth, and small size for gestational age by analyzing data from the birth certificates of 173,205 singleton infants born alive to multiparous mothers in Utah from 1989 to 1996. RESULTS: Infants conceived 18 to 23 months after a previous live birth had the lowest risks of adverse perinatal outcomes; shorter and longer interpregnancy intervals were associated with higher risks. These associations persisted when the data were stratified according to and controlled for 16 biologic, sociodemographic, and behavioral risk factors. As compared with infants conceived 18 to 23 months after a live birth, infants conceived less than 6 months after a live birth had odds ratios of 1.4 (95 percent confidence interval, 1.3 to 1.6) for low birth weight, 1.4 (95 percent confidence interval, 1.3 to 1.5) for preterm birth, and 1.3 (95 percent confidence interval, 1.2 to 1.4) for small size for gestational age; infants conceived 120 months or more after a live birth had odds ratios of 2.0 (95 percent confidence interval, 1.7 to 2.4);1.5 (95 percent confidence interval, 1.3 to 1.7), and 1.8 (95 percent confidence interval, 1.6 to 2.0) for these three adverse outcomes, respectively, when we controlled for all 16 risk factors with logistic regression. CONCLUSIONS: The optimal interpregnancy interval for preventing adverse perinatal outcomes is 18 to 23 months.     

Evaluation of low birthweight in African Americans

This study evaluates risk factors associated with low birthweight in an African-American population. Records of 225 women delivering liveborn, nonanomalous singletons weighing < 2500 g were reviewed. The next parturient, matched for race only, of a similar infant weighing > or = 2500 g constituted the control. This case-control study was conducted among women delivering at University Hospital in New Orleans during 1996-1997. Mothers of infants weighing < 2500 g were more likely to not have finished high school (49% versus 38%), to have received no prenatal care (26% versus 7%), or to have five or fewer visits if care was obtained (52% versus 33%). The mother was more likely to weigh < 60 kg (49% versus 32%), to smoke (24% versus 11%), or to have used cocaine (18% versus 5%) or alcohol (11% versus 5%). Parturients of low birthweight newborns were more likely to have had a prior low birthweight infant (44% versus 19%) and themselves to have had a birthweight < 2500 g (30% versus 13%). Regression analysis confirmed the importance of three parameters as associated with low birthweight: no prenatal care (odds ratio [OR] = 6.0 [1.1-31.4]), alcohol use (OR = 5.2 [1.1-24.8], and low maternal birthweight (OR = 3.9 [1.9-7.9]. These results indicate that evaluations of low birthweight in African Americans should consider maternal birthweight and that efforts to improve pregnancy outcome should be structured in terms of generations.     

Long-term morbidity and mortality of overweight adolescents. A follow-up of the Harvard Growth Study of 1922 to 1935.

BACKGROUND. Overweight in adults is associated with increased morbidity and mortality. In contrast, the long-term effect of overweight in adolescence on morbidity and mortality is not known. METHODS. We studied the relation between overweight and morbidity and mortality in 508 lean or overweight adolescents 13 to 18 years old who participated in the Harvard Growth Study of 1922 to 1935. Overweight adolescents were defined as those with a body-mass index that on two occasions was greater than the 75th percentile in subjects of the same age and sex in a large national survey. Lean adolescents were defined as those with a body-mass index between the 25th and 50th percentiles. Subjects who were still alive were interviewed in 1988 to obtain information about their medical history, weight, functional capacity, and other risk factors. For those who had died, information on the cause of death was obtained from death certificates. RESULTS. Overweight in adolescent subjects was associated with an increased risk of mortality from all causes and disease-specific mortality among men, but not among women. The relative risks among men were 1.8 (95 percent confidence interval, 1.2 to 2.7; P = 0.004) for mortality from all causes and 2.3 (95 percent confidence interval, 1.4 to 4.1; P = 0.002) for mortality from coronary heart disease. The risk of morbidity from coronary heart disease and atherosclerosis was increased among men and women who had been overweight in adolescence. The risk of colorectal cancer and gout was increased among men and the risk of arthritis was increased among women who had been overweight in adolescence. Overweight in adolescence was a more powerful predictor of these risks than overweight in adulthood. CONCLUSIONS. Overweight in adolescence predicted a broad range of adverse health effects that were independent of adult weight after 55 years of follow-up.