Fetal Development and Maternal Adaptations

goal gestation

37-42 wks

preterm

<37 weeks gestation

early term

37-38/6 wks

full term

39-40/6 wks

late term

41-41/6 wks

postterm

>42 wks gestation

antepartum

prior to labor and childbirth

intrapartum

onset of labor through the delivery of the placenta

postpartum

after birth and until return of reproductive organs to normal nonpregnant state (estaminte 6 wks)

gestation

process of carrying embryo/fetus in the uterus

abortion

loss prior to 20 wks gestation

stillbirth

fetal death occuring at 20 wks or later

gravida

pregnancy

parity

birth after 20 wks

nulligravida

never been pregnant

primigravida

first pregnancy

multigravida

multiple pregnancies

nullipara

no pregnacy beyond the stage of viability

primipara

one pregnancy who’s reached at least 20 wks gestation

multipara

multiple pregnancies that reached at least 20 wks gestation

TPAL

term

preterm

abortion

living

What is the GP-TPAL?

Mrs. Smith has been pregnant 4 times. Her first pregnancy resulted in SAB at 8 wks. 2nd & 3rd pregnacy delivered at 38/4 and 37/6. The 4th pregnancy delivered at 36/2. She has 2 boys and 1 girl living.

G: 4

P: 3

T: 2

P: 1

A: 1

L:3

What is the GP-TPAL?
Mrs. Youing is pregnant for the 5th time. Her first 3 pregnancies resulted in SAB at 7 wks, 8 wks, and 6 wks. Her 4th pregnancy she delivered twins at 37/1 who are now 3 y/o.

G: 5

P: 1

T: 1

P: 0

A: 3

L: 2

embryonic stage

implantation to end of 8th wk post conception

fetal stage

beginning of 9th wk post conception-birth

about 11wks gestation

Factors Affecting Embryonic & Fetal Development

Quality of Ova & Sperm: miscarriage, anomalies, chromosomal, & genetic problems

Intrauterine Environment: unsuitable uterus = SAB, STI, STD surgieries, infections

Teratogens: agents can cause development of abnormal sturctures - drugs, virues, alcohol, stress

Teratogens

chemical: alcohol, tobacco, vape, illicit drugs, medications (accutane, lithium, coumadin, phenytoin)

infections: rubella, cytomegalovirus (CMV), syphilis, toxoplasmosis, zika

embryonic membranes

chorion: outermost layer w/ finger like projections (chorionic vili) assist in attaching and implanting into uterus → placenta

amnion: fuses w/ chorion to become amniotic sac (thin inner protective membrane contains the embryo and amniotic fluid)

amniotic fluid

fetus swallows and urinates it

T: 700-1,000mL

polyhydramnios

>2000mL

caused by GI problems/anomalies

oligohydramnios

<500 mL

caused by renal anomalies; poor placental perfusion

amniotic fluid functions

shields against pressure and provides cushion

helps control temp

allows symmetrical growth & development

MSK development

protects against cord compression

prevents membranes from adhering to fetal parts: amniotic bands

placenta

one layer of cells between maternal/fetal circulation

metabolic and nutrient exchange

many things cross

endocrine gland: produces hormones for pregnancy

Human Chorionic Gonadotropin (HCG)

serum 7-10 days after fertilization

urine at missed menses

stays high until placenta is fully functioning and producing its own estrogen and progesterone

Estrogen

growth in uterus & breasts

increased vascularity

increased vasodilation

progesterone

essential for pregnancy

development of endometrium for implantation

decreases contractility of uterus

prolactin

importan role in lactation

Human Placental Lactogen (HPL)

stimulates changes in maternal metabolism

insulin resistance → gestational DM

Relaxin

softens ligaments and cartilage in skeletal system

quiets the myometrium

Umbilical Cord

connects embryo/fetus to placenta

1 large vein (oxygenated → embryo/fetus) and 2 small arteries:AVA (deoxygenated → placenta)

Wharton’s jelly

insertion of cord: center

check cord at birth for vessels

check for nuchal cord, knots

Fetal Circulation

placenta

umbilical vein (oxygenated blood)

ductus venosus (liver)

foramen ovale (between 2 atriums)

ductus arteriosus

2 umbilical arteries (unoxygenated blood)

