The timing of maternal weight gain during pregnancy and fetal growth

Inadequate maternal weight gain in the third trimester increases the risk of intrauterine growth restriction in rural Bangladesh

OBJECTIVE

To estimate the effect of inadequate maternal weight gain in the third trimester on the risk of intrauterine growth restriction (IUGR) in rural Bangladesh.

METHODS

This study analyzed data from 1,463 mother-infant pairs in Matlab, Bangladesh which were available through the electronic databases of Matlab Health and Demographic Surveillance System and Matlab hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b). All the mothers were admitted to Matlab hospital for childbirth from January 2012 to December 2014, and they had singleton live births at term. Third-trimester weight gain (kg) was calculated by subtracting the estimated weight at the end of the second trimester from the weight taken before childbirth. Inadequate third-trimester weight gain was defined as 4 kg or less irrespective of pre-gravid nutritional status. IUGR was defined as a birth weight below 2500 g in full-term newborns (LBW-Term), and a birth weight for gestational age and infant sex less than the 10th percentile (SGA-10th) and 2 standard deviations below the mean birth weight (SGA-2SD) based on the international newborn standards from the INTERGROWTH-21st project. Multivariable logistic regression models were fitted to determine the independent effect of inadequate weight gain in the third trimester on the risk of IUGR.

RESULTS

A total of 824 (56.3%) women experienced inadequate weight gain in the third trimester of pregnancy. In this study, 215 (14.7%), 573 (39.2%) and 220 (15.0%) infants were born as LBW-Term, SGA-10th and SGA-2SD, respectively. In the multivariable logistic regression models, compared to adequate weight gain in the third-trimester, the odds ratios (OR) for LBW-Term, SGA-10th and SGA-2SD for inadequate weight gain were 1.8 (95% CI: 1.3, 2.5; p < 0.001), 1.4 (95% CI: 1.1, 1.8; p = 0.002) and 1.8 (95% CI: 1.3, 2.4; p = 0.001), respectively.

CONCLUSIONS

Both inadequate third-trimester weight gain and IUGR are prevailing public health concerns in rural Bangladesh. Inadequate weight gain in the third trimester substantially increased the risk of IUGR. Public health programs focusing on the promotion of adequate weight gain in the third trimester of pregnancy with an ultimate aim to decrease IUGR should be implemented.

Timing of Gestational Weight Gain on Fetal Growth and Infant Size at Birth in Vietnam

OBJECTIVE

To examine the importance of timing of gestational weight gain during three time periods: 1: ≤ 20 weeks gestation), 2: 21-29 weeks) and 3: ≥ 30 weeks) on fetal growth and infant birth size.

METHODS

Study uses secondary data from the PRECONCEPT randomized controlled trial in Thai Nguyen province, Vietnam (n = 1436). Prospective data were collected on women starting pre-pregnancy through delivery. Maternal conditional weight gain (CWG) was defined as window-specific weight gains, uncorrelated with pre-pregnancy body mass index and all prior body weights. Fetal biometry, was assessed by ultrasound measurements of head and abdomen circumferences, biparietal diameter, and femoral length throughout pregnancy. Birth size outcomes included weight and length, and head, abdomen and mid upper arm circumferences as well as small for gestational age (SGA). Adjusted generalized linear and logistic models were used to examine associations.

RESULTS

Overall, three-quarters of women gained below the Institute of Medicine guidelines, and these women were 2.5 times more likely to give birth to a SGA infant. Maternal CWG in the first window (≤ 20 weeks), followed by 21-29 weeks, had the greatest association on all parameters of fetal growth (except abdomen circumference) and infant size at birth. For birth weight, a 1 SD increase CWG in the first 20 weeks had 3 times the influence compared to later CWG (≥ 30 weeks) (111 g vs. 39 g) and was associated with a 43% reduction in SGA risk (OR (95% CI): 0.57 (0.46-0.70).

