Maternal: Care for the Fetus

1. Assessment of maternal and fetal

   health

2. Providing nursing care

3. Health teachings

Nursing role and Nursing care during normal pregnancy (3)

1. Pre-embryonic (1st 2 weeks, beginning with fertilization)

2. Embryonic (weeks 3-8)

3. Fetal (from week 8 through birth)

Stages of fetal development (3)

Ovum

WHAT IS IT CALLED: ovulation to fertilization

Zygote

WHAT IS IT CALLED: from fertilization to implantation

Embryo

WHAT IS IT CALLED: from implantation to 5 – 8 weeks

Fetus

WHAT IS IT CALLED: 5 – 8 weeks until term

Conceptus

WHAT IS IT CALLED: Developing embryo and placental structures throughout pregnancy

Age of viability

earliest age at which fetus survives if they are born

1. If 24 weeks

2. Fetus weighs more than 500-600g

What is the age of viability?

Fertilization

Conception and impregnation

Fertilization

Union of an ovum and a spermatozoon

Fertilization

Occurs at the outer third of the fallopian tube – ampullar region

Implantation

Contact betwen the growing structure & uterine endometrium

Implantation

Occurs approximately 8 – 10 days after ovulation

Implantation

Occurs high in the uterus on the posterior surface

embryo

Once implanted, the zygote is called an ?

human chorionic gonadotrophin (hCG); trophoblast

After fertilization, the corpus luteum in the ovary continues to function rather than atrophying under the influence of ? a hormone secreted by the ? cells

DECIDUA

The uterine endometrium instead of sloughing off as in a normal menstrual cycle continues to grow in thickness and vascularity becoming?

Decidua; it will be discarded after birth of the child

Latin word for falling off because?

1. Decidua basalis

2. Desidua capsularis

3. Decidua vera

Decidua has 3 separate areas:

Decidua basalis

WHICH DESIDUA AREA: part of the endometrium that lies directly under the embryo

Decidua basalis

WHICH DESIDUA AREA: the portion where the trophoblast cells are establishing communication w/ maternal blood vessels

Decidua capsularis

WHICH DESIDUA AREA: the portion of the endometrium that stretches or encapsulates the surface of the trophoblast

Decidua vera

WHICH DESIDUA AREA: the remaining portion of the uterine lining

Desidua capsularis

also known as desidua parietalis

decidua capsularis

As the embryo continues to grow, it pushes the ? before it like a blanket

chorionic villi

As early as the 11th or 12th day after fertilization, miniature villi, resembling probing fingers and termed ?, reach out from the trophoblast cells into the uterine endometrium to begin formation of the placenta.

200

At term almost ? villi have formed

cotyledons

30 separate segments (in a matured placenta) =

Chorionic villi

have a central core of loose connective tissue surrounded by a double layer of trophoblast cells

syncytiotrophoblast

Outer layer of the chorionic villi of the 2 covering layers is termed the ? or the syncytial layer which is instrumental in the production various placental hormones

cytotrophoblast or Langhan’s layer; 12 days

The middle or inner layer of the chorionic villi is called the ? or ? which is present as early as ? days of gestation

Cytotrophoblast or Langhans’ layer

appears to have a second function to protect the growing embryo and fetus from certain infectious organisms such as the spirochete of syphilis early in pregnancy.

syncytiotrophoblast, or the syncytial layer

Which layer of the chorionic vili is instrumental in the production various placental hormones:
-hCG

-Somatomammotropin

-Estrogen

-Progesterone

Inner layer – cytotrophoblast or Langhan’s layer

WHICH LAYER OF THE CHORIONIC VILLI: Disappears between 20th and 24th week

Inner layer – cytotrophoblast or Langhan’s layer

WHICH LAYER OF THE CHORIONIC VILLI: Offers little protection viral invasion @ any point

Placenta

Latin for pancake

The Placenta

Arises out of trophoblast tissue (fetal in origin)

The Placenta

Serves as fetal lungs, kidneys, and GI tract, and as a separate endocrine organ throughout pregnancy

THE PLACENTA

grows from a few identifiable trophoblastic cells at the beginning of pregnancy to an organ 15 to 20 cm in diameter and 2 to 3 cm in depth, covering about half the surface area of the internal uterus at term

blastocyst

is a hollow fluid-filled ball

Formation of Placenta

the blastocyst and uterine wall about 5 days after fertilization.

trophoblast cells

what cells form the placenta?

