Lecture 8.1: Gestational and Placental Disorders Flashcards
Spontaneous abortion (aka miscarriage) is defined as pregnancy loss before ______ weeks of gestation
20 weeks of gestation (most often occurs before week 12)
What are 2 common fetal chromosomal anomalies associated with spontaneous abortion?
Turner Syndrome (45, XO) and trisomy 16
What are some maternal endocrine factors which may lead to spontaneous abortion?
- Luteal-phase defect
- Poorly controlled diabetes
Which systemic disorder of the vascular is associated with spontaneous abortions and a false positive syphilis test?
Antiphospholipid antibody syndrome
What is the most important predisposing condition (35-50%) for ectopic pregnancy?
Chronic salpingitis secondary to PID –> intralumenal fallopian tube scarring
What are some of the risk factors for ectopic pregnacy?
- Chronic salpingitis secondary to PID
- Scarring of fallopian tubes due to: appendicits, endometriosis, and/or prior surgery
- IUD use = 2x ↑ risk
- Smoking
Why is it important to recognize a potential ectopic pregnancy?
- Rupture of tubal pregnancy = emergency!
- May lead to intraperitoneal hemorrhage –> hemorrhagic shock –> DEATH!
Diagnosis of ectopic pregnancy is based on what?
- ↑ serum levels of hCG
- Pelvic sonography
- Endometrial biopsy showing decidua w/o chorionic villi or implantation site
- Laparoscopy
Typical clinical presentation of ectopic pregnancy?
Onset of moderate-severe abdominal pain + vaginal bleeding 6-8 weeks after last menstrual period
What are the 3 basic types of twin placentas?
- Diamnionic dichorionic (may be fused)
- Diamnionic monochorionic
- Monoamnionic monochorionic
Twin-twin transfusion syndrome is a complication of what type of twin placenta; what occurs in this syndrome?
- Complication of monochorionic twin pregnancy
- Monochorionic placentas have vascular anastomoses that connect the circulation of each fetus; sometimes including one or more AV shunts
- Shunt preferentially ↑ blood flow to one twin (polyhydramnios) at expense of other (oligohydramnios)
What is the placenta previa; leads to what complications?
- Placenta implants in lower uterine segment or cervix, often leads to serious 3rd trimester bleeding
- Complete placenta previa covers internal cervical os and requires delivery via C-section
What is placenta accreta; leads to what complication?
- Partial or complete absence of the decidua, such that placental villous tissue adheres directly to myometrium
- Leads to failure of placental separation at birth —> important cause of severe, life-threatening postpartum bleeding
Which pathway is the most common for placental infections and is caused by what?
Ascending infections caused by bacteria i.e., Gonorrhea and Chlamydia
Preeclampsia is what type of syndrome and due to dysfunction of what?
SYSTEMIC syndrome due to endothelial dysfunction
What is the triad of preeclampsia?
- HTN (endothelial dysf. –> vasoconstriction)
- Edema (↑ vascular permeability)
- Proteinuria (↑ vascular permeability)
Development of what makes preeclampsia become eclampsia?
Develop hyperreflexia and convulsions
Preeclampsia usually occurs in what trimester and which women are at greater risk?
- Third trimester (after 34 weeks gestation)
- Most common in primiparas (women pregnant for 1st time)
How is preeclampsia distinguished from gestational HTN?
Gestational HTN lacks proteinuria
Some women w/ severe preeclampsia can develop HELLP syndrome, which stands for what?
- Microangiopathic Hemolytic anemia
- _E_levated _L_iver enzymes
- _L_ow _p_latelets
Abnormal placental vasculature formation as part of the pathogenesis of preeclampsia is due to what 2 major events?
- Abnormal trophoblastic implantation
- Failure of physiologic remodeling of the maternal vessels
In response to hypoxia the ischemic placenta releases what 2 placenta-derived antiangiogenic factors into maternal circulation and what does each antagonize the effects of?
- soluble FMS-like tyrosine kinase (sFltl) antagonizes VEGF
- Endoglin antagonizes TGF-β