CONCLUSION

There is a need to target women before or early in pregnancy to ensure adequate nutrition to maximize impact on fetal growth and birth size.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01665378.

Ultrasound measurement of fetal size in rural Guatemala

OBJECTIVES

To describe the fetal growth pattern of a population from rural Guatemala and determine when during gestation growth faltering becomes evident.

METHODS

Ultrasound examinations were conducted for 319 women. Femur length (FL), biparietal diameter (BPD), abdominal (AC) and head circumference (HC) were compared with reference values.

RESULTS

FL and AC were similar to reference values throughout gestation. BPD and HC were below the 50th percentile by 30 weeks' gestation and below the 10th percentile later in gestation. We expected all four dimensions to show marked growth restriction during gestation. Measurement differences may explain the results but would call into question the value of cross-study comparisons. Infants born small for gestational age were small in all measures as early as 15 weeks.

CONCLUSIONS

Fetal growth faltering begins in early gestation among infants who were born small. The lack of deviation from reference data for FL and AC requires further clarification.

Associations of Early and Late Gestational Weight Gain with Infant Birth Size

OBJECTIVES

Associations of gestational weight gain (GWG) during specific periods of pregnancy with infant birth size have been inconsistent. Infant sex-specific differences in these associations are unknown

METHODS

Information on GWG (kg) [total, early (<20 weeks gestation), and late (≥20 weeks gestation)] and indices of infant birth size including birthweight (BW), ponderal index (PI), crown-heel length (CHL), and head circumference (HC) was collected from 3,621 pregnant women. We calculated adjusted mean differences and 95 % confidence intervals (CIs) relating total, early and late GWG to infant birth size using multivariable linear regression procedures. We used stratified analyses and interaction terms to test whether associations differed by infant sex.

RESULTS

One-kg increases in total, early or late GWG were associated with BW increases of 17.2 g (95 % CI 13.8-18.9), 14.1 g (95 % CI 10.3-18.0), and 21.0 g (95 % CI 16.7-25.4), respectively. Early GWG-BW and late GWG-BW associations were different (p = 0.026). Sex-stratified total GWG-BW associations were similar to overall results. There were sex-specific differences in early GWG-BW and late GWG-BW associations. Among females, early GWG-BW (12.0 g, 95 % CI 6.7-17.2) and late GWG-BW (24.2 g, 95 % CI 18.2-30.3) associations differed (p = 0.0042); the corresponding associations did not differ among males. Total, early, and late GWG were associated with CHL and HC, but not with PI. Associations did not differ for early or late GWG.

CONCLUSIONS FOR PRACTICE

For comparable GWG, late-GWG-related BW increase is greater than early-GWG-related BW increase, particularly among female infants.

The Pattern of Gestational Weight Gain is Associated with Changes in Maternal Body Composition and Neonatal Size

OBJECTIVES

The pattern of gestational weight gain (GWG) reflects general nutrient availability to support growing fetal and maternal compartments and may contribute to later health, but how it relates to changes in maternal body composition is unknown. We evaluated how the pattern of GWG related to changes in maternal body composition during pregnancy and infant size at birth.

METHODS

A prospective, multi-ethnic cohort of 156 pregnant women and their infants was studied in New York City. Prenatal weights were used to estimate total and rate (kg/week) of GWG by trimester. Linear regression models evaluated the association between trimester-specific GWG group (low, medium, high GWG) [total (low ≤25, high ≥75 percentile) or rate (defined by tertiles)] and infant weight, length and maternal body composition changes from 14 to 37 weeks, adjusting for covariates.

RESULTS

Compared to the low gain group, medium/high rate of GWG in the second trimester and high rate of GWG in the third trimester were associated with larger gains in maternal fat mass (β range for fat Δ = 2.86-5.29 kg, all p < 0.01). For infant outcomes, high rate of GWG in the second trimester was associated with higher birth weight (β = 356 g, p = 0.001) and length (β = 0.85 cm, p = 0.002). First and third trimester GWG were not associated with neonatal size.

