Understanding Nutrition
Chapter 15
Life Cycle Nutrition:
Pregnancy and Lactation
By
A. Fellah, Ph.D.
Growth and Development During Pregnancy
 Placental Development:
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conception: the union of the male sperm and the female
ovum; fertilization.
Placenta: the organ that develops inside the uterus early in
pregnancy, through which the fetus receives nutrients and
oxygen and returns carbon dioxide and other waste
products to be excreted.
Uterus: the muscular organ within which the infant develops
before birth.
Amniotic sac: the "bag of waters" in the uterus, in which the
fetus floats.
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Umbilical cord: the rope-like structure through which:
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The fetus's veins and arteries reach the placenta.
The route of nourishment and oxygen to the fetus.
The route of waste disposal from the fetus.
The scar in the middle of the abdomen that marks the former
attachment of the umbilical cord is the umbilicus, commonly
known as the "belly button."
 Ovum: the female reproductive cell, capable of developing into
a new organism upon fertilization; commonly referred to as an
egg.
 Sperm: the male reproductive cell, capable of fertilizing an
ovum.
 zygote: the product of the union of ovum and sperm;
so-called for the first two weeks after fertilization.
 Implantation: the stage of development in which the
zygote embeds itself in the wall of the uterus and
begins to develop; occurs during the first two weeks
after conception.
 Embryo: the developing infant from two to eight weeks
after conception.
 Fetus: the developing infant from eight weeks after
conception until term.
The Placenta
The placenta is a sort of pillow of tissue in which maternal blood vessels lie side
by side with fetal blood vessels entering it through the umbilical cord.
This close association between the two circulatory systems permits the
mother’s bloodstream to deliver nutrients and oxygen to the fetus and to carry
away fetal waste products.
Embryonic and Fetal Development: 1 of 4
A newly fertilized
ovum is about the
size of the period at
the end of this
sentence.
This zygote at less
than one week after
fertilization is not
much bigger and is
ready for
implantation.
Embryonic and Fetal Development: 2 of 4
After implantation, the
placenta develops
and begins to provide
nourishment to the
developing embryo.
An embryo five weeks
after fertilization is
about 1/2 inch long.
Embryonic and Fetal Development: 3 of 4
A fetus after 11
weeks of
development is just
over an inch long.
Notice the umbilical
cord and blood
vessels connecting
the fetus with the
placenta.
Embryonic and Fetal Development: 4 of 4
A newborn infant after nine months of development measures
close to 20 inches in length. From eight weeks to term, this infant
grew 20 times longer and 50 times heavier.
Critical Periods
 Critical periods: finite periods during development, in which
certain events occur that will have irreversible effects on later
developmental stages; usually a period of rapid cell division.
 gestation: the period from conception to birth. For human
beings gestation lasts from 38 to 42 weeks Pregnancy is often
divided into thirds, called trimesters.
 neural tube defect: a serious central nervous system birth
defect that often results in lifelong disability or death.
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Anencephaly: an uncommon and always fatal type of
neural tube defect, characterized by absence of brain.
Spina bifida: one the most common types of neural tube
defects, characterized by the incomplete closure of the
spinal cord and its bony encasement
The Concept of Critical Periods
Critical periods
occur early in
development.
An adverse
influence felt early
can have a much
more severe and
prolonged impact
than one felt later
on.
The
concept
of Critical
Periods
Neural Tube Development: 1 of 2
At four weeks, the neural tube has yet to close
(notice the gap at the top).
Neural Tube Development: 2 of 2
At six weeks, the neural tube (outlined by the delicate red
vertebral arteries) has successfully closed.
Successful development of the neural tube depends, in
part on the vitamin folate
Spina Bifida: 1 of 3
A neural tube defect.
Spina Bifida: 2 of 3
Spina Bifida: 3 of 3
Folate Supplementation
Rich Folate sources
Weight prior to Conception
 Underweight: has a high risk of having a low birthweight infant.
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Preterm (infant): an infant born prior to the 38th week of
pregnancy; also called a premature infant.
 Overweight: has a high risk of medical complications such as
hypertension, gestational diabetes, and postpartum infections.
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A term infant is born between the 38th and 42nd week of
pregnancy.
Post term: an infant born after the 42nd week.
Cesarean section: a surgically assisted birth involving
removal of the fetus by an incision into the uterus, usually by
way of the abdominal wall.
Weight Gain during Pregnancy
 Recommended Weight Gains:
Prepregnancy Wt. Status
Underweight
Normal weight
Overweight
Obese
Recommended Wt. Gain
28-40 lb
25-35 lb
15-25 lb
15 lb minimum
 Weight-Gain Patterns: 3.5 lb during the 1st trimester
and 1 lb per week thereafter.
Components of Weight Gain During Pregnancy
Energy and Nutrient Needs during Pregnancy
 Energy: ~300 kcalories above the allowance for nonpregnant
women-and only during the 2nd and 3rd trimester.
