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MATERNAL and INFANT NUTRITION
Vocabulary
Zygote:
Placenta:
Critical Period:
Gestational Diabetes:
Amenorrhea:
Stages of Fetal Development
• A newly fertilized ovum (zygote) begins as a single cell, and divides to become many cells
during the days after fertilization
• Within 2 weeks, the zygote embeds itself into the uterine wall (implantation)
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Stages of Fetal Development
After implantation, the placenta develops and begins to provide nourishment to the developing
embryo
The placenta develops inside the uterus, and it provides nutrients and oxygen, as well as a way
for the developing embryo to return carbon dioxide and other wastes to be excreted
An embryo at 5 weeks after fertilization is ~ ½ and inch long
At 8 weeks, the 1¼ inch long embryo has a complete nervous system, a beating heart, a
digestive system, well-defined fingers, and toes, and the beginnings of facial features
The fetus continues to grow during the next 7 months
Fetal growth is phenomenal – weight increase from less than an ounce to ~ 7.5 pounds
Critical Periods
Times of intense development and rapid cell division are called critical periods (cellular
activities can only occur at these times)
Each tissue and organ is most vulnerable to adverse influences during its own critical period
Adverse influences include nutrient deficiencies or toxins
An adverse influence felt early = irreversibly impairs development
An adverse influence felt late = may only temporarily impair development
• Critical period for neural tube development is 17 to 30 days gestation – folate supplementation
reduces the risk for neural tube defects
• Maternal anemia during the critical period of placental growth alters the pattern of blood
vessel growth, which may affect the cardiovascular health of the infant
• Malnutrition during the critical period of pancreatic cell growth may contribute to the
development of diabetes in adulthood
MATERNAL WEIGHT
• A woman’s weight prior to conception influences fetal growth
• Underweight: higher risk of a LBW infant, higher risk of a preterm infant
• Overweight: higher risk of medical complications such as hypertension, gestational diabetes,
and postpartum infections. Also since the baby may be larger then normal - may lead to
difficult labor, delivery, and birth trauma
• However, weight loss during pregnancy is NEVER advisable
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Weight Gain During Pregnancy
• All pregnant women must gain weight – fetal growth depends on it
• Maternal weight gain during pregnancy correlates closely with infant birthweight, which is a
strong predictor of the health of the infant
• Normal weight women should gain ~3 lbs. in the first trimester, and just under 1 lb/week
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thereafter
Underweight women: 1st trimester = 5 lbs., 1 lb/week thereafter
Overweight women: 1st trimester = 2 lbs., 2/3 lb/week thereafter
Components of Weight Gain
• Most of the weight gain supports the growth and development of the placenta, uterus, blood,
and breasts, as well as an optimally healthy infant
• A small amount goes into maternal fat stores, and that fat has a special purpose: to provide
energy for labor and lactation
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Weight Loss After Pregnancy
The pregnant women loses some weight at delivery
In the following weeks, she loses more as her blood volume returns to normal and she sheds
accumulated fluids
The typical women does not return to pre-pregnancy weight, most tend to retain a couple of
pounds with each pregnancy
In general, the more weight a women gains beyond the needs of pregnancy, the more she will
retain
Nutrition During Pregnancy
• From conception to birth, all parts of the infant – bones, muscles, organs, skin, and other
tissues – are made from the nutrients in the food that mother eats
• ENERGY: extra 340 calories in the 2nd, and 450 calories in the 3rd trimesters
• PROTEIN: 25 grams per day higher than the RDA (most are already getting that)
• ESSENTIAL FATTY ACIDS: the brain is largely made up of lipid material, and it depends
highly on the omega 3 and omega 6 fatty acids for its growth, function, and structure
• Pregnant women are advised to include seafood, leafy greens, nuts, and seeds in their diet
Nutrients for:
