Maternal and Fetal Phys

Uterine enlargement effect on heart position

Heart rotates on its long axis with left-upward displacement, causing apical beat to shift laterally

Heart size change during pregnancy

Increases by about 12% due to increase in both myocardial mass and volume

Blood volume expansion timeline

Begins in 1st trimester, increases rapidly in 2nd trimester, plateaus in 30th week

Blood volume increase in pregnancy

50% elevation in plasma volume triggered by pregnancy hormones

Cardiac output change in pregnancy

Increases by 40% during pregnancy as a result of hormonal changes

Maternal heart rate change

Increases by 15 beats/min at rest

Multiple gestations cardiovascular effect

Have even more profound effect on maternal cardiovascular system

Kidney size change during pregnancy

Length increases by 1-1.5cm

Ureter changes during pregnancy

Become dilated

Renal plasma flow change

Increases by 50-85% above nonpregnant values

Bladder changes during pregnancy

Displaced upward and flattened

Early urinary sign of pregnancy

Increased urinary frequency

GI organs position change

Stomach pushed upward, large and small bowels extend upward

Appendix position change

Displaced superiorly in the right flank area

Reflux symptoms prevalence

Heartburn affects 30-80% of pregnant women

Gastrin production during pregnancy

Increases, raising volume and acidity of gastric secretions

Lower esophageal sphincter change

Becomes dilated, leading to reflux

Intestinal transit times in pregnancy

Decreased in 2nd and 3rd trimesters

Intestinal transit postpartum recovery

Returns to normal within 2-4 days postpartum

Hormone causing GI changes

Progesterone enhances water absorption, predisposing to constipation

Gallbladder function in pregnancy

Slowed and incomplete emptying, increasing risk for gallstone formation

RBC change during pregnancy

Expand by 33%, more with iron supplementation

Cause of anemia of pregnancy

Expanded blood volume with proportionally less increase in RBCs

Iron utilization in pregnancy

Enhanced erythropoiesis increases utilization

Maternal-fetal iron relationship

Placenta actively transports iron from mother to fetus, protecting fetus from maternal anemia

WBC count during pregnancy

Increases to as high as 16,000

WBC count during labor

Can range 20,000-25,000

Platelet changes in pregnancy

Increased along with consumption

Third trimester platelet phenomenon

Can fall below 150,000 in 6% of gravidas (gestational thrombocytopenia)

Clotting factors that increase markedly

Fibrinogen (factor I) and Factor VIII

Common skin changes in pregnancy

Hyperpigmentation including melasma, linea nigra, and striae gravidarum

Placenta endocrine function

Releases numerous hormones and enzymes into maternal bloodstream

Placenta transport function

Transports all fetal nutrients, metabolic products, oxygen and CO2

Substances that don't cross placenta

Heparin and insulin due to large molecular size

Drug transport across placenta

Drugs binding to plasma albumin may have higher unbound concentrations and higher placental gradient

Umbilical cord arterial composition

2 umbilical arteries carry blood from embryo to chorionic villi

Umbilical cord venous composition

1 umbilical vein returns blood to embryo

Wharton's Jelly function

Connective tissue surrounding arteries and vein in umbilical cord

Nuchal cord prevalence

23% of spontaneous vertex deliveries occur with loops of umbilical cord around baby's neck

Mature umbilical cord dimensions

About 50-60cm in length and 12mm in diameter

Fetal lung function in utero

Essentially nonfunctional with complete support from mother via placenta

Fetal lung fluid elimination

Forced out during delivery by chest compression and air entry

First breath preparation process

Chest squeeze pushes amniotic fluid out of nose and mouth

Organ maturation pattern

Organs mature at different rates and times during gestation

Effect of preterm delivery

May alter normal sequences of organ maturation events

Neonatal respiratory requirement

Must suddenly initiate and maintain oxygenation

Infant oxygen sensitivity

Very sensitive to hypoxia

Vascular resistance at birth

Rises as blood flow through placenta ceases

First breath circulatory changes

Pulmonary vascular resistance falls, foramen ovale closes, ductus arteriosus begins to constrict

Foramen ovale anatomy

Connection between the two atria

Ductus arteriosus anatomy

Connection between pulmonary artery and arch of the aorta

Postnatal blood flow change

Deoxygenated blood returning to right ventricle goes to lung and becomes oxygenated

Late gestation lung fluid

Contains large amounts of surfactant

Surfactant function at birth

Spreads along alveoli epithelial lining and decreases surface tension at end of expiration

Normal newborn heart rate at birth

150-180 beats per minute

Normal newborn heart rate after birth

130-140 beats per minute

Heart rate indicating distress

Less than 100 beats per minute

Normal newborn respiratory rate

40-60 breaths per minute

Resuscitation initiation timing

After 30 seconds of unsuccessful suctioning, drying, and warming

Key initial newborn assessment

Skin color

Additional stimulation methods

Slapping/flicking soles of feet or rubbing infant's back