Aminiotic Fluid and Human Milk

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Aminiotic Fluid
Amniotic Fluid and your food preferences later in life…
• Food choices during pregnancy and lactation are influenced by a variety
of factors.
• While internal factors, such as cravings and aversions, play an
important role especially during the first trimester of pregnancy,
environmental factors such as cultural food practices and beliefs often
dictate the types of foods eaten throughout pregnancy and lactation.
• Such traditional food practices serve to predispose infants to flavors that
are characteristic of their mother’s culture and geographical region.
• Amniotic fluid and human milk are composed of flavors that directly
reflect the foods, spices, and beverages eaten by or inhaled by (e.g.,
tobacco) the mother.
• Because the olfactory and taste systems are functioning by the last two
trimesters, these flavors are detected early in life, and early experience
can bias behavioral response to these flavors later in life.
♦ Amniotic fluid:
• Is a clear, slightly yellowish liquid
that surrounds the unborn baby
(fetus) during pregnancy.
• It is contained in the amniotic sac.
• pH of is around 7.2.
• Specific gravity of 1.0069 – 1.008.

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◘ Origin and Production
• The fluid is produced by the mother’s placenta during the first trimester
and the early part of the second trimester, until the baby’s kidneys are
mature enough to take over the task.
• The baby swallows the fluid as they “breathe” and then excretes it again
as urine, thus maintaining the constant circulation of the fluid.
• However, the urine making up the fluid is not pure waste material as the
majority of the fetal waste is passed through the placenta to be filtered
by the mother’s kidneys.
♦ Function
The primary functions of the fluid are:
• To provide a protective cushion for the fetus.
• Allow fetal movement.
• Stabilize the temperature to protect the fetus from extreme temperature
changes.
• To permit proper lung development.
• Exchanges of water and chemicals, also take place between the fluid, the
fetus, and the maternal circulation.
• Helps with the uniform growth of the body parts and organs of the baby.
• Assists with the proper bone and muscle development.

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• The fluid is released when the amnion ruptures, commonly known as
when a woman's "water breaks".
• When this occurs during labour at term, it is known as "spontaneous
rupture of membranes" (SROM).
• If the rupture precedes labour at term, however, it is referred to as
"premature rupture of membranes" (PROM).
♦ Amniotic Fluid: Circulation
• The water content of the amniotic fluid changes every three hours
• Large volume moves in both directions between the fetal & maternal
circulations mainly through the placental membrane.
• It is swallowed by the fetus, is absorbed by respiratory & GIT and
enters fetal circulation.

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• It then passes to maternal circulation through placental membrane.
During final stages of pregnancy fetus swallows about 400ml of
amniotic fluid per day.
• Excess water in the fetal blood is excreted by the fetal kidneys and
returned to the amniotic sac through the fetal urinary tract.
♦ Volume By Age
– 10 weeks = 30 ml
– 20 weeks = 350 ml
– 38 weeks = 1000 ml
– Term (40 weeks) = 500 ml
– Post term (more than 40 weeks) = <500 ml
♣ Volume
• The amount of amniotic fluid increases throughout pregnancy, reaching
a peak of approximately 1 L during the third trimester, and then
gradually decreases prior to delivery.
• The volume of amniotic fluid is positively correlated with the growth of
fetus.
• From the 10th to the 20th week it increases from 25ml to 400ml
approximately.
• From the 8th week, when the fetal kidneys begin to function, fetal urine
is also present in the AF.
• Then the relationship between AF and fetal growth stops.
• It reaches the high peak of 800ml at the 28 week.

