High gestational weight gain does not improve birth weight in a cohort of African American adolescents

Association between maternal lifestyle factors and low birth weight in preterm and term births: a case-control study

Background

It has been reported that lifestyle factors may affect birth weight; however, few studies have explored the association between lifestyle factors and low birth weight in preterm and term births in China. The objective of this study was to explore the effect of lifestyle on low birth weight in preterm and term births.

Methods

This case-control study was conducted in fourteen hospitals in Jiangmen, Guangdong Province. Data were collected from August 2015 to May 2016 using a standard questionnaire. Data were analysed using logistic regression.

Results

Women who delivered preterm and were physically active (1–3 times per week and ≥ 4 times per week) had reduced odds of having low birth weight babies (aOR = 0.584, 95%CI = 0.394–0.867 and, aOR = 0.516, 95%CI = 0.355–0.752, respectively). Pregnant women who had insufficient gestational weight gain had increased odds of having low birth weight babies (aOR = 2.272, 95%CI = 1.626–3.176). Women exposed to passive smoking had an increased risk of delivering low birth weight infants (aOR = 1.404, 95%CI = 1.057–1.864). Insufficient gestational weight gain and excessive gestational weight gain were both significantly associated with low birth weight (aOR = 1.484, 95%CI = 1.103–1.998 and aOR = 0.369, 95%CI = 0.236–0.577, respectively) for term deliveries. In addition, parity, history of low birth weight, antenatal care and gestational hypertension were significantly associated with the likelihood of low birth weight.

Conclusion

Pregnant women without exercise contraindications should remain physically active. Pregnant women should be aware of the negative effects of smoke and be aware of strategies to protect themselves from passive smoke exposure. Hospitals should inform pregnant women of the importance appropriate gestational weight gain. These recommendations should be put into practice to decrease the prevalence of low birth weight infants.

Gestational weight gain among minority adolescents predicts term birth weight

BACKGROUND

In adolescents, there is limited evidence on the independent and additive effect of prepregnancy body mass index (BMI) and gestational weight gain on infant birth weight. Data also show that this effect may vary by race. We sought to examine the impact of maternal prepregnancy BMI and gestational weight gain on birth weight and risk of large for gestational age (LGA) in term newborns of minority adolescent mothers.

METHODS

This was a retrospective cohort study of 411 singleton live term infants born to mothers ≤ 18 years. Data were abstracted from electronic medical records.

RESULTS

Gestational weight gain was related to infant birth weight (ρ = 0.36, P < 0.0001), but BMI was not (ρ = 0.025, P = 0.61). On regression analysis, gestational weight gain, gestational age and Hispanic ethnicity were independent predictors of birth weight, controlling for maternal age, BMI, parity, tobacco/drug use and preeclampsia. The probability of having an LGA infant increased with weight gain [adjusted odds ratio (aOR) 1.14, 95% confidence interval (CI) 1.07-1.21] but not with BMI. Mothers who gained weight in excess of 2009 Institute of Medicine (IOM) recommendations had a greater risk of having an LGA infant compared to those who gained within recommendations (aOR 5.7, 95% CI 1.6-19.5).

CONCLUSIONS

Minority adolescents with greater gestational weight gain had infants with higher birth weight and greater risk of LGA; BMI was not associated with either outcome. Further studies are needed to examine the applicability of the 2009 BMI-specific IOM gestational weight gain recommendations to adolescents in minority populations.

Gestational weight gain and preterm birth: disparities in adolescent pregnancies

OBJECTIVE

To examine racial differences in the association between gestational weight gain and preterm birth subtypes among adolescents.

STUDY DESIGN

We conducted a retrospective cohort study of 211 403 adolescents using 2012 United States natality data. The outcome was preterm birth and the primary exposure was gestational weight gain. Multinomial logistic regression analyses were used to estimate adjusted odds ratios, stratified by race and body mass index (BMI).

RESULTS

Black and White mothers who gained below the recommendations had increased risks for spontaneous preterm birth in all BMI categories, except obese. All Hispanic mothers who gained below the recommendations had increased risks of spontaneous preterm birth. White normal and overweight mothers and Black, Hispanic and Other normal weight mothers who exceeded the recommendations had decreased risks of spontaneous preterm birth.

CONCLUSION

The effect of gestational weight gain on spontaneous and medically indicated preterm birth is modified by race and BMI.

