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Nutrition
Conditions &
Interventions
during Pregnancy
Learning Objectives
Some pregnancy complications are related to women’s nutritional status
Nutritional interventions for pregnancy complications can benefit maternal and infant health
Should be based on scientific evidence for safety, effectiveness, & affordability
Introduction
Health conditions impacting pregnancy include:
Hypertensive disorders of pregnancy
Preexisting & gestational diabetes
Obesity
Multifetal pregnancies
HIV/AIDS
Eating disorders
Fetal alcohol spectrum
Adolescent pregnancy
Hypertensive Disorders of Pregnancy
Hypertension (HTN): defined as systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg
Affects 6-8% of pregnancies
Contributes to stillbirths, fetal & newborn deaths, & other complications
Previously known as “Pregnancy-induced hypertension”
Hypertensive Disorders of Pregnancy, Oxidative Stress, & Nutrition
HTN in pregnancy is related to: Inflammation Oxidative stress
Damage to the endothelium (cells lining the inside of blood vessels)
Consequences of endothelial
dysfunction: Impaired blood flow Increased tendency to clot Plaque formation
Ways to Reduce Oxidative Stress
Exclude trans fats from diet
Adequate intake of vitamins C & E, the carotenoids, & antioxidants from plants
Ample physical activity
Weight loss if overweight (not recommended during pregnancy)
Consume low-glycemic index foods
Chronic Hypertension HTN present before pregnancy or
diagnosed <20 weeks
Estimated incidence is 1-5%
More common in: African American, obese, >35 years of age, or
history of HTN with previous pregnancy
Blood pressure ≥ 160/110 mm Hg
associated with increased risk of: fetal death, preterm delivery, & fetal growth
retardation
Nutritional Interventions for Women with Chronic Hypertension in Pregnancy
Intervention should aim to achieve adequate & balanced diets for pregnancy
Weight gain is same as for other pregnant women
If salt-sensitive, Na restriction required for blood pressure control yet without too little that could impair fetal growth
Gestational Hypertension
Hypertension diagnosed for first time after 20 weeks of pregnancy
If blood pressure returns to normal by 12 weeks postpartum, it’s called transient hypertension of pregnancy
Preeclampsia-Eclampsia
A pregnancy-specific syndrome occurring >20 weeks gestation accompanied by proteinuria
Proteinuria: urinary excretion of ≥0.3 gram
protein in 24-hour urine sample (or >30 mg/dL protein or ≥2 on dipstick reading)
Eclampsia: occurrence of seizures not attributed to other causes
Characteristics of Preeclampsia-Eclampsia Oxidative stress, inflammation, & endothelial
dysfunction
Blood vessel spasms & constriction
Increased blood pressure
Adverse maternal immune system responses to the placenta
Platelet aggregation & blood coagulation due to deficits in prostacyclin relative to thromboxane
Alterations of hormonal & other systems related to blood volume & pressure control
Alteration in calcium regulatory hormone
Reduced calcium excretion
Outcomes related to the existence of preeclampsia during pregnancy
Nutrient Intake & Preeclampsia
Diabetes in Pregnancy Diabetes: 2nd leading complication in
pregnancy
Forms of diabetes include:
Type 1 diabetes: results from destruction of insulin-producing cells of pancreas
Type 2 diabetes: due to body’s inability to use insulin normally, or produce enough insulin
Gestational: CHO intolerance with 1st onset during pregnancy
Gestational Diabetes
Seen in ~3-7% of pregnant women
Women who develop gestational diabetes appear to be predisposed to insulin resistance & type 2 diabetes
Associated with increased levels of blood glucose, triglycerides, fatty acids & blood pressure
Potential Consequences of Gestational Diabetes
Elevated glucose from mother reaches fetus resulting in increased insulin production Increased insulin leads to increased glucose
uptake & triglyceride formation in fetus
Fetal changes may increase likelihood of complications later in life such as: Insulin resistance
Type 2 diabetes
High blood pressure
Diagnosis of Gestational Diabetes
Glucose screening recommended for women at high risk
Risk factors are listed below:
Marked obesity
Diabetes in a parent or sibling
History of glucose intolerance
Previous macrosomic infant
Current glucosuria
Treatment of Gestational Diabetes
First approach is to normalize blood glucose levels with diet & exercise
If postprandial glucose remains high 2 weeks after adhering to diet & exercise, insulin injections are added
Medical nutrition therapy decreases risk of adverse perinatal outcomes
Exercise Benefits & Recommendations
Regular aerobic exercise decreases insulin resistance & blood glucose in gestational diabetes
Exercise should approximate 50-60% of VO2 max
Nutritional Management of Women with Gestational Diabetes
1. Assess dietary & exercise habits
2. Develop individualized diet & exercise plan
3. Monitor weight gain
4. Interpret blood glucose & urinary ketone results
5. Ensure follow-up during & after pregnancy
Type 1 Diabetes during Pregnancy
Potentially, a more hazardous condition than most cases of gestational diabetes
Mother with type 1 is at risk of:
Kidney disease
Hypertension
Other complications
Newborn born to her is at risk of:
