Different weight gain in women of normal weight before pregnancy: postpartum weight and birth weight

Association of Dietary Change during Pregnancy with Large-for-Gestational Age Births: A Prospective Observational Study

Being born with large birthweight is considered as a risk of non-communicable diseases later in life. However, it is not fully understood what kind of maternal dietary intake during pregnancy affect large birthweight. Therefore, we examined the association of dietary intakes and its changes during pregnancy with large-for-gestational-age (LGA) births in Japanese pregnant women. In the prospective study, 245 pregnant women who visited Kyoto Medical Center were enrolled. Nutrition survey using brief-type self-administered diet history questionnaire (BDHQ) at all trimester was completed in 171 pregnant women. Based on birthweight and gestational age, participants were divided into three groups, such as small-for-gestational-age (<10th, SGA, n=17), appropriate-for-gestational-age (≥10th and <90th, AGA, n=144), and LGA (≥90th, n=10) groups. Compared with those without LGA births, mothers with LGA births showed: 1) greater weight gain during pregnancy (LGA: 14.0±3.2 kg, AGA: 9.9±3.9 kg, SGA: 8.4±3.1 kg, p<0.05); 2) higher energy intake throughout pregnancy (LGA: 310±368 kcal, AGA: 7±490 kcal, SGA: -97±293 kcal, p_trend<0.05); 3) larger changes in plant oil and sucrose consumptions from the 1st to 2nd trimester, probably due to the results of greater consumption of bread, Western confectionery, Japanese confectionery, and mayonnaise and dressing during the same period (p_trend<0.05, respectively). Our results suggest that higher energy intake throughout pregnancy, as well as greater consumption of plant oil and sucrose from the first to second trimester could be associated with LGA births.

Development of a dietary screening questionnaire to predict excessive weight gain in pregnancy

Excessive gestational weight gain (GWG) is a risk factor for several adverse pregnancy outcomes, including macrosomia. Diet is one of the few modifiable risk factors identified. However, most dietary assessment methods are impractical for use in maternal care. This study evaluated whether a short dietary screening questionnaire could be used as a predictor of excessive GWG in a cohort of Icelandic women. The dietary data were collected in gestational weeks 11–14, using a 40‐item food frequency screening questionnaire. The dietary data were transformed into 13 predefined dietary risk factors for an inadequate diet. Stepwise backward elimination was used to identify a reduced set of factors that best predicted excessive GWG. This set of variables was then used to calculate a combined dietary risk score (range 0–5). Information regarding outcomes, GWG (n = 1,326) and birth weight (n = 1,651), was extracted from maternal hospital records. In total, 36% had excessive GWG (Icelandic criteria), and 5% of infants were macrosomic (≥4,500 g). A high dietary risk score (characterized by a nonvaried diet, nonadequate frequency of consumption of fruits/vegetables, dairy, and whole grain intake, and excessive intake of sugar/artificially sweetened beverages and dairy) was associated with a higher risk of excessive GWG. Women with a high (≥4) versus low (≤2) risk score had higher risk of excessive GWG (relative risk = 1.23, 95% confidence interval, CI [1.002, 1.50]) and higher odds of delivering a macrosomic offspring (odds ratio = 2.20, 95% CI [1.14, 4.25]). The results indicate that asking simple questions about women's dietary intake early in pregnancy could identify women who should be prioritized for further dietary counselling and support.

Food Insecurity Increases the Odds of Obesity Among Young Hispanic Children

Obesity is a growing public health concern and is more prevalent among low-income and minority populations. Food insecurity may increase the odds of obesity in children. We investigated the association between food insecurity and obesity among low-income, Hispanic, mother-child dyads (n = 74). The United States Department of Agriculture 18-item Household Food Security Survey was used to determine food security status. The majority of households were food insecure (74 %) and one-third (30 %) of children were obese. Food insecurity increased the odds of childhood obesity (OR 10.2; 95 % CI 1.2, 85.5) with stronger associations found within households where mothers were also overweight/obese compared to normal weight (p-for interaction < 0.05). Rates of household food insecurity and childhood obesity were high among this low-income Hispanic sample. Future studies should elucidate the mechanisms through which food insecurity impacts childhood obesity.