Gestational weight gain in women with systemic lupus erythematosus

Objective The objective of this study was to estimate the proportion of pregnant women with systemic lupus erythematosus meeting Institute of Medicine guidelines for gestational weight gain and determine correlates of adherence to guidelines. Methods Singleton, live births in the Hopkins Lupus Pregnancy Cohort 1987-2015 were included. Pre-pregnancy weight was the weight recorded 12 months prior to pregnancy/first trimester. Final weight was the last weight recorded in the third trimester. Adherence to Institute of Medicine guidelines (inadequate, adequate, or excessive) was based on pre-pregnancy body mass index. Fisher's exact test and analysis of variance determined factors associated with not meeting guidelines. Stepwise selection estimated predictors of gestational weight gain. Results Of the 211 pregnancies, 34%, 24% and 42% had inadequate, adequate and excessive gestational weight gain, respectively. In exploratory analyses, differences in Institute of Medicine adherence were observed by pre-pregnancy body mass index, race, elevated creatinine during pregnancy and pre-pregnancy blood pressure. Odds of inadequate and excessive gestational weight gain increased 12% with each 1 kg/m² increase in pre-pregnancy body mass index. Lower maternal education was associated with increased odds of inadequate and excessive gestational weight gain. Conclusions As in the general population, most women with systemic lupus erythematosus did not meet Institute of Medicine guidelines. Our results identified predictors of gestational weight gain to aid in targeted interventions to improve guideline adherence in this population.

Gestational Weight Gain and Perinatal Outcomes in Adolescent Mothers: A Retrospective Cohort Study

OBJECTIVE

Optimal gestational weight gain (GWG) may differ for adolescents since they themselves may continue to grow throughout pregnancy. We examined the associations between GWG and perinatal outcomes among adolescents aged < 20 years and determined whether they differed from the associations among adult women aged 20 to 35 years.

METHODS

We conducted a retrospective cohort study of live born, singleton deliveries to 3725 adolescents and 50 400 adult women in Nova Scotia between 2003 and 2014. GWG was categorized as below, within, or above the 2009 Institute of Medicine recommendations. Primary outcomes were preterm birth (< 37 weeks), small for gestational age (SGA; < 10(th) percentile), large for gestational age (LGA; > 90th percentile), and delivery by Caesarean section. Adjusted odds ratios (OR) with 95% confidence intervals (CI) were estimated from logistic regression models.

RESULTS

Adolescent mothers with GWG above the recommendations (relative to mothers who gained within the recommendations) had higher odds of having an LGA neonate (OR 2.20; 95% CI 1.62 to 2.99) and having a Caesarean section (OR 1.33; 95% CI 1.07 to 1.64), but lower odds of having an SGA neonate (OR 0.65; 95% CI 0.51 to 0.84). Adolescent mothers with low GWG had decreased odds of having an LGA neonate (OR 0.58; 95% CI 0.34 to 0.98) and increased odds of having an SGA neonate (OR 1.72; 95% CI 1.30 to 2.27).

CONCLUSION

Among adolescents, GWG was significantly associated with several perinatal outcomes. More research considering other outcomes is needed to determine the optimal GWG for adolescent women.

Prepregnancy Body Mass Index and Gestational Weight Gain Have No Negative Impact on Maternal or Neonatal Iron Status

OBJECTIVE

To assess the impact of maternal obesity and excessive gestational weight gain (GWG) on maternal and neonatal iron status and to explore the possible mediating role of inflammation on hepcidin.

METHODS

This analysis included 230 pregnant adolescents (13-18 years) enrolled in either a longitudinal or a cross-sectional study. Prepregnancy body mass index (ppBMI) and GWG were obtained from medical records. Maternal iron status (hemoglobin, serum iron, ferritin, transferrin receptor, total body iron, and hepcidin) and inflammation (interleukin-6 [IL-6] and leptin) were assessed at midgestation (26.2 ± 3.3 weeks) in the longitudinal cohort and at delivery (39.8 ± 1.3 weeks) in both study cohorts. Cord blood was collected in both studies and analyzed for iron indicators.

RESULTS

Approximately 40% of the adolescents entered pregnancy overweight or obese. Multivariate analysis identified ppBMI as a negative predictor of serum iron at midgestation (P = .009) and a positive predictor of serum hepcidin at delivery (P = .02). None of the other maternal iron status indicators were significantly associated with ppBMI or GWG. Serum IL-6 was significantly positively associated with hepcidin at delivery (P = .0001) but not at midgestation. There was a positive relationship between ppBMI and cord hemoglobin (P = .03).

CONCLUSION

These results suggest that adiposity-related inflammation does not override the iron-mediated signals that regulate hepcidin production during pregnancy, and in this adolescent cohort, there is no strong evidence for a detrimental effect of maternal obesity and excessive weight gain on iron status in the offspring at birth.

Gestational Weight Gain in Adolescent Compared with Adult Pregnancies: An Age-Specific Body Mass Index Approach

OBJECTIVE

To determine current trends in gestational weight gain (GWG) in adolescents, using adolescent specific body mass index (BMI), in relation to the 2009 Institute of Medicine GWG guidelines.

STUDY DESIGN

Population-based retrospective cohort using Ohio birth records (2006-2012). Analyses were limited to primiparous women with singleton nonanomalous live births and available data on BMI and GWG. GWG percentiles were stratified by maternal age (less than 15, 15-17, 18-19, and 20-34 years old) and prepregnancy BMI category. Adolescent specific BMI definitions were used for mothers less than 19 years.

