Placental and Maternal Phys Flashcards
1
Q
How long does the fertilized egg stay in the fallopian tubes? When does it arrive in the uterus?
A
- for the first 3 days
- day 4
2
Q
Outer and inner layer of the zona pellucida?
A
- outer layer= trophoblast = placenta and fetal membranes
- inner layer = cell mass to become embryo and fluid
3
Q
When does the trophoblast implant into the endometrium?
A
- day 6-7
4
Q
How does implantation of the blastocyst occur?
A
- in response to 17-OH progesterone from the corpus luteum, the endometrium glands are filled with glycogen, mucus, and rich blood supply (the secretory endometrium)
- implantation takes several days
- the conceptus is genetically diff from the mother
- genetically foreign cells usually rejected by immune system - this doesn’t occur during normal pregnancy - due to modifications of mother’s immune system
5
Q
Progenitor cytotrophoblast cells differentiate into what 2 layers?
A
- extravillous cytotrophoblast (inner)
- villous cytotrophoblast (outer)
6
Q
What is the importance of the extravillous cytotrophoblast?
A
- invasive into the decidua and myometrium
- invasive into spiral arteries which are remodeled into wide uteroplacental arteries (which anastomose with endometrial veins to form a lacunar system of low resistance)
- form core of villi (covered in synctiotrophoblast)
7
Q
Impt of villous cytotrophoblast?
A
- able to become syncytiotrophoblast
- forms placental villi with base of cytotrophoblast cells (Langhans layer) with overlying syncytiotrophoblast on surface
- specialized epithelium w/o distinct cell boundaries covering villous tree: transport of gases, nutrient and wastes as well as synthesis of peptide and steroid hormones that influence placental, fetal and maternal systems
- also forms 2 umbilical arteries and 1 vein
8
Q
What is the decidua influenced by? What do the decidual cells form?
A
- influenced by progesterone and later with invasion of trophoblasts (implantation), the stromal cells of secretory endometrium become decidual cells
- decidual cells directly under implantation site form basal plate of placenta (decidua basalis) and a factor limiting myometrial invasion
9
Q
What always separates the embyronic circulation from maternal blood and decidua?
A
- layer of trophoblast cells
10
Q
What is nitabuch’s layer?
A
- a layer of fibrin b/t the boundary zone of compact endometrium and cytotrophoblastic shell in the placenta
- possible role in preventing host/graft rejection
- allows for separation of placenta after delivery
11
Q
Why is the placenta considered an extra brain?
A
b/c:
- interface b/t mother and fetus
- prevents rejection of fetal allograft
- enables respiratory gas exchange
- transports nutrients
- eliminates fetal waste products
- secretes peptide and steroid hormones
12
Q
What are the metabolic fxns of the placenta?
A
- glycogen synthesis: uptake of glucose from maternal circulation, glycogen as an energy reserve
- cholesterol synthesis: as precursor for production of progesterone and estrogen
- removal of lactate: a waste product of placental metabolism is transferred to maternal circulation
- protein metabolism
13
Q
What are the placental peptide hormones?
A
- hCG: maintains corpus luteum production of progesterone until placenta takes over at 6-8 wks, regulates placental steroid production
- hPL: antagonizes maternal secretion of insulin to increase fetal glucose supply
- placental CRH: stimulates fetal ACTH resulting in fetal adrenal making DHEA-S as precursor to placental estrogen, in latter gestation, fetal cortisol stimulates CRH release which stimulates fetal ACTH that acts as an endocrine mediator of onset of labor
- IGF: regulates fetal growth
- VEGF
- placental growth factor
14
Q
What are the placental steroid hormones? Fxns?
A
- progesterone: maintains a non-contractile uterus, also anti-inflammatory and immunosuppressive to protect fetus
- estrogens: stim by placental HCG, also maternal and fetal blood supply DHEAS as substrate for additional estrogens (mostly from fetal adrenal)
15
Q
Role of enzymes that degrade maternal glucocorticoids?
A
- placenta regulates exposure of fetus to glucocortiocoids
- this has an impt role in regulating fetal organ development and maturation
16
Q
What materials are being transfered across the placenta? Where is this occurring?
A
- occurs at syncytiotrophoblast layer
- CO2 and O2 exchange
- glucose
- amino acid: fetus dependent on these for protein synthesis
- fatty acids from breakdown of maternal TGs
- immunoglobulin G (maternal abs)
- drugs (high MW least likely)
17
Q
Role of estrogen in pregnancy?
A
- enlargement of uterus
- breast enlargement and growth of ductal structure
- enlargement of external genitalia
- relaxation of pelvic ligaments
- affects many aspects of fetal development
18
Q
Role of progesterone in pregnancy?