Maternal stress predicts postpartum weight retention

Postpartum weight retention (PPWR) is a significant contributor to the development of overweight and obesity in women of childbearing age. Stress may be a key mechanism making it more difficult for mothers to lose weight in the year following delivery. The aim of this study was to assess whether specific aspects of parenting stress and life stress influence postpartum weight retention in new mothers. Women in late pregnancy or up to 2 months postpartum (n = 123) were enrolled in the study and followed through the first year postpartum. Linear regression models evaluated the associations of parenting stress (isolation, attachment and depressive symptoms) as well as overall life stress at 2, 6, and 12 months postpartum with PPWR at 6 and 12 months. During the first year postpartum, higher depression and life stress were significantly associated with greater PPWR. As the effect of depression diminished, the effect of life stress became significant. Contrary to hypothesized relationships, fewer problems with attachment and less social isolation were significantly associated with greater PPWR. Higher gestational weight gain and African American race were also significantly associated with greater PPWR at both 6 and 12 months. Different types of stress predict weight retention in first time mothers during the first year postpartum. Understanding the relationships between parenting stress, concurrent life stress and PPWR can enhance the development of future interventions that specifically target self-identified stressors, leading to improved weight related outcomes.

Maternal fat mass at mid-pregnancy and birth weight in Brazilian women

BACKGROUND

The relationship between maternal body composition and foetal development is unclear.

AIM

To determine the relationship between maternal body composition [fat mass (FM) and fat-free mass (FFM)] and foetal growth and birth weight, independent of potential confounding factors.

SUBJECTS AND METHODS

This study consisted of 92 women, normal and overweight/obese, recruited from the Instituto Fernandes Figueira in Rio de Janeiro, Brazil. Body composition (FM and FFM) was estimated using bioelectrical impedance. Foetal growth was assessed using serial ultrasound measurements at the second and third trimester and infant's weight and length were measured at birth. Multiple linear regression analyses were used to determine the association between maternal FM and FFM and birth weight adjusted for gestational age (BWt) and change in estimated foetal weight (ΔEFW), controlling for infant gender, maternal serum glucose, energy intake, parity, height and income.

RESULTS

Maternal FM, but not FFM, was positively associated with BWt (p = 0.02) and borderline with ΔEFW (p = 0.05). FM expressed as a percentage of body weight (%FM) showed a significant positive association with BWt (p < 0.001) and ΔEFW (p < 0.01). Using backward linear regression analysis, FM was a significant predictor of BWt (p < 0.001) and ΔEFW (p = 0.03), but not change in femur length.

CONCLUSION

In this small sample of normal and overweight/obese women, maternal FM at mid-pregnancy is associated with neonatal BW and foetal growth.

Exercise interventions for weight management during pregnancy and up to 1 year postpartum among normal weight, overweight and obese women: a systematic review and meta-analysis

BACKGROUND

The prevalence of excessive gestation weight gain, extended postpartum weight retention and pregravid obese women is increasing and is associated with numerous adverse health outcomes.

OBJECTIVE

To review the evidence from studies employing exercise-only interventions for weight management among pregnant and postpartum women.

SEARCH STRATEGY

Ten databases were searched for randomised controlled trials conducted during pregnancy or within the 12 months following childbirth and published between 1990 and 2013.

SELECTION CRITERIA

There were no restrictions to the type, frequency, duration or intensity of exercise intervention. Interventions not specifically designed to target weight were excluded. The outcomes were a change in body weight (kg) or body mass index (BMI; kg/m(2)).

DATA COLLECTION AND ANALYSIS

All data were continuous and were reported as weighted mean differences (WMD), with 95% CIs. Data were analysed with a fixed-effect model and heterogeneity was determined using the I(2) statistic.

RESULTS

Five studies were included in this review. Exercise significantly reduced gestational weight gain (WMD=-2.22 kg, CI -3.14 to -1.3, p≤0.00001) and had no significant effect on postpartum weight loss (WMD=-1.74 kg, CI -3.59 to 0.10, p=0.06) or BMI during pregnancy (WMD=-2.8 kg/m(2), CI -5.60 to 0.00, p=0.05) or postpartum (WMD=-0.54 kg/m(2), CI -1.17 to 0.08, p=0.09).

