Lecture 2 - Antepartum Family & Fetal Development Flashcards
What is supine hypotension?
When a pregnant patient lies supine and the weight of their abdomen compresses their vena cava and aorta - causes pre/syncope and hypoTN.
Intervention: Position pt on side until S/S subside and vitals stabilize.
What are the three stages of uterine development?
Menstruation (day 1) - shed on lining
Proliferation (day 7-14) - cell growth
Secretory (15-28) - glycogen secretion
What are the three stages of intrauterine development?
- Zygote/Pre-embryonic (Conception-Day 14)
- Embryo (Day 15-8 weeks)
- Fetus (9+ weeks)
What are the three primary germ layers? When are they differentiated?
Differentiated during 3rd week following conception
Ectoderm, Mesoderm, Endoderm
What is ectoderm?
Upper layer of embryonic disk
–> NS, skin, nails, hair
What is mesoderm?
The middle layer of embryonic disk
–> Bones & teeth, muscles, circulatory systems
What is endoderm?
Lower layer of embryonic disk
–> digestive system, lungs, liver, glands
What is chorion?
The outermost fetal membrane - covers the fetal side of the placenta. Contains major umbilical blood vessels that reach over surface of the placenta.
What are the two layers of embryonic membranes?
Chorion - outermost
Amnion - innermost
What membrane holds amniotic fluid?
The amnion - innermost membrane
How much amniotic fluid is present at term?
700-1000 mL
What are the purposes of amniotic fluid?
–> Maintaining body temperature
–> Barrier from infection
–> Cushion to protect fetus and umbilical cord
–> Enhancing fetal lung development by filling lungs and expanding alveoli
–> Encourages symmetrical growth
What is oligohydramnios? What is it associated with?
Having less than 300mL of amniotic fluid
–> Associated with fetal renal abnormities
What is polyhydramnios? What is it associated with and what complications can it cause?
More than 2L of fluid
–> Associated with GI and other malformations
–> Risk of pre-term labour, subinvolution (PP hemorrhage), risk of cord prolapse and issues with engagement.
What is a yolk sac? What is its purpose? When does it disappear?
Aids in transferring maternal nutrients and oxygen which have diffused through the chorion to the embryo.
–> Completely separated from the embryo by week 5-6
What are chorionic villi?
Villi that branch from the chorion and burrow into the uterine lining - areas of gas and nutrient exchange.
Maternal blood is present in subvillous space.
When does the umbilical cord develop? How many blood vessels does it have?
Develops from the connective stalk by end of 5th week.
–> 2 arteries, 1 vein.
How long is the umbilical cord?
Ave 55 cm at term
What is Wharton’s jelly?
A mucoid connective tissue that prevents compression of blood vessels in the umbilical cord.
What is a Nuchal cord?
When the umbilical cord is wrapped around the fetal neck.
–> Document how many times it is wrapped
What are cotyledons?
Functional unit of the placenta
What are the primary components of preconception care?
- Health promotion
- Risk factor assessment
- Interventions
What is a definition of infertility?
Those below the age of 35 who have been trying to conceive for a year.
When is the first week of a pregnancy (gestational age)?
First day of last menstrual period
Egg matures in ovaries from day 1-14, ovulation occurs on day 14
When is the fertile window?
Days 11-14 of menstrual cycle
What is lanugo?
Fine hair. Falls off round the 35 week mark
–> More common in pre-term babies.
What is the age of viability?
The age at which a baby has a reasonably good chance of surviving outside the uterus
–> 22-25 weeks at present with NICU support.
What is a zygote?
First 2 weeks of pregnancy
–> From fertilization to implantation.
What is gestational vs postconception age?
Gestational Age
–> Based on first day of last period
Postconception Age
–> Begins two weeks after last period - used when speaking about fetal development
Why is the 4-5 week mark of embryonic development so significant?
Formation of most vital organs, hematopoiesis.
What is quickening?
When childbearing person begins to feel fetal movement
–> 18 weeks for first pregnancy, 16 weeks in following pregnancies.
When does sex differentiation occur in fetal development?
possible by week 12.
Teratogens have the largest impact on fetal development in the first ____ weeks.
12
When is the placenta complete?
It is structurally complete at 12 weeks and continues to widen until 20 weeks. Then continues thickening.
What hormones are released by the placenta?
progesterone, estrogen, HPL (chorionic somatomammotropin)
What is the source and effects of HCG?
Secreted by the fertilized ovum and then replaced by chorionic villi
–> Maintains corpus luteum production of estrogen and progesterone until the placenta takes over function
What is the source of progesterone during pregnancy? What is its purpose?
