Term
| Total blood vol. in pregnancy |
|
Definition
Plsma + RBC's
increases 30-40%
Starts at 6-8w, peaks at 28-34w
1.5L at 34weeks |
|
|
Term
|
Definition
| increases 45-50%, 5200 mls arout 32weeks |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| Mean Cell Hg concentration (MCHC) in pregnancy |
|
Definition
should be stable
if decreased = Iron defficiency anemia |
|
|
Term
| Mean cell vol. (MCV) in pregnancy |
|
Definition
should be stable
if decreased = IDA |
|
|
Term
|
Definition
|
|
Term
| Maternal need for iron in pregnancy |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
decreases 30% due to hemodilution
Usually stabilizes by 25w in women with healthly stores of ferratin.
Checking serum Ferritin at 28W is a better indicator than Hg levels because it measures the body's reserve of iron. |
|
|
Term
|
Definition
|
|
Term
| total iron binding capacity in preg. |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| plasma albumin levels in preg |
|
Definition
| decrease due to hemodilution |
|
|
Term
|
Definition
|
|
Term
| factor VII, VIII, and X (coagulation factors) in pregnancy |
|
Definition
|
|
Term
|
Definition
|
|
Term
| Cardiac output in pregnancy |
|
Definition
increases due to inc. blood volume.
50% increase by week 8.
Back to near-normal by 1w pp.
If a woman is going to have cardiac issues in pregnancy it will be noted early due to early onset of increased cardiac output. |
|
|
Term
| stroke volume in pregnancy |
|
Definition
|
|
Term
|
Definition
|
|
Term
| systemic vascular resistance in pregnancy |
|
Definition
decreases 20-30% to help the increased cardiac output be accomplished without an increase in bp.
starts by week 5, reaches low point at 16-34w. |
|
|
Term
| spiral arteries (uterine) are remodeled causing |
|
Definition
| low resistance uteroplacetnal circulation in normal pregnancies |
|
|
Term
|
Definition
increased in first trimester
dec in second trimester (reaches nadir-lowest point)
back to normal in third trimester |
|
|
Term
| related common discomforts in pregnancy |
|
Definition
varicosities
hemorrhoids
fainting |
|
|
Term
| supine hypotensive syndrome |
|
Definition
pressure on inferior vena cava and aorta causes hypotension (dec venous return causes decreased stroke vol., causes decreased cardiac output, causes decreased BP) when lying supine.
fix with L lateral position.
Not common and doesnt start until 20w. |
|
|
Term
| Normal RBC count for NON pregnant women |
|
Definition
|
|
Term
| Normal RBC count for pregnant women |
|
Definition
| 3.8-4.4 million/mm3 (dec level due to hemodilution) |
|
|
Term
| average increase in RBC mass in pregnancy |
|
Definition
|
|
Term
| Uterine blood requirements at term |
|
Definition
| 10-20% of maternal cardiac output |
|
|
Term
|
Definition
|
|
Term
| Arginine Vasopressin (AVP or atrial naturetic peptide) in pregnancy |
|
Definition
|
|
Term
| Systolic heart murmur in pregnancy |
|
Definition
NOT pathologic
92-95% women have in 2nd & 3rd trimester
Due to increased blood volume
Heard at base of heart when blood vol is the highest. |
|
|
Term
| How does RBC count change each trimester? |
|
Definition
Increasing levels of erythropoietin (EPO)occur in the first, second and third trimester, increasing RBC production.
Magnitude of change varies influenced by the woman’s iron stores.
Increase occurs at a stable rate, but slower than plasma volume (ie:
hemodilution causes drop in RBC levels), and may accelerate slightly in the third trimester. |
|
|
Term
| What is the basis for the change in H&H levels in pregnancy? |
|
Definition
Plasma volume is three times greater than the RBC volume increase, so the net result is a dec. in total RBC count, H&H.
The H&H dec. from the 2nd trimester on as plasma volume peaks (Hemodilution).
Total body hemoglobin increases 85 to 150 g in pregnancy, but net hemoglobin decreases due to hemodilution.
The mean hematocrit is 33.8% at term. |
|
|
Term
| What are the mechanisms that will facilitate the intestinal absorption of iron in pregnancy? |
|
Definition
Iron stores affect iron absorption.
Women who have good iron stores have minimal increases in absorption during the first trimester, and then increase absorption during the second trimester. By later pregnancy, iron stores may be exhausted, and iron needs met primarily from intestinal absorption.
Slow transit time in bowel will help increase absorption. |
|
|
Term
| Is it true that folate metabolism is increased in pregnancy? |
|
Definition
Folate requirements increase throughout the pregnancy, and are higher in multiple pregnancy.
Folate demands increase at least threefold during pregnancy from 50mg/day to 300 to 500mg/day during pregnancy.
The changes in folate metabolism during pregnancy are due to decreased serum folate and RBCs, increased plasma clearance, increased urinary excretion, and altered histidine metabolism. |
|
|
Term
| Describe the changes in red blood cell morphology in pregnancy. |
|
Definition
| The mean cell diameter and thickness of the RBCs change due to Epo & rapid RBC production, resulting in a cell that is more spherical in shape. |
|
|
Term
| Describe how the iron requirements change during pregnancy and why. |
|
Definition
The minimum iron reserve requirement in pregnancy is 500 g.
