Bibliography Tag: gestational length

Haas et al., 2015

Haas, D. M., Parker, C. B., Wing, D. A., Parry, S., Grobman, W. A., Mercer, B. M., Simhan, H. N., Hoffman, M. K., Silver, R. M., Wadhwa, P., Iams, J. D., Koch, M. A., Caritis, S. N., Wapner, R. J., Esplin, M. S., Elovitz, M. A., Foroud, T., Peaceman, A. M., Saade, G. R., Willinger, M., Reddy, U. M., & NuMo, M. b study; “A description of the methods of the Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be (nuMoM2b);” American Journal of Obstetrics & Gynecology, 2015, 212(4), 539 e531-539 e524; DOI: 10.1016/j.ajog.2015.01.019.


OBJECTIVE: The primary aim of the “Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be” is to determine maternal characteristics, which include genetic, physiologic response to pregnancy, and environmental factors that predict adverse pregnancy outcomes.

STUDY DESIGN: Nulliparous women in the first trimester of pregnancy were recruited into an observational cohort study. Participants were seen at 3 study visits during pregnancy and again at delivery. We collected data from in-clinic interviews, take-home surveys, clinical measurements, ultrasound studies, and chart abstractions. Maternal biospecimens (serum, plasma, urine, cervicovaginal fluid) at antepartum study visits and delivery specimens (placenta, umbilical cord, cord blood) were collected, processed, and stored. The primary outcome of the study was defined as pregnancy ending at <37+0 weeks’ gestation. Key study hypotheses involve adverse pregnancy outcomes of spontaneous preterm birth, preeclampsia, and fetal growth restriction.

RESULTS: We recruited 10,037 women to the study. Basic characteristics of the cohort at screening are reported.

CONCLUSION: The “Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be” cohort study methods and procedures can help investigators when they plan future projects.


Donahue et al., 2010

Donahue, S. M., Kleinman, K. P., Gillman, M. W., & Oken, E., “Trends in birth weight and gestational length among singleton term births in the United States: 1990-2005,” Obstetrics and Gynecology, 2010, 115(2 Pt 1), 357-364. DOI: 10.1097/AOG.0b013e3181cbd5f5.


OBJECTIVE: To estimate changes over time in birth weight for gestational age and in gestational length among term singleton neonates born from 1990 to 2005.

METHODS: We used data from the U.S. National Center for Health Statistics for 36,827,828 singleton neonates born at 37-41 weeks of gestation, 1990-2005. We examined trends in birth weight, birth weight for gestational age, large and small for gestational age, and gestational length in the overall population and in a low-risk subgroup defined by maternal age, race or ethnicity, education, marital status, smoking, gestational weight gain, delivery route, and obstetric care characteristics.

RESULTS: In 2005, compared with 1990, we observed decreases in birth weight (-52 g in the overall population, -79 g in a homogenous low-risk subgroup) and large for gestational age birth (-1.4% overall, -2.2% in the homogenous subgroup) that were steeper after 1999 and persisted in regression analyses adjusted for maternal and neonate characteristics, gestational length, cesarean delivery, and induction of labor. Decreases in mean gestational length (-0.34 weeks overall) were similar regardless of route of delivery or induction of labor.

CONCLUSION: Recent decreases in fetal growth among U.S., term, singleton neonates were not explained by trends in maternal and neonatal characteristics, changes in obstetric practices, or concurrent decreases in gestational length.



Catov et al., 2016

Catov, J. M., Lee, M., Roberts, J. M., Xu, J., & Simhan, H. N., “Race Disparities and Decreasing Birth Weight: Are All Babies Getting Smaller?,” American Journal of Epidemiology, 2016, 183(1), 15-23. DOI: 10.1093/aje/kwv194.


The mean infant birth weight in the United States increased for decades, but it might now be decreasing. Given race disparities in fetal growth, we explored race-specific trends in birth weight at Magee-Womens Hospital, Pittsburgh, Pennsylvania, from 1997 to 2011. Among singleton births delivered at 37-41 weeks (n = 70,607), we evaluated the proportions who were small for gestational age and large for gestational age and changes in mean birth weights over time. Results were stratified by maternal race/ethnicity. Since 1997, the number of infants born small for their gestational ages increased (8.7%-9.9%), whereas the number born large for their gestational ages decreased (8.9%-7.7%). After adjustment for gestational week at birth, maternal characteristics, and pregnancy conditions, birth weight decreased by 2.20 g per year (P < 0.0001). Decreases were greater for spontaneous births. Reductions were significantly greater in infants born to African-American women than in those born to white women (-3.78 vs. -1.88 per year; P for interaction = 0.010). Quantile regression models indicated that birth weight decreased across the entire distribution, but reductions among infants born to African-American women were limited to those in the upper quartile after accounting for maternal factors. Limiting the analysis to low-risk women eliminated birth weight reductions. Birth weight has decreased in recent years, and reductions were greater in infants born to African-American women. These trends might be explained by accumulation of risk factors such as hypertension and prepregnancy obesity that disproportionately affect African-American women. Our results raise the possibility of worsening race disparities in fetal growth. FULL TEXT