 One extra serving from each of the five food groups.
 Protein: ~ 10 g/day higher than for nonpregnant women.
 Essential Fatty Acids: a diet that includes seafood has a
balance of the omega-3 and omega-6 fatty acids.
 Folate: ~ 600µg/day.
 Vitamin B12: 2.6µg/day.
 Iron: 27 mg/day.
 The increased need cannot be met by diet or by existing
stores. Therefore, iron supplements are recommended
during the 2nd and 3rd trimesters.
Common Nutrition-Related Concerns of Pregnancy
 Nausea: morning sickness.
 Constipation and Hemorrhoids.
 Heartburn.
 Food Craving and Aversions.
 Nonfood Craving.
High-Risk Pregnancies
 High-Risk: a pregnancy characterized by indicators
that make it likely the birth will be surrounded by
problems such as premature delivery, difficult birth,
retarded growth, birth defects, and early infant death.
 Low-Risk: a pregnancy characterized by indicators
that make a normal outcome likely.
 Fertility: the capacity of a woman to produce a normal
ovum periodically and of a man to produce normal
sperm; the ability to produce.
 Low birthweight: a birthweight of 5.5 lb or less;
indicates poor health in the newborn and poor nutrition
status in the mother.
Newborn classification system based on birthweight.
Maternal Health
 Preexisting Diabetes: depends on how well it is
controlled before and during pregnancy.
 Gestational Diabetes: abnormal glucose tolerance that
is first detected during pregnancy.
 Transient Hypertension: high blood pressure that
develops in the second half and resolves after
childbirth.
 Preeclampsia: a condition characterized by
hypertension, fluid retention, and protein in the urine;
formerly known as pregnancy-induced hypertension.
 Eclampsia: a sever stage characterized by
convulsions seizures and coma. Maternal death
during pregnancy and childbirth is extremely
rare. Demands prompt medical attention.
 Down Syndrome: a genetic abnormality that
causes mental retardation, short stature, and
flattened facial features.
Practices Incompatible with Pregnancy
 Alcohol: cause irreversible mental and physical retardation of
the fetus.
 Medicinal Drugs.
 Herbal Supplements: seeks a physician’s advice.
 Illicit Drugs: cocaine and marijuana is common among some
pregnant women.
 Smoking and chewing Tobacco: exert harmful effects.
 Sudden Infant Death Syndrome (SIDS): the unexpected and
unexplained death of an apparently well infant; the most
common cause of death between the 2nd week and the end of
the first year of life.
Caffeine
crosses the
placenta
Placenta
previa, an
effect of
smoking
during
pregnancy
Typical Facial Characteristics of Fetal Alcohol Syndrome
The severe facial
abnormalities
shown here are
just outward signs
of the severe
mental
impairments within.
The internal organs
also suffer
irreversible
damage that, while
hidden, may create
major problems for
a child’s health.
A Child with Fetal Alcohol Syndrome
This child was born
to a woman who
drank heavily
during pregnancy.
In addition to the
unusual facial
characteristics,
children with Fetal
Alcohol Syndrome
experience growth
and mental
retardation.
Fetal Alcohol Effect (FAE)
Alcohol Content and Caloric Value
Alcohol content and caloric value of common
alcohol-containing beverages.
Foods can slow
down the
absorption of
drugs in the
digestive tract.
Summary
 Adequate nutrient and energy intake is important for
the normal growth and development of the fetus and
the health of the mother.
 Energy needs increase during pregnancy, especially
during the second and third trimester.
 There is also increased need for protein, thiamin,
riboflavin, niacin, vitamin B6, folate, vitamin B12,
vitamin D, iron and zinc.
 These needs can be met by consuming a balanced
diet with additional servings of nutrient dense foods
from the five food groups.
 Iron supplementation may be required.
Summary
 Many nutrition-related problems can occur during pregnancy.
 These include nausea, constipation, hemorrhoids, heartburn,
food cravings and aversions and nonfood cravings.
 High risk pregnancies result from various conditions.
 Maternal weight (either low or high), nutritional deficiencies or
toxicities, improper weight gain, poor socioeconomic status,
preexisting or gestational diabetes, preexisting or transient
hypertension, adolescent pregnancy and alcohol/drug abuse
all increase risk to pregnancy.
 The mother's age may influence the course of a pregnancy.
 The most common outcome of high risk pregnancy is a low
birth weight infant.
Summary
 Practices incompatible with pregnancy include alcohol and
drug use, herbal supplements and tobacco use.
 Lactation is a physiological process. Breastfeeding is a
learned behavior that needs a supportive environment.
 Nutrient needs of the mother during breastfeeding include
increased need for energy, vitamins and minerals, and water.
 Iron supplements may be necessary. Exercise is important.
 Breastfeeding mothers need to be concerned about the use
of alcohol, caffeine, smoking, colds, HIV infections, chronic
diseases and environmental contaminants.