LEC 2.2-2.3: Amniotic Fluid to Fetal Immune System :

Amniotic Fluid

Clear, straw-colored fluid in which the fetus floats. It originates both from the fetus & the mother. It is produced by the amniotic membrane.

10th

In the ___ week of fetal life, the fetal urine contributes to the fluid.

800-1200 mL

Volume of amniotic fluid

Oligohydramnios; Kidney Problem

If amniotic fluid index is less than 500 mL, what is this called? Indicating what about the fetus?

Polyhydramnios; Esophageal atresia

If amniotic fluid index is more than 2000 mL, what is this called? Indicating what about the fetus?

Meconium

What does green colored amniotic fluid indicate?

Hemolytic dss or break down of RBC at a fast rate

Causesr

What does golden colored amniotic fluid indicate?

1. Shock absorber

2. Medium of excretion

3. Fetal Drink & Specimen

4. Maintains fetal temperature

Purpose of Amniotic Fluid

Umbilical Cord

Conduit between the developing embryo or fetus and the placenta.

55 cm

Approximate size of the umbilical cord

3; AVA (2 arteries, 1 vein)

__ blood vessels of umbilical cord

Wharton’s Jelly

What is the gelatinous mucopolysaccharide that covers the umbilical cord called?

Nuchal Cord

Case where umbilical cord wraps around the neck of the fetus

1. Pre-embryonic stage

2. Embryonic

3. Fetal

Stages of Intrauterine Development

20-24 mL; 500 grams

For a fetus to be considered viable, it needs to have released ___ ago of station and greater than ___.

Germ Layer

group of cells in an embryo that interact with each other as the embryo develops and contribute to the formation of all organs and tissues.

1. Ectoderm

2. Mesoderm

3. Endoderm

Germ Layers

Ectoderm

Germ layer

responsible for the formation of the nervous system, hair, nails, skin, epidermis, sebaceous and sweat glands, cellivari glands, mucous membrane of the mouth, epithelium of nasal oral passages.

Mesoderm

Germ layer

the middle layer and envelope; cardiovascular system, reproductive musculoskeletal system, urogenital system except for the bladder

Mesoderm; 16th day of life

What layer does the cardiovascular system develop from. starting what day?

Fetal Doppler: 10-12 weeks

Fetal Scope: 16 weeks

Stethoscope: 20

When is the fetal heart tone audible?

Irregular; 110-160 bpm; 28 weeks

Fetal heart tone is ___ in the first few weeks but regulates within ___ bpm starting ____weeks.

Hemoconcentrated

Quality of fetal blood in which high concentrations of red blood cells compared to adults.

Fetal Doppler

Hears or monitor the heart rate or the heartbeat of their fetus.

Probe

Apply a lubricating gel similar to that of an ultrasound, and you are to apply it on the fetal back.

Fetoscope

Connected to a stethoscope.

The doctor will be able to hear the heartbeat of the fetus using this as well.

Shunts

Small passages that direct blood that needs to be oxygenated

Purpose is to bypass the lungs and liver because these organs will not fully work until after birth

1. Foramen Ovale

2. Ductus Arteriosus

3. Ductus Venosus

3 Shunts

Foramen Ovale

• Shunt that bypasses the lungs

• Moves blood from the right atrium —> left atrium, which abnormally happens in adults.

• Bypasses the right ventricle rather it goes directly to the left atrium

Ductus Arteriosus

• Shunt that moves the blood from the pulmonary artery —> aorta

• Oxygen and nutrients from the mother's blood are sent across the placenta to the fetus.

• The enriched blood flows through the umbilical cord to the liver and splits into 3 branches.

• blood then reaches the inferior vena cava

Ductus Venosus

• Where most blood is sent throguh

• Coming from the placenta directly to the inferior vena cava

• Shunt that lets highly oxygenated blood bypass the liver to the inferior vena cava and then to the right atrium of the heart for pumping.

ligamentum venosum

• The ductus venosus is open at the time of birth, making central venous access possible through the umbilical vein.

• As fibrin infiltrates the ductus venosus, It usually closes within 3-7 days. After it closes the remnant is known as ___ ___

4th week AOG

The respiratory system develops from 1 hollow tube for esophagus and traches until ___ week AOG

3rd month AOG

Respiratory movement at ___ month AOG

Endoderm

What germ layer does the respiratory system originate from?

Surfactant

At 24 weeks AOG, what does the fetu sproduce which decreases alveolar surface tension on expiration, preventing alveolar prolapse and improving the infant’s ability to maintain respirations in the outside environment

Betamethasone

In cases wherein the mother is about to be in labor, they are immediately given intramuscular doses of steroid or ____, which stimulates the synthesis and released of the surfactants

Ectoderm

What germ layer does the nervous system originate from?