A
- induces endometrial secretory cells to decidual cells
- contributes to development of conceptus b/f implantation, affects cell cleavage in developing embryo
- inhibits myometrial contractions
- may be involved with immune tolerance of fetus
- influences breasts for lactation
- helps develop thick mucous plug of cervix (helps prevent infection)
- along with estrogen changes cervix, vagina, vulva to allow for sufficient stretching to allow delivery
19
Q
What ophthalmic changes occur in pregnancy?
A
- cornea thickens: may cause problems for contact lens wearers, may cause blurred vision. Pregnancy is CI for refractory surgery
- decrease in IOP
- visual field changes or double visions are abnormal
- diabetic retinopathy may worsen dramatically during pregnancy
- with toxemia of pregnancy, choroidal vascular insufficiency causes secondary retinal detachments
20
Q
Dental changes in pregnancy?
A
- gingivitis: hormonal changes soften the tissues in the mouth contributing to bleeding or inflammation
- epulis of pregnancy: hyperplastic, grandulomatous lesion. Composed mainly of capillary vessels and endothelial proliferation, referred to as “pregnancy tumor”.
similar lesions seen in non-preg individuals with dilantin therapy
21
Q
GI changes in pregnancy?
A
Mostly due to progesterone (relaxation of smooth muscle)
- relaxation of esophageal sphincter - increased GERD
- decreased PUD due to increased mucus and decreased gastric secretion
- gallbladder empties incompletely in response to meals during pregnancy (results in increased risk of gall stones)
- delayed gastric emptying, slowed small bowel transit and decreased large bowel peristalsis - constipation, impaction
- increased portal venous pressure (but not central venous pressure)
- N/V (nausea gravidarum: 4-16 wks tx with Vit B6 (pyridoxine) 50-100 mg daily
- hyperemesis gravidarum: persistent and severe N/V = wt loss, dehydrayion, elect. imbalances, caused by rapid rising serum levels of hCG and estrogen: more comon in mult reg tx with IV fluids, antiemetics
22
Q
Renal and urinary changes in pregnancy?
A
- progesterone relaxes bladder wall and reduces ureteral tone and peristalsis, effect may persist 12-16 wk postpartum
- physiological hydroureter of pregnancy: can hold 200-300 ml of urine: enlarging uterus can compress ureter at pelvic brim (R more than L)
- hydronephrosis is common (R more than L)
- changes predispose preg women to UTIs and pyelonephritis
23
Q
What happens to the urinary bladder in pregnancy? Common complaints of preg lady? What else can occur, and what is this assoc with? Screening?
A
- enlarging uterus displaces and flattens bladder decreasing capacity, assoc with incontinence
- common complaints: increased frequency, nocturia, be vigilant about eval for UTI!
- asx bacteruria: 2-7% of women, assoc with acute pyelo, preterm labor and low birth wt infants. Tx prevents 80% cases of pyelo and reduces risk of preterm delivery
- screen 12-14 wks with MSCC urine culture and tx if + (E. coli MC)
- 30-40% will develop sx UTI
- any preg woman with pyelo must be admitted to hospital
24
Q
What happens to the renal fxn in pregnancy?
A
- both kidney increase in size 1-1.5 cm
- renal blood flow and GFR increase 40-50% by mid trimester
- Cr drops 0.3 mg/dl, BUN 50% drop and uric acid 33% drop
- hyperventilation (low PaCO2) of preg casues respiratory alkalosis which is compensated by renal excretion of bicarb
- extracellular volume increases (total body water increases 6-8 L, 2/3 of this is extravascular space)
25
CV changes in pregancy?
- stroke volume: increases 10-30%
- HR: increases 12-18 beats/min
- CO increases 40% by 20-24 wk
- systolic vascular resistance decreases 5-10% mmHg
- systolic BP: decreases 4-6 mmHg
- diastolic BP: decreases 8-15 mmHg
- mean BP decreases 6-10 mmHg
- O2 consumption for any given level of exercise increases 20%
- uterine blood flow approx 700 ml/min
- maternal blood flow to placental site: 500 ml/min
- muscle mass of heart increases
- heart is shifted to left
- apical pulse moves to 4th intercostal space at midclavicular line
- louder heart sounds
- wide split S1 and S2 heart sounds by 3rd trimester
26
What is supine hypotensive syndrome?
lying on back - IVC is compressed so decreased blood flow back to heart - pt with have nausea, just doesn't feel well
- also predisposes lower extremities to varicosities
27
Why is there physiologic anemia of pregnancy?
- plasma vol increases 50%
- red cell mass increases 20-35% - hemodilution and decrease in hemoglobin concentration
- total blood volume increases 40-50%
- anemia is common in normal preg women and may be beneficial as decrease in viscosity may help with perfusion
- anemia defined as Hg less than 11 (or less than 10.5 in 2nd tri) or Hct less than 33
28
What is the iron requirement in pregnancy?