CONCLUSIONS

There is currently limited evidence to suggest that exercise can be used to limit maternal gestational weight gain.

Does milk and dairy consumption during pregnancy influence fetal growth and infant birthweight? A systematic literature review

It is increasingly acknowledged that the maternal diet influences fetal development and health of the child. Milk and milk products contribute essential nutrients and bioactive substances; they are of ample supply and have a long tradition in Nordic countries. To revise and update dietary guidelines for pregnant women valid in Nordic countries, the Pregnancy and Lactation expert group within the NNR5 project identified a need to systematically review recent scientific data on infant growth measures and maternal milk consumption. The objective of this study was to assess the influence of milk and dairy consumption during pregnancy on fetal growth through a systematic review of studies published between January 2000 and December 2011. A literature search was run in June 2011. Two authors independently selected studies for inclusion from the 495 abstracts according to predefined eligibility criteria. A complementary search in January 2012 revealed 64 additional abstracts published during the period June to December 2011, among them one study of interest previously identified. Of the 33 studies extracted, eight were relevant research papers. Five were prospective cohort studies (including a retrospective chart review), one was a case–control study, and two were retrospective cohort studies. For fetal length or infant birth length, three studies reported no association and two reported positive associations with milk or dairy consumption. For birthweight related outcomes, two studies reported no associations, and four studies reported positive associations with milk and/or dairy consumption. There was large heterogeneity in exposure range and effect size between studies. A beneficial fetal growth-increase was most pronounced for increasing maternal milk intake in the lower end of the consumption range. Evidence from prospective cohort studies is limited but suggestive that moderate milk consumption relative to none or very low intake, is positively associated with fetal growth and infant birthweight in healthy, Western populations.

Maternal weight change between 1 and 2 years postpartum: the importance of 1 year weight retention

Pregnancy weight gain may lead to long-term increases in maternal BMI for some women. The objective of this study was to examine maternal body weight change 1y-2y postpartum, and to compare classifications of 2y weight retention with and without accounting for 1y-2y weight gain. Early pregnancy body weight (EPW, first trimester) was measured or imputed, and follow-up measures obtained before delivery, 1 year postpartum (1y) and 2 years postpartum (2y) in an observational cohort study of women seeking prenatal care in several counties in upstate New York (n = 413). Baseline height was measured; demographic and behavioral data were obtained from questionnaires and medical records. Associations of 1y-2y weight change (kg) and 1y-2y weight gain (≥2.25 kg) with anthropometric, socioeconomic, and behavioral variables were evaluated using linear and logistic regressions. While mean ± SE 1y-2y weight change was 0.009 ± 4.6 kg, 1y-2y weight gain (≥2.25 kg) was common (n = 108, 26%). Odds of weight gain 1y-2y were higher for overweight (OR(adj) = 2.63, CI(95%) = 1.43-4.82) and obese (OR(adj) = 2.93, CI(95%) = 1.62-5.27) women than for women with BMI <25. Two year weight retention (2y-EPW ≥2.25 kg) was misclassified in 38% (n = 37) of women when 1y-2y weight gain was ignored. One year weight retention (1YWR) (1y-EPW) was negatively related to 1y-2y weight change (β(adj) ± SE = -0.28 ± 0.04, P < 0.001) and weight gain (≥2.25 kg) (OR(adj) = 0.91, CI(95%) = 0.87-0.95). Relations between 1y weight retention and 1y-2y weight change were attenuated for women with higher early pregnancy BMI. Weight change 1y-2y was predicted primarily by an inverse relation with 1y weight retention. The high frequency of weight gain has important implications for classification of postpartum weight retention.