Pulmonary pressure

high

takes path with least resistance

systemic pressure

low

gets blood to the body

FHR w/ doppler

8-12 wks

quickening

20 wks

earlier for multipara

earliest point of viability

22 wks

production of surfactant

more developed respiratory system

28 wks

sucking reflex

32 wks

survival w/ little support

36 wks

lung maturation

22wks surfactant is starting to be produced

further into gestation more surfactant is produced

surfactant

mixture of fats and proteins that reduces surface tension and coats the alveoli

prevents alveoli from sticking together

presumptive signs (subjective)

amenorrhea

N/V

breast tenderness/changes

fatigue

reported weight gain

increased urinary frequency

quickening

probable signs (objective)

Hegar sign

Chadwick sign

Goodell signs

Positive pregnancy tests (serum/urine)

Ballottement

Enlarging abdomen

Fetal outline felt by examiner

Positive signs

fetal visualization (US)

FHT

fetal movement detected/palpated by examiner

Pregnancy tests

hCG: 7-10 days after conception

serum hCG-blood (high accuracy)

urine hCG (home pregnancy tests) - first voided morining, repeat in one wk if negative or no period, follow up w. PCP.

McDonald’s Rule - fundal height

level of umbilicus by approx. 20 wks; approx; 1 cm per week

findal heigh correlates with gestational age: 32 wks = 32 cms

uterus

quickening 16-20wks

ballottement 16-18wks

braxton hicks 20wks

lightening 38-40wks - fundal height decreases as fetus descends into pelvis for birth

cervix

Chadwicks sign

Goodell’s sign

Mucus plug

increased friability

ripening last 4 wks of gestation

vag

pH changes (more alkaline)

Glycogen rich (candidiasis - yeast)

leukorrhea (increased clear/white slippery vaginal discharge)

breasts

enlargement (heaviness, fullness, and tenderness)

nipple and areola become larger and darker

integumentary

striae gravidarum

chloasma/melasma

linea nigra

cardiovascular

increase blood volume (30-50%)

increase HR, systolic murmur, S3

32 wks: 10-15bpm increase from baseline

vasodilation

pseudo-anemia (hemodilution) - Hgb 12-16, Hct 38-47

elevated clotting factors = hypercoagulable state

Vena cava syndrome - supine hypotension

respiratory

O2 increases

Increase RR

3rd trimester: larger uterus pushed diaphragm upward → pressure on lungs

→ SOB & decreased lung capacity

GI

N/V

constipation

heartburn

food aversions/cravings

PICA

Renal

increased GFR

increased urianry frequency

OP remains same

MSK

relaxin

icnreased mobility (pelvic joints → pain, lordosis)

change in center of gravity/balance

diastasis recti

Endocrine/Metabolic

increased BMR

increase intake of calories, protein, carbs, & water

placenta (endocrine gland) → hCG, estrogen, progesterone, HPL, etc

weight gain

pattern

• 3.5-5 lbs (1st trimester)

• 1lb per week (2nd/3rd trimester)

recommendations (IOM)

energy

additional 340 kcal 2nd tirmester

450 kcal 3rd trimester

fluids

8-10 glasses per day

4-6 glasses → water

protein

element basic to growth

calcium

• bone and teeth formation of developing fetus

  • milk, nuts, legumes, dark green leafy vegetables

water soluble vitamins

folic acid (foalte) 400/600 mcg → reduce neural tube defects

• fortified grains/cereals/breads, leafy vegetables, dried peas/beans, seeds, orange juice

pyridoxine (B6) → helps w/ N/V

Vit C (ascorbic acid) → enhance absorption of iron

Iron

iron supplements → prenatal plan (2nd and 3rd trimesters)

• empty stomach/between meals

• combine w/ Vit C for enhanced absorption

• avoid milk, caffeine, and tea

• can cause GI discomfort & constipation

  • before bed to avoid N/V

  • stool softners

  • green, tarry, thick bowel movements

fetal liver stores (3rd trimester)

Pregnancy (nutritional issues)

No alcholol

avoid caffeine

• no more than 200mg daily

• infertility, SAB, IUGR

Fish & mercury levels (avoid shark, swordfish, tuna, king mackerel, tile fish)

Listeriosis

• avoid hotdogs, lunch meat, deli meat, soft cheeses (brie, feta)

• avoid unpasteurized milk/dairy

PICA

Risk: family hx, childhood hx, low SES, iron/zinc deficiency