RESULTS

A total of 1,034,552 births occurred during the study period; 326,368 were included for analysis. Less than one-quarter of women gained the recommended amount of weight (20.6%). A large proportion of pregnancies had excessive GWG: 59.8% of mothers less than 15 years of age, compared with older adolescent (59.9%, 62.6%) and adult mothers (64.6%), P < .001. Average, median, and IQRs of GWG were similar for all women within the same BMI category, regardless of age. Except in underweight women, the average GWG was at the high end or above the 2009 Institute of Medicine recommendations, for adolescents in all BMI groups, similar to adults, median 35 (IQR 24-47) pounds.

CONCLUSIONS

Current GWG trends indicate that excessive weight gain is nearly as common in adolescents as in adult mothers.

Maternal weight gain in pregnancy and risk of obesity among offspring: a systematic review

OBJECTIVES

To systematically review the evidence from prospective and retrospective cohort studies on the association between gestational weight gain (GWG) and offspring's body weight.

METHODS

Electronic databases PubMed, Web of Science, CINAHL, and Academic Search Premiere were searched from inception through March 18, 2013. Included studies (n = 23) were English articles that examined the independent associations of GWG with body mass index (BMI) and/or overweight status in the offspring aged 2 to 18.9 years. Two authors independently extracted the data and assessed methodological quality of the included studies.

RESULTS

Evidence from cohort studies supports that total GWG and exceeding the Institute of Medicine maternal weight gain recommendation were associated with higher BMI z-score and elevated risk of overweight or obesity in offspring. The evidence of high rate of GWG during early- and mid-pregnancy is suggestive. Additionally, the evidence on inadequate GWG and net GWG in relation to body weight outcomes in offspring is insufficient to draw conclusions.

CONCLUSIONS

These findings suggest that GWG is a potential risk factor for childhood obesity. However, findings should be interpreted with caution due to measurement issues of GWG and potential confounding effects of shared familial characteristics (i.e., genetics and maternal and child's lifestyle factors).

Gestational weight gain and exposure of newborns to persistent organic pollutants

BACKGROUND

Exposure to persistent organic pollutants (POPs) during fetal development can increase the risk of adverse health effects during childhood. Maternal characteristics and physiological changes during gestation, such as gestational weight gain (GWG), may have an influence in the overall burden of POPs in neonates. However, the associations between GWG and POP concentrations are still not well established.

OBJECTIVE

We examined the association of GWG with cord serum POPs concentrations after adjusting for prepregnancy maternal body mass index (BMI) and other potential determinants of the transfer of POPs into newborns. The GWG values were evaluated after grouping by the reference guidelines of the Institute of Medicine (IOM).

METHODS

We measured levels of 14 organochlorine pesticides, 7 polychlorobiphenyls (PCBs), and 14 polybrominated diphenyl ethers (PBDEs) in 325 cord serum samples from a Spanish birth cohort. Multivariable models were used to estimate associations of GWG, prepregnancy BMI, and other maternal determinants on cord serum concentrations of POPs.

RESULTS

Neonatal concentrations of POPs were inversely associated with GWG after adjustment for age, prepregnancy BMI, educational level, and fish consumption. On average, neonates of women with IOM-recommended GWG have lower POP concentrations than do neonates of mothers with inadequate GWG.

CONCLUSIONS

The present findings suggest an association between neonatal exposure to POPs and inadequate GWG during pregnancy. Encouraging pregnant women to meet the recommended IOM guidelines for GWG may reduce the accumulation of POPs in newborns.

Maternal pre-pregnancy underweight and fetal growth in relation to institute of medicine recommendations for gestational weight gain

PURPOSE

Maternal nutritional status is one of the most important factors of fetal growth and development. Consequently, the currently increasing prevalence of underweight women worldwide has come in the focus of interest of perinatal medicine. The aim of the study was to assess the effect of low pre-pregnancy body mass index (BMI) on fetal growth.

MATERIALS AND METHODS

Data on 4678 pregnant women and their neonates were retrospectively analyzed. Pre-pregnancy BMI of study women was categorized according to the WHO standards. Fetal growth was assessed by birth weight and birth length, birth weight for gestational age, and ponderal index.

RESULTS

Study group included 351 (7.6%) women with pregestational BMI<18.5kg/m(2), while all women with pregestational BMI 18.5-25kg/m(2) (n=3688; 78.8%) served as a control group. The mean birth weight and birth length of neonates born to underweight mothers were by 167g and 0.8cm lower in comparison with the neonates born to mothers of normal nutritional status, respectively (P<0.001 both). The prevalence of small for gestational age (SGA) births was twofold that found in the control group of mothers of normal nutritional status (9.7% vs. 4.9%; P<0.001). The inappropriately low gestational weight gain additionally increased the rate of SGA infants in the group of mothers with low pre-pregnancy BMI (21.4% vs. 10.4%; P=0.02). Pre-pregnancy BMI category did not influence neonatal growth symmetry.