Mortality
Being SGA or LGA
Hypoglycemia within 12 hours after birth
Nutritional Management of Type 1 Diabetes during Pregnancy
Control of blood glucose levels
Nutritional adequacy of diet
Achieve recommended weight gain
Careful home monitoring of glucose levels & dietary intake, exercise, insulin dose, & urinary ketone levels
Multifetal Pregnancies
U.S. rates of multifetal pregnancies have increased Linked to assisted reproductive
technologies
Only 1 in 5 triplets are spontaneously conceived
Incidence highest in women 45 to 54 y/o (1 in 5 are multifetal)
Background Information About Multifetal Pregnancies
Dizygotic
2 eggs are fertilized
AKA Fraternal
~70% of twins
Different genetic “fingerprints”
Incidence increased by perinatal nutrient supplements
Monozygotic
1 egg is fertilized
AKA Identical
(or almost identical)
Always same sex
~30% of twins
Rates appear not to be influenced by heredity
Differences in Placentas & Amniotic Sacs
Twins with 2 amniotic sacs, 2 chorions, & 2
placentas
Twins with 1 amniotic sac, 1
chorion, & 1 placenta
Twins with 2 amniotic sacs, 1 chorion, & fused
placentas
Nutrition & the Outcome of Multifetal Pregnancy
Weight gain in multifetal pregnancy 35-45 pounds
Rate of weight gain in twin pregnancy 0.5 pounds per week in 1st trimester
1.5 pounds per week in 2nd & 3rd trimesters
Weight gain in triplet pregnancy Gain of ~50 pounds or 1.5 pounds per week
Nutrition & the Outcome of Multifetal Pregnancy
Dietary intake in twin pregnancy
Benefits from increases in essential fatty acids, iron & calcium
Vitamin and mineral supplements
Needs unknown
Nutritional recommendations
Based on logical assumptions & theories
HIV/AIDS during Pregnancy
Treatment of HIV/AIDS
Needed before, during, & after pregnancy
Consequences of HIV/AIDS during pregnancy
Infection does not appear to be related to adverse pregnancy outcome
Nutritional factors and HIV/AIDS during pregnancy
Nutritional needs increase the most in advanced stages of HIV/AIDS
Nutritional Management for Women With HIV/AIDS during Pregnancy
Goals for nutritional management include: Maintenance of positive nitrogen balance &
preservation of lean muscle & bone mass
Adequate intake of energy & nutrients to support maternal physiological changes & fetal growth & development
Correction of elements of poor nutritional status identified by nutritional assessment
Avoid foodborne infection
Eating Disorders in Pregnancy
Rare in pregnancy since most females with disorders are subfertile or infertile
Bulimics more likely to become pregnant than those with anorexia nervosa
Eating disorder symptoms subside in 2nd & 3rd trimester but return postpartum
Eating Disorders in Pregnancy
Consequences of eating disorders in pregnancy
Treatment of women with eating disorders during pregnancy
Nutritional interventions for women with eating disorders
Fetal Alcohol Spectrum “Fetal alcohol spectrum” describes range of effects that fetal alcohol exposure has on mental development & physical growth
Effects include
Behavioral problems Mental retardation Aggressiveness Nervousness & short attention span Stunting growth & birth defects
Fetal Alcohol Spectrum
Fetal exposure to alcohol is a leading preventable cause of birth defects ~1 in 12 American pregnant
women drink alcohol
1 in 30 consume ≥5 drinks on 1 occasion at least monthly
1 in 1000 newborns are affected by fetal alcohol syndrome
Effects of Alcohol on Pregnancy Outcome
Alcohol easily crosses placenta to fetus
Alcohol remains in fetal circulation because fetus lacks enzymes to break down alcohol
Alcohol exposure during critical periods of growth & development can permanently impair organ & tissue formation
Effects of Alcohol on Pregnancy Outcome
Heavy drinking (4-5 drinks/day) increases risk of miscarriage, stillbirth, & infant death
~40% of fetuses born to women who drink heavily will have fetal alcohol syndrome
A “safe” dose of alcohol consumption during pregnancy has not been identified
Recommendation: women should not drink alcohol while pregnant
Nutrition & Adolescent Pregnancy
Growth during adolescent pregnancy
Teen growth in height & weight at expense of fetus
Infants born to teens average 155g less than those born to older adults
Risks Associated with Adolescent Pregnancy
Obesity, Excess Weight Gain, & Adolescent Pregnancy
Overweight & obese adolescents are at increased risk for:
Cesarean delivery
Hypertensive disorders of pregnancy
Gestational diabetes
Delivery of excessively large infants
Dietary Recommendations for Pregnant Adolescents
Adolescents may need more calories to support their own growth as well as that of fetus
Caloric need should be from a nutrient-dense diet
Calcium DRI for pregnant teens is 1300 mg
Nutritional Management of Adolescent Pregnancy
Multidisciplinary counseling services should include:
Individualized nutrition assessment
Intervention education
Guidance on weight gain
Follow-up birthweight outcomes
Nutritional Management of Adolescent Pregnancy
Services should focus on:
Psychosocial needs
Support/discussion groups
Home visits
Evidence-Based Practice
“Enormous amounts of new knowledge are barreling down the information highway, but they are not arriving at the doorsteps of our patients.”
Claude Lenfant, National Institutes of Health