Pre-pregnancy body mass index and weight gain during pregnancy: relations with gestational diabetes and hypertension, and birth outcomes

To study the relationship between pre-pregnancy body mass index (BMI) and weight gain during pregnancy with pregnancy and birth outcomes, with a focus on gestational diabetes and hypertension and their role in the association with fetal growth. We studied 1,884 mothers and offspring from the Eden mother-child cohort. Weight before pregnancy (W1) and weight after delivery (W2) were collected and we calculated BMI and net gestational weight gain (netGWG = (W2 - W1)/(weeks of gestation)). Gestational diabetes, hypertension gestational age and birth weight were collected. We used multivariate linear or logistic models to study the association between BMI, netGWG and pregnancy and birth outcomes, adjusting for center, maternal age and height, parity and average number of cigarettes smoked per day during pregnancy. High BMI was more strongly related to the risk of giving birth to a large-for-gestational-age (LGA) baby than high netGWG (odds ratio OR [95% CI] of 3.23 [1.86-5.60] and 1.61 [0.91-2.85], respectively). However, after excluding mothers with gestational diabetes or hypertension the ORs for LGA, respectively weakened (OR 2.57 [1.29-5.13]) for obese women and strengthened for high netGWG (OR 2.08 [1.14-3.80]). Low in comparison to normal netGWG had an OR of 2.18 [1.20-3.99] for pre-term birth, which became stronger after accounting for blood pressure and glucose disorders (OR 2.70 [1.37-5.34]). Higher net gestational weight gain was significantly associated with an increased risk of LGA only after accounting for blood pressure and glucose disorders. High gestational weight gain should not be neglected in regard to risk of LGA in women without apparent risk factors.

Optimizing weight gain in pregnancy to prevent obesity in women and children

Pregnancy is now considered to be an important risk factor for new or persistent obesity among women during the childbearing years. High gestational weight gain is the strongest predictor of maternal overweight or obesity following pregnancy. A growing body of evidence also suggests that both high and low gestational weight gains are independently associated with an increased risk of childhood obesity, suggesting that influences occurring very early in life are contributing to obesity onset. In response to these data, the US Institute of Medicine (IOM) revised gestational weight gain guidelines in 2009 for the first time in nearly two decades. However, less than one third of pregnant women achieve guideline-recommended gains, with the majority gaining above IOM recommended levels. To date, interventions to optimize pregnancy weight gains have had mixed success. In this paper, we summarize the evidence from human and animal studies linking over-nutrition and under-nutrition in pregnancy to maternal and child obesity. In addition, we discuss published trials and ongoing interventions to achieve appropriate gestational weight gain as a strategy for obesity prevention in women and their children.

Mothers' pre-pregnancy BMI and weight gain during pregnancy and risk of breast cancer in daughters

Previous studies have established that higher birthweight is associated with increased risk of breast cancer. However, the mechanisms underlying this association remain unclear. We explored whether maternal pregnancy weight gain and pre-pregnancy body mass index (BMI), which influence birthweight, are associated with risk of breast cancer in offspring. The Nurses' Mothers case-control study of breast cancer was nested in the Nurses' Health Study I and II cohorts. Mothers of 814 nurses with and 1,809 nurses without breast cancer completed questionnaires with information on pre-pregnancy height and weight, pregnancy weight gain, and other aspects of their pregnancies with the nurse daughters. We calculated odds ratios for breast cancer using conditional logistic regression. Mean pregnancy weight gain was 23 lb, and average pre-pregnancy BMI was 21 kg/m². Mothers' weight gain during pregnancy was not associated with the daughters' risk of breast cancer. Compared to women whose mothers gained 20-29 lb, women whose mothers gained less than 10 lb had a relative risk of 0.92 (95% confidence interval [CI]: 0.62-1.36), adjusting for the age of the nurses. Women whose mothers gained 40 or more pounds had a relative risk of 0.82 (95% CI: 0.55-1.23). Mothers' pre-pregnancy BMI was not associated with the daughters' risk of breast cancer. Women whose mothers had a pre-pregnancy BMI of 30 or more had a relative risk of 0.77 (95% CI: 0.34-1.74) compared to those with BMI less than 20. Additional adjustment for prenatal factors or for nurses' characteristics later in life had no effect on the results. The association between birthweight and breast cancer risk is likely due to factors independent of mothers' weight gain during pregnancy or pre-pregnancy BMI. Because BMIs and pregnancy weight gains were lower in this population than today, we cannot rule out associations for very high pre-pregnancy BMIs or pregnancy weight gains.