To meet the iron demands of pregnancy, women must absorb an additional 500 – 700 mg (2-8mg/day) more than normal.
Iron requirements increase during pregnancy by about 1 gram over the usual body iron stores of 2-2.5 grams in adult women.
This need for iron begins early in the second trimester, and peaks in the second half of pregnancy.
Increased iron is needed for expanision of RBC's, fetal and placental iron, to replace external iron loss and blood loss at birth. |
|
|
Term
| Pregnancy is an acquired hypercoagulable state. Describe the changes that occur in pregnancy to make it so. |
|
Definition
Hemostatic changes during pregnancy are thought to result in an ongoing low-grade activation of the coagulation system in the uteroplacental circulation.
Increased fibrin in UP circulation.
Increased fibrinogen, thrombin, coagulation factors I, VII, VIII, X, and Von Willebrand factor angigen.
Decreased fibrinolysis. |
|
|
Term
| How much blood is lost at delivery for a normal, singleton, vaginal delivery? |
|
Definition
|
|
Term
| How much blood is lost at delivery for caesarean section? |
|
Definition
|
|
Term
| Describe the changes in the hematological system during labor. |
|
Definition
Hemoglobin levels tend to increase during labor d/t hemoconcentration. This is related to increases in erythropoiesis by the kidneys as a stress responses, as well as muscular activity and dehydration.
WBCs increase up to 30,000/mm3 d/t neutrophil increase as a stress response.
During placental separation, tissue factor is released from the placenta and the decidua, activating coagulation.
The hypercoagulable state of pregnancy is further magnified during the laboring and childbirth process, presumably to prevent maternal hemorrhage . |
|
|
Term
| Adaptive changes in the cardiovascular system during pregnancy begin as early as: |
|
Definition
|
|
Term
| What are the most important hemodynamic changes in the maternal circulation during pregnancy? |
|
Definition
Increased stroke volume, HR, cardiac output, total blood volume, oxygen consumption
Decreased systemic vascular resistance, pulmonary vascular resistance, osmotic pressure, and BP. |
|
|
Term
| Describe the changes in the position and size of the heart in pregnancy. |
|
Definition
As the uterus grows, the diaphragm is displaced upward, and the heart shifts to a more horizontal position. The LV point of maximum impact may be shifted to the left.
All four chambers of the heart enlarge, with the greatest change seen in the left atrium. Cardiac ventricular wall muscle mass increases by 10-15% in the first trimester.
Increases in left atrial diameter parallels increases in blood volume, peaking around 30 weeks.
Thus the pregnant woman has a dilated heart with increased compliance. |
|
|
Term
| What is the cause of the physiologic systolic murmur often heard at the base of the heart in pregnancy as early as 12-20 weeks gestation? |
|
Definition
| Increased blood volume = increased cardiac load = heart murmur |
|
|
Term
| Uterine blood flow in pregnancy |
|
Definition
Increases
10 weeks: blood flow is 50 ml/m
28 weeks it is 200 ml/m.
Term: 500-800 ml.
The uteroplacental arteries are dilated and no longer responsive to circulating pressor agents or influences of the autonomic nervous system.
There is a large pool of blood within the uterus to maintain fetoplacental blood flow and oxygenation. |
|
|
Term
| Renal blood flow in pregnancy |
|
Definition
| Increases by the end of the first trimester and then decreases to term. |
|
|
Term
| Skin blood flow in pregnancy |
|
Definition
Increases significantly
Steady rise up to 18 – 20 weeks.
Sharp increase between 20-30 wks; nothing significant after that.
Lasts until 1w pp. |
|
|
Term
| Peripheral vasodilation in pregnancy |
|
Definition
Causes the dissipation of excessive heat created by fetal metabolism.
Increased peripheral flow in the mucous membranes of the nasal passages, explaining nasal congestion. |
|
|
Term
| Liver blood flow in pregnancy |
|
Definition
| Absolute blood flow to the liver does not change significantly however, the percentage of cardiac output perfusing the liver decreases. |
|
|
Term
| Breast blood flow in pregnancy |
|
Definition
| Increased evidenced by engorgement (early in pregnancy) and dilation of veins, accompanied by a sensation of heat and tingling. |
|
|
Term
| How is uterine blood flow affected by exercise? |
|
Definition
Redistribution of blood flow away from the visceral organs and to the skin and skeletal muscles.
Yields reduction of utero-ovarian blood flow.
The net result is that less blood flows to the uterus as more blood flows into skeletal muscles during exercise. |
|
|
Term
| What are the physiologic benefits of exercise in pregnancy? |
|
Definition
| Women have been shown to have shorter labors and fewer perinatal complications. |
|
|
Term
| Describe the changes to the cardiovascular system during labor. |
|
Definition
Significant hemodynamic changes attributed to the pain and anxiety associated with labor and delivery.
Release of catecholamines and increased systemic vascular tone.