CONCLUSIONS

The trimester specific pattern and rate of GWG reflect changes in maternal body fat and body water, and are associated with neonatal size, which supports the importance of monitoring trimester-specific GWG.

Patterns of body composition among HIV-infected, pregnant Malawians and the effects of famine season

We describe change in weight, midupper arm circumference (MUAC), arm muscle area (AMA) and arm fat area (AFA) in 1130 pregnant HIV-infected women with CD4 counts > 200 as part of the BAN Study ( www.thebanstudy.org ), a randomized, controlled clinical trial to evaluate antiretroviral and nutrition interventions to reduce mother-to-child transmission of HIV during breast feeding. In a longitudinal analysis, we found a linear increase in weight with a mean rate of weight gain of 0.27 kgs/week, from baseline (12 to 30 weeks gestation) until the last follow-up visit (32-38 weeks). Analysis of weight gain showed that 17.1% of the intervals between visits resulted in a weight loss. In unadjusted models, MUAC and AMA increased and AFA declined during late pregnancy. Based on multivariable regression analysis, exposure to the famine season resulted in larger losses in AMA [-0.08, 95% CI -0.14, -0.02; p = 0.01] while AFA losses occurred irrespective of season [-0.55, 95%: -0.95, -0.14, p = 0.01]. CD4 was associated with AFA [0.21, 95% CI 0.01, 0.41, p = .04]. Age was positively associated with MUAC and AMA. Wealth was positively associated with MUAC, AFA, and weight. While patterns of anthropometric measures among HIV-infected, pregnant women were found to be similar to those reported for uninfected women in sub-Saharan Africa, effects of the famine season among undernourished, Malawian women are of concern. Strategies to optimize nutrition during pregnancy for these women appear warranted.

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.

Rate and pattern of weight gain in Indian women from the upper income group during pregnancy and its effect on pregnancy outcome

Maternal weight gain and pattern of weight gain during pregnancy influence the ultimate outcome of pregnancy. Pregravid body mass index (BMI), maternal dietary intake, maternal height and age all determine the weight gain during pregnancy. The study was taken up with an objective to observe maternal weight gain and its pattern in pregnancy in women from an upper income group and to find out their association with pregnancy outcome. 180 normal primiparous pregnant Indian women (20-35 years) from an upper income group were recruited between the 10th and 14th weeks of pregnancy and were followed up throughout their pregnancy to record total and trimester-wise weight gain. Neonatal birth weights were recorded. The results showed that mothers with high pregravid BMI gained more weight during pregnancy than the recommended weight gain; in addition, weight gain in the first trimester was significantly correlated with birth weight of the neonates (P = 0.019). Significant correlation was found between weight gain in the third trimester and birth weight of the neonate irrespective of maternal BMI. The rate of weight gain was significantly correlated with neonatal birth weights irrespective of maternal pregravid BMI (P = 0.022) and as per its categories (P = 0.027). Thus, overall it can be concluded that adequate maternal nutrition before and during pregnancy is important for adequate weight gain by the mother and can result in better outcome of pregnancy. The rate of weight gain is also an important contributing factor.

Low preconception body mass index is associated with birth outcome in a prospective cohort of Chinese women