CONCLUSION

Low maternal pregestational BMI is associated with fetal growth assessment. Improvement of the maternal nutritional status before pregnancy can increase the likelihood of perinatal outcome.

Effect of multivitamin supplements on weight gain during pregnancy among HIV-negative women in Tanzania

Multivitamin supplementation has been shown to reduce the risk of low birthweight. This effect could be mediated through gestational weight gain. However, the effect of multivitamin supplementation on weight gain during pregnancy has not been fully studied. The objective of this study was to examine the effects of multivitamins on pregnancy weight gain. We enrolled 8468 HIV-negative women from Dar es Salaam, Tanzania, in a randomised, placebo-controlled trial of multivitamins on birth outcomes. Women were randomly assigned to receive either a daily oral dose of multivitamin tablets or a placebo and were weighed every 4 weeks from enrolment until the last visit before delivery. Intent-to-treat analyses were carried out to examine the effects of multivitamins on pregnancy weight gain. Multivariate linear and binomial regression models with the log-link function were used to examine the association of weight gain during pregnancy to birthweight. The overall total weight gain was 253 g (SE: 69, P: 0.0003) more, while the overall 4 weekly weight gain was 59 g greater (SE: 18, P: 0.005) among women who received multivitamins compared to placebo. Women in the lowest quartile of gestational weight gain had babies with an average birthweight of 3030 g (SD: 524), while women in the highest quartile had babies weighing 3246 g (SD: 486), on average. Prenatal multivitamin supplements increased gestational weight gain, which was a significant predictor of birthweight.

Evaluating body mass index-specific trimester weight gain recommendations: differences between black and white women

INTRODUCTION

We compared the gestational weight gains of black and white women with the 2009 Institute of Medicine (IOM) recommendations to better understand the potential for successful implementation of these guidelines in clinical settings.

METHODS

Prenatal and birth data for 2760 women aged 18 to 40 years with term singleton births from 2004 through 2007 were abstracted. We examined race differences in mean trimester weight gains with adjusted linear regression and compared race differences in the distribution of women who met the IOM recommendations with chi-square analyses. We stratified all analyses by prepregnancy body mass index.

RESULTS

Among normal-weight and obese women, black women gained less weight than white women in the first and second trimesters. Overweight black women gained significantly less than white women in all trimesters. For both races in all body mass index categories, a minority of women (range 9.9%-32.4%) met the IOM recommended gains for the second and third trimesters. For normal-weight, overweight, and obese black and white women, 49% to 80% exceeded the recommended gains in the third trimester, with higher rates of excessive gain for white women.

DISCUSSION

Less than half of the sample gained within the IOM recommended weight gain ranges in all body mass index groups and in all trimesters. The risk of excessive gain was higher for white women. For both races, excessive weight gain began by the second trimester, suggesting that counseling about the importance of weight gain during pregnancy should begin earlier, in the first trimester or prior to conception.

Serum 1,25-dihydroxyvitamin D and calcium intake affect rates of bone calcium deposition during pregnancy and the early postpartum period

BACKGROUND

Factors affecting bone calcium deposition across pregnancy and lactation are not well characterized.

OBJECTIVE

The impact of maternal age, calcium intake, race-ethnicity, and vitamin D status on the rate of bone calcium deposition (VO+) was assessed across pregnancy and lactation.

DESIGN

Stable calcium isotopes were given to 46 women at pre- or early pregnancy (trimester 1), late pregnancy (trimester 3), and 3-10 wk postpartum. Three cohorts were included: 23 adolescents from Baltimore (MD), aged 16.5 ± 1.4 y (mean ± SD; Baltimore cohort); 13 adults from California, aged 29.5 ± 2.6 y (California cohort); and 10 adults from Brazil, aged 30.4 ± 4.0 y (Brazil cohort). The total exchangeable calcium pool, VO+, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D [1,25(OH)₂D], parathyroid hormone, and calcium intake were evaluated.

RESULTS

At trimester 3, inverse associations between 1,25(OH)₂D and VO+ were evident in the Baltimore (P = 0.059) and Brazil (P = 0.008) cohorts and in the whole group (P = 0.029); calcium intake was not a significant determinant of VO+ in any group during pregnancy. At postpartum, a significant positive association was evident between VO+ and calcium intake (P ≤ 0.002) and between VO+ and African ethnicity (P ≤ 0.004) in the whole group and within the Baltimore and Brazil cohorts.