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○ The amount of fluid declines to roughly 400 ml at 42 weeks age.
• An excessive amount of amniotic fluid is called polyhydramnios.
• This condition can occur with multiple pregnancy (twins or triplets),
congenital anomalies, or gestational diabetes.
• An abnormally small amount of amniotic fluid is known as
oligohydramnios.
• This condition may occur with late pregnancies, ruptured membranes,
placental dysfunction, or fetal abnormalities.
• Abnormal amounts of amniotic fluid may cause the health care provider
to watch the pregnancy more carefully.
• Removal of a sample of the fluid, through amniocentesis, can provide
information about the sex, health, and development of the fetus.
♦ Chemical Composition
• The placenta is the ultimate source of amniotic fluid water and solutes.
• Amniotic fluid has a composition similar to that of the maternal plasma
and contains a small amount of sloughed fetal cells from the skin,
digestive system, and urinary tract.
• The fluid also contains biochemical substances that are produced by the
fetus, such as bilirubin, lipids, enzymes, electrolytes, nitrogenous
compounds, and proteins that can be tested to determine the health or
maturity of the fetus.
• A portion of the fluid arises from the fetal respiratory tract, fetal urine,
the amniotic membrane, and the umbilical cord.
• As would be expected, the chemical composition of the amniotic
fluid changes when fetal urine production begins.

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• The concentrations of creatinine, urea, and uric acid increase, whereas
glucose and protein concentrations decrease.
• The concentrations of electrolytes, enzymes, hormones, and metabolic end
products also vary (change) but are of little clinical significance.
• Measurement of amniotic fluid creatinine has been used to determine fetal age.
• Prior to 36 weeks’ gestation, the amniotic fluid creatinine level ranges between
1.5 and 2.0 mg/dL.
• It then rises above 2.0 mg/dL, thereby providing a means of determining fetal
age as greater than 36 weeks.
♦ Specimen Collection
• Amniocentesis is recommended when screening blood tests such as the
maternal serum alpha feto protein test [AFP], human chorionic gonadotropin
[hCG], and unconjugated estriol [UE3]), yield results that are abnormal.
• Fetal epithelial cells in amniotic fluid indicate the genetic material of the fetus
and the biochemical substances that the fetus has produced.
• These cells can be separated from the fluid, cultured, and examined for
chromosome abnormalities by karyotyping, Fluorescence in situ
hybridization (FISH) , and DNA testing.
♦ Ultrasonography
• Fetal body measurements taken with ultrasonography accurately estimate the
gestational age of the fetus and provide an assessment of the size and growth of
the fetus throughout pregnancy.
• Finding an abnormality on the ultrasound could indicate potential fetal
development problems and indicate the need for an amniocentesis and laboratory
measurements of fetal lung maturity.

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♦ Amniotic Fluid Index
• Amniotic Fluid Index (AFI) is a measure of the amount of amniotic
fluid and is an index for the fetal wellbeing.
• It is a part of the Biophysical profile.
• AFI is the score given to the amount of amniotic fluid (by adding up
centimeters of depth of four pockets of fluid) seen on pregnant uterus by
ultrasound.
• An AFI < 5-6 is considered as Oligohydramnios and an AFI > 18-22 is
considered as Polyhydramnios.
• Storage Instructions: Freeze within 4 hours to transport to laboratory;
stable refrigerated up to 1 week.
• Protect from light.
• Avoid repeated freezing and thawing of the specimen, which may cause
the sample to precipitate, resulting in a lower than expected value.
• If cell culture is requested the specimen should be kept at 37o
C.
◘ Indications For Performing Amniocentesis
 Mother’s age of 35 or more at delivery.
 Family history of chromosome abnormalities, such as trisomy 21
(Down syndrome).
 Parents carry an abnormal chromosome rearrangement.
 Parent is a carrier of a metabolic disorder.
 Three or more miscarriages.
 Fetal lung maturity.

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♦ Collection
• Amniotic fluid is obtained by needle aspiration into the amniotic sac, a
procedure called amniocentesis.
• The procedure most frequently performed is a transabdominal
amniocentesis.
• Using continuous ultrasound for guidance, the physician locates the
fetus and placenta to safely perform the procedure.
• A maximum of 30 mL of amniotic fluid is collected in sterile syringes.
The first 2 or 3 mL collected can be contaminated by maternal blood,
tissue fluid, and cells and are discarded.
• Fluid for bilirubin analysis in cases of hemolytic disease of the
newborn (HDN) must be protected from light at all times.
♣ What About Normal Activities After An Amniocentesis?
• After an amniocentesis, it is best to go home and relax for the remainder
of the day.
• No exercise or strenuous activity should be performed, don’t lift
anything over 20 pounds (including children), and sexual relations
should be avoided.
• To relieve discomfort two Tylenol (acetaminophen) every 4 hours, may
be taken.
• The day after the procedure, normal activities may be resumed unless
otherwise directed by the doctor.
• Call your doctor if you develop a fever or have bleeding, vaginal
discharge, or abdominal pain that is more severe than cramps.

