Lifecycle Nutrition: Pregnancy and Lactation

TA: Helen Corless

Nutrition before Pregnancy

• Maintain a healthy weight

• Nutrient status– Folate– Iron– Vitamin B12– Vitamin A

• Chronic conditions

• Substance use

Nutrition & Male Fertility

• Weight • Zinc• Antioxidants• Alcohol

Fetal Development

Physiology of Pregnancy

• Fetal growth:– Zygote: fertilized ovum– Blastocyst: first 2 weeks

•Cells differentiate into fetus & placenta

– Embryo: weeks 2-8 •Development of organ systems

– Fetus: week 9-delivery•Growth

– Newborn

Physiology of Pregnancy

• Placental Development – Placenta: metabolically active organ•Interwoven fetal and maternal blood vessels

•Exchange of oxygen, nutrients, and waste products

– Amniotic sac– Umbilical cord

Placental Development

Stages of Development

Day 23

• 2mm long (=) • Beginning development of major organs

• Critical stage for neural tube development

Day 28

• 6mm long (===) • At this point, the heart is beating,

• Lim buds will form the arms and legs

Week 9

• 44mm long• Embryo has become a fetus

• Complete CNS, beating heart, digestive system, well-defined fingers and toes, beginnings of facial features

Week 12

• 82mm long, weighs about 1oz

• Arms, hands, fingers, legs, feet and toes formed

• Organs grow and mature

• Less affected by nutritional deficiencies

Week 26

• 250mm long, weighs 2-3 lbs

• 3rd trimester• Rapid growth• Able to survive if born prematurely– Lungs– Nutrient stores– Feeding

Week 40

• Baby ready to be born

• Less amniotic fluid, baby almost fills uterus

• Plump arms and legs

• Full term fetus usually weighs between 7 and 9 lbs at birth

• Full term: 38-42 weeks

Definition of a Successful Pregnancy

• Gestation at least 37 weeks– Lung development

• Birth weight >5.5 lb• Otherwise

– Low birth weight (LBW)– Small for gestational age (SGA)– Preterm vs. SGA

• Potential for catch-up growth• Malnutrition

If a baby is born at 38 weeks and weighs 4lbs, he/she would be considered:

a) Low birth weight (LBW)b) Small for gestational age

(SGA)c) Pretermd) Both a and be) All of the above

If a baby is born at 38 weeks and weighs 4lbs, he/she would be considered:

a) Low birth weight (LBW)b) Small for gestational age

(SGA)c) Pretermd) Both a and be) All of the above

Critical Periods

•Times of intense development and rapid cell division– Cellular activities can occur only during these times

•Organ and tissue development most vulnerable to adverse influences

•First trimester

Neural Tube Development

• Critical period is 17-30 days gestation

• Most women unaware they are pregnant during this time

• Vulnerable to – Nutrient deficiencies– Nutrient excesses– Toxins

Neural Tube Defects

• Anencephaly– Brain either missing or fails to develop

• Spina bifida– Incomplete closure of spinal cord and its bony encasement

• Affects 30/100,000 newborns in US

Neural Tube Development

Spina Bifida

Neural Tube Defects

• Cause unknown• Risk factors

– Family history– Maternal diabetes– Maternal obesity– Anti-seizure medications– Mutations in enzymes

Which of the following has been shown to prevent neural tube defects?

a) Vitamin B12b) Vitamin Dc) Calciumd) Folate

Which of the following has been shown to prevent neural tube defects?

a) Vitamin B12b) Vitamin Dc) Calciumd) Folate

Folate Supplementation

• Prevents & reduces severity of neural tube defects

• Folate status important prior to pregnancy and during 1st trimester

• RDA: 600 micrograms• Fortification of grains

– 50% of pregnancies are unplanned

Fetal Programming

• Adverse influences at critical stages in utero may set the stage for chronic disease development later in life

• Maternal nutrition status may change gene expression in fetus

• Examples:– beta cell growth and diabetes– blood vessel growth, lipid metabolism and CVD

Maternal Factors

Physiology of Pregnancy

• Organ & tissue enlargement– Breasts– Uterus– Adipose tissue

• BMR increases• Circulatory system changes

• Joint flexibility• Fluid retention

– Estrogen

How much weight should a healthy-weight woman carrying a single fetus gain during pregnancy?

a) 5-15 poundsb) 15-25 poundsc) 25-35 poundsd) 35-45 pounds

How much weight should a healthy-weight woman carrying a single fetus gain during pregnancy?

a) 5-15 poundsb) 15-25 poundsc) 25-35 poundsd) 35-45 pounds

Maternal Weight

• Birth weight is most reliable indicator of infant health

• Maternal weight prior to conception influences fetal growth – Underweight

•Risk of LBW, preterm, infant death

– Overweight and obesity•Medical complications for mother•Risks for infant

Maternal Weight

• Weight gain during pregnancy–Correlates closely to infant birth weight

–Recommendations (single birth)•Healthy weight: 25-35lbs•Underweight: 28-40lbs•Overweight: 15-25lbs

–Most women gain more than recommended!