CONCLUSIONS

Elevated 1,25(OH)₂D was associated with decreased rates of bone calcium deposition during late pregnancy, a finding that was particularly evident in pregnant adolescents and adult women with low calcium intakes. Higher dietary calcium intakes and African ethnicity were associated with elevated rates of bone calcium deposition in the postpartum period.

Gestational weight gain in adolescents: a comparison to the new Institute of Medicine recommendations

STUDY OBJECTIVE

To examine the gestational weight gain distributions of healthy adolescents with optimal birth outcomes and compare them to the current 2009 Institute of Medicine (IOM) recommendations.

DESIGN

Secondary data analysis to conduct a population-based, cross-sectional study.

SETTING

The Central and Finger Lakes regions of New York state (Perinatal Database System).

PARTICIPANTS

6995 adolescents with healthy singleton pregnancies (1996 to 2002).

MAIN OUTCOME MEASURES

Percentiles of the gestational weight gain distributions were compared within body mass index (BMI) groups categorized using 2 different classification schemes: adolescent BMI percentiles and adult BMI cut-points. We compared these distributions overall and within racial and age groups.

RESULTS

The gestational weight gain distribution does not differ considerably when BMI is classified using adolescent or adult cutoffs. Adolescents have good birth outcomes across a wider gestational weight gain range than recommended by the Institute of Medicine regardless of how pre-pregnancy weight status is categorized. For example, overweight adolescents by adult cutoffs have a range of gestational weight gain from 5.0 kg to 30.0 kg, and overweight adolescents by percentile cutoffs have a range from 5.4 kg to 29.5 kg, whereas the IOM range is 7.5-11.5 kg. Black and young adolescents have a similar distribution to their white and older counterparts.

CONCLUSION

Practitioners can safely use the new IOM gestational weight gain ranges to monitor weight gain in pregnant adolescent patients using adult BMI classifications. Future research should examine the range of gestational weight gain in adolescents considering a broader scope of birth and maternal outcomes.

Obesity in rural youth: looking beyond nutrition and physical activity

Contributors to excessive obesity in rural youth include well-documented nutrition and physical activity behaviors. However, emerging research suggests that preventing excessive weight gain and smoking during pregnancy, teen pregnancy, and child abuse also could reduce obesity in this vulnerable population. These traditional and emerging, nontraditional factors need to be addressed within the confines of current challenges faced by rural communities. An enhanced ecological model provides a framework for combining traditional and nontraditional factors into a more comprehensive approach that addresses the complexity of the issues contributing to youth obesity.

Adolescent pregnancy and gestational weight gain: do the Institute of Medicine recommendations apply?

OBJECTIVE

The purpose of this study was to examine the Institute of Medicine (IOM) guidelines for gestational weight gain in adolescents.

STUDY DESIGN

We studied a retrospective cohort using the Missouri Birth Certificate Registry and included subjects who were primiparous, who had singleton gestations, who were <20 years old, and who delivered at 24-44 weeks gestation. The exposure was defined as weight gain less than, within, or greater than IOM recommendations. Outcomes that were examined were small-for-gestational-age (SGA) infants, large-for-gestational age (LGA) infants, preterm delivery, infant death, preeclampsia, cesarean delivery, and operative vaginal delivery. The analysis was stratified by body mass index category.

RESULTS

In any body mass index category, inadequate weight gain was associated with increased odds of SGA infants, preterm delivery, and infant death. When subjects gained more than the IOM recommendations, the number of SGA infants decreased, with slight increases in the number of LGA infants, preeclampsia, and cesarean delivery.

CONCLUSION

Adolescents should be counseled regarding adequate weight gain in pregnancy. Further research is necessary to determine whether the IOM recommendations recommend enough weight gain in adolescents to optimize pregnancy outcomes.

Should gestational weight gain recommendations be tailored by maternal characteristics?

The authors tested whether the relation between gestational weight gain (GWG) and 5 adverse pregnancy outcomes (small-for-gestational-age (SGA) birth, large-for-gestational-age (LGA) birth, spontaneous preterm birth, indicated preterm birth, and unplanned cesarean delivery) differed according to maternal race/ethnicity, smoking, parity, age, and/or height. They also evaluated whether GWG guidelines should be modified for special populations by studying GWG and risk of at least 1 adverse outcome within different subgroups. Data came from a cohort of 23,362 normal-weight mothers who delivered singletons at Magee-Womens Hospital in Pittsburgh, Pennsylvania (2003-2008). Adequacy of GWG was defined as observed GWG divided by recommended GWG. The synergy analysis found that the combination of smoking, black race/ethnicity, primiparity, or short height with poor GWG was associated with an excess risk of SGA birth, while high GWG combined with each of these characteristics diminished risk of LGA birth in comparison with the same GWG among the women's counterparts. Nevertheless, there were no significant or meaningful differences in the risk of at least 1 adverse outcome between the GWG recommended by the Institute of Medicine in 2009 and the GWG that minimized risk of the composite outcome. These findings do not support the tailoring of GWG guidelines on the basis of a mother's smoking status, race/ethnicity, parity, age, or height among normal-weight women.