Post-partum weight change patterns in the WHO Multicentre Growth Reference Study

The interplay of factors that affect post-partum loss or retention of weight gained during pregnancy is not fully understood. The objective of this paper is to describe patterns of weight change in the six sites of the World Health Organization (WHO) Multicentre Growth Reference Study (MGRS) and explore variables that explain variation in weight change within and between sites. Mothers of 1743 breastfed children enrolled in the MGRS had weights measured at days 7, 14, 28 and 42 post-partum, monthly from 2 to 12 months and bimonthly thereafter until 24 months post-partum. Height, maternal age, parity and employment status were recorded and breastfeeding was monitored throughout the follow-up. Weight change patterns varied significantly among sites. Ghanaian and Omani mothers lost little or gained weight post-partum. In Brazil, India, Norway and USA, mothers on average lost weight during the first year followed by stabilization in the second year. Lactation intensity and duration explained little of the variation in weight change patterns. In most sites, obese mothers tended to lose less weight than normal-weight mothers. In Brazil and Oman, primiparous mothers lost about 1 kg more than multiparous mothers in the first 6 months. In India and Ghana, multiparous mothers lost about 0.6 kg more than primiparas in the second 6 months. Culturally defined mother-care practices probably play a role in weight change patterns among lactating women. This hypothesis should stimulate investigation into gestational weight gain and post-partum losses in different ethnocultural contexts.

Preconception predictors of weight gain during pregnancy: prospective findings from the Central Pennsylvania Women's Health Study

OBJECTIVES

We examined preconception (prepregnancy) predictors of pregnancy weight gain and weight gain that exceeds the 2009 Institute of Medicine (IOM) recommendations based on pre-pregnancy body mass index (BMI), in a prospective study.

METHODS

Data are from a population-based cohort study of 1,420 women who were interviewed at baseline and 2 years later. The analytic sample includes 103 women who were not pregnant at baseline and gave birth to full-term singletons during the follow-up period. Preconception maternal weight category as well as health behaviors, psychosocial stress, parity, and age were examined as predictors of pregnancy weight gain and of weight gain in excess of the IOM recommendations using multiple linear and logistic regression analysis.

RESULTS

Pregnancy weight gain averaged 33.01 pounds, with 51% of women gaining weight in excess of the 2009 IOM recommendations for their preconception weight category. Preconception overweight (BMI = 25-29.9) increased the odds of excessive pregnancy weight gain nearly threefold, whereas preconception physical activity levels meeting activity guidelines reduced the odds of excessive weight gain but was marginally statistically significant.

CONCLUSION

Although future research examining the role of physical activity in relation to pregnancy weight gain is needed, preconception overweight and physical activity levels are prime targets for interventions to avoid excessive pregnancy weight gain.

Active Mothers Postpartum (AMP): rationale, design, and baseline characteristics

BACKGROUND

Pregnancy and the postpartum period have been suggested as important contributors to overweight and obesity among women. This paper presents the design, rationale, and baseline participant characteristics of a randomized controlled intervention trial to enhance weight loss in postpartum women who entered pregnancy overweight or obese.

METHODS

Active Mothers Postpartum (AMP) is based on the rationale that the birth of a child can be a teachable moment. AMP's primary objectives are to promote and sustain a reduction in body mass index (BMI) up to 2 years postpartum via changes in diet and exercise behavior, with a secondary aim to assess racial differences in these outcomes. Women in the intervention arm participate in ten physical activity group sessions, eight healthy eating classes, and six telephone counseling sessions over a 9-month period. They also receive motivational tools, including a workbook with recipes and exercises, a pedometer, and a sport stroller.

RESULTS

Four hundred fifty women aged > or =18 (mean 30.9), with a BMI > or = 25 kg/m(2) (mean 33.0) at baseline (6 weeks postpartum) were enrolled; 45% of the final sample are black and 53% are white. Baseline characteristics by study arm and by race are presented.