Neural Plate

A thickened portion of the ectoderm, is apparent by 3 weeks AOG.

tube; CNS, brain, and spinal cord

The top portion of the neural plate differentiates into the neural ___ which will form the ___

crest; PNS

The bottom portion of the neural plate differentiates into the neural ___ which will develop the ___

Folic Acid

What vitamin is needed to avoid spinal cord disorder such as meningocele?

Endoderm

What germ layer does the digestive system develop from?

sterile; Vitamin K

Fetuses have a ___ intestine, causing low ___ levels since the bacteria that synthesized it are absent.

Atresia

Condition wherein an orifice or passage in the body is abnormally closed or absent.

Stenosis

Narrowing of the GI tract

Omphalocele

When the abdomen fails to close anteriorly, this may result into this or a birth defect in which an infant’s intestine or other abdominal organs are outside the body because of a hole in the naval area.

Fetal Liver

Functioning as a filter between the incoming blood and the fetal circulation and as deposit site for fetal spores such as iron and glycogen. It is still immature at birth.

• Hypoglycemia

• Hyperbilirubinemia

What may the immature fetal liver lead to?

Mesoderm

What germ layer does the reproductive system come from?

6 weeks AOG

When does gonads develop?

12th; 16th; 500 mL/day

• Urine formation at ___ week and excreted into the amniotic fluid by ___ week

• Fetal urine is excreted ___ ml/day

36 weeks AOG

The skin of the fetus appears clear and almost translucent until subcutaneous fat begins to be deposited at about ___ weeks AOG

Lanugo

16 weeks AOG; 36 weeks AOG

• Skin is covered by soft downing hairs that serves as insulation to preserve warmth

• Develops at __ weeks AOG and diminishes at __ weeks AOG.

Vernix caseosa; 20 weeks AOG

• A cream cheese like substance that is important for lubrication and prevention of the skin from macerating in utero.

• Forms by the end of ___ weeks AOG.

IgG

What antibody gives the fetus temporary passive immunity against diseases for which the mother has antibodies?

IgA & IgM

Presence of what antibodies proves the fetus has been exposed to a disease?

insulin

Fetal pancreas produces ___ needed by the fetus since it is one of the few substances that can’t cross the placenta from the mother to fetus

metabolic; calcium

estrogen

The thyroid and parathyroid glands play vital roles in fetal ___ function and ___ balance

Fetal adrenal glands supply a precursor for ___ synthesis by the placenta

cartilage

During the first 2 weeks of fetal life, ___ prototypes provide position and support to the fetus.

Ossification; 12th

___ of this cartilage in the bone begins at about ___ week and continues all throughout fetal life and into adulthood. carpals, tarsals, and sternal bones generally do not ossify until birth is imminent.

11th

16-20

• Fetal movement seen at UTZ by ___ week (mother does not feel movement or quickening)

• Until at ___-___ weeks AOG, mother can feel Quickening

  • It is usually felt earlier with multigravida women

Month 1

Identify the month:

As the fertilized egg grows, a water-tight sac forms around it, gradually filling with fluid. This is called the amniotic sac, and it helps cushion the growing embryo.

The placenta also develops. The placenta is a round, flat organ that transfers nutrients from the mother to the baby, and transfers wastes from the baby.

A primitive face will take form with large dark circles for eyes. The mouth, lower jaw, and throat are developing. Blood cells are taking shape, and circulation will begin.

The tiny “heart” tube will beat 65 times a minute by the end of the 4th week. By the end of the first month, your baby is about 1⁄4 inches long – smaller than a grain of rice.

Month 2

Identify the month:

Your baby’s facial features continue to develop. Each ear begins as a little fold of skin at the side of the head. Tiny buds that eventually grow into arms and legs are forming. Fingers, toes and eyes are also forming.

The neural tube (brain, spinal cord, and other neural tissue of the central nervous system) is well formed. The digestive tract and the sensory organs begin to develop. Bone starts to replace cartilage.

The head is large in proportion to the rest of the baby’s body. By the end of the second month, your baby is about 1 inch long and weighs about 1/30 of an ounce.

At abut 6 weeks, baby’s heart beat can be usually detected. After the 8th week, your baby is called a fetus instead of an embryo.

Month 3

Identify the month:

Your baby’s arms, hands, fingers, feet, and toes are fully formed. Your baby can open and close its fists and mouth. Fingernails and toenails are beginning to develop and the external ears are formed.

The beginnings of teeth are forming. Your baby’s reproductive organs also develop, but the baby’s gender is difficult to distingush on ultrasound.

By the end of the third month, your baby is fully formed. All the organs and extremities are present and will continue to mature in order to become functional.