Sleep deprivation, physical activity and low income are risk factors for inadequate weight gain during pregnancy: a cohort study

AIM

To determine the possible risk factors for inadequate gestational weight gain.

METHODS

A population-based cohort study was carried out in Sri Lanka from May 2001 to April 2002. Pregnant women were recruited on or before 16 weeks' gestation and followed up until delivery; the sample size was 710. Trimester-specific exposure status and potential confounding factors were gathered on average at the 12th, 28th and 36th weeks of gestation. Maternal weight was measured at the first antenatal clinic visit and at delivery. Inadequate weight gain was defined as weight gain below the Institute of Medicine recommendations in 2009. Multiple logistic regression was applied and the results were expressed as odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

The risk factors for inadequate weight gain were low per-capita monthly income (OR 1.63, 95% CI 1.03, 2.58), multiparity (OR 1.96, 95% CI 1.34, 2.87), sleeping <8 h/day during the second, third, or both second and third trimesters (OR 1.60, 95% CI 1.05, 2.46), standing and walking ≥5 h/day during the second trimester (OR 1.50, 95% CI 1.04, 2.15), and the newborn being of the male sex (OR 1.50, 95% CI 1.04, 2.16), controlling for the effect of body mass index and gestational age.

CONCLUSIONS

Risk factors for inadequate gestational weight gain were low income, being multiparous, sleep deprivation, physical activity in terms of standing and walking, and the male sex of baby.

Birth outcomes and risk factors in adolescent pregnancies: results of a Taiwanese national survey

BACKGROUND

This study explores birth outcomes and determinants in adolescent pregnancies, using subjects drawn from the Taiwan Birth Cohort Study (TBCS) from 2005.

METHODS

Through completed interviews and surveys with mothers or other family members, differences in birth outcomes and personal, pregnancy and social profiles of mothers were analyzed.

RESULTS

A total of 533 adolescent mothers (<20 years old) and 9347 adult mothers (20-34 years old) were included in our study. There was a significantly higher incidence of low birthweight (LBW) (<2500 g, 10.2% vs 5.6%) and premature birth (<37 weeks, 14.8% vs 8.6%) in the adolescent group. When adjusted for covariates in the multiple-variable model, youth remained a risk factor for LBW (OR = 1.50, 95%CI 1.09, 2.07) and premature delivery (OR = 1.42, 95%CI 1.07, 1.89). Age, prenatal care and weight gain during pregnancy are important predictors of LBW and premature birth.

CONCLUSION

Adolescent pregnancy carries a high-risk of LBW and premature birth. Inadequate prenatal care and weight gain during pregnancy are contributing factors that could be improved through strategies of health education, family support and case management.

Relationship between maternal growth, infant birthweight and nutrient partitioning in teenage pregnancies

OBJECTIVE

Teenagers are susceptible to delivering small-for-gestational-age (SGA) infants. Previous studies suggest that maternal growth may contribute, as a result of preferential nutrient partitioning to the mother. We investigated the impact of maternal growth on birthweight in pregnant teenagers in the UK, and examined endocrine mediators of nutrient partitioning.

DESIGN

A prospective observational multicentre study, About Teenage Eating, conducted between 2004 and 2007.

SETTING

Four hospitals in socially-deprived areas of Manchester and London.

POPULATION

A total of 500 pregnant adolescents (14-18 years of age) with a singleton pregnancy were recruited at 10-21 weeks of gestation, with follow-up studies on 368 subjects. A cohort of 80 pregnant adults (25-40 years of age) provided a control group for determining growth.

METHODS

Skeletal growth, weight gain and skinfold thickness were measured from first to third trimester, together with maternal levels of micronutrients and metabolic hormones: insulin-like growth factor (IGF) system and leptin. Dietary analyses were performed.

MAIN OUTCOME MEASURE

SGA birth.

RESULTS

Maternal growth was not associated with SGA birth: growing mothers delivered more large-for-gestational-age infants (OR 2.51; P < 0.05). Growers had greater weight gain (P < 0.001), fat accrual (P < 0.001) and red cell folate concentrations (P < 0.01) than non-growers. Maternal IGF-I (P < 0.01) and leptin (P < 0.001) were positively associated with maternal and fetal growth, whereas IGF-I (P < 0.001) was negatively associated. Teenagers that were underweight at booking or with low weight gain were at greater risk of SGA birth.

CONCLUSIONS

Maternal growth was not detrimental to fetal growth in this UK population of teenagers. Greater weight gain and higher concentrations of IGF-I in growing teenagers may provide anabolic drive for maternal and fetal growth.

Vitamin D insufficiency is prevalent among pregnant African American adolescents

STUDY OBJECTIVE

Recent attention has focused on vitamin D insufficiency but few data exist on vitamin D status among pregnant minority youth.