Corpus luteum until replaced by placenta at 14 weeks
–> Maintains pregnancy by relaxing smooth muscles and decreasing uterine contractility
–> Fat deposits in subcutaneous tissues
–> Decreases mother’s ability to use insulin
What is the source of estrogen during pregnancy? What is its purpose?
Corpus luteum until replaced by placenta at 14 weeks
–> Promotes enlargement of genitals, uterus, and breasts
–> Causes fat to deposit in subcutaneous tissue
–> Relaxes pelvic ligaments & joints
–> Decreases mother’s ability to use insulin
–> Interferes with folic acid metabolism (increases clearance rate)
What is the source of human placental lactogen during pregnancy? What is its purpose?
Placenta
–> Growth hormone - contributes to breast development
–> Decreases maternal metabolism of glucose
–> Increases amount of fatty acids for metabolic needs
What are normal findings for the umbilical cord?
–> Vessels, length, location on placenta
AVA, 55cm, located centrally on placenta.
What are the three shunts seen in fetal circulation?
Ductus arteriosus
–> Between pulmonary arteries and aorta
Ductus Venosus
–> Allows blood from umbilical vein to bypass liver, being shunted to inferior vena cava
Foramen Ovale
–> Shunts from right to left atria, bypassing right ventricle and pulmonary circulation
Oxygenated blood from the placenta enters fetal body through umbilical vein. It is then shunted where by what structure?
Majority is shunted via ductus venosus into inferior vena cava, bypassing liver.
Enters R-atrium
From the right atrium, what does blood in fetal circulation do?
Most of it is shunted through the foramen ovale into the left atrium, where it is sent through the aorta.
If fetal blood did enter the right ventricle and is pumped through the pulmonary arteries, where does it go from there?
Most of it is shunted by the ductus arteriosus to bypass the lungs and enter the aorta.
What causes the foramen ovale to close into the fossa ovalis after birth?
Changes in pressure
–> Lower in RA and higher in LA following birth
What causes the ductus arteriosus to become a ligament following birth?
increase in oxygen levels
What causes the ductus venosus to change into a ligament following birth?
Closes with clamping of cord and d/t BV constriction caused by cold air and changes in oxygen.
What are dizygotic twins? Which embrionic structures do they share?
Fraternal
–> Each with their own chorion, amnion, and placenta.
What are the three presentations of monozygotic twins?
Early division: Diamniotic & Dichorionic w two placentas
Division between 4-8 days: Two amnions, one chorion w 1 placenta
–> shared placenta can mean unequal distribution of blood flow,
8+ day: Common amnion, chorion, placenta
–> concern for tangling of umbilical cord
What stimulates uterine enlargement?
Early: Estrogen + progesterone, increased vascularity, hyperplasia, hypertrophy, decidua
After month 3: Growing fetus, placenta, amniotic fluid
How is uterine enlargement measured?
From the pubic symphysis to the highest part of the uterus (fundus)
Often correlates closely with weeks pregnant. Note that uterus will descend during lightening as the fetus begins to engage in the pelvis.
What is Hegar’s sign?
At 6 weeks, the lower uterine segment softens - can be palpated vaginally.
–> Results in uterine anteflexion during 1st trimester, presses on bladder and causes urinary frequency.
How do uterine walls change during 2nd trimester?
Uterine walls strengthen and become more elastic
What are the 1st trimester changes of the uterus?
Softening of the lower uterine segment (Hegar’s Sign) at 6 weeks, results in uterine anteflexion and urinary frequency
When do Braxton Hicks Contractions occur? What are their purposes?
Irregular uterine contractions - occur after 4th month
–> Facilitate blood flow through intervillous spaces of placenta
How do Braxton Hicks contraction differ from preterm labour?
–> BHCs usually cease with ambulation
–> Do not increase in intensity or duration
–> Do not cause cervical dilation
Placental perfusion depends on maternal blood flow to uterus. How much blood usually travels through uterus at term?
450-650 mL/min at term
Compared to 50-200mls in non pregnant state
Two kinds of sounds can be heard when listening to intrauterine sounds with a doppler. What is uterine souffle?
Rushing or blowing sound of maternal blood flowing through uterine arteries to the placenta
–> Synchronous with maternal pulse
Two kinds of sounds can be heard when listening to intrauterine sounds with a doppler. What is funic souffle?
Bruit caused by fetal blood flowing through umbilical cord
–> Synchronous with fetal heartbeat
What cervical changes are observed at week 6 of pregnancy?
Goodell’s Sign
–> Softening of cervical tip d/t vascularity, hypertrophy, hyperplasia
Friability leads to increased bleeding and pain.
