4/14 Complications + Pathophysiology of Pregnancy Flashcards Preview

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Flashcards in 4/14 Complications + Pathophysiology of Pregnancy Deck (40):
1

causes of maternal mortality in us?

  • infection
  • Hemorrhage
  • HTN d/o of pregnancy 
  • Venous thromboembolism
  • Indirect causes such cardiovascular disease and non-obstetric injuries

2

What is Puerperal fever in pregnancy?

defined as T ≥100.4°F (38°C) that occurs for ≥2 consecutive days during the first 10 postpartum days

3

What are causes of puerperal sepsis?

complications?

causes:

  • endometritis (infection in the uterus)
  • perineal wounds
  • C-section wounds

complications:

  • risk of septic shock
  • pelvic thrombophlebitis
  • pelvic abscess

4

What is endometritis and how does it occur?

endometritis (infection in the uterus)

  • occur due to ∆s at the placenta-maternal interface, where
    • alkaline amniotic fluid, blood, and lochia (vaginal discharge) neutralize vaginal pH allowing bacterial growth
      • normally, vagina acidity (pH 4-5) usually protects against overgrowth of bacteria
  • Necrotic endometrium and placenta fragments make the uterine cavity favorable for the growth anaerobic bacteria

5

What are the common pathogens of endometritis?

70% caused by mixed anaerobic organisms

6

risk factors for endometritis?

  • Poor nutrition and hygiene
  • Premature or prolonged rupture of membranes
  • Chorioamnionitis
  • Prolonged labor
  • Numerous vaginal examinations or manual removal of placenta
  • C-section
  • Retained placental fragments or fetal membrane

7

What are the major causes of 

ANTEPARTUM HEMORRHAGE? 

POSTPARTUM HEMORRHAGE?

ante: placenta previa + placenta abruptio

post: uterine atony (80% of cases)

8

What is placenta previa?

How do you tell if a woman has it? 

“latin root of previa – going before”

placenta is partially or wholly in the lower uterine segment, over the cervical os

presentation: painless vaginal bleeding (70%)

9

What are the 4 types of placenta previa?

  • Total/complete - placenta covers internal os completely
  • Partial - placenta covers internal os partially
  • Marginal - lower edge of placenta reaches internal os, but does not cover it
  • Low-lying - Placenta is in lower segment, but the lower edge does not reach 

10

Risk factors for placenta previa?

  • Multiparity/multi-gestation – women with a lot of babies
  • Older maternal age
  • Prior hx of placenta previa
  • Prior C-section (placenta may adhere to scarred uterus)
  • Tobacco use

11

How do you diagnose placenta previa?

US (transabdominal or transvaginal)

12

What is placenta abruptio? 

How does a patient typically present?

premature separation of the “normally” implanted placenta due rupturing of maternal spiral arterioles in the decidua basalis, where it interfaces with the anchoring villi of the placenta; accumulating blood separates the decidua from its placental attachment to the uterus

presentation: painful vaginal bleeding, uterine tenderness and contractions

13

How does Placental abruptio form?

hypothesized to be an underlying abnormality in how the placenta has attached to the decidua or an inherent weakness or abnormality in the spiral arterioles, or trauma 

14

What happens if there is a complete placental abruptio?

  • fetal death - detached portion of the placenta is unable to exchange gases and nutrients; when the remaining fetoplacental unit is unable to compensate for this loss of function
  • placenta will also become infarcted since it’s not being perfused properly

15

2 types of placental abruptio?

  • Concealed hemorrhage occurs when blood dissects upward toward the fundus without vaginal bleeding
  • External or revealed hemorrhage occurs when blood dissects towards the cervix; presents with vaginal bleeding 

16

Risk factors for placental abruptio?

  • Maternal HTN
  • Placental abruption in a prior pregnancy
  • Trauma (blunt, falls, MVC) – big risk factor
  • Polyhydramnios with rapid decompression – rapid ∆ of the placental shape -> shearing force 
  • Premature rupture of membranes
  • Tobacco use

17

How do you diagnose placenta abruptio?

US (identifies abruption only 50% of the time!)

  • US is indicated to exclude previa, since abruptio may coexist with a previa

18

When does postpartum hemorrhage usually occur?

how is it diagnosed? 

  • usually occurs immediately following delivery
  • Hemorrhage criteria:
    • 10% drop in hematocrit
    • need for transfusion
    • signs/sx of acute anemia after a vaginal delivery or C-section

19

Major cause of postpartum hemorrhage and how does it occur?

Uterine atony (80%) ****

  • Normally the myometrium contracts around the myometrial spiral arterioles and decidual veins of the intervillous spaces and acts as a physiologic “ligature” to cut off blood flow
  • failure of the uterus to contract after placental separation (atony) puts these vessels at risk of bleeding post-partum

20

Other potential causes post-partum hemorrhage

  • Genital tract trauma/laceration during delivery
  • Cervix, vagina, perineum, extension of hysterotomy with laceration of uterine arteries 
  • Retained placental tissue
  • Low placental implantation in the uterus
  • Uterine inversion –uterus inverts as the placenta is delivered
  • Coagulation disorders

UTERINE ATONY is the major cause

21

Risk Factors of postpartum hemorrhage?