The circulatory and urinary systems are working and the liver produces bile. At the end of the third month, your baby is about 4 inches long and weights about 1 ounce.

Since your baby’s most critical development has taken place, your chance of miscarriage drops considerably after three months.

Month 4

Identify the month:

Your baby’s heartbeat may now be audible through an instrument called a doppler. The fingers and toes are well defined. Eyelids, eyebrows, eyelashes, nails, and hair are formed.

Teeth and bones become denser. Your baby can even suck his or her thumb, yawn, stretch, and make faces.

The nervous system is starting to function. The reproductive organs and genitalia are now fully developed, and your doctor can see on ultrasound if you are having a boy or a girl.

By the end of fourth month, your baby is about 6 inches long and weighs about 4 ounces.

Month 5

Identify the month:

You may begin to feel your baby move, since he or she is developing muscles and exercising them. This first movement is called QUICKENING.

Hair begins to grow on the baby's head. Your baby’s shoulders, back, and temples are covered by a soft fine hair called lanugo. This hair protects your baby and is usually shed at the end of the baby’s first week of life.

The baby’s skin is covered with a whitish coating called vernix caseosa. This “cheesy” substance is thought to protect baby’s skin from the long exposure to the amniotic fluid. This coating is shed just before birth.

By the end of the 5th month, your baby is about 10 inches long and weighs from 1⁄2 to 1 pound.

Month 6

Identify the month:

Your baby’s skin is reddish in color, wrinkled, and veins are visible through the baby’s translucent skin.

Baby’s fingers and toe prints are visible. The eyelids begin to part and the eyes open.

Baby responds to sounds by moving or increasing the pulse. You may notice jerking motions if baby hiccups.

If born prematurely, your baby may survive after the 23rd week with intensive care. By the end of the sixth month, you baby is about 12 inches long and weighs about 2 pounds.

Month 7

Identify the month:

Your baby will continue to mature and develop reserves of body fat. Your baby’s hearing is fully developed. He or she changes position frequently and responds to stimuli, including sound, pain, and light.

The amniotic fluid begins to diminish. At the end of the 7th month, your baby is about 14 inches long and weighs about 2-4 pounds. If born prematurely, your baby would be likely to survive after the 7th month.

Month 8

Identify the month:

Your baby will continue to mature and develop reserves of body fat. You may notice that your baby is kicking more. Baby’s brain is developing rapidly at this time, and your baby can see and hear.

Most internal systems are well developed, but the lungs may still be immature. Your baby is about 18 inches long and weighs as much as 5 pounds.

Month 9

Identify the month:

Your baby continues to grow and mature: the lungs are nearly fully developed. Your baby’s reflexes are coordinated so he or she can blink, close the eyes, turn the head, grasp firmly and respond to sounds, light, and touch.

Baby is definitely ready to enter the world! You may notice that your baby moves less due to tight space. Your baby’s position changes to prepare itself for labor and delivery.

The baby drops down in your pelvis. Usually, the baby’s head is down toward the birth canal. Your baby is about 18 to 20 inches long and weighs about 7 pounds.

1st trimester

period of rapid organogenesis susceptible to teratogens

2nd trimester

• most comfortable period

• since initial signs of pregnancy stabilizes during this time and the fetus continues to grow.

3rd trimester

• rapid fetal growth

• As there would be rapid disposition of fats, iron, and calcium

Naegele’s Rule

Identify the rule involved:

LMP - 3 months + 7 days = Expected Due Date

1. History taking

   1. Nutritional intake

   2. personal habits (smoking, drug use, exercise etc)

   3. Accidents or intimate partner abuse

2. Fundus

How to assess fetal growth

Xiphoid process

Fundus is a firm muscle beneath the ___ ___ and above the detus

Bartholomew’s Rule of Fours

Identify the way to assess fetal growth:

• 12 weeks: fundus slightly palpated above symphysis pubis

• 16 weeks: between symphysis pubis and umbilicus

• 20 weeks: fundus is palpable at the level of the umbilicus

• Full term/9th lunar month: fundus at the level of xiphoid process (37th-41st week). If AOG passes the 41st week, induction is needed

12 weeks

According to Bartholomew’s Rule of fours, fundus slightly palpated above symphysis pubis

16 Weeks

According to Bartholomew’s Rule of Fours, between symphysis pubis and umbilicus

20 weeks

According to Bartholomew’s Rule of Fours, fundus is palpable at the level of the umbilicus

Full Term

According to Bartholomew’s Rule of Fours, fundus at the level of xiphoid process (37th-41st week). If AOG passes the 41st week, induction is needed

McDonald’s Rule

Follow a symphysis fundal height measurement determining during mid pregnancy that a fetus is growing in utero

Make measurements using tape measure