How does the cervix change between nulliparous and following parity?
Nulliparous: rounded
After Birth: Oval
What is ballottement? When can it be performed?
Gently bouncing the fetus by tapping the cervix/uterus and feeling it rebound.
–> 16th-18th week
What is Chadwick’s sign? When is it observed?
A blue/purple hue to the cervix and vagina seen during pregnancy d/t increased vascularity.
–> Noted at week 6-8
How does estrogen change the vagina during pregnancy?
Thickening of mucosa
Loosening of Connective Tissue
Hypertrophy of smooth muscle
Lengthening of vaginal vault
What is Leukorrhea?
A whitish mucous discharge seen during pregnancy
What is the operculum?
A mucous plug that protects against bacterial invasion. Expelled when cervix effaces and dilates closer to birth.
What breast changes are seen due to estrogen and progesterone during pregnancy?
Feeling of fullness, heightened sensitivity, tingling, heaviness
Inhibits lactation
What accounts for breast enlargement during the 2nd and 3rd trimester of pregnancy?
Mammary gland growth
Lactation is inhibited by ____ until levels decrease after birth. However, colostrum may be expressed as early as ____
Inhibited by estrogen + progesterone
Expressed as early as 16 weeks - avoid expressing until 37 weeks.
What causes cardiac hypertrophy during pregnancy?
Increased blood volume + CA
Heart will return to normal size after birth
How does heart position change during pregnancy?
Diaphragm elevates
–> Heart is lifted upwards and rotated forward and left so apical pulse is shifted upward and laterally.
How does pulse rate change during pregnancy?
Increases by 10-15 bpm during 2nd trimester and persists until term
How does maternal BP change during pregnancy?
1st trimester
–> Decrease in BP
2nd trimester
–> Lowest
3rd Trimester
–> Gradual increase to pre-pregnancy levels
Late: Enlarged uterus reduces flow in the legs from compression of iliac veins and inferior vena cava –> dependent edema, varicose veins, hemorrhoids
What is the physiologic anemia of pregnancy?
Decreased hematocrit + hemoglobin d/t increase in plasma that is higher than increase in erythrocytes.
Can be prevented/treated with iron supplements
What changes in blood occur during pregnancy?
Increase in blood volume
–> Plasma increase causes hemodilution
Increased leukocytes
Increases coagulability and venous stasis
How does cardiac output change during pregnancy?
Increases from 30-50% above non-pregnant state by 32 weeks gestationally
–> Decreases to 20% increase above non pregnant level by 40 weeks
Which position can prevent supine hypotensive syndrome in pregnancy?
Left side or use of wedge.
How do progesterone and estrogen affect the respiratory system during pregnancy?
Both lower threshold for Co2, increasing sensitivity to it
Estrogen relaxes rib cage ligaments, allowing chest expansion - chest expansion replaced abdominal breathing as diaphragm lifts 4 cm. Increased vascularity can cause epistaxis and nasal stuffiness.
Which structural changes occur to the renal system during pregnancy?
Ureter dilation leads to increased risk of urinary stasis (risk of UTI)
How does GFR change during pregnancy?
GFR increases
In what position is kidney function more and less efficient during pregnancy?
Most: lateral recumbent
Least: Supine
Increase in melanotropin during pregnancy can cause hyperpigmentation in which forms?
Darkening of nipples, areolae, axillae, vulva
Chloasma (mask of pregnancy)
Linea nigra
Changes in center of gravity during pregnancy can cause which MSK changes?
Lordosis, curvature of thoracic area d/t weight of breasts.
–> Low backache
–> Waddling gait
The pressure of enlarging uterus effects the rectus abdominal muscles in which ways?
Causes diastasis
–> Separation of rectus abdominis muscles
N&V during 1st trimester is caused by which hormone?
Increase in hCG + carbohydrate metabolism
How do mineral requirements change during pregnancy?
Phosphorus + Calcium
Why does appetite increase during 2nd trimester?
Increased fetal need and loss of N/V associated with 1st term.
Changes in taste and smell can also cause increased dietary habits
Pregnancy can cause ptyalism. What is this?
Excessive salivation
What causes pyrosis in pregnancy?
Increased progesterone cause decreased tone and motility of smooth muscle leading to:
–> esophageal regurgitation
–> slowed gastric emptying
–> Reverse peristalsis
Pregnancy can cause constipation. What causes this?
Slowed gastric emptying, decreased intestinal motility leads to increased water reabsorption.
–> May exacerbation by iron supplementation
What might cause risk of gallstones during pregnancy?
Distension of gallbladder, increased emptying time, thickening of bile
How does thyroxine affect fetal development?