CONCLUSIONS

Our intervention is designed to be disseminated broadly to benefit the public health. Behavior change interventions based on principles of social cognitive theory, stage of readiness, and other models that coincide with a teachable moment, such as the birth of a child, could be important motivators for postpartum weight loss.

Docosahexaenoic acid in red blood cells of women of reproductive age is positively associated with oral contraceptive use and physical activity

Optimal intake of the long-chain n-3 polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA) and proper balance between intake of n-6 PUFA and n-3 PUFA are important for human health. Considerable evidence exists to show that DHA has a marked benefit during pregnancy. Lifestyle factors can affect the biosynthesis of DHA from dietary precursors, incorporation into membranes and degradation. The purpose of this study was to investigate the PUFA composition of red blood cells (RBCs) from women (n=40) in reproductive age, and how it is affected by diet and other lifestyle factors. Of all the lifestyle factors tested oral contraceptive use and physical activity were the ones correlated with DHA in RBCs, after adjustment for DHA intake. The findings indicate that oral contraceptive use and physical activity have a positive impact on the DHA status, as assessed by RBC level, of women in reproductive age.

Cross-sectional study of weight gain and increase in BMI throughout pregnancy

OBJECTIVE

To generate reliable new reference ranges for weight gain and increase in body mass index (BMI) during pregnancy from a large population.

STUDY DESIGN

In a prospective cross-sectional study at the Obstetric outpatient clinic, Zurich University Hospital, weight gain and BMI, before gestation and at the booking visit, were determined in 4034 pregnant women with accurately dateable singleton pregnancies (Caucasian: N = 3242, Asian (predominantly from Sri Lanka, Thailand and the Philippines): N = 578 and Black: N = 214). Women with known insulin-dependent diabetes mellitus before pregnancy were excluded. Fifth, 50th and 95th centiles were presented for Caucasians and corresponding centile curves for Asians and Blacks. Simple and multiple regression analyses were performed for various risk factors. A significance level of P < 0.05 was used in all tests.

RESULTS

Mean weight gain was 15.5+/-5.9 kg (34.2+/-13.0 lb) at term with values >25.4 kg (56.0 lb) and <5.7 kg (12.6 lb) for the 95th and the 5th centile, respectively. Mean BMI increased slightly and steadily to 28 kgm(-2) at term. Parity and pre-pregnancy BMI were significant determinants in Caucasians. Weight gain and BMI was slightly lower in Asians and Blacks.

CONCLUSIONS

BMI centile curves have the advantage in that they consider height during the whole course of pregnancy. It may be an additional helpful tool in controlling weight gain in pregnancy. Further studies are required to determine the prognostic implications of values > or = 95th centile and < or = 5th centile.

Relationship between dietary intake of cod liver oil in early pregnancy and birthweight

OBJECTIVE

To investigate the possible association between birth outcome and marine food and cod liver oil intake of healthy women in early (prior to 15 weeks of gestation) pregnancy.

DESIGN

An observational study.

SETTING

Free-living conditions in a community with traditional fish and cod liver oil consumption.

POPULATION

Four hundred and thirty-five healthy pregnant Icelandic women without antenatal and intrapartum complications.

METHODS

Dietary intake of the women was estimated with a semi-quantitative food frequency questionnaire (FFQ) covering food intake together with lifestyle factors for the previous three months. Questionnaires were filled out at between 11 and 15 weeks and between 34 and 37 weeks of gestation. The estimated intake of marine food and cod liver oil was compared with birthweight by linear and logistic regression controlling for potential confounding.

MAIN OUTCOME MEASURES

Birthweight, cod liver oil intake, lifestyle factors (alcohol, smoking).

RESULTS

Fourteen percent of the study population used liquid cod liver oil in early pregnancy. Regression analysis shows that these women gave birth to heavier babies (P < 0.001), even after adjusting for the length of gestation and other confounding.

CONCLUSIONS

Maternal intake of liquid cod liver oil early in pregnancy was associated with a higher birthweight. Higher birthweight has been associated with a lower risk of diseases later in life and maternal cod liver oil intake might be one of the means for achieving higher birthweight.

