8. Gestational disorders Flashcards
Types of gestational disorders
- Disorders of early pregnancy
- Spontaneous abortion
- Ectopic pregnancy - Disorders of late pregnancy
- Placental inflammation
- Toxemias of pregnancy
- Placental abnormalities - Trophoblastic disease
- Hydatiform moles
- Invasive mole
- Choriocarcinoma - Infertility
Definition of spontaneous abortion
loss of pregnancy before 20 weeks’ gestation
Etiology of spontaneous abortion
- Maternal:
- Abnormalities of the reproductive organs
i. Septate uterus
ii. Uterine leiomyomas
iii. Uterine adhesions
iv. Cervical incompetence
- Systemic diseases
i. diabetes mellitus, hyperthyroidism, hypothyroidism, genetic disorders, infections, hypercoagulability (e.g., antiphospholipid syndrome, which is associated with recurrent miscarriages)
- Fetoplacental:
- Chromosomal abnormalities account for up to half of all spontaneous abortions
- Congenital anomalies
- Anembryonic pregnancy - Miscellaneous:
- Trauma
- Iatrogenic
- Environmental
- Unknown
Complications of spontaneous abortion
- Septic abortion
- Complication of a missed, inevitable, or incomplete abortion in which retained products of conception become infected - Retained products of conception result in release of thromboplastin into systemic circulation → disseminated intravascular coagulation
- Endometritis
Definition of ectopic pregnancy
A pregnancy in which the fertilized egg attaches in a location other than the uterine endometrium
Etiology of ectopic pregnancy
Risk factors
- Anatomic alteration of the fallopian tubes
- History of PID (e.g., salpingitis)
- Previous ectopic pregnancy
- Surgeries involving the fallopian tubes
- Endometriosis
- Ruptured appendix
- Kartagener syndrome - Nonanatomical risk factors
- Smoking
- Advanced maternal age
- Pelvic inflammatory disease
- Intrauterine device
- In vitro fertilization
Clinical features of ectopic pregnancy
General symptoms:
- Lower abdominal pain and guarding (ectopic pregnancy is often mistaken for appendicitis due to the similarity of symptoms)
- Possibly, vaginal bleeding
- Signs of pregnancy
- Amenorrhea
- Nausea
- Breast tenderness
- Frequent urination - Tenderness in the area of the ectopic pregnancy
- Cervical motion tenderness, closed cervix
- Enlarged uterus
Tubal rupture:
- Acute course with sudden and severe lower abdominal pain (acute abdomen)
- Signs of hemorrhagic shock (e.g., tachycardia, hypotension, syncope)
Diagnostics for ectopic pregnancy
- Serum β-hCG level
- Transvaginal ultrasound (TVUS)
- Endometrial biopsy
Infection of the placenta
villitis
Infection of the membranes
chorioamnionitis
Infection of the umbilical cord
funisitis
Etiology of placental infections
- STD: Syphilis & Chlamydia
- Bacterial: Streptococcus & Listeriosis
- Viral: Rubella & Cytomegalovirus
- Protozoal: Toxoplasmosis
Ascending infection - through birth canal
Hematogenous - TORCH
T - toxoplasmosis, O - Other (hepatitis B), R - Rubella, C - Cytomegalovirus, H - Herpes simplex virus
Definition of toxaemia of pregnancy
A systemic syndrome characterised by widespread maternal endothelial dysfunction
Types of toxaemia of pregnancy
- Preeclampsia
2. Eclampsia
Definition of preeclampsia
New-onset gestational hypertension with proteinuria or end-organ dysfunction
Definition of HELLP syndrome
A life-threatening form of preeclampsia characterized by Hemolysis, Elevated Liver enzymes, and Low Platelets
Definition of eclampsia
Eclampsia: a severe form of preeclampsia with convulsive seizures and/or coma
Pathophysiology of preeclampsia
- Overview: Multiple maternal, fetal, and placental factors are involved in placental hypoperfusion, which leads to maternal hypertension and other consequences.