Maternal Weight Gain

•Normal: 3.5lbs in 1st tri, then 1lb/week after that•Underweight: 5lbs in 1st tri, then just over 1lb/week•Overweight: 2lbs in 1st tri, then 2/3lb per week

What makes up the weight?

• Weight gain supports growth and development of…– Placenta– Uterus– Blood supply– Fluid volume– Breasts– Infant

• Fat stores (small amount)

Weight gain (lb)

1st trimester 2nd trimester 3rd trimester

2Increase in breast size

Increase mother's fluid volume

4

Placenta 1 1/2

Increase in blood supply to the placenta

4

Amniotic fluid 2

Infant at birth 7 1/2

Increase in size of uterus and supporting muscles

2

Mother's necessary fat stores

7

30Stepped Art

Fig. 15-8, p. 502

Which of the following is true about exercise and pregnancy?

a) Pregnant women should exercise very little and rest as much as possible

b) Pregnant women should get as much exercise as possible, even if they did not exercise prior to getting pregnant

c) Pregnant women can continue an exercise regimen that they had prior to getting pregnant with some adjustments

Which of the following is true about exercise and pregnancy?

a) Pregnant women should exercise very little and rest as much as possible

b) Pregnant women should get as much exercise as possible, even if they did not exercise prior to getting pregnant

c) Pregnant women can continue an exercise regimen that they had prior to getting pregnant with some adjustments

Exercise during Pregnancy

• Benefits of physical activity – improve fitness– manage or prevent gestational diabetes– facilitate labor– reduce stress– fewer discomforts– strength to carry weight

• Inactive women should not begin an intense exercise program during pregnancy

Exercise during Pregnancy

Recommendations• Regular, mild to moderate

• Low-impact• Avoid sports with risk of falling or being hit

• Protect abdomen• Maintain adequate diet

• Heat and hydration

Nutrition during Pregnancy

Energy & Nutrient Needs

• Needs tend to be higher than any other time in life

• To meet needs– Make careful selections– Body maximizes absorption– Body minimizes losses

Key Nutrients During Pregnancy

• Calories • First trimester: No or little extra• Second trimester: +340 kcals/day• Third trimester: +450 kcals/day

• Protein • +25 g/day (or 1.1 g/kg body weight)

• Carbohydrate• 175 g/day

Key Nutrients During Pregnancy

• Folate• B12• Iron• Zinc

These nutrients are needed for the synthesis of DNA and new cells

Key Nutrients During Pregnancy

• Folate – Non-pregnant women: 400 g/day– Pregnant women: 600 g/day

• B12– Non-pregnant women: 2.4 g/day– Pregnant women: 2.6 g/day

Key Nutrients During Pregnancy

• Iron – Premenopausal women: 18 mg/day– Pregnant women: 27 mg/day

• Zinc– Non-pregnant women: 8 mg/day– Pregnant women: 11 mg/day

Key Nutrients During Pregnancy

• Vitamin D– AI does not increase during pregnancy– Critical for bone and teeth development

• Calcium– AI does not increase during pregnancy– Absorption and retention increases– Deficiency common; needed to conserve maternal stores

Nutrition during Pregnancy

• Vegetarians – Able to meet most nutrient needs through diet alone

– Exception: iron

• Vegans– May require supplementation for B12, calcium, vitamin D

– B12 deficiency: spinal chord damage, psychomotor retardation

Common Concerns

• Nausea & vomiting– “Morning sickness”– Hormonal changes

• Constipation and hemorrhoids• Heartburn• Food cravings and aversions

– Hormone changes– Pica

Malnutrition and Pregnancy

• Fertility– Amenorrhea– Sperm– Loss of sexual interest

• Placental development – Poor development– Risk of LBW, physical and cognitive abnormalities

Malnutrition and Pregnancy

•Fetal development–Fetal growth retardation–Birth defects–Miscarriage and stillbirth–Premature birth–LBW

Risks During Pregnancy

• Gestational diabetes– Affects 1/25 women– Increased risk of type 2 diabetes and hypertension later in life

– Complications during labor & delivery

– Effects on infant•High birth weight•Birth defects

– Avoid excessive weight gain

Risks During Pregnancy

• Preexisting hypertension– Risk of LBW infant– Risk of placental separation; stillbirth

• Gestational hypertension– 50% mild, no adverse effect– 50% early sign of preeclampsia

Risks During Pregnancy

• Preeclampsia (pregnancy-induced)– Gestational hypertension + protein in urine

– Affects nearly all maternal organs; may retard fetal growth

– Risk of placental separation– Cause unknown– Genetic predisposition?

