208, 209, 210 Pregnancy Flashcards
What changes occur in the uterus during pregnancy?
massively increases in size and volume
hypertrophy from estrogen (and maybe progesterone)
increased blood flow
What changes occur in the cervix during pregnancy?
softening, cyanosis (early pregnancy)
hypertrophy and hyperplasia with eversion of columnar endocervical glands
production of mucus rich in immunoglobulins (protects from vaginal bacteria)
What changes occur in the vagina during pregnancy?
increased vascularity (Chadwick sign)
increased mucosal thickness
loosened connective tissue
hypertrophy of smooth muscles
How long is the corpus luteum present and functional during pregnancy?
until 7 weeks gestation
What are the symptoms of a luteoma?
maternal virilization
no effect on fetus
What cardiac changes are normal in pregnancy?
heart displaces up and to the left (looks in larged on CXR)
increased blood volume (50%)
increased resting heart rate (15%)
both of which lead to increased cardiac output
What vascular changes are normal in pregnancy?
blood pressure decreases in second trimester and returns to normal levels in third trimester
impaired venous return with an increase in SVR
What respiratory changes are normal in pregnancy?
elevated diaphragm and increased subcostal angle
increased tidal volume, decreased residual volume
What GI changes are normal in pregnancy?
displacement of stomach and intestines by uterus
increased hepatic blood flow (can have “abnormal” alk phos and albumin)
reduced gallbladder contractility
What renal/urinary changes are normal in pregnancy?
increased kidney size and GFR (may need to serum creatinine decrease)
uterine displacment of ureters
increased bladder pressure
What hematologic changes are normal in pregnancy?
hypervolemia
increased erythrocyte volume (slight increase in Hb and Hct)
increased iron requirement
can have slight leukocytosis (increased CD8, decreased CD4)
increased clotting factors
What factors regulate placental transfer of nutrients?
maternal blood flow and surface area of exchange
concentration of nutrients and mode of transport
rate of fetal blood flow and surface area of exchange
What changes to fetal circulation occur at birth?
foramen ovale closes
ductus venosus and umbilical vessels collapse
closure of ductus arteriosus (due to marked decrease in pulmonary vascular resistance because of loss of fluid)
What makes most of the amniotic fluid volume?
fetal kidneys secreting urine (after 16 weeks of gestation)
What is the difference in O2 saturation between fetal and adult hemoglobin?
fetal hemoglobin has increased oxygen affinity relative to adult hemoglobin
What is the role of CRH in labor and delivery?
stimulates maternal adrenals to produce DHES –> increases placental estrogen synthesis –> stimulates myometrial contractility
also accelerates maturation of fetal lungs
What factors mediate myometrial contractility for labor and delivery?
prostaglandin F2alpha and oxytocin bind to cells and promote calcium channel opening –> depolarizes cells and leads to contraction of myocytes
Frequency of contractions is controlled by ____________; force of contractions is controlled by ____________.
Frequency of contractions is controlled by frequency of action potentials; force of contractions is controlled by numer of fibers activated.
What are the milestones of stage 1 of labor?
interval between onset of labor and full cervical dilation
oncet of painful contractions with variable duration
rapid survical change
What are the milestones of stage 2 of labor?
interval between full cervical dilation and delivery of fetus
can last up to 4 hours (nulliparas) or 3 hours in multiparas
epidural analgesia decreases duration
What are the milestones of stage 3 of labor?
interval between delivery of neonate and delivery of placenta
usually occurs 10-30 mins after delivery
A 33 yo G3P2 at 28 weeks presents to her internist for her flu shot. She appears well but her resting heart rate is 100 bpm and her BP is 90/60. Her internist orders a CXR, which demonstrates a mildly enlarged cardiac silhouette. A d-dimer is elevated. An ABG is done that demonstrates mild respiratory alkylosis. What is her most likely diagnosis?
a) pulmonary embolus
b) acute influenza
c) cardiomyopathy
d) normal pregnancy
d) normal pregnancy
all of these changes (increased HR, decreased BP, enlarged CXR cardiac silhouette, elevated coagulation factors, mild respiratory alkylosis) are normal in pregnancy
A 38 yo G2P1 @ 7 weeks of pregnancy is taken to the operating room for suspected ovarian torsion. Laparoscopy confirms this diagnosis and the left ovary is removed. Pathology confirms the presence of a corpus luteum cyst on the removed ovary. What should be given to maintain her pregnancy?
