Gestational and Placental Disorders Flashcards
Why are diseases of pregnancy and pathologic conditions of the placenta important?
- Due to causes of fetal intrauterine or perinatal death, congenital malformations, intrauterine growth restriction, maternal death, and morbidity for both the mother and child
How does blood enter the placenta?
- Through the intervillous space through endometrial arteries and circulates around the villi to allow gas and nutrient exchange
- Deoxygenated blood enters the placenta through two umbilical arteries that branch radially to form fetal chorionic arteries which branch until they form an extensive capillary system
What are some functions of the placenta?
- Nutrient and waste diffusion
- Hormone production –> hCG, progesterone, and hPL
- Immunologic organ (down regulates antigen expression)
Does fetal and maternal blood mix?
- No but sufficient free fetal DNA reaches the maternal circulation to permit prenatal genetic testing
What is prenatal cell free DNA screening used?
- Method to screen for certain chromosomal abnormalities
What is spontaneous abortion defined as?
- Pregnancy loss before 20 weeks gestation
What are some causes of spontaneous abortion?
- Fetal chromosomal anomalies
- Maternal endocrine factors
- Physical defects of uterus
- Systemic disorders affecting the maternal vasculature
- Infections with protozoa, bacteria, or a number of viruses
What are some fetal chromosomal anomalies that cause spontaneous abortion?
- Aneuploidy
- Polyploidy
- Translocations
What are some maternal endocrine factors that can cause spontaneous abortion?
- Luteal phase defects
- Poorly controlled diabetes
- Other endocrine disorders
What are some physical defects of the uterus that can cause spontaneous abortion?
- Submucosal leiomyomas
- Uterine polyps
- Uterine malformations that may prevent or disrupt implantation
What are some systemic disorders that affect maternal vasculature that can cause spontaneous abortion?
- Antiphospholipid antibody syndrome
- Coagulopathies
- Hypertension
What are the most common microorganisms that cause preterm labor?
- Ureaplasma urealyticum
- Mycoplasma hominis
- Gardnerella vaginalis
- Trichomonas
- Gonorrhea
- Chlamydia
When do most spontaneous abortions occur?
- Occur before end of first trimester
- Most are clinically not recognized as a pregnancy
What is an ectopic pregnancy?
- Implantation of the fetus in a site other than the normal intrauterine locations
What is the most common location for an ectopic pregnancy?
- Extrauterine fallopian tube
What are some other sites of ectopic pregancy?
- Ovary
- Abdominal cavity
- Intrauterine portion of fallopian tube
What is the most common cause of hematosalpinx (blood filled fallopian tube?
- Tubal pregnancy
What is a predisposing condition that leads to ectopic pregnancy?
- Chronic salpingitis
- Fallopian tube scarring/adhesions also can be due to appendicitis, endometriosis, or prior surgery
- IUD increases ectopic pregnancy
What does an ectopic pregnancy look like?
- Onset of moderate to severe abdominal pain and vaginal bleeding 6 to 8 weeks after the last menstrual period
- Patient may rapidly develop hemorrhagic shock and signs of acute abdomen with tubal rupture
How is diagnosis made for ectopic pregnancy?
- Determination of chorionic gonadotropin titers
- Pelvic sonography
- Endometrial biopsy
- Laparoscopy
What is hCG?
- Produced by trophoblasts and maintains the corpus luteum
- Levels double every 2 days during the first 4 weeks of pregnancy
What is a classic ultrasound sign of ectopic pregnancy?
- Donut sign
When do disorders of late pregnancy show up?
- During the third trimester and are related to the complex anatomy of the maturing placenta
What are the two pathways that infections use to cause premature rupture of amniotic membranes and delivery?
- Ascending infection (most common) and almost alway bacterial
- Hematogenous dissemination (viruses, Toxo, mycoplasma, listeria, chlamydia, ureaplasma)
What is the normal color of amniotic fluid?
- Colorless or pale yellow
What location of a retroplacental hemorrhage threatens both the mother and the fetus?
- Interface of placenta and myometrium
- May have bleeding to warn there is something going on
What is placental previa?
- Condition where the placenta is attached close to or covering the cervix
- Could be total, partial, or marginal coverage
What is placenta accreta?
- Partial or complete absence of the decidua, such that the placental villous tissue adheres directly to the myometrium leading to failure of placental separation at birth
- Could be a cause of severe, life-threatening postpartum bleeding
What causes uteroplacental vascular insufficiency?
- Diabetes
- Hypertension
- Maternal conditions predisposing to blood clots
- Smoking
- Cocaine or other drugs
What is twin-twin transfusion syndrome?
- Occurs when women are pregnant with identical twins
- Blood begins to flow unevenly, with one fetal twin receiving too much blood and the other receiving too little
What happens to the twin receiving too much blood in twin-twin transfusion syndrome?
- May experience heart failure due to continual strain on its heart and blood vessels
What happens to the twin receiving not enough blood in twin-twin transfusion syndrome?