• Eclampsia: seizures & coma

Risks During Pregnancy

Fetal Alcohol Syndrome

• Irreversible mental and physical retardation

• Recall CNS critical period

• Entirely preventable

Risks during Pregnancy

Smoking• Restricts blood supply to fetus

• Lung development• Increased risk for:– Complications– LBW infant– Lung problems– SIDS

• Preventable!

Risks during Pregnancy

Mercury• Omega-3 fatty acids

• Fish contain high amounts of mercury

• Mercury can impair fetal growth and CNS development

Lactation

Were you breastfed as an infant?

a) Yesb) Noc) Unsure

Which of the following is true for you (females)?a) I plan to breastfeedb) I plan to formula feedc) I plan to do a combination of

both d) I have never thought about how

I am going to feed my offspringe) I do not plan on having

children

Which of the following is true for you (males)?a) I want my future wife to

breastfeedb) I do not care whether my

children are breastfed or notc) I have never thought about how

I want my offspring to be fedd) I do not plan on having

children

Recommendations• American Academy of Pediatrics• American Academy of Family Physicians• American College of Obstetricians and Gynecologists• American College of Nurse-Midwives• American Dietetic Association,• American Public Health Association

– Officially recommend that most infants

breastfeed for at least 12 months. – Also recommend that for about the first six months infants be exclusively breastfed, meaning that they not be given any foods or liquids other than breast milk.

Healthy People 2020

• Breastfeeding ever – 81.9%• Breastfeeding at 6 months – 60.5%• Breastfeeding at 1 year – 34.1% • Exclusively through 3 months – 44.3%• Exclusively through 6 months – 23.7%• Reduce the proportion of breastfed newborns who

receive formula supplementation within the first 2 days of life – to 15.6% (from 25.6%)

How far is the US from these goals?

U.S. Rates Healthy People 2020 Goals

Breastfeeding Ever

75% 81.9%

Breastfeeding at 6 months

43% 60.5%

Breastfeeding at 12 months

22.4% 34.1%

Benefits for infant• Optimal nutrition

– Nutritionally superior to formula– Sterile and always fresh– More easily digestible

• Immune protection • Fewer allergies and intolerances• Fewer respiratory, GI, and ear infections

• Cognitive benefits • Infant-led feeding• May protect against some chronic diseases later in life

Benefits to Mother

• Increased rate of uterine contraction after childbirth and consequent reduced risk of postpartum blood loss

• Possible reduced risk of pre-menopausal breast and ovarian cancers

• Amenorrhea and decreased fertility• Promotes mother-infant bond• Weight loss• Convenience• Economic benefits

Anatomy of the Breast

Hormonal Control of Lactation

• Hormonal controls– Prolactin– Oxytocin: MER

• Sucking stimulus signals release of prolactin

• Supply follows demand

Composition of Breast Milk

• Colostrum – First fluid, thick, yellowish– Rich in immune factors and protein– About 20 kcal/oz

– Bifidus flora• In first 24hrs, total intake: 10-108ml

• Transitional milk: 6-13 days postpartum

Composition of Breast Milk

• 20 calories per ounce• Whey:Casein (70:30)

– More easily digested• Foremilk vs. hindmilk: fat content

– Don’t limit time at breast– No clear distinction

• Contains small amount of Fe– Sufficient for first 6 months– Absorption is facilitated by high vitamin C concentration

A newborn baby needs to be given small amounts of water in addition to breastmilk to meet

his/her needs

a) Trueb) False

Nutrient Requirements for Lactation

• Energy requirement –Extra 500 kcals/day –Higher needs than pregnancy

• Increased need for carbohydrate• Fluid intake• Inadequacies reduce quantity and not quality of milk

Contraindications to Breastfeeding

• Maternal HIV• Inborn errors of metabolism of child (galactosemia)

• Alcohol• Certain medications• Smoking• Illicit drugs• Caffeine

Common Problems

• Sore nipples• Engorgement• Plugged duct• Mastitis

Breastfeeding is a LEARNED SKILL!

Improper Latch!

That’s Better!

Formula Feeding

• Safety and adequacy• Preparation• Can interfere with breastfeeding– Supply & demand– Nipple confusion/preference

• More likely to be overfed– Increased risk of obesity?

Nipple Confusion

Nipple Confusion

Baby Friendly Hospital Initiative

1. A written bf policy routinely communicated to staff

2. Train staff in skills to implement policy3. Inform pregnant women about benefits and

management of breast feeding4. Help mothers initiate bf within 30 minutes of

delivery5. Show mothers how to initiate and maintain bf 6. Give newborns no food or drink other than breast

milk unless medically indicated7. Practice rooming in: allow mothers and infants to

stay together8. Encourage breast feeding on demand9. Give no pacifiers 10. Foster establishment of support groups and refer

mothers to them

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Questions?