DESIGN

A screening study was undertaken in adolescents having prenatal blood samples drawn for other routine tests obtained during the second trimester (18+/-1.8 week gestation, n=44) or third trimester of pregnancy (28.4+/-2.1 week gestation, n=36). Serum 25- hydroxyvitamin D (25(OH)D) was measured and significant determinants of vitamin D insufficiency in this cohort were identified.

SETTING

Urban prenatal clinic.

PARTICIPANTS

Eighty pregnant African American adolescents (< or = 18 y of age).

MAIN OUTCOME MEASURE(S)

Vitamin D status, STDs, hemoglobin, season, birth weight

RESULTS

Serum 25(OH)D in this group averaged 21.6+/-8 ng/mL (age 16.5+/-1.1 y, n=80), and did not significantly differ between the second (20.95+/-8.2 ng/mL, n=44) and third trimester cohorts (22.5+/-7.9 ng/mL, n=36). Vitamin D insufficiency (< 20 ng/mL) was evident in 46.25% and vitamin D deficiency (<15 ng/mL) was evident in 21.25% of those studied. Significant predictors of suboptimal vitamin D status included sampling during the winter months (P=0.004), lower hemoglobin concentration (P=0.019), and higher second trimester leptin levels (P=0.018). Inverse associations between 25(OH)D and bacterial vaginosis were evident when controlled for season of sampling (P=0.02, n=80).

CONCLUSIONS

Vitamin D insufficiency was prevalent among urban pregnant minority adolescents. Further studies are needed to address the impact of this finding on maternal and neonatal calcium homeostasis and bone health.

A systematic review of outcomes of maternal weight gain according to the Institute of Medicine recommendations: birthweight, fetal growth, and postpartum weight retention

This systematic review focuses on outcomes of gestational weight gain, specifically birthweight, fetal growth, and postpartum weight retention, for singleton pregnancies with respect to the 1990 Institute of Medicine weight gain recommendations. A total of 35 studies met the inclusion criteria and were reviewed. There was strong evidence to support associations between excessive gestational weight gain and increased birthweight and fetal growth (large for gestational age) as well as inadequate gestational weight gain and decreased birthweight and fetal growth (small for gestational age). There was moderate evidence to support the association between excessive gestational weight gain and postpartum weight retention. Clear clinical recommendations based on this review are challenging because of several limitations in the literature. Improvements in future research include the use of consistent definitions of gestational weight gain and outcomes of interest, assessment of confounders, and better collection of weight and weight gain data.

Obesity in minority women: calories, commerce, and culture

Obesity is increasing at epidemic rates in all women, but especially in minority women and children. Factors that contribute to this include changes in caloric intake and expenditure (calories), cost and ease of acquiring food along with pressures from the marketplace and media (commerce) and the community response to the increasing prevalence of obesity and sedentary lifestyle (culture).

Perceived barriers to physical activity among pregnant women

OBJECTIVE

Physical activity generally declines during pregnancy, but barriers to activity during this time period are not well understood. The objective was to examine barriers to physical activity in a large cohort of pregnant women and to explore these barriers in more depth with qualitative data derived from a separate focus group study using a socioecologic framework.

METHOD

A total of 1535 pregnant women (27-30 weeks' gestation) enrolled in the Pregnancy, Infection, and Nutrition Study were asked an open-ended question about their primary barrier to physical activity; responses were coded into categories according to the socioecologic framework. To further elucidate, 13 focus groups of a total of 58 pregnant women (20-37 weeks' gestation) were conducted among Hispanic, African American, and White participants.

RESULTS

Among the 1535 pregnant women participating in the survey, 85% reported an intrapersonal barrier to physical activity, of which almost two-thirds were health related. Only 2% of the women reported their main barrier to physical activity as interpersonal and 3% reported a neighborhood or environmental barrier. These results were supported by the focus group data, overall and by race/ethnicity and body mass index. Although women discussed barriers to physical activity at a variety of levels, the intrapersonal level was the most frequently cited and discussed factor in both studies.

CONCLUSIONS

Since pregnancy may trigger the development of obesity and since physical activity is recommended for healthy pregnant women, it is imperative to promote physical activity in a more relevant way. These quantitative and qualitative studies revealed many barriers to physical activity among pregnant women and some suggestions for interventions.