- May experience life-threatening anemia, insufficient nutrition and oxygen due to inadequate blood supply
What is fetus papyraceus?
- A mummified fetus associated with multiple gestations where one fetus dies and is flattened between the membranes of the living fetus and uterine wall
What is preeclampsia?
- Systemic syndrome characterized by widespread maternal endothelial dysfunction that present during pregnancy with a triad of symptoms
What are the symptoms of preeclampsia?
- Hypertension
- Edema
- Proteinuria
What is eclampsia?
- Preeclampsia symptoms along with seizures
What do some women develop with severe preeclampsia?
- Microangiopathic hemolytic anemia, elevated liver enzymes, and low platelets (HELLP syndrome)
What plays a central role in preeclampsia?
- The placenta
- Symptoms disappear rapidly after delivery of placenta
What remodeling fails to occur in preeclampsia?
- Extravillous trophoblast cells destroy the vascular smooth muscle and replace the maternal endothelial cells with fetal trophoblast cells
- This converts the decidual spiral arteries from small caliber resistance vessels to large capacity uteroplacental vessels lacking a smooth muscle coat
- Failure of this remodeling system leaves the placenta ill equipped to meet the increased circulatory needs of late gestation
What does an ischemic placenta release?
- Factors into the maternal circulation which antagonize the angiogenic effects of maternal VEGF and TGFB leading to systemic maternal endothelial dysfunction and the clinical symptoms of disease
What is preeclampsia associated with?
- A hypercoagulable state that may lead to formation of thrombi in arterioles and capillaries throughout the body (like liver, kidneys, brain, and pituitary)
What is the hypercoagulability in preeclampsia related to?
- Reduced endothelial production of PGI2 (potent antithrombotic factory, stimulated by VEGF) and increased release of procoagulant factors
What are the periportal sinusoids that contain fibrin deposits associated with?
- Hemorrhage into the space of Disse, leading to periportal hepatocellular coagulative necrosis
What is the management of preeclampsia dependent on?
- Gestational age and severity of disease
What is the management of preeclampsia for term pregnancies?
- Delivery is treatment of choice regardless of disease severity
What is the management of mild preeclampsia for preterm pregnancies?
- Managed expectantly by closely monitoring the mother and fetus
What is the management of eclampsia, severe preeclampsia with maternal end organ dysfunction, fetal compromise, or the HELLP syndrome?
- Delivery regardless of gestational age
When does proteinuria regress?
- Within 1 to 2 weeks following delivery
What is at long term risk following preeclampsia?
- Vascular disease of the heart and brain
What are different types of gestational trophoblastic disease?
- Hydatidiform mole
- Invasive mole
- Choriocarcinoma
- Placental site trophoblastic tumor (PSTT)
What is a hydatidiform mole?
- Hydatid = a cyst containing watery fluid
- Associated with increased risk of persistent trophoblastic disease or choriocarcinoma
How is a hydatidiform mole diagnosed?
- Diagnosed early in pregnancy with sonogram
What age is at an increased risk for hydatidiform mole?
- Teens and 40-50s
- 2x as common in southeast asia
What is the clinical presentation of molar pregnancies?
- Spontaneous miscarriages or undergo curettage because of ultrasound findings (snowstorm) of abnormal villous enlargement
- In a complete mole, hCG levels will greatly exceed those of a normal pregnancy of similar gestation (rate is also greater than that of a normal gestation)
How does a complete hydatidiform mole form?
- One sperm fertilizing an empty ovum OR two sperm fertilizing and empty ovum
- No maternal DNA, no fetal tissue
How does a partial hydatidiform mole form?
- Two sperm fertilize a regular ovum
What is an invasive mole?
- An infiltrative lesion that penetrates or even perforates the uterine wall
- Villi may invade parametrial tissue and blood vessels and may even embolize to distant sites (like lungs and brain) –> emboli do not grow
What is gestational choriocarcinoma?
- Rapidly invasive malignant neoplasm of syncyio and cytotrophoblasts derived from a previously normal or abnormal pregnancy that metastasizes widely
- Very uncommon
What is the clinical presentation of gestational choriocarcinoma?
- Irregular vaginal bleeding of bloody, brown fluid
- Enlarged uterus
- May present with mets to lung, vagina, brain, liver, bone, kidney
- hCG usually very high, unless tumor is necrotic
What is the treatment for gestational choriocarcinoma?
- Depends on stage of the tumor and usually consists of evacuation of the contents of the uterus and chemotherapy
How effective is chemotherapy for gestational choriocarcinoma?
- Spectacular and result in nearly 100% remission and a high rate of cures
What is a placental site trophoblastic tumor?
- Tumor of extravillous/intermediate trophoblasts
- Produce human placental lactogen (hPL)
- May follow a normal pregnancy, spontaneous abortion, or hydatidiform mole
- Localized disease have an excellent prognosis
