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