• Blood production and cell growth – folate, B12, iron, and zinc
• Bone development – vitamin D, calcium, phosphorus, magnesium, and fluoride
Mercury in Fish
•FDA has issued an advisory to all pregnant women, women who may become pregnant, lactating
mothers, and young children – avoid eating large amounts of mackerel, swordfish, shark, tuna,
and tilefish
• Pregnant and lactating women – one can of tuna per week
•Young children – less than a can per month
•http://www.doh.wa.gov/fish/FishAdvWomen.htm
Supplementation
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• Women who make wise food choices during pregnancy can meet most of their nutrient needs,
however, iron and folate are two nutrients that may need to be supplemented
• Women of childbearing age who are capable of becoming pregnant are advised to consume
400 micrograms of folate per day (supplements are convenient, better absorbed)
• Iron supplements are recommended during the 2nd and 3rd trimesters of pregnancy (30 mg per
day)
Nutrition-Related Concerns
• Nausea – hormonal changes appear to be responsible for a woman’s sensitivities to the
appearance, smell, or taste of foods
• Suggestions:
• Constipation – as the hormones of pregnancy alter muscle tone and the growing fetus crowds
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the intestinal organs
Suggestions:
• Heartburn – the hormones relax the digestive muscles, and the growing fetus puts increased
pressure on the mother’s stomach
• Suggestions:
Gestational Diabetes
• A condition of abnormal glucose tolerance, usually during the second half of pregnancy,
which resolves after birth
• Consequences of GD – complications during delivery, high infant birthweight, and birth
defects (heart damage, limb deformities, and neural tube defects)
• Risk Factors:
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Practices Incompatible with Pregnancy
Alcohol
Medicinal and illicit drugs
Tobacco
Environmental contaminants
Vitamin-Mineral megadoses
Caffeine
Weight-loss dieting
Low birthweight (less than 5.5 lbs. or 2500 grams) is the factor most associated with infant
mortality. Babies who are low birthweight are 40 times more likely to die in their first year than
healthy babies. Those who survive are more vulnerable to serious health and developmental
problems, such as blindness, deafness, mental retardation and learning disabilities.
Causes of Low Birthweight Infants
Poor nutrition
Genetics
Disease conditions
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Smoking
Drug use (including alcohol)
LACTATION
• Lactation is an automatic process that virtually all mothers are capable of doing
• Breastfeeding is a learned behavior
BENEFITS of BREASTFEEDING
For Infants:
• Provides the perfect balance of nutrients with high bioavailability
• Provides hormones that promote physiological development
• Improves cognitive development
• Protects against a variety of infections
• May protect against some chronic diseases (IDDM, hypertension)
• Protects against food allergies
BENEFITS of BREASTFEEDING
For Mothers
• Contracts the uterus
• Delays the return of regular ovulation
• Conserves iron stores (by prolonging amenorrhea)
• May protect against breast cancer
• May help the mother to lose weight gained during pregnancy (~650 cal/day)
• It’s cheap! (A nursing mother produces over 35 gallons of milk during the first six months,
saving ~$450 in formula costs)
Composition of Breast Milk
• Lipids: triglycerides are the major energy source, also rich in cholesterol, EFAs, EPA, and
DHA
• Carbohydrates: lactose is the major CHO
• Proteins: Whey proteins predominate, all essential amino acids, lactoferrin (protects infants
from infection), other immunoglobulins
• Vitamins and Minerals: a perfect balance of all essential vitamins and minerals
• Other: digestive enzymes, anti-infective factors, hormones, and growth factors
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Nutrient Needs During Lactation
Energy RDA during lactation – extra 330-400 kcal/day (1800 kcal/day minimum)
Protein RDA during lactation – same as pregnancy
Vitamins and Minerals – milk quality is maintained at the expense of the maternal stores
Nutrients in breast milk most likely to decline in response to inadequate stores are – B6, B12,
Vitamin A and D
In general, nutritional inadequacies reduce the quantity, not the quality of breast milk
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