Low maternal prepregnancy BMI is associated with adverse birth outcomes, but the BMI at which risk increases is not well defined. We assessed whether the relationship between prepregnancy BMI and birth outcomes is influenced by the extent to which mothers were underweight in a prospective study in Anhui, China. The women (n = 575) were 20-34 y old, married, nulliparous and nonsmokers. All measures of infant growth increased with increasing maternal BMI until a plateau was reached at a BMI of 22-23 kg/m2. Infants born to the 27% of women who were severely underweight before pregnancy (BMI < or = 18.5 kg/m2) were at increased risk for fetal growth deficits associated with infant morbidity. Compared with a normal BMI, being severely underweight was associated with mean (+/- SEM) reductions of 219 +/- 40 g in infant birthweight and 6.7 +/- 1.3% in the birthweight ratio and an 80% increase in risk of intrauterine growth restriction [odds ratio (OR) 1.8; 95% CI: 1.0, 3.3; P = 0.05]. Being severely underweight was also associated with smaller infant head circumference and lower ponderal index. Being moderately underweight (18.5 < BMI < 19.8 kg/m2) was not significantly associated with adverse pregnancy outcomes. Gestational age and risk of preterm birth were not associated with maternal BMI. More than half of the women in this study were underweight before pregnancy. Although being moderately underweight was not associated with increased risk of adverse pregnancy outcomes, being severely underweight was an important risk factor for reduced fetal growth.

Changes in maternal weight from the first to second trimester of pregnancy are associated with fetal growth and infant length at birth

BACKGROUND

Despite our knowledge of the negative consequences of stunting during early childhood and the important role that maternal nutritional status plays in the development of intrauterine growth retardation, we do not know the extent to which maternal nutritional status influences the growth in length of the fetus or whether a sensitive period for fetal linear growth exists during gestation.

OBJECTIVE

Our objective was to explore the relation between maternal weight gain during different stages of pregnancy and linear growth of the fetus.

DESIGN

Ultrasound examinations were conducted at 15-24 (x: 17.5) and 28-32 (x: 29.9) wk of gestation in 200 women from 4 rural Guatemalan villages. The associations between maternal weight gain from approximately 10 to 20 and 20 to 30 wk of pregnancy (from the first to the second and from the second to the third trimester, respectively) and fetal linear growth were tested with the use of ordinary least-squares regression.

RESULTS

Maternal weight gain from the first to the second trimester was associated with fetal femur and tibia lengths measured at both means of 17 and 30 wk (P < 0.05) and infant length at birth (P < 0.001). Weight gain from the second to the third trimester of pregnancy did not predict fetal linear growth or infant length at birth.

CONCLUSIONS

Maternal weight change from the first to the second trimester of pregnancy is strongly associated with fetal growth. Mid-gestation may be a sensitive period for fetal linear growth.

Ponderal index is a poor predictor of in utero growth retardation

OBJECTIVE

To evaluate the usefulness of ponderal index (PI) and related indices of weight and length in identifying asymmetric growth, body thinness and organ asymmetry associated with IUGR.

DESIGN

Cross sectional study.

SETTING

Aberdeen Maternity Hospital.

POPULATION

The population includes term (>/=37 weeks) singleton live births (n= 53,934) between 1986 and 1996, ultrasound measurements in 2522 pregnancies, 712 unselected term pregnancies in 1979/1980 and stillbirths (24-36 weeks) between 1986 and 1995 where the fetus was diagnosed as suffering from acute (n= 73) or chronic (n= 30) anoxic death.

METHODS

The strength of association between direct measures of IUGR and various indices of weight and length was determined by linear and multiple stepwise linear regression.

MAIN OUTCOME MEASURES

Weight, length, PI and skinfold thicknesses (triceps, biceps, flank thighs, back) were measured at birth. Abdominal circumference, biparietal diameter and femur length were measured by ultrasound at >/=37 weeks. Ratio of liver, heart and kidney to brain were measured in stillbirths.

RESULTS

Weight alone was a better predictor of skinfold thickness, abdominal circumference and the ratio of abdominal circumference to biparietal diameter than weight divided by length raised to the power 1, 2, 3 (PI), 4 or 5. The inclusion of gestational age made little difference to the predictive ability of weight for these full term births. Weight, but not PI, was significantly different between the two groups of stillborn fetuses (chronic and acute), which had significantly different (P < 0.001) organ ratios.