Position of the American Dietetic Association: nutrition and lifestyle for a healthy pregnancy outcome

It is the position of the American Dietetic Association that women of child-bearing ages should maintain good nutritional status through a lifestyle that optimizes maternal health and reduces the risk of birth defects, suboptimal fetal growth and development, and chronic health problems in their children. The key components of a health-promoting lifestyle during pregnancy include appropriate weight gain; appropriate physical activity; consumption of a variety of foods in accordance with the Dietary Guidelines for Americans 2005; appropriate and timely vitamin and mineral supplementation; avoidance of alcohol, tobacco, and other harmful substances; and safe food handling. Pregnant women with inappropriate weight gain, hyperemesis, poor dietary patterns, phenylketonuria, certain chronic health problems, or a history of substance abuse should be referred to a registered dietitian for medical nutrition therapy. Prenatal weight gain within the Institute of Medicine recommended ranges has been associated with better pregnancy outcomes. Most pregnant women need 2,200 to 2,900 kcal a day, but prepregnancy body mass index, rate of weight gain, maternal age, and appetite must be considered when tailoring this recommendation to the individual. The consumption of more food to meet energy needs, and the increased absorption and efficiency of nutrient utilization that occurs in pregnancy, are generally adequate to meet the needs for most nutrients. However, vitamin and mineral supplementation is appropriate for some nutrients and situations. This position paper also includes recommendations pertaining to use of alcohol, tobacco, caffeine, and illicit drugs.

The thrifty phenotype as an adaptive maternal effect

Human diseases in adulthood are increasingly associated with growth patterns in early life, implicating early-life nutrition as the underlying mechanism. The thrifty phenotype hypothesis proposed that early-life metabolic adaptations promote survival, with the developing organism responding to cues of environmental quality by selecting an appropriate trajectory of growth. Recently, some authors have proposed that the thrifty phenotype is also adaptive in the longer-term, by preparing the organism for its likely adult environment. However, windows of plasticity close early during human development, and subsequent environmental changes may result in the selected trajectory becoming inappropriate, leading to adverse effects on health. This paradox generates uncertainty as to whether the thrifty phenotype is indeed adaptive for the offspring in humans. The thrifty phenotype should not be considered a dichotomous concept, rather it refers to the capacity of all offspring to respond to environmental information during early ontogenetic development. This article argues that the thrifty phenotype is the consequence of three different adaptive processes - niche construction, maternal effects, and developmental plasticity - all of which in humans are influenced by our large brains. While developmental plasticity represents an adaptation by the offspring, both niche construction and parental effects are subject to selection on parental rather than offspring fitness. The three processes also operate at different paces. Human offspring do not become net calories-producers until around 18 years of age, such that the high energy costs of the human brain are paid primarily by the mother, even after weaning. The evolutionary expansion of human brain volume occurred in environments characterised by high volatility, inducing strong selective pressure on maternal capacity to provision multiple offspring simultaneously. The thrifty phenotype is therefore best considered as a manipulation of offspring phenotype for the benefit of maternal fitness. The information that enters offspring phenotype during early development does not predict the likely future environment of the offspring, but rather reflects the mother's own developmental experience and the quality of the environment during her own maturation. Offspring growth trajectory thus becomes aligned with long-term maternal capacity to provision. In contemporary populations, the sensitivity of offspring development to maternal phenotype exposes the offspring to adverse effects, through four distinct pathways. The offspring may be exposed to (1) poor maternal metabolic control (e.g. gestational diabetes), (2) maternally derived toxins (e.g. maternal smoking), or (3) low maternal social status (e.g. small size). Adverse consequences of these effects may then be exacerbated by (4) exposure either to the "toxic" western environment in postnatal life, in which diet and physical activity levels are mismatched with metabolic experience in utero, or at the other extreme to famine. The rapid emergence of the epidemic of the metabolic syndrome in the 20th Century reflects the rapid acceleration in the pace of niche construction relative to the slower physiological combination of developmental plasticity and parental effects.

Are the Institute of Medicine Recommendations for Gestational Weight Gain Appropriate for Adolescents?

OBJECTIVE

To explore the use of Centers for Disease Control and Prevention body mass index percentiles for adolescents to classify adolescents for gestational weight gain recommendations.

DESIGN

A descriptive study using secondary data analysis.

SETTING

Memphis, Tennessee.

PARTICIPANTS

Three hundred forty-seven primiparous Black adolescents, aged 12 to 19 years, who delivered full-term infants.

MAIN OUTCOME MEASURES

Adult and adolescent body mass index categories, gestational weight gain patterns, and neonatal birthweight.

RESULTS

Adolescents, especially smaller adolescents, were misclassified when the current Institute of Medicine adult body mass index categories were used to classify them for gestational weight gain when compared to the use of the Centers for Disease Control and Prevention body mass index percentiles for adolescents as a gestational weight gain classification schema. Mean neonatal birthweights were similar no matter which schema was used. A large proportion of adolescents gained more than is recommended by the Institute of Medicine.

CONCLUSIONS

The current gestational weight gain recommendations based on adult body mass index categories may not be sufficiently specific to attain the best maternal and neonatal outcomes for adolescents. Creation of gestational weight gain recommendations based on the Centers for Disease Control and Prevention body mass index percentiles would potentially assist clinicians in counseling adolescents regarding gestational weight gain.