APP Module (GTown) - Pregnancy (Hrs 1 and 2) Flashcards
How long is a full gestation term?
40 weeks, which includes two weeks from LNMP to conception
Why do we date from a patient’s LNMP?
Because date of conception is questionable usually
Why is gestation split into different trimesters?
Because these mark important developmental milestones and come with differing physiology
What is considered pre-term?
Pregnancy before 37 weeks.
What is considered an early and full term pregnancy?
37 to 39 weeks for early term, 39 to 41 weeks for full term
What is considered post-term?
More than 42 weeks
What is gravidity?
The state of being pregnant or how many pregnancies a woman has had
What is parity?
The number of total outcomes of pregnancy
What secretes beta-hcg?
placenta
What does hcg usually maintain?
corpus luteum
What does the corpus luteum secrete?
progesterone
When does the corpus luteum involute?
2nd/3rd trimester
What hormone is critical for early pregnancy?
progesterone
What are the three ways you can diagnose and detect an early pregnancy?
1) beta-hcg levels in serum or urine
2) ultrasound @ around 5 weeks
3) fetal cardiac activity at 6-8 weeks
By how much does plasma volume change in pregnancy?
Increases by ~50%
What are sequela of an increase in plasma volume?
- systolic murmur
- decreased blood viscosity
By how much does RBC volume change in pregnancy?
20-30% increase
The smaller increase in RBC volume as compared to plasma volume results in what?
physiologic dilutional anemia
Why is dilutional anemia not a real anemia?
Because there is an increase in RBCs overall
How much does CO change in pregnancy?
increases 30-50%
What results from an increase in CO?
increase in blood volume, decrease in afterload, uterine blood flow, and increase in HR by late pregnancy
What happens to systemic vascular resistance in pregnancy?
SVR falls in first two trimesters of pregnancy
Why is it thought that SVR falls in pregnancy?
decreased responsiveness to vasoconstrictive hormones
What drops because of a decrease in SVR?
blood pressure (systolic by more than diastolic)
What are the three main pulmonary physiologic changes that happen in pregnancy?
1) increase in O2 consumption by 15-20%
2) increase in TV by 30-40%
3) decrease in TLC by 5% due to elevated diaphragm from growing uterus
How many women experience late dyspnea of pregnancy?
50-70%
How is minute ventilation increased in pregnancy?
By increase in tidal volume, maintaining a normal respiratory rate
The hyperestrogenic state of pregnancy leads to an increased risk of what complication?
VTE
A hyperinsulinemic and hyperglycemic state leads to pregnancy being called what?
diabetogenic
What does progesterone cause in pregnancy?
smooth muscle relaxation of the uterine smooth muscle
What drives the parturition process?
the fetus
What induces oxytocin receptors on the uterus?
estrogen surge
What is the positive feedback loop of the labor process?
increase in oxytocin leads to an increase in contractions of the uterus which calls for more release of oxytocin, etc.
What two things does oxytocin stimulate?
- increased uterine contractions
- uterine prostaglandin secretion
What stimulates maternal oxytocin release?
cervical dilation
What are the three stages of labor? Which is the longest?
1) dilation and effacement (longest)
2) expulsion of the fetus
3) placental delivery
Which stage is the biggest risk for hemorrhage?
the delivery of the placenta
What is considered full dilation of the cervix?
10 cm
What are the top three indications given for a C-section?
1) labor arrest
2) non-reassuring fetal tracing
3) malpresentation
What is the rate of C-sections in the US?
~30%
What is the recommended rate for C-sections according to WHO?
10-15%
What is a spontaneous abortion?
pregnancy loss at less than 20 weeks gestation
When are spontaneous abortions the most common? rare?
1st trimester is the most common. 2nd trimester is the rarest.
What is the most common cause of spontaneous abortions?
fetal chromosomal abnormalities (~50%)
What are some other causes of miscarriage?
anembryonic ovum, teratogen exposure, endocrine (thyroid) abnormalities, and ↓ space in the uterus
What are some risk factors for miscarriage?
- advanced maternal age
- previous miscarriages
- smoking
- intrauterine trauma
What are the symptoms of a miscarriage?
- abdominal pain
- vaginal bleeding
- open cervical os
- expulsion of fetal content
What is a threatened abortion?
vaginal bleeding in the first trimester with a closed cervical os
What is a complete and incomplete abortion?