Effets maternels et fœtaux d'une prise de poids maternelle excessive au cours de la grossesse dans une population de patientes de poids normal avant la grossesse

OBJECTIVE

To study the effects of increased gestational weight gain in women of normal prepregnant weight.

PATIENTS AND METHODS

We compared 174 patients gaining more than 18 kg to 174 patients gaining between 9 and 15 kg. Body mass index was normal for every woman included in the study.

RESULTS

Weight gain > or =18 kg was associated with increased risk of vascular complications (5.2% vs. 1.1%, P < 0.05) but not with increased risk of mellitus diabetes (5.2% vs. 4.0%, NS). Weight gain > or =18 kg prolonged labor length (414.4 +/- 147 min vs. 376.5 +/- 166.4 min, P < 0.05) and increased the rate of cesarean section (19.5% vs. 10.3%, P < 0.05). Neonatal outcome was similar in both groups, mean birth weight was greater (3413.6 +/- 427.0 g vs. 3163.4 +/- 495.1 g, P < 0.05) and the frequency of infants weighing more than 4000 g at birth was increased (8.0% vs. 4.0%, P < 0.05) among women gaining more than 18 kg.

CONCLUSION

Excess weight gain in pregnancy affects gestational and delivery outcomes and results in higher frequency of fetal macrosomia. These results confirm recommendations on weight gain in pregnancy as guidelines for pregnant women.

Relation between maternal body composition and birth weight

In order to establish the relationship between maternal body composition indicators (fat-free mass, fat mass, total body water) and birth weight, a cross-sectional study was designed, based on 196 pairs of mothers and live singleton newborns with gestational age of 37 weeks or more. Immediately after delivery, the mothers were interviewed to obtain information about different birth weight predictors. An analysis of maternal body composition through bioelectric impedance was held. Multiple linear regression was used to measure the effect of each variable on birth weight. The birth weight mean was 3,251 +/- 514 g. Maternal height was 160.44 +/- 6.3 cm, total net weight gain was 5.85 +/- 5.15 kg, fat mass consisted of 15.84 +/- 6.72 kg, and fat-free mass was 50.42 +/- 7.65 kg; total body water was 34.82 +/- 5.61 liters. The model which included total body water and all predictors found to be associated with birth weight in the bivariate analysis (maternal age, gestational age, gender, placenta weight, and placenta weight squared) was found to be the best in explaining the variability of birth weight (R(2) = 45.26%). Fat mass was an important predictor only in the subgroup of women within the low tertile of body mass index. In conclusion, fat-free mass and total body water explained a major proportion of the variability of birth weight in comparison with the mother's weight gain during the pregnancy period, which has already been considered an important predictor of birth weight.

Association of birth weight and breast-feeding with coronary heart disease risk factors at the age of 6 years

BACKGROUND AND AIM

It has been shown that early growth and nutrition affect health in childhood and later life. The aim of this study was to assess the association of birth weight and breast-feeding in infancy with body mass index (BMI) and serum lipids at the age of six years. The contributions of current macronutrient intake, maternal age and BMI were assessed.

METHODS AND RESULTS

This was a longitudinal observational study of 120 randomly chosen children whose birth weight and duration of breast-feeding had been recorded. At the age of six years, their weight and height, and serum cholesterol (total, LDL and HDL) and triglyceride levels were measured at healthcare centres in Iceland. Dietary intake at six years was estimated using 3-day weighed food records. The duration of breast-feeding negatively correlated with BMI in 6-year-old boys (B = -0.19 +/- 0.07, p = 0.011) but not in girls; after adjusting for maternal BMI, the relationship in boys was of borderline significance (p = 0.087). The 6-year-old boys who had been breast-fed for < 6 months had a significantly higher BMI (18.0 +/- 2.5 kg/m2) than those breast-fed for 8-9 months (15.8 +/- 1.2 kg/m2, p = 0.006) or > or = 10 months (15.7 +/- 1.2 kg/m2, p = 0.005). A longer duration of breast-feeding was related to higher HDL-cholesterol levels in 6-year-old girls (B = 0.03 +/- 0.01, p = 0.032), but not boys. Birth weight was not related to BMI or serum lipid levels at the age of 6 years.