Each contraction contributes approximately 300-500 ml of additional volume to the circulation significantly increasing cardiac output.
Hemodynamic changes during ctxn lead to improved venous return, transient tachycardia, increased circulating volume, and increased bp that returns to normal after ctxn. |
|
|
Term
| Increased circulating estrogen will cause increased mucous and membrane swelling of the nasopharnyx and ears. What are some common problems associated with these changes? |
|
Definition
| Stuffy nose, swelling of the airway, difficulty w/ intubation if needed, hoarseness, nose bleeds, rhinitis. |
|
|
Term
| Describe the anatomical changes to the thorax and breathing related to pregnancy. |
|
Definition
The AP & transverse diameters of the chest wall and the chest wall circumference increase which allows for diaphragm to rise as much as 4cm.
Lung capacity decreases by 4%.
Increased thoracic breathing.
Inspiratory capacity increases throughout pregnancy.
Ventillation increases by deeper respirations.
Many women experience SOB, this is NON pathologic. It is caused by the body's sensitivity to CO2 which increases RR. |
|
|
Term
| Progesterone stimulates the respiratory areas in the brainstem thereby increasing maternal pulmonary ventilation by: |
|
Definition
|
|
Term
| Describe the change in PCO2 levels during pregnancy. What is the hormone involved in this change? |
|
Definition
| Progesterone causes an increased respiratory rate which leads to mild hyperventillation = decreased CO2. |
|
|
Term
| What is the function of carbonic anhydrase B? |
|
Definition
| facilitate the transfer of CO2 and lowering of the PCO2. |
|
|
Term
| How does increased progesterone affect carbonic anhydrase levels? |
|
Definition
| Progesterone increases RBC levels of carbonic anhydrase B. |
|
|
Term
| What is the advantage of mild respiratory alkalosis in pregnancy? |
|
Definition
| Mild respiratory alkalosis in pregnancy facilitates the transfer of O2 from the mother to the fetus and CO2 from the fetus to the mother by increasing arterial carbon dioxide pressure gradient. |
|
|
Term
| Which prostaglandins act as bronchoconstrictors? |
|
Definition
|
|
Term
| Describe the anatomical changes to the maternal kidneys and urinary tract. |
|
Definition
Progesterone causes kidneys and ureters to dilate (esp R side).
Kidneys grow in vol.(inc by 30%) and length (1cm) d/t proliferation of tissue and vascular relaxation.
Ureters elongate and become tortuous as displaced by the uterus.
Ureters may contain as much as 300cc urine by 3rd trimester. Urine stasis leads to inc. risk for infection.
Bladder hyperplasia (primarily of the the trigone) and hyperemia cause bladder to grow and change by week 12.
Reduced bladder capacity from uterus pressure and later from presenting fetal part.
Progesterone decreases bladder tone = relaxed bladder. |
|
|
Term
| What four elements are involved in the changes in the kidneys and urinary tract? |
|
Definition
Uterine pressure
Progesterone influence
Relaxin hormone
Cardiovascular changes |
|
|
Term
| What is the trigone and how is it affected by estrogen? |
|
Definition
The triangular regional muscle of bladder wall.
Estrogen causes elevation or growth between the ureters and the urethral openings.
This change slows the flow of blood and lymph to the lower area.
The pt may have inflamed lymph nodes in groin area related to this trigone elevation.
Right ureter enlargement on scan would be a normal finding during preg due to pressure on the pelvic brim. |
|
|
Term
| Describe the physiologic changes in the renal system related to blood flow. |
|
Definition
Renal blood flow (RBF) increases 50-80% by mid second trimester.
The mean kidney lenght increases by approx 1cm due to inc RBF. |
|
|
Term
| Describe the physiologic changes in the renal system related to Glomerular filtration. |
|
Definition
GFR is increased by 40-60% during pregnancy, and its rise at 6 weeks precedes plasma volume expansion and increased cardiac output.
In 25% of people inc GRF can be detected at 2w OB.
GFR is measured by creatinine clearance. |
|
|
Term
| Describe the physiologic changes in the renal system related to tubular function. |
|
Definition
The elevated GFR increases the concentration of solutes and volume of fluid within the tubular lumen by 50-100%.
Tubular reabsorption increases in order to prevent rapid depletion from the body of sodium, chloride, glucose, potassium, and water. |
|
|
Term
| What maternal position enhances glomerular filtration rate and lowers blood pressure? |
|
Definition
|
|
Term
| Describe the changes to the renal system that occur postpartum. |
|
Definition
The postpartum period is characterized by rapid and sustained natriuresus and diuresis, especially days 2-5 as sodium and water retention is reversed. Since pitocin is an anti-diuretic hormone, it’s usage during L&D can exacerbate the effects of this diuresis.
Renal plasma flow (RPF) decreases in the first 5 days after delivery.
GFR remains elevated during the first postpartum day and then decreases over the next 2 weeks, but remains 20% elevated.
RPF, GFR, plasma creatinine, creatinine clearance, and BUN return to nonpregnant levels by 2-3 months postpartum. |
|
|