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♦ Color and Appearance
• Normal amniotic fluid is colorless and may exhibit slight to moderate
turbidity from cellular debris, particularly in later stages of fetal
development.
• Blood-streaked fluid may be present as the result of a traumatic tap,
abdominal trauma, or intra-amniotic hemorrhage.
• The presence of bilirubin gives the fluid a yellow color and is indicative
of red blood cell destruction resulting from HDN.
◘ Differentiating Maternal Urine From Amniotic Fluid
• Differentiation between amniotic fluid and maternal urine may be
necessary to determine possible premature membrane rupture or
accidental puncture of the maternal bladder during specimen collection.
• Chemical analysis of creatinine, urea, glucose, and protein aids in the
differentiation.
• Levels of creatinine and urea are much lower in amniotic fluid than in
urine.
• Creatinine does not exceed 3.5 mg/dL and urea does not exceed 30
mg/dL in amniotic fluid.
• Whereas values as high as 10 mg/dL for creatinine and 300 mg/dL for
urea may be found in urine.
• Measurement of glucose and protein by a reagent strip is a less reliable
indicator, because glucose and protein are not uncommon urine
constituents during pregnancy.

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♦ Fetal Distress
• Clinical analysis of amniotic fluid assesses both fetal well being and
maturation.
• Because amniotic fluid is a product of fetal metabolism, the constituents
that are present in the fluid provide information about the metabolic
processes taking place and the progress of fetal maturation.
• The oldest routinely performed laboratory test on amniotic fluid
evaluates the severity of the fetal anemia produced by hemolytic disease
of the newborn.
• Those infants are referred to as (Rh babies).
• The incidence of this disease has been decreasing rapidly since the
development of methods to prevent anti-Rh antibody production.
• The destruction of fetal red blood cells by antibodies that are present in
the maternal circulation results in the appearance of the red blood cell
degradation product, bilirubin, in the amniotic fluid.
• By measuring the amount of bilirubin present in the fluid, it is possible
to determine the degree of hemolysis taking place and to assess the
danger of this anemia presents to the fetus.
• In cases of premature or prolonged rupture of the amniotic membranes
there is concern over possible infection of the mother and fetus.

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♦ Can Amniotic Fluid Be Tested To Look For Infections?
• Yes, there are a few tests that can be performed on amniotic fluid to
detect infections that are passed from mother to baby during pregnancy
(congenital infections).
• Some of these infections may have serious consequences for the
developing fetus.
• A few examples include tests for cytomegalovirus (CMV),
toxoplasmosis, and bacterial infections.

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Human Milk
• Characteristic of the class Mammalia is the ability to produce milk.
• It is the most appropriate source of nutrition for the infant up to
the age of 6 months.

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• It contains: bioactive components such as
the maternal antibodies, chemical mediator, vitamins,
enzymes and some types of white blood cells.
◘ Types of breast milk:
• Colostrum or early milk
• Transitional milk
• Fore milk
• Hind milk
1- Colostrum (Also called “the first milk”)
 (2-3 days after birth).
 It has a yellowish to cream colored thick
appearance.
 Contains antibodies, immune-system cells
and Lactobacillus bifidus factor (bacteria
that inhibits negative bacteria and parasites
in the infant).
 It is high in protein especially antibodies, vitamins, minerals, but
very low in fat and carbohydrate compared to mature breast milk.
2- Transitional milk
 It occurs after colostrum stage and lasts for
approximately two weeks until it is replaced by
mature milk.
 it contains high levels of fat, lactose, and
vitamins to help the baby regain any weight lost
after birth.