- Uterine spiral arteries normally develop into high-capacity blood vessels. This process is defective in patients with preeclampsia, which leads to hypoperfusion of the placenta and fetus
- Arterial hypertension with systemic vasoconstriction causes placental hypoperfusion → release of vasoactive substances → ↑ maternal blood pressure to ensure sufficient blood supply of the fetus
- Systemic endothelial dysfunction causes placental hypoperfusion → ↑ placental release of factors; → endothelial lesions that lead to microthrombosis - Consequences of vasoconstriction and microthrombosis
- Organ ischemia and damage
i. HELLP syndrome; (thrombotic microangiopathy of the liver)
- Chronic hypoperfusion of the placenta → insufficiency of the uteroplacental unit and fetal growth restriction
Systemic effects of hypertensive pregnancy disorders
- Kidney: Glomerular endothelial dysfunction and hypertension-induced vasoconstriction
- Proteinuria
- Impaired renal function - Liver: Vasoconstriction and microthrombotic obstruction of liver sinusoids → liver cell damage
- Liver impairment and liver swelling - Brain: Hypertension-induced vasoconstriction and endothelial damage → disruption of cerebral microcirculation with microthrombi → vasospasms in the CNS
- Seizures
Complications of hypertensive pregnancy disorders
- Maternal complications
- Placental abruption
- DIC
i. Injury to placenta → tissue factor release → unregulated activation of the coagulation cascade
ii. ∼ 20% of patients with HELLP syndrome
- Cerebral hemorrhage, ischemic stroke
- Acute respiratory distress syndrome (ARDS)
- Acute renal failure
- Maternal death - Fetal complications: occur due to insufficient placental perfusion
- Fetal growth restriction
- Preterm birth
- Seizure-induced fetal hypoxia
- Fetal death
Types of placental abnormalities
- Placenta previa
- Abruptio placentae
- Abnormal placentation
- Placenta accrete
- Placenta increta
- Placenta percreta
Definition of placenta previa
Presence of the placenta in the lower uterine segment; partial or full obstruction of the neck of the uterus with high risk of hemorrhage (rupture of placental vessels) and birth complications
Clinical features of placenta previa
- Sudden, painless, bright red vaginal bleeding
- Usually occurs during the 3rd trimester (before rupture of the membranes), stops spontaneously after 1–2 hours, and recurs during birth
Definition of abruptio placentae
Partial or complete separation of the placenta from the uterus prior to delivery
Epidemiology of abruptio placentae
Occurs most often in the third trimester
Clinical features of abruptio placentae
- Continuous vaginal bleeding
- Concealed abruptio placentae
- Sudden-onset abdominal pain or back pain, uterine tenderness
Complications of abruptio placentae
- Intrauterine fetal death
- Maternal DIC and hypovolemic shock: occurs as a result of blood loss and massive coagulation; the placenta is rich in tissue thromboplastin, which is released as a result of the placental abruption.
- Couvelaire uterus
- Retroplacental hemorrhage may extend through the uterus into the peritoneum
- uterine rupture
Definition of abnormal placentation
Defective decidual layer of the placenta leading to abnormal attachment and separation during postpartum period
Placenta accreta
Chorionic villi attach to the myometrium (but do not invade or penetrate the myometrium); (up to 75% of cases)
Placenta increta
Chorionic villi invade or penetrate into the myometrium
Placenta percreta
Chorionic villi penetrate the myometrium, penetrate the serosa
Clinical features of abnormal placentation
- Abnormal uterine bleeding
2. Postpartum hemorrhage at the time of attempted manual separation of the placenta
Classification of gestational trophoblastic disease
- Hydatidiform mole
a. Partial mole
b. Complete mole - Choriocarcinoma
Etiology of partial mole
Fetal karyotypes: 69XXX, 69XXY, 69XYY
Mechanism of partial mole
Fertilization of an egg containing a haploid set of chromosomes with two sperms
Clinical features in partial mole
- Vaginal bleeding
- No change in uterine size
- Pelvic tenderness
Diagnostics for partial mole
- β-hCG
- Ultrasound
- Fetal parts may be visualized.
- Fetal heart tones may be detectable.
- Amniotic fluid is present.
- Increased placental thickness
Histopathological exam of partial mole
- Microscopy:
- Partial occurrence of hydropic villi, minimal trophoblastic proliferation - P57 staining:
- Positive
Etiology of complete mole
Fetal karyotypes: 46XX (∼ 90% of cases), 46XY (∼ 10% of cases)
Mechanism of complete mole
Fertilization of an empty egg that does not carry any chromosomes
Clinical features in complete mole
- Vaginal bleeding during the first trimester
- Uterus size greater than normal for gestational age
- Pelvic pressure or pain
- Passage of vesicles
- Endocrine symptoms (e.g, hyperemesis gravidarum, ovarian theca lutein cysts)
Diagnostics in complete mole
- β-hCG
- Ultrasound:
a. Echogenic mass interspersed with many hypoechogenic cystic spaces (referred to as “snowstorm”)
b. No fetal parts
c. Lack of fetal heart tones
d. No amniotic fluid
e. Theca lutein cysts
Histopathological exam in complete mole
- Microscopy: Diffuse hydropic villi, marked circumferential trophoblastic proliferation
- P57 staining:
- Negative
Etiology of choriocarcinoma
Most cases of choriocarcinoma are preceded by hydatidiform mole (50%)
Mechanism of choriocarcinoma
Malignant transformation of cytotrophoblastic and syncytiotrophoblastic tissue
Clinical features of choriocarcinoma
- Postpartum vaginal bleeding
- Inadequate uterine regression after delivery
- Multiple theca lutein cysts
- Additional symptoms (e.g., dyspnea or hemoptysis from metastases in the lungs)
Diagnostics for choriocarcinoma
- β-hCG
- Ultrasound
a. Mass of varying appearance
b. Hypervascular on color Doppler
Histopathological exam for choriocarcinoma
Microscopy:
Cytotrophoblasts and syncytiotrophoblasts without chorionic villi
Prognostic factors for choriocarcinoma
- Distant metastases
- Failure of chemotherapy
- Choriocarcinoma following term pregnancy
Complications / risks of hydatidiform mole
- Uterine haemorrhage
- Coagulopathy
- Infection
- Continued trophoblastic activity (16% invasive mole; 2.5% choriocarcinoma)
Mechanism of invasive mole
Trophoblasts invade the myometrium → increased risk of bleeding and hematogenous spread