- avg iron stores in normal men: 819 mg
- in women: 254 mg ( menses)
- total iron requirements during pregnancy: 1040 mg
- 1-2 mg of iron absorbed/day from food: 270-540 mg
- Fe deficit: 256-480 mg
- amt of iron absorbed from diet plus strored iron is insufficient to meet requirments of pregnancy
29
What nutritional supplements should women of reproductive age take? What else should be considered?
- all women of reproductive age should take folic acid 4-8 mg daily
- Can begin oral iron 6 months b/f conception to offset iron lost with menses
- if taking vitamin that has magnesium take at diff time than Fe (mg interferes with Fe absorption)
- Fe tablets can be lethal in small kids
30
What are the coag. changes in pregnancy?
- increase of procoag fibrinogen and clotting factors II, VII, VIII, X, IX, XII, and XIII
- decrease in protein S levels and inhibition of fibrinolysis
- hypercoagulable state
- these changes may be impt for minimizing intrapartum blood loss, there is prothrombotic state with an increased risk of thromboembolism during pregnancy and post-partum period (6-8 wks to baseline)
31
What happens to WBCs in pregnancy?
- leukocytosis
32
Respiratory tract changes in pregnancy?
- increased nasopharyngeal blood flow:
nose bleeds (epistaxis)
nasal congestion
polyp (specific to pregnancy)
- upper respiratory tract: increased phagocytic activity
- residual lung capacity decreases 20% due to enlarging uterus
33
Respiratory tract changes due to progesterone effects?
- stim. respiratory drive centrally
- minute ventilation increases 50% w/o a change of respiratory rate
- tidal volume increase
- oxygen consumption increases 20% to meet demands of the placenta, fetus, and maternal organs
- PaO2 ranges from 100-110 mmHg
- PaCO2 decreases to 27-32mmHg
34
What are the musculoskeletal changes in pregnancy?
- 25-35 lb wt gain on avg during pregnancy
- jt laxity in anterior and posterior ligaments of lumbar spine
- exaggerated lumbar lordosis and forward flexion of the neck
- separation and stretching of abdominal muscles put more strain on paraspinal muscles
- SI jts and pubic symphsis widen and have increased mobility
- pelvis tilted more anteriorly, increasing use of hip extensors, abductor muscles and stance is widened (low back pain)
- capral tunnel syndrome: preg causes inflammation, fluid retention and swelling
- sciatic nerve pain: common, extra wt and pressure caused by preg. can cause compression of sciatic nerve. The sxs will usually go away after childbirth. May reqr use of cane, walker or even crutches
35
Endocrine adaptations of what occur in pregnancy?
- interactions of fetal-placental maternal unit
- hypothalamus
- pituitary
- parathyroid
- thyroid
- adrenal glands
36
What are the hypothalamic hormones involved in pregnancy?
- GnRH: levels increase during pregnancy, main source is placental GnRH
- CRH: placental HPA axis is stimulated by maternal cortisol to release CRH from the decade-trophoblast-membranes:
Placental CRH drives the maternal and fetal pituitary
High CRH levels in maternal circulation
37
What happens to the anterior pituitary gland in pregnancy?
- decline in circulating gonadotropins due to high estradiol and progesterone levels
- GH declines, replaced by placental-derived GH
- increase in ACTH - pregnancy state hypercortisolim
- TSH mildly reduce in 1st trimester and modestly elevated at term
- serum prolactin levels increase throughout pregnancy
38
What happens to the intermediate lobe of the pituitary in pregnancy?
- increases in volume
- MSH elevated: linea nigra and melasma
- fetus is source of alpha-melanotropin (skin changes)- stimulates fetal growth
39
What happens to ADH in pregnancy? (stim from?)
- posterior pituitary
- ADH: preg women are less sensitive to action of ADH b/c of inactivating enzyme from placenta for ADH
- ADH has major role in controlling osmolality of plasma (largely Na+ conc) therefore slight decrease in plasma Na of 2-4 mEq/L
40
Oxytocin's role in pregnancy? Stim from?
- posterior pituitary
- maternal plasma levels increase throughout pregnancy
- involved in onset of labor
- involved in milk let down during lactation with nipple stimulation triggering release of oxytocin
41
What happens to parathyroid glands in pregnancy?
- PTH levels increase
- maternal Ca++ homeostasis adapts to meet Ca++ needs of fetus - 200 mg/day in 3rd trimester and 30 g total
- PTH facilitates transfer of Ca across placenta to fetus
- PTH mobilizes Ca++ from maternal skeleton
- Maternal Ca++ intake requirement increases
42
What happens to thyroid glands in pregnancy?