12 days

Formation of placenta happens about ? days after fertilization

12 days after fertilization

What day of the formation of the Placenta: Maternal blood (red) is flowing into communicating spaces that develop within the giant syncytial trophoblast cell that covers the surface of the developing placenta (blue)

12 days after fertilization

What day of the formation of the Placenta: The baby’s blood and blood vessels have not yet developed. The baby (embryo) has now developed into two layers.

cotyledons

At third-trimester placenta with baby, the placenta (blue) consists of about 30 tree-like structures called

12th day of p

maternal blood begins to collect in the intervillous spaces of the uterine endometrium surrounding the chorionic villi. (WHAT DAY OF PREGNANCY)

third week

By the ? week, oxygen and other nutrients such as glucose, amino acids, fatty acids, minerals, vitamins, and water osmose from the maternal blood through the cell layers of the chorionic villi into the villi capillaries.

True: exchange is carried out by selective osmosis thru the chorionic villi

TRUE or FALSE: For practical purposes, there is no direct exchange of blood between the embryo and the mother during pregnancy. WHY?

fetal cells, fetal enzymes, and alpha fetoprotein (AFP) produced by fetal liver

Because chorionic villi layer is only one cell thick - what can cross in maternal blood?

True

TRUE OR FALSE: Almost all drugs are able to cross into fetal circulation

cotyledons

These compartments, known as ?, are what make the maternal side of the placenta look rough and uneven.

Maternal blood pressure and pH of the fetal and maternal plasma

All of the specific mechanisms or processes that allow nutrients to cross the placenta are affected by: (2)

1. Diffusion

2. Facilitated Diffusion

3. Active Transport

4. Pinocytosis

Mechanisms by which Nutrients Cross the Placenta

Diffusion

WHICH MECHANISM for nutrients to cross placenta: When there is a greater concentration of a substance on one side of a semi-permeable membrane than on the other, substances of correct molecular weight cross the membrane from the area of higher concentration to the area of lower concentration.

Diffusion

WHICH MECHANISM for nutrients to cross placenta: Oxygen, carbon dioxide, sodium, and chloride cross the placenta by this method

Facilitated Diffusion

WHICH MECHANISM for nutrients to cross placenta: A carrier moves the substance into and thru the membrane

Facilitated Diffusion

WHICH MECHANISM for nutrients to cross placenta: Glucose is an example of a substance that crosses by this process

Active Transport

WHICH MECHANISM for nutrients to cross placenta: This process requires energy and action of an enzyme to facilitate transport

TRUE

TRUE OR FALSE: Amino acid concentration in the fetal plasma are twice what they are in the mother

Active Transport

WHICH MECHANISM for nutrients to cross placenta: Essential amino acids and water-soluble vitamins cross the placenta against the pressure gradient or from an area of lower molecular concentration to an area of greater molecular concentration.

Pinocytosis

WHICH MECHANISM for nutrients to cross placenta: Absorption by the cellular membrane of microdroplets of plasma and dissolved substances.

Pinocytosis

WHICH MECHANISM for nutrients to cross placenta: Gamma globulin, lipoproteins, phospholipids, and other molecular structures that are too large for diffusion and that cannot participate in active transport cross in this manner

Pinocytosis

WHICH MECHANISM for nutrients to cross placenta: Viruses that can infect the fetus can also cross in this manner.

100

how many maternal uterine arteries supply the mature placenta

50 mL/min; 500 – 600 mL/min

Rate of uteroplacental blood flow in pregnancy increases 🡪 from ? at 10 weeks to ? at term

first 3 months

No additional maternal arteries appear after the ? months of pregnancy; instead, to accommodate the increased blood flow, the arteries increase in size.

increase

The woman’s heart rate, total cardiac output, and blood volume all? to supply blood to the placenta

Braxton Hicks contractions

barely noticeable and painless uterine contractions

Braxton Hicks contractions

This contractions are present from about 12th weeks of pregnancy

Braxton Hicks contractions

aid in maintaining pressure in the intervillous spaces by closing off uterine veins momentarily w/ each contraction

left side

Uterine perfusion and placental circulation are most efficient when the mother lies on her ?, as this position lifts the uterus away from the inferior vena cava, preventing blood from becoming trapped in the woman’s lower extremities.