  • Prolonged labor, augmented labor, or rapid labor
  • History of postpartum hemorrhage
  • Overdistended uterus (macrosomia, twins, hydramnios) – uterus doesn’t have the ability to contract down well
  • Operative delivery
  • Magnesium sulfate (agent used to relax smooth muscles)
  • Infection
  • Chorioamnionitis

22

What are the major hypertensive d/o of pregnancy?

pre-eclampsia + eclampsia

23

How often does hypertensive d/o in pregnancy occur?

occurs in 7-10% of pregnancies; accounts for ~20% of maternal deaths in US (usually due to maternal-cerebrovascular accidents)

24

What are the characteristic features of pre-eclampsia?

HTN, proteinuria, edema (leads toweight gain)

25

When does pre-eclampsia occur?

  • usually in the FIRST pregnancy (unusual in subsequent pregnancies)
  • usually 3rd trimester problem 

26

How is pre-eclampsia theorized to form?

  • Imbalance of decr. angiogenic (VEGF, PGF) and incr. anti-angiogenic factors (sFlt1, endoglin)

  • abnormal cytotrophoblast invasion and remodeling of uterine spiral arterioles at the time of implantation leads to placental hypoxia/ischemia 

  • Endothelial dysfunction leads to an imbalance of vasoactive substances  -> vasoconstriction

    • decr. PG-E2 and prostacyclin (vasodilators)

    • decr. Endothelial NO - (vasodilator and platelet-aggregation inhibitor)

    • incr. PG-F and thromboxane (vasoconstrictors)

    • incr. Endothelin-1 (vasoconstrictor and activator of platelets aggregation)

27

Risk factors for pre-eclampsia?

  • pre-existing HTN
  • Glucose intolerance of pregnancy
  • Baseline thrombophilia
  • More trophoblast (twins/triplets)

28

systemic effects of pre-eclampsia: cardiovascular

incr. SVR, HTN -> edema

29

systemic effects of pre-eclampsia: renal

afferent arteriolar constriction -> decr. GFR , GBM injury -> HTN, proteinuria, oliguria, or ARF

30

systemic effects of pre-eclampsia: GI system

hepatic vasoconstriction with periportal necrosis and hemorrhage, incr. LFT, RUQ pain, and rarely hepatic hematoma, capsule rupture

31

systemic effects of pre-eclampsia: CNS

cerebral vasoconstriction -> incr. resistance of cerebral vascular blood flow, decr. cerebral O2 delivery, HA, vision hallucinations, seizures, hyperreflexia, encephalopathy, stroke

32

systemic effects of pre-eclampsia: respiratory

incr. capillary permeability -> pulmonary edema

33

systemic effects of pre-eclampsia: reproductive

incr. uterine artery vascular resistance, decr. placental blood flow, nutrient/O2 delivery, abruptio placentae

34

systemic effects of pre-eclampsia: Fetal and neonatal complications

growth restriction, prematurity, and perinatal

35

What is the difference between mild + severe pre-eclampsia?

  • MILD Preeclampsia
    • New-onset HTN after 20 wks; systolic ≥ 140 mmHg or diastolic ≥ 90 mmHg
    • New-onset proteinuria  > 300 mg/ 24 hrs (2+) after 20 weeks 
  • SEVERE Preeclampsia
    • Systolic ≥ 160 mmHg or diastolic ≥ 110 mmHg on two occasions at least 6 hr apart
    • Proteinuria  > 5 g/24 hr or qualitative value of 3+ in urine dips 4 hr apart
    • Oliguria <500 mL in 24 hr

36

What is SEVERE Preeclampsia most at risk for?

seizures (eclampsia)

37

What is HELLP?

What is it caused by?

HELLP syndrome - variant of severe preeclampsia w/ high morbidity 


Hemolysis 




Elevated Liver enzymes 






Low Platelet count 







 

problem: general activation of thecoagulation cascade

  • fibrin -> MAHA (microangiopathic hemolytic anemia)
  • periportal necrosis - main site where this occurs
  • consumption of platelets -> DIC + thrombocytopenia

38

How would you treat a patient with pre-eclampsia early in the pregnancy? late in the pregnancy? 

  • Hydrate
  • treat HTN
  • anti-seizure Rx prophylaxis
  • if later in the term: delivery to get rid of placenta (remember, this is a placental problem!)

39

What are the characteristic features of eclampsia?

when does it occur?

(tonic clonic) SEIZURES + hypertension, proteinuria, edema

Timing is variable with most cases < 24 hours following delivery

40

What's going on in these two pictures?

Top: normal – myometrium + decidua is ready for implantation. Trophoblasts invade maternal blood vessels (spiral arteries) and make them bigger so that the placenta is adequately perfused

Bottom: Pre-eclampsia – no remodeling of spiral arteries (no invasion of trophoblasts) -> underperfusion of placenta