Date Available

1-7-2022

Year of Publication

2019

Document Type

Doctoral Dissertation

Degree Name

Doctor of Philosophy (PhD)

College

Nursing

Department/School/Program

Nursing

Advisor

Dr. Kristin Ashford

Abstract

More than 85% of American adults do not consume recommended amounts of fruits or vegetables. Preterm birth and hypertensive disorders of pregnancy are common adverse conditions affecting pregnancy and are leading causes of maternal and fetal morbidity and mortality. Preterm birth affects nearly 10% of all births in the United States and is on the rise, as are hypertensive disorders, which have increased by 25% over the last two decades. Pregnancy is a state of controlled inflammation, and dysregulation has been linked to preterm birth and other adverse gestational outcomes. A healthy diet is recommended in pregnancy, but little is known about the effect fruit and vegetable intake on perinatal outcomes. Omega-3 (n-3) fatty acids are essential dietary components and are known to affect inflammatory state, but little is known about how they affect inflammation in pregnancy. As current evidence is lacking, further research is needed to investigate the relationships between maternal nutrition in pregnancy, inflammation and birth outcomes.

The purposes of this dissertation were to: 1) to review and evaluate the current evidence on the relationship between n-3 fatty acids and inflammation in pregnancy; 2) to evaluate the current state of the science on the impact of maternal dietary consumption of fruits and vegetables on preterm birth, gestational diabetes, preeclampsia, small for gestational age, gestational weight gain and measures of inflammation or oxidative stress in pregnancy; and 3) to examine relationships between maternal dietary intake of fruits and vegetables, cytokine expression in early and mid-pregnancy, preterm birth and gestational hypertension.

A critical review of literature examining the relationship between inflammation and n-3 intake during pregnancy found that multiple inflammatory cytokines in maternal and fetal tissues were lower in women who received n-3 supplements. A second review of literature review supported an inverse relationship between fruit and vegetables and risk of preeclampsia and suboptimal fetal growth. The available evidence was insufficient to establish relationships between fruit and vegetable intake and gestational diabetes, preterm birth or inflammation. A study evaluating the relationships between maternal fruit and vegetable intake, inflammation and birth outcomes was conducted. This study

provided evidence supporting a relationship between first and second trimester cytokine expression and maternal dietary intake of fruits and vegetables. Those who met recommended vegetable intake in the first trimester had higher first trimester serum CRP, IL1-α, IL-6 and TNF-α and lower first trimester cervicovaginal IL-6 levels. Those who met recommendations for first trimester fruit intake had 56% lower risk for preterm birth. Those who met second trimester vegetable intake recommendations had more than twice the risk of developing gestational hypertension.

The results of this dissertation provide support for the beneficial effects of omega-3 fatty acids and fruit and vegetable intake in pregnancy. Maternal intake of these dietary components may promote optimal immune status during pregnancy. Supplementation of maternal omega-3 fatty acids may help regulate inflammation via the anti-inflammatory effects their bioactive eicosanoids exert. Fruit and vegetables have antioxidant and anti-inflammatory effects that may also help balance the inflammatory state during pregnancy. These dietary components may help promote favorable immune status during pregnancy and reduce risk of adverse perinatal outcomes such as poor fetal growth, hypertensive disorders of pregnancy and preterm birth.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2020.030

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