a) nothing
b) estrogen
c) progesterone
d) hCG
c) progesterone
Oxygenated blood is delivered to the fetus from the:
a) umbilical arteries
b) umbilical vein
c) fetal lungs
b) umbilical vein
What treatments should be offered during preterm labor?
antenatal corticosteroids (fetal lung development)
antibiotics for GBS infection
diagnosis and treatment of underlying causes
What strategies may be used to prevent preterm birth?
17-hydroxyprogesterone caproate
vaginal progesterone
cerclage in short cervix (a stitch) if prior preterm labor
screen/treat bacteriuria
treat symptomatic bacterial vaginosis
smoking cessation
longer intervals between pregnancies
What is the definition of cervical insufficiency?
painless cervical dilation in absence of contractions, usually mid-trimester
may result in membrane prolapse, preterm premature rupture of membranes (PPROM) and preterm labor
What is the difference between PROM and PPROM?
PROM = rupture of membranes prior to onset of labor
PPROM = rupture of membranes prior to onset of labor and before 37 weeks gestation
How is premature membrane rupture diagnosed?
sterile speculum exam with vaginal pooling of basic fluid and microscopic “ferning” patterns
How is PROM/PPROM managed?
hospitalize for duration of pregnancy with expectant management + steroids/antibiotics (if < 34 weeks)
What is placenta previa?
implantation of placenta in location where it covers cervical os
characterized by painless bright red vaginal bleeding
What are the risk factors for placenta previa?
prior cesarean delivery, multiparity, advanced maternal age, prior placenta previa, smoking
What are the treatments for placenta previa?
monitor with pelvic rest
planned C-section at 37 weeks
expectant management if appropriate
monitor for progression to placenta accreta
What is vasa previa? How is it diagnosed?
vaginal bleeding from fetal vessels
can theoretically diagnose with an Apt test (fetal blood cells won’t lyse in alkaline solution), but usually does not happen becuase this is an indication for rapid delivery (only takes minutes for a fetus to bleed out)
What is placental abruption?
premature separation of placenta from the uterine wall and most typically characterized by vaginal bleeding in the presence of uterine contractions
vaginal bleeding may not always be evident (can be concealed bhind placenta)
What are the risk factors for placental abruption?
hypertension, prior abruption, abdominal trauma, smoking, cocaine, uterine anomalies or submucosal fibroids, PPROM
What is the definition of fetal growth restriction? What are common causes?
fetus less than 10th percentile for a given gestational age
fetal: aneuploidy, fetal anomalies, infection, multiple gestation
uteroplacental: chronic hypertension, preeclampsia, chronic abruption
maternal: malnutrition, drug use, smoking, chronic medical conditions
What is the definition of preeclampsia?
new-onset hypertension and proteinuria
can have severe features (BP >160/110, maternal symptoms like headache/RUQ pain, hepatic injury/failure, renal injury/failure, pulmonary edema, coagulopathy, HELLP syndrome)
What is the definition of Rh alloimmunization?
exposure of Rh negative mother to Rh positive fetal blood leads to antibody production that can result in hemolytic disease of fetus/newborn in subsequent pregnancies
prevent by giving Rh Ig to all pregnant women who are Rh negative
What are the common etiologies of spontaneous abortion/miscarriage?
definition: pregnancy loss before week 20 of gestation
chromosomal abnormalities (most common), congenital anomalies, infection, uterine anomaly, maternal medical condition
What are the common etiologies of intrauterine fetal demise/stillbirth?
definition: pregnancy loss after 20th week gestation
chromosomal abnormalities, congenital anomalies, maternal medical conditions, hypertensive disorders of pregnancy, infection, multiple gestations
What is the mechanism of disease leading to Rh alloimmunization of the fetus? What is the earliest gestational age at which this can occur?
maternal IgG antibodies can cross placenta and directly hemolyze fetal RBCs that are Rh positive
treat starting at 28 weeks gestation
How do fetal growth restriction and preeclampsia result in preterm delivery?
both are iatrogenic indicators –> balance of risk of harm to mother/fetus is higher with continued pregnancy than with delivery
What is the difference between cervical insufficiency and preterm labor?