Complete means all the fetal contents have been expelled; incomplete means there is fetal content being retained.
What is there an increased risk of if there are retained products of conception?
endometritis
How do you surgically remove retained products of conception?
Dilatation and curettage (D and C)
What is the medical treatment for retained products of conception?
methotrexate
What does ectopia mean?
abnormal location or position
What is an ectopic pregnancy?
fetal implantation outside the uterus
Where do the majority of ectopic pregnancies happen?
~90% in the Fallopian tubes
What is the incidence of ectopics and where is it going?
1-2% and rising
What are the main risk factors for ectopic pregnancy?
1) PID
2) prior tubal surgeries
3) endometriosis
4) IUD
5) smoking
6) IVF
Why is PID a risk factor for ectopic pregnancy?
Because it causes scarring in the reproductive tract upon healing
How does a ectopic pregnancy present?
pelvic pain, missed menses, vaginal bleeding
Is ectopic pregnancy an emergency?
Yes, if it ruptures!
Why is it difficult to assess if a pregnancy is ectopic or not?
Early on its difficult to distinguish an ectopic pregnancy from a pregnancy of unknown location. It also presents similarly to other pathologies
What is the first thing any female of reproductive age complaining of acute onset of abdominal pain gets when they come to the emergency room?
Test to see if preggers or no
What is the beta-hgc threshold limit for visualization of a fetus on ultrasound?
1500 IU/L (or mIU/mL)
What makes an abnormal pregnancy likely?
if beta-hcg is positive but does not increase appropriately over time
How should a beta-hcg increase over time in early pregnancy?
It should DOUBLE every 2-3 days
What would you consider as a possible diagnosis if the patient had IVF?
Heterogenous pregnancy (one ectopic and one normal)
When do you repeat the beta-hcg if it is positive but below threshold?
2-3 days
What happens if the patient is hemodynamically unstable?
Means rupture is likely, active hemorrhage means SURGERY PRONTO!
What is the medical treatment for ectopic pregnancy?
MTX, methotrexate and very close management to make sure beta-hcg goes to zero, but only in select healthy patients
What are the two surgical options for ectopic pregnancy? Which one is more invasive?
salpingostomy and salpingectomy. The salpingectomy involves removal of the whole fallopian tube and is more invasive
What is the mechanism of action of methotrexate?
folic acid antagonist which inhibits DNA synthesis and thus targets rapidly dividing cells
What are the two possible criteria for diagnosing gestational hypertension?
BP over 140/90; or increased over pre-pregnancy levels
When does gestational hypertension usually happen?
3rd trimester
What percentage of pregnancies have hypertensive problems?
5-10%
What is a risk factor for gestational hypertension?
Multiple gestations
What is gestational hypertension a risk factor for?
pre-eclampsia
What are the two criteria to diagnose pre-eclampsia?
- hypertension
- proteinuria
What other symptom do you usually see in pre-eclampsia?
non-dependent edema
What is severe pre-eclampsia defined by?
- BP >160/110
- severe proteinuria
- edema
- signs of end organ damage
- HELLP syndrome
What is HELLP syndrome?
Syndrome of Hemolysis, Elevated Liver Enzymes, and Low platelets
What lab criteria are seen in hemolysis?
Increased bilirubin and LDH (RBC breakdown products)
burr cells, schistocytes, and other abnormal RBCs
What are schistocytes?
They are RBC fragments
What is eclampsia diagnosed by?
Symptoms of pre-eclampsia and seizures
What lab criteria are seen with low platelets?
Platelet count below 100
What lab criteria are seen with elevated liver enzymes?
Increased AST, ALT, Alk Phos, and LDH
What is the key pathophysiological concept behind pre-eclampsia?
shallow placental implantation
What are the three main pathophysiological aberrations seen in pre-eclampsia?
- abnormal placental vasculature
- coagulopathies
- endothelial dysfunction and imbalance in angiogenesis and antiangiogenesis factors
What do the placental changes cause?
Placenta will release chemicals that cause maternal systemic vasoconstriction and endothelial dysfunction
Why is a shallow implantation of the placenta and failure for the cytotrophoblast to invade the myometrium a cause of problems?
Does not allow for the remodeling of spiral arteries which lead to narrow vessel formation and placental hypoperfusion
What is the immune system rejection of the paternal antigen?
