Disease (prevalence)	Clinical manifestation	Diagnostic testing	Treatment	Comments
Gestational thrombocytopenia (5% to 11%)	Most common cause of thrombocytopenia in pregnancy (80%) Mild thrombocytopenia (> 80 × 103 per μL) Typically develops in second trimester	NA	None indicated	Resolves after pregnancy Infant not affected Can be difficult to distinguish from mild immune thrombocytopenia during pregnancy
Preeclampsia (5%)/HELLP syndrome (0.2% to 0.8%)	Onset of hypertension after 20 weeks' gestation (85% present after 34 weeks' gestation) Mild to moderate thrombocytopenia Severe symptoms: altered mental status, visual disturbances, dyspnea, persistent headache, abdominal pain	Proteinuria Thrombocytopenia Hepatic or renal dysfunction in severe cases Hemoconcentration Uric acid elevation Mild lactate dehydrogenase elevation Hemolysis	Magnesium sulfate Timing of delivery Term pregnancy (37 weeks' gestation) to delivery Preterm pregnancy (less than 37 weeks' gestation: expectant management in absence of severe features	Less consensus on management of preterm pregnancies from 34 to 36 weeks and 6 days in absence of severe disease HELLP syndrome complications include hemorrhage, disseminated intravascular coagulation, abruptio placentae, renal failure, pulmonary edema
Eclampsia (0.015% to 0.1%)	Similar to preeclampsia with presence of tonic-clonic seizures	Similar to preeclampsia	Magnesium sulfate Intravenous antihypertensive therapy Emergent delivery	Initial management is prevention of hypoxia
Acute fatty liver of pregnancy (0.005% to 0.01%)	Third trimester Abdominal pain, malaise, nausea and vomiting, mental status change	Thrombocytopenia Hepatic or renal dysfunction Hypoglycemia Coagulopathy Elevated ammonia Ultrasound or magnetic resonance imaging of liver shows fatty infiltration	Prompt delivery when feasible Supportive care	Can be difficult to distinguish from HELLP syndrome; however, blood pressure is typically normal in acute fatty liver of pregnancy Hypoglycemia is not typical for HELLP syndrome