CI presents from weeks 16-24 with painless cervical dilation
preterm labor occurs later with painful uterine contractions and cervical changes
What are the contents of the umbilical cord?
2 umbilical arteries (deoxygenated)
1 umbilical vein (oxygenated)
stroma (Wharton’s jelly)
covered by amnion
What structures of the placental disc come from the mother vs. fetus?
maternal: intervillous blood, decidua of disc and membranes
fetal: cord, chorionic plate, villous tree, chorion + amnion of membranes, trophoblasts in decidua
What is uteroplacental insufficiency?
problems with getting maternal blood from circulation into the placenta, associated with hypertension and preeclampsia
caused by failure of fetal trophoblasts to remodel maternal vessels –> hypertension secondary renal arterial stenosis
What are the placental manifestations of uteroplacental insufficiency?
abnormal maternal vessels (thick walled), global underperfusion problems (ex. growth restriction), focal/regional underperfusion (infarct, placental abruption)
What is fetal vascular malperfusion?
problems getting fetal blood into the placenta and back
associated with cord accident and problems with fetal circulation (ex. heart disease, abnormal umbilical cord, thrombosis)
What are causes of acute placental inflammation?
neutrophil-predominant inflammation in the placenta
caused by vaginal/GI microbes or hematogenous spread
What are the maternal and fetal responses to acute placental inflammation?
maternal response: subchorionitis, chorionitis, amnion necrosis
fetal response: phlebitis, umbilical arteritis, necrotizing funisitis
What is chronic placental inflammation?
lymphocyte or macrophage inflammation of the placenta
caused by infection or maternal anti-fetal rejection
What are the complications of placenta previa?
requires c-section
if delivery attempted, can lead to severe hemorrhage with maternal and/or fetal demise
What are the types of abnormally adherent placenta?
accreta = placental tissue on myometrium
increta = invasion of fetal placental tissues into myometrium
percreta = invasion of fetal placental tissues through uterine serosa and onto adjacent structures
What are the different placental manifestations of twins?
dichorionic, diamniotic (thick dividing membrane)
monochorionic, diamniotic (thin dividing membrane)
monochorionic, monoamniotic (no membrane)
What gametes make up a partial mole? What is the hCG level? What are the findings?
gametes: 1 egg + 2 sperm (69 chromosomes)
elevated hCG
fetal parts present, some hydropic placental villi
What gametes make up a complete mole? What is the hCG level? What are the findings?
gametes: empty ovum + 2 sperm (46 chromosomes)
very elevated hCG
no fetal tissue, many hydropic villi (“grapes” and snowstorm on ultrasound)
Which type of molar pregnancy has a higher risk of choriocarcinoma?
complete moles
What are the components of the fetoplacental interface? Is there normally mixing of maternal and fetal blood in the placenta?
fetoplacental interface = barrier between fetal and maternal vasculature
chorionic villous is where it resides
formed in midtrimester out of cytotrophoblasts and syncytiotrophoblasts
barrier allows for exchange of gasses and nutrients WITHOUT mixing of the two circulations
When there is amniotic fluid infection, acute inflammatory cells emanate from both fetal and maternal circulations in response to chemotactic stimuli and can be seen in placental tissues. In which anatomic components of the placenta are you most likely to see maternal inflammatory cells? fetal inflammatory cells?
maternal acute inflammatory cells (neutrophils) can be seen in the membranes of the placenta where they originate from the blood vessels in the parietal decidua; also in the subchorionic space
fetal acute inflammatory cells can also be seen in the chorionic plate, emanating from the large fetal vessels; also seen exiting the umbilical vessels in the umbilical cord
A woman undergoes a spontaneous 1st trimester abortion. Examination of the passed tissue shows a fetus and an abnormal appearing placenta. Genetic testing by karyotype shows the conceptus is triploid, 69 XXY. Is this a complete mole? Partial mole? Is more testing needed?
this is likely a partial mole (complete mole would be diploid)
need additional testing to be sure