There is some evidence that closer the father is to the mother and more intimate, the less likely the pregnant mother is to experience pre-eclampsia
What are the risk factors for pre-eclampsia?
- genetics
- previous personal and/or family hx of pre-eclampsia
- hx of vascular dysfunction
What is the treatment of pre-eclampsia?
delivery!
What criteria factor into delivery of the fetus?
- disease severity and amount of maternal or fetal distress
- fetus’ gestational age
What can be used to buy more time if delivery would be too premature?
- inpatient monitoring
- mag sulfate
- corticosteroids for fetus
What are four other major complications of pre-eclampsia/eclampsia?
1) possibility of seizures post-delivery
2) high recurrence rate with severe disease
3) fetal risks in eclamptic state
4) maternal long-term vascular disease
What is the problem with delivering a fetus before it is due?
prematurity adds morbidity to infant’s life
What is gestational DM?
DM in pregnancy! Not including those who were diagnosed with DM prior to pregnancy
When does GDM usually manifest? When is it usually screened for?
Usually manifests in third trimester when insulin resistance is highest. Screened for in second trimester
What is the incidence of GDM among pregnancies?
2-12%
What is the hormonal dysfunction thought to cause GDM?
human placental lactogen
What does human placental lactogen do endocrine wise?
increases BS and increases IR
What does hPL do to the mother’s carbohydrate metabolism?
STRESSES it. Increased risk for DM later in life
What are the risk factors for GDM?
Same as those for T2DM: obesity, high cholesterol, ethnicity, sedentary lifestyle
What is the initial screen for GDM?
Drink 50g glucose load and check BS after 1 hr.
What is a positive on an OGTT?
2 blood glucose readings over 200 up to 2 hours after 100g glucose load
How is GDM managed?
- prepregnancy weight counseling, i.e. fetus should only add 300 calories to diet a day
- same management of T2DM after diagnosis: exercise, weight management, oral diabetic drugs, etc
What complications does GDM lead to for the mother?
- pre-eclampsia
- C-section delivery
- future risk for T2DM
What complications does GDM lead to for the infant?
- macrosomia (BIG baby)
- neonatal hypoglycemia due to decreased glucose load and increased insulin levels
- poorer outcomes, higher morbidity
What is placenta previa?
Placental placement obstructing the cervical os
What is placental abruption?
premature separation of the placenta from uterus AFTER 20 weeks gestation
What does placenta previa present as?
painless bleeding after 20 weeks gestation
What does placental abruption present as?
painful bleeding after 20 weeks gestation
What are the two things that determine risk factors for placenta previa?
1) anything that interferes with normal placental migration
2) abnormal endometrium in the upper uterine cavity
What are the risk factors for placenta previa?
- prior C-section or prior previa
- uterine surgery
- multiple gestations
- multiparity
- smoking
- advanced age
How is placenta previa diagnosed?
Via transabdominal ultrasound
What is contraindicated with placenta previa?
pelvic exam
What is there a higher risk for during a placenta previa pregnancy?
hemorrhage
How are placenta previa babies delivered?
Through C-section at 36-37 weeks
What is placental abruption linked to and what does it cause?
Linked to early placental disease and causes uteroplacental insufficiency.
What is the fetal mortality rate in placental abruption?
12%
What are risk factors for placental abruption?
- HTN, pre-eclampsia
- cocaine use
- trauma with shearing force
How is placental abruption diagnosed and managed?
- clinical diagnosis as it is difficult to diagnose on US
- support and preparation for possible delivery
- vaginal delivery is mild, but immediate delivery if unstable
What are the three other abnormal placental attachments?
1) placenta accreta
2) placenta increta
3) placenta percreta
What do abnormal placental attachments in general lead to a higher risk of in birth?
hemorrhage
What does overuse of C-section lead to?
Increased risks of complications in birth
What does underuse of C-section lead to?
increased overall maternal and fetal risk
What are the maternal risks of C-section?
Those of general surgery: longer hospital stay, longer recovery, risk of cardiac event or VTE
What are the fetal risks of C-section?
- considered high-risk delivery for fetus
- future risk of asthma
- increased fetal mortality, fetal resp. distress
What is shown in CXRs of babies with C-section more so than those in natural deliveries?
increase in retained fluid