- increased TBG due to estrogen: increases thyroxine and triiodothyronine but not free T4 and T3
- increased TSH stim by hCG
- increased maternal iodine needs (investigate any goiter)
43
What happens to adrenal glands in pregnancy?
- cortisol is also affected by placental CRH
- RAAS is stim in pregnancy by high levels of estrogen and progesterone: regulates aldosterone secretion which stimulates absorption of Na+ and secretion of K+, aldosterone levels rise throughout pregnancy
- decreased vascular responsiveness to angiotensin II: uterine artery demonstrates refractoriness to vasoconstriction by infused angiotensin II
44
Glucose metabolism in pregnancy? What can this lead to?
- insulin resistant state develops in mother sparing glucose for preg. uterus
- diabetogenic hormones: GH, CRH, chorionic somatomammotropin (human placental lactogen) and progesterone
- maternal hyperglycemia and diabetes have detrimental effects on developing embryo at several stages of development - birth defects
- hyperplasia of pancreatic B cells
- increased insulin secretion
- fasting glucose: levels decreased by about 3 mg/dL in 1st trimester
- relative insulin resistance and hypoglycemia with increased lipolysis
- mother preferentially uses fat for fuel preserving glucose and AAs for fetus
- minimizes protein catabolism
- placenta readily transfers glucose, AAs, and ketone bodies but is impermeable to large lipids
45
Lipid metabolism in pregnancy?
- serum TGs (300%) and cholesterol (50%) levels rise during pregnancy
- High TG concentrations provide maternal fuel
- elevated LDL aids placental steroidogenesis
- 2nd trimester: fat accumulation
- 3rd trimester: maternal consumption of stored fat
- leptin: a hormone secreted by adipose tissue and the placenta plays plays key role in fat metabolism
46
Why is increased protein intake impt in pregnancy?
- to meet needs of growing fetus and placenta
- to meet maternal changes - increase in red cells
- avg daily allowance: 60 g
47
Water changes in pregnancy?
- avg inrease is 3 L - evident as ankle and leg edema -normal finding in many pregnant women (bilateral swelling compared to unilateral swelling if DVT)
48
What are the changes to the reproductive organs that occur in pregnancy?
- uterine enlargement 70 g to 1000 g
- at term 20% of CO is to uterus
- cervix, vagina, vulva: increased blood supply causing cyanotic changes, also cervix softens (due to relaxin) allowing dilation and passage of baby
- vulvar varicosities: disappear after delivery
- vulvar condylomata: grow rapidly during pregnancy and usually disappear after delivery (probably result of immunological changes)
49
Skin changes in pregnancy?
- straiegravidarum
| - rosacea worsens and clears after delivery
50
Hair and nail changes?
- increased or decreased rate
- many have some degree of hirsutism on face, limbs and back
- delivery may initiate a shedding cycle
- nails grow faster but may be more brittle, may have transverse grooves, and onycholysis
51
Vascular changes in pregnancy?
- spider telangiectasias
- palmar erythema
- aphenous, vulvar, hemorrhoidal varicosities in 40% of women
52
What is PUPP? Tx?
- pruritic urticarial papules and plaques of pregnancy:
- MC preg related dermatosis (1/130-300 pregnancies)
- PUPP assoc rash with intense PRURITUS
- develops in 3rd trimester
- first appears on abdomen
- common in 1st pregnancies and multiple gestations
- tx: antihistamines and topical corticosteroids
53
Immunologic changes in pregnancy?
- promote maintenance of the antigenic fetus in the maternal environment
- suppression of T cell mediated immunity
- levels of most cytokines are depressed particularly during the initial 20 wks of pregnancy, which is an impt phase to sustain the fetus
- whether this suppressed immune system translates into an increased risk of infections during pregnancy is still not clear with available data
54
Breast changes in pregnancy - stimulated by?
- stimuated by estrogen and progesterone
- 25-50% increase in size
- nipples and areola increase in size and pigmentation
- colostrum secretion in late pregnancy and after delivery
55
Breast changes in early pregnancy?
- influenced by chorionic gonadotropin
- increase in size
- tenderness
- breasts may tingle with temp change
- secretory glands begin to develop
* nausea and breast tenderness: first sxs women will notice even b/f late period
56
Breast changes in late pregnancy?
- proliferation of new acini is reduced
- lumen of units already formed become distended with secretory material (colostrum)
- parturition - new wave of mitotic activity and further growth and differentiation with milk secretion
57
Stages of lactogenesis?
- stage 1: secretory initiation - 2nd half of pregnancy - during late pregnancy many women are able to express colostrum
- stage 2: secretory activation - copious milk production after delivery - triggered by rapid decline in progesterone and elevated levels of prolactin, cortisol and insulin