Possibly plays a role in early neural development
What causes gestational diabetes?
Reaction that occurs in some d/t increased insulin resistance during pregnancy
What are the presumptive signs of pregnancy?
Signs that are associated often with pregnancy, but that do not guarantee that one is occurring. Subjective.
–> Breast changes, amenorrhea, N/V, urinary frequency, fatigue, quickening
What are probable signs of pregnancy?
Objective signs that indicate pregnancy
–> Changes in pelvic organs, hCG levels, Braxton Hicks, Ballottement
When does hCG appear in blood and urine during pregnancy?
Blood: 7-10 days after conception
Urine: 1 day after missed menses
What are the positive signs of pregnancy?
Definitive and objective signs of pregnancy
–> Visualization of fetal heartbeat, visualization of fetus, fetal movement palpated or visible.
What is Naegele’s rule to estimate DOB of fetus?
First day of last menstrual period
–> Subtract 3 months, add 7 days
Ensure year is updated.
What does Nulligravida mean?
Person who is not or has never been pregnant.
What do the letters in GTPAL stand for?
Gravidity, term, preterm, abortion, living children
What questions should you ask on top of GTPAL when collecting obstetrical history?
Stillbirths and neonate or child death
What is considered a stillbirth?
End of pregnancy lasting more than 20 weeks, or that weighed more more than or equal to 500 grams with no signs of life.
How does the need for prenatal visits change over the course of a pregnancy?
The longer the pregnancy, the more frequent the visits.
What is the provincial standardized documentation for prenatal care?
The 2017 Ontario Perinatal Record (OPR)
How do folate needs change during pregnancy?
Preconceptual (planning): 0.4 mg
During Pregnancy: 0.6 mg
What caloric changes are necessary during pregnancy?
2-3 extra food servings from any group
2nd trimester - 230 extra calories
3rd trimester - 452 extra calories
How does expected weight gain change with pregnancy?
The less a person’s BMI is before pregnancy, the more weight they are expected to gain.
What teas are safe in moderation (2-3 cups a day) and should be avoided during pregnancy?
Safe in moderation: citrus peel, ginger, lemon balm, rosehip, linden flower, peppermint
To avoid: Chamomile, aloe, coltsfoot, juniper berries, pennyroyal, buckthorn bark, labrador tea, sassafras, duck roots, lobelia, and senna leaves
What is the T-ACE screening tool?
A screening tool for alcohol dependence.
T- tolerance
A - Annoyed
C - Cut back
E - Eye opener
What is the Calgary Family Assessment Model?
A model that allows for comprehensive assessment of family strengths, resources, problems, and illness through targeted questions about family structure, development, and function.
A mental health screening should be used routinely how often during the antenatal period?
At least one.
Protein in the urine during pregnancy can be a sign of what?
Pre-eclampsia
A nuchal translucency test can be used to detect what?
Measures the amount of fluid behind a fetus’s developing neck
–> Can detect Down syndrome, trisomy 18, and congenital heart defects
When is a routine morphology ultrasound done during pregnancy?
18-20 weeks
When is chorionic villus sampling done?
Between weeks 10-13
When would an amniocentesis be performed during pregnancy?
15-20 weeks.
What is pulmonary surfactant?
Secreted by type I and II cells that line the interior of alveoli and decrease surface tension
–> Lecithin, Sphingomyelin
–> Ratios of these two are used to determine fetal lung maturity from amniotic fluid samples.
What is cephalocaudal development?
Head-to-rump development in utero that is encourages by the heart, head, neck and arms receiving the most oxygen-rich blood.
When is fetal heartbeat detectable by ultrasound and doppler?
Ultrasounds: 6 weeks
Doppler: 8-17
What does gravida mean?
A pregnant person
What does primagravida mean?
Person pregnant for first time
What does multigravida mean?
Person who has been pregnant 2 or more times
What does nullipara mean?
A person who has not completed up to 20 weeks of pregnancy
What does primapara mean?
A person who has completed one pregnancy of more than 20 weeks.
What is multipara?
A person who has completed 2 or more pregnancy of longer than 20 weeks.
Which five pages are included in the Ontario Perinatal Record?
Record 1 - ID, Pregnancy summary, Hx
Record 2/3 - Prenatal
4 - Resources: Screening for anxiety, depression, alcoholism. Weight gain recommendations
5 - Postnatal visit
Poor dental care in pregnancy is a risk factor for which complications?
Pre-eclampsia
PTB, SGA
What is pruritis gravidarum? What causes it?
Sever Itching during Pregnancy
–> Associated with hyperbilirubinemia caused by pregnancy induced cholecatasis
