Search Results

Methods: Empirical, English-language articles examining the effects of economic change at either the aggregate or individual level on birthweight, length of gestation, neonatal mortality and the secondary sex ratio were identified using PubMed and ISI Web of Knowledge. Studies were organized by level of analysis and birth outcome and evaluated for internal and external validity.

Results: One individual-level study reported a strong association between individual shift to inadequate employment and decreased birthweight. Of seven aggregate-level studies on birthweight, five exhibited moderate to strong validity but reported inconsistent findings. Similarly, findings from five studies (four with moderate to strong validity) examining rates of neonatal mortality reported inconsistent findings. Three of four moderate to strong studies reported a reduced secondary sex ratio following economic contraction.

Conclusions: Associations between economic contraction and birthweight, neonatal mortality and the secondary sex ratio remain speculative. Consensus on methodology is needed to compare findings across studies. Further research on economic contraction and the secondary sex ratio, as well as individual-level birthweight and length of gestation, is warranted.

Methods: Data on health behaviors among 7,074 pregnancies in the National Longitudinal Survey of Youth 1979 were linked to monthly unemployment rates in maternal state of residence. The study examined associations between exposure to unexpected economic contraction (higher than expected state-level unemployment) during each trimester of pregnancy and maternal smoking, alcohol use, and gestational weight gain using generalized linear models.

Results: Economic contraction was not associated with maternal smoking or gestational weight gain. Associations between economic contraction and maternal alcohol use differed by maternal race/ethnicity and education. Among Black/non-Hispanic women, exposure to economic contraction during the first and second trimester of pregnancy were associated with a 42% (95% CI: 1.08, 1.85) and 33% (95% CI: 1.01, 1.74) increased risk of alcohol use, respectively.

Conclusions: Findings suggest that exposure to extreme economic contraction during pregnancy may be associated with increased use of alcohol with differences by maternal race/ethnicity and educational attainment. Economic contraction was not associated with other maternal pregnancy behaviors.

Methods. I examined the association between maternal exposure to state-level labor market perturbations during each trimester of gestation and fetal growth, as measured by birth weight for gestational age percentile. The study population included 6,715 gestations and births between 1982 and 2000 to women enrolled in the National Longitudinal Survey of Youth 1979 (NLSY79). I calculated birth weight for gestational age percentiles using national reference data and categorized births <10th percentile as small for gestational age (SGA).

I defined perturbations to labor market security as months in which the state unemployment rate was higher than its statistically expected value (i.e., unexpectedly high labor market insecurity) and months in which the state unemployment rate was lower than its statistically expected value (i.e., unexpectedly high security). I derived statistically expected values using ARIMA modeling me thods to account for autocorrelation. Gestations in the NLSY79 were classified as either exposed or unexposed to labor market insecurity or security in the first, second, and third trimester if one of these labor market perturbations occurred in the maternal state of residence during that trimester.

I used linear and logistic regression models to examine the association between labor market perturbations in each trimester and birth weight percentile and odds of SGA. I also examined whether any observed associations differed by maternal race/ethnicity, childhood socioeconomic status, educational attainment, marital status, employment status, or poverty status. Finally, I explored whether any observed associations were mediated by individual economic change (i.e., changes in maternal employment status or household income) or maternal pregnancy behaviors (i.e., smoking, first trimester utilization of prenatal care, or net gestational weight gain). If associations were mediated by one these factors, I calculated the proportion of the total association explained by that factor.

Results. Exposure to labor market insecurity in the first trimester was significantly associated with a decrease in birth weight for gestational age of 4.05 percentile points (95% CI = -6.87, -1.22) and higher odds of SGA (OR = 1.50, 95% CI = 1.21, 1.86). Exposure to labor market insecurity in the second and third trimesters was not significantly associated with either outcome. Exposure to labor market security was not associated with birth weight for gestational age percentile or SGA.

The association between exposure to labor market insecurity in the first trimester and birth weight percentile differed significantly by maternal childhood SES, educational attainment, and employment status but not by race/ethnicity, marital status, or poverty status. Exposure to labor market insecurity in the first trimester was associated with decreases in birth weight percentile of 5.52 (95% CI = -10. 0, -1.04) and 8.66 points (95% CI = -14.04, -3.29) among women with average or high childhood SES, respectively, while the association was not significant among women with low childhood SES. Exposure to labor market insecurity in the first trimester was associated with a decrease in birth weight percentile of 9.22 points (95% CI = -15.77, -2.88) among women with <12 years educational attainment, while the association was not significant among women with 12 years or >12 years educational attainment. Exposure to labor market insecurity was associated with a decrease in birth weight percentile of 7.10 points (95% CI = -12.33, -1.87) and 10.27 points (95% CI = (-18.82, -1.71) among women keeping house and out of the labor force, respectively, while the association was not significant among employed and unemployed women.

My exploration of mediation by individual economic change and maternal pregnancy behaviors found that approximately 11% of the association between exposure to labor market insecurity in the first trimester and birth weight percentile was explained by net maternal gestational weight gain. The association also differed significantly by maternal smoking, with the association only significant among smokers. No other individual economic change or maternal pregnancy behaviors mediated greater than one percent of the association.

Conclusions. Findings support my hypothesis that fetal growth responds to a contemporary ecological perturbation, i.e., unexpectedly high labor market insecurity. Exposure to this perturbation appears to have more impact on fetal growth if it occurs in the first trimester of gestation. The finding that associations between exposure to labor market insecurity and birth weight percentile were stronger among women with high childhood SES, <12 years education, and those keeping house or out of the labor force suggests that these women may be more vulnerable to economic perturbations. Although further research on mediation is needed , initial findings suggest that maternal gestational weight gain may represent one pathway through which economic perturbations affect fetal growth.

Methods: We used a multilevel design to examine associations between exposure to state-level unexpected economic contraction during each trimester of gestation and birth weight for gestational age percentile and small for gestational age (SGA), using the National Longitudinal Survey of Youth 1979. We examined differences in observed associations by maternal educational attainment, race/ethnicity, employment status, and poverty status.

Results: Exposure in the first trimester was associated with a 3.7 percentile point decrease in birth weight for gestational age (95% confidence interval [CI] = −6.8 to −0.6). This association appeared stronger for women “keeping house” or with <12 years education. Exposure in the first trimester was also associated with increased odds of SGA (odds ratio = 1.5 [95% CI = 1.1 to 2.1]) and term SGA (odds ratio = 1.6 [95% CI = 1.2 to 2.3]).

Conclusions: Unexpected economic contraction during early pregnancy may be associated with reduced fetal growth.

STUDY DESIGN: We estimated associations between GWG (continuous and within categories defined by the Institute of Medicine), maternal prepregnancy body mass index, and each outcome in 4496 births in the National Longitudinal Survey of Youth 1979, which was a prospective cohort.

RESULTS: GWG (kilograms) was associated with decreased risk of SGA and increased risk of LGA, cesarean delivery, postpartum weight retention, and child overweight independent of maternal demographic and pregnancy characteristics. Gain above the Institute of Medicine guidelines was associated with decreased risk of SGA and increased risk of all other outcomes.

CONCLUSION: Excessive gain may have long-term consequences for maternal and child body size, but the benefits of lower gain must be balanced against risk of SGA. Copyright © 2010 Mosby, Inc. All rights reserved.