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3- Mature milk
 It is the final milk that is produced and lasts throughout lactation.
 90% is water, which is necessary to maintain hydration
of the infant.
 The other 10% is carbohydrates, protein,
and fats, which are necessary for both growth and energy.
 There are two types of mature milk: Foremilk and hindmilk.
 It contains Docosahexaenoic acids (DHA), long chain omega-
3 fatty acids.
 Used for synthesis of brain tissues, central nervous system and eyes.
 DHA and cholesterol not found in human milk substitutes.
◘ Proteins In Breast Milk
1-Casein:
 It is the main protein.
 It complexes with calcium thus promoting its absorption.
 These are present in breast milk in much lower concentration than
in cow's milk.
Mature Human Milk- CHO
♦ Lactose
– Disaccharide of galactose and glucose.
– Dominant carbohydrate in human milk.
– Enhances calcium absorption.

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♦ Other carbohydrates
– Monosaccharides, glucose.
– Polysaccharides
• Contribute calories.
• Stimulate the growth of bifidus bacteria in the gut.
• Inhibit the growth of E. coli and other bacteria.
• Which prevents infection & diarrhea.
The Immunologic Components of Mature Milk
♣ Immunoglobulins
• Mature milk
contains all of the different antibodies (M,A, D, G, E), but secretory
immunoglobulin A (sIgA) is the most abundant.
♣ Lactoferrin
It has antimicrobial activity (bacteriocide, fungicide). Human colostrum has
the highest concentration, followed by human milk, then cow milk
♣ Lysozyme
Enhances sIgA bactericidal activity against gram-negative organisms.
♣ Mucins
Adhere to bacteria and viruses and help eliminate them from the body.
♣ Leukocytes
With the transition from colostrum to mature milk, the percentage of
macrophages increases from 40-60% of the cells to 80-90%.

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◘ Physical Properties of Milk
White appearance due to the presence of:
 the calcium salt of casein.
 the emulsified lipids.
The pH of milk is 6.6-6.8.
The Volume of milk at the high level of lactation is 1.5 liters of milk.
◘ Milk Formation
The formation and secretion of milk depend on:
• Prolactin
• Growth hormones
• Cotrisol
• Parathyroid hormone

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1. During Pregnancy:
2. After Birth:
 Milk ejection is promoted by:
1- Neurogenic stimulant (stimulated by suckling)
2- Hormonal reflex (oxytocin & prolactin)
Alcohol
Nicotine
Caffeine
Marijuana and
other drugs
Environmental
Exposures
Genes

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♦ Alcohol
 The alcohol transfers to the breast milk and affect
directly on the baby.
 It slows let down reflex (oxytocin hormone).
♦ Nicotine
 The nicotine in the milk is 1.5- 3 times higher
than in the blood.
 Over time the infant could metabolize it
in liver and emit nicotine into kidneys.
♦ Caffeine
♦ Marijuana and other drug abuse
Marijuana, cocaine, and heroin.
Very harmful for mother and affect the infant directly and negatively.
Each drug may include bacteria, heavy metals, pesticides.
♦ Environmental Exposures
Avoid eating swordfish, king mackerel, and
shark from freshwaters that are contaminated.
 Avoid exposure to paints, glues, furniture strippers, nail
polish and gas fumes.

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♦ Genes
•Different variations of Apolipoproteins affect on
the amount of fat absorbed into the bloodstream
and fat metabolism, then affect the breast milk composition.
Cows milk vs. human milk
Human milk Cow’s milk
• Higher content of water and
lactose.
• Lower content of protein than
cows milk.
• Contain vitamins and minerals
that are necessary for human
growth.
• It lacks some
of the immunological
components that are
required by the
human infant.
• It contains foreign proteins
that may trigger allergic
reactions in some babies.

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◘ Benefits of Mother’s Milk
1. It is high in nutritional value.
2. It is rich in immunological components .
3. It is sterile and cheap.
♣ It has positive effects on mother health:
It reduces the risk of developing breast cancer.
Causes weight loss.
Delays menstruation.
Causes low iron loss.