supine hypotension (i.e., very low maternal blood pressure and poor uterine circulation)

If the woman lies on her back and the weight of the uterus compresses on the vena cava, known as vena cava syndrome, placental circulation can be so sharply reduced that ? can occur

400 – 600 gms (1lb.); 1/6

At term – placenta weighs ? or ? the weight of the baby

inadequate circulation to the fetus

Smaller placenta =

circulation to the fetus was threatened because placenta was forced to spread out in an unusual manner to maintain sufficient blood supply

Bigger placenta =

larger than usual

The fetus of a woman with diabetes may also develop a ? placenta from excess fluid collected between cells.

syncytial (outer)

Besides serving as the source of oxygen and nutrients for the fetus, the ? layer of the chorionic villi develops into a separate and important hormone-producing system.

1. Human Chorionic Gonadotropin

2. Progesterone

3. Estrogen

4. Human Placental Lactogen (Human Chorionic Somatomammotropin)

WHAT HORMONES ARE PRODUCED BY THE SYNCYTIAL LAYER?

Human Chorionic Gonadotrophin (hCG)

WHICH HORMONE PRODUCED BY THE PLACENTA: 1st hormone produced

Human Chorionic Gonadotrophin (hCG)

WHICH HORMONE PRODUCED BY THE PLACENTA: Can be found in maternal blood and urine as early as the 1st missed menstrual period (shortly after implantation has occurred) through about 100th day of pregnancy

1 to 2 weeks

The pregnant woman’s blood serum will be completely negative for hCG within ? to ? weeks after birth.

placental tissue is no longer present.

Finding no serum hCG after birth can be used as proof that ?

Purposes of Human Chorionic Gonadotrophin (hCG)

purpose is to act as a fail-safe measure to ensure the corpus luteum of the ovary continues to produce progesterone and estrogen so the endometrium of the uterus is maintained.

Human Chorionic Gonadotrophin (hCG)

play a role in suppressing the maternal immunologic response so placental tissue is not detected and rejected as a foreign substance.

Human Chorionic Gonadotrophin (hCG)

if the fetus is male, it exerts an effect on the fetal testes to begin testosterone production and maturation of the male reproductive tract

8th week

? week of pregnancy: outer layer of cells of the developing placenta begins to produce progesterone – production of hCG begins to decrease

estrogen

WHICH HORMONE PRODUCED BY THE PLACENTA: is often referred to as the “hormone of women,”

estrogen

WHICH HORMONE PRODUCED BY THE PLACENTA: influences a female appearance

Estrogen

WHICH HORMONE PRODUCED BY THE PLACENTA: Produced as a 2nd product of the syncytial cells of the placenta

Estrogen

WHICH HORMONE PRODUCED BY THE PLACENTA: Contributes to the mother’s mammary gland development in preparation for lactation

Estrogen

WHICH HORMONE PRODUCED BY THE PLACENTA: Stimulates uterine growth to accommodate the developing fetus

Progesterone

WHICH HORMONE PRODUCED BY THE PLACENTA: “hormone of mothers”

Progesterone

WHICH HORMONE PRODUCED BY THE PLACENTA: is necessary in pregnancy to maintain the endometrial lining of the uterus

Progesterone

WHICH HORMONE PRODUCED BY THE PLACENTA: Present in serum – as early as 4th week of pregnancy – as a result of the continuation of the corpus luteum

Progesterone

WHICH HORMONE PRODUCED BY THE PLACENTA: Reduce contractility of the uterine musculature during pregnancy = preventing premature labor

Progesterone

WHICH HORMONE PRODUCED BY THE PLACENTA: probably produced by a change in electrolytes (potassium and calcium), w/c decreases contraction potential of the uterus

Human Placental Lactogen (Human Chorionic Somatomammotropin)

WHICH HORMONE PRODUCED BY THE PLACENTA: is a hormone w/ both growth-promoting and lactogenic (milk-producing) properties

Human Placental Lactogen (Human Chorionic Somatomammotropin)

WHICH HORMONE PRODUCED BY THE PLACENTA: produced by the placenta beginning the 6th week of pregnancy – increasing to a peak level at term