CONCLUSION

Body weight alone was a better predictor of anthropometric ratios, organ asymmetry and measures of thinness at birth thought to be associated with IUGR than the PI. The inclusion of a length term generally reduced the predictive ability with the highest powers resulting in the poorest prediction.

Timing is everything: a reconsideration of fetal growth velocity patterns identifies the importance of individual and sex differences

Fetal growth has been posited to follow a "timing hypothesis" sequence in which the second trimester favors a single growth velocity peak in body length and the third trimester accommodates a single growth velocity peak in weight accrual. To our knowledge, this proposition has never been tested with high-frequency longitudinal ultrasound data from normally growing human fetuses. The present study examined whether fetal growth in leg length had its peak velocity at or about 20-26 gestational weeks and declined subsequently and whether estimated fetal weight velocity was maximal at or about 33 weeks and declined subsequently; if the greatest acquisition of leg length occurred in the second trimester and weight in the third trimester; and if birth outcomes reflected these relationships. The data in this study included approximately weekly longitudinal ultrasound data collected from 44 maternal/fetal pairs in Brussels, Belgium. Diaphyseal lengths of the femur and tibia provided information on leg growth and estimated fetal weight was assessed from the biparietal and occipital-frontal head diameters and transverse and anterior-posterior diameters of the abdomen. Growth patterns were investigated from individual growth curves derived from daily growth velocity z-scores. Paired t-tests compared individuals' trimestral increments in leg length and fetal weight. Least-squares regression models employing the robust procedure for repeated measurements were used to test for relationships between trimester, size, growth rates, and birth outcome, controlling for day of measurement, sex, maternal smoking, and gestational age at birth. The normal fetuses in this study grew by pulsatile patterns of leg and estimated weight acquisition, not a single peak and decline process. Greater incremental growth in estimated fetal weight occurred during the second trimester and leg length in the third trimester. Individual and sex effects were significant in growth velocity patterns. Girls grew with greater synchrony between leg and weight growth and were accelerated by comparison with boys, with faster leg growth predicting lower ponderal index by the second trimester. Birth outcomes were sex-specific in timing effects and predictive variables. These results support the importance of sex-specific analyses, reemphasize the common notion that girls grow faster than boys, and direct attention to cross-talk between energy resources and growth.

Effect of multivitamin and vitamin A supplements on weight gain during pregnancy among HIV-1-infected women

BACKGROUND

The pattern of weight gain during pregnancy among HIV-infected women is largely unknown. Multivitamin supplementation was shown to be effective in preventing adverse pregnancy outcomes among HIV-positive women. These protective effects could be mediated in part by an improvement in the pattern of gestational weight gain.

OBJECTIVE

We examined the effects of multivitamin and vitamin A supplements on weight gain during the second and third trimesters of pregnancy among HIV-infected women.

DESIGN

We enrolled 1075 pregnant, HIV-1-positive women from Dar es Salaam, Tanzania, in a randomized, placebo-controlled trial. Using a 2-by-2 factorial design, we assigned each woman to 1 of 4 regimens: multivitamins (thiamine, riboflavin, niacin, folic acid, and vitamins B-6, B-12, C, and E), vitamin A, multivitamins including vitamin A, or placebo. The women took these oral supplements daily and were weighed monthly until the end of pregnancy.

RESULTS

The mean rate of weight gain was 306 g/wk during the second trimester and 247 g/wk during the third trimester. During the third trimester, average weight gain was significantly greater (by 304 g; 95% CI: 17, 590; P = 0.04) and the risk of low rate of weight gain (<or= 100 g/wk) was significantly lower (relative risk: 0.73; 95% CI: 0.58, 0.93) in women who received multivitamins than in women who did not. Multivitamins including vitamin A were protective against low weight gain during the second trimester compared with multivitamins alone.

CONCLUSION

Multivitamin supplementation during pregnancy improves the pattern of weight gain among HIV-infected women.