CONCLUSION

In this high birth weight population, a longer duration of breast-feeding may be effective in preventing childhood overweight, at least among boys. Breast-feeding also seems to be related to an improved lipid profile in girls.

Relationships between cigarette smoking during pregnancy, gestational age, maternal weight gain, and infant birthweight

OBJECTIVE

To estimate the effect of smoking on infant birthweight independent of gestational age and maternal weight gain during pregnancy.

METHODS

Stepwise regression was used to identify sets of maternal and infant characteristics not modified by prenatal smoking that were predictors of infant birthweight, gestational age, and net maternal weight gain. These were then included in regression analyses to assess the effects of smoking, as measured by cigarette consumption, exhaled carbon monoxide, or urinary cotinine on gestational age, net maternal weight gain, and infant birthweight.

RESULTS

After adjustment for nonmodifiable factors, smoking accounted for 1.5-3.1% of the variance in gestational age at delivery. It accounted for 5.3-7.7% of the variance in net maternal weight gain after adjustment for nonmodifiable factors and gestational age. After adjustment for gestational age and net maternal weight gain, and the nonmodifiable factors, smoking accounted for 2.7-5.2% of the variance in infant birthweight.

CONCLUSIONS

Most of the gain in infant birthweight on quitting smoking is due to the independent effect of smoking on fetal growth restriction, with much smaller gains related to increased maternal weight gain and a slightly longer gestational age.

Relationship between size at birth and hypertension in a genetically homogeneous population of high birth weight

OBJECTIVE

To investigate the association between birth size and hypertension within a genetically homogeneous population of high birth weight.

DESIGN

Cohort-study with retrospectively collected data on size at birth.

SUBJECTS AND SETTING

The study included 4601 men and women born 1914-1935 in Reykjavik, Iceland, who participated in the Reykjavik Study of the Icelandic Heart Association.

MAIN OUTCOME MEASURES

Birth size measurements, adult blood pressure (BP) and body mass index (BMI), and family history of hypertension.

RESULTS

Birth weight was inversely related to hypertension in adulthood in women (P for trend < 0.001). The relationship was of borderline significance in men (P for trend = 0.051). A low ponderal index was significantly associated with high BP in women (P for trend = 0.025) but not men (P > 0.05). For women with an adult BMI > 26 kg/m2, the odds ratio for hypertension for those born weighing < 3.45 kg was 2.1 [95% confidence interval, 1.3-3.3, compared with women born weighing > 3.75 kg. The association was only significant in women without a family history of hypertension.

CONCLUSIONS

An inverse association between size at birth and adult hypertension was seen in a population of greater birth size than has previously been investigated. The relation was strongest among women born small who were overweight in adulthood, and for those without a family history of hypertension. The results support the hypothesis that the association between birth weight and hypertension is not of genetic origin only. The large birth size of Icelanders might be protective and partly explain the lower mean systolic blood pressure in Iceland than in related nations.

Effect of maternal weight gain on infant birth weight

OBJECTIVE

To ascertain whether increased weight gain during pregnancy resulted in higher birth weight infants.

METHODS

A database was constructed from valid data of a sample of 159 healthy women between 19 to 37 years of age. The inclusion criteria were: maternal age of 19-37 years, term gestations (37-42 weeks), a baseline weight obtained at 0-15 weeks gestation, and a final weight obtained within 2 weeks of delivery. Weight gain was calculated by subtracting baseline weight from the final weight. A documented height enabled calculation of BMI. A negative screen for gestational diabetes was required.

RESULTS

Women with lower first trimester BMI (< 25) had infants of lower birth weight than women of higher BMI (> 25). Women with lower gain (< 35 lbs) delivered smaller infants than women with higher gain (> 35 lbs). Women of higher BMI and higher gain delivered the largest infants (F = 5.37; p = 0.0015). Underweight women (BMI < 19) gained less weight than women of normal weight (BMI 19-25), who gained the most weight. Obese women (BMI > 29) gained the least weight (F = 6.26; p = 0.0005).

CONCLUSION

The results confirmed that excessive maternal weight gain in pregnancy (> 35 lbs), does result in higher birth weight infants.