Eskenazi et al., 2004

Brenda Eskenazi, Kim Harley, Asa Bradman, Erin Weltzien, Nicholas P. Jewell, Dana B. Barr, Clement E. Furlong, and Nina T. Holland, “Association of in Utero Organophosphate Pesticide Exposure and Fetal Growth and Length of Gestation in an Agricultural Population,” Environmental Health Perspecitives, 112:10, 2004, DOI: 10.1289/ehp.6789


Although pesticide use is widespread, little is known about potential adverse health effects of in utero exposure. We investigated the effects of  organophosphate pesticide exposure during pregnancy on fetal growth and gestational duration in a cohort of low-income, Latina women living in an agricultural community in the Salinas Valley, California. We measured nonspecific metabolites of organophosphate pesticides (dimethyl and diethyl phosphates) and metabolites specific to malathion (malathion dicarboxylic acid), chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridinyl) phosphoro-thioate], and parathion (4-nitrophenol) in maternal urine collected twice during pregnancy. We also measured levels of cholinesterase in whole blood and butyryl cholinesterase in plasma in maternal and umbilical cord blood. We failed to demonstrate an adverse relationship between fetal growth and any measure of in utero organophosphate pesticide exposure. In fact, we found increases in body length and head circumference associated with some exposure measures.
However, we did find decreases in gestational duration associated with two measures of in utero pesticide exposure: urinary dimethyl phosphate metabolites [βadjusted = –0.41 weeks per log10 unit increase; 95% confidence interval (CI), –0.75––0.02; p = 0.02], which reflect exposure to dimethyl organophosphate compounds such as malathion, and umbilical cord cholinesterase (βadjusted = 0.34 weeks per unit increase; 95% CI, 0.13–0.55; p = 0.001). Shortened gestational duration was most clearly related to increasing exposure levels in the latter part of pregnancy. These associations with gestational age may be biologically plausible given that organophosphate pesticides depress cholinesterase and acetylcholine stimulates contraction of the uterus. However, despite these observed associations, the rate of preterm delivery in this population (6.4%) was lower than in a U.S. reference population.   FULL TEXT

Winchester et al., 2016

Winchester P, Proctor C, Ying J, “County-level pesticide use and risk of shortened gestation and preterm birth,” Acta Paediatrica, 2016, 105:3, DOI: 10.1111/apa.13288.


AIM: This study assesses the association between pesticide exposure in pregnancy, preterm birth (PTB) and shortened gestation.

METHODS: Pregnancy information was abstracted from the Centers for Disease Control (CDC) Non-Public Use Natality Datasets 1990-2005. Pesticide use in maternal county of residence was calculated using California Pesticide Use Reporting (PUR) data 1990-2005. Counties were ranked by pesticide use, and birth months were sorted by peak (May-June) or nonpeak (other months) pesticide use. Multivariate logistical regression models were used.

RESULTS: Counties with higher pesticide use were associated with higher PTB (low 8.59 ± 0.11%, moderate 9.25 ± 0.07%, high 10.0 ± 0.06%, p’s < 0.001) and shorter gestations (low 39.197 ± 0.014 weeks, moderate 39.126 ± 0.011 weeks, high 39.049 ± 0.011 weeks, p’s < 0.001). Peak pesticide months were associated with higher PTB (10.01 ± 0.05% vs. 9.36 ± 0.05%, p < 0.001) and shorter gestations (39.069 ± 0.007 weeks vs. 39.122 ± 0.007 weeks, p < 0.001). The pesticide effect on shortened gestation and higher PTB was found in all racial groups. Pesticide use was highest for fungicides > insecticides > fumigants > herbicides > others. Each pesticide type was found to be associated with higher PTB and shorter gestation.

CONCLUSION: PTB and shortened gestation were significantly associated with pesticide use in maternal county of residence regardless of race, gestation at birth, and in most risk categories.   FULL TEXT