PRE-ECLAMPSIA SUPERIMPOSED ON CHRONIC HTN.pptx

Obstetrics

1. Pre-eclampsia superimposed on chronic hypertension OBGYN 3.2 BMS SERIAL NO. 34 - 44

2. Definition Superimposed preeclampsia (on chronic hypertension) is characterized by (1) new-onset proteinuria (≥300 mg/24 h) in a woman with hypertension but no proteinuria before 20 weeks' gestation and (2) a sudden increase in proteinuria or BP, or a platelet count of less than 100,000/mm3, in a woman with hypertension and proteinuria before 20 weeks' gestation.

3. Chronic hypertension refers to high blood pressure that is present before pregnancy or that develops before 20 weeks of gestation and does not resolve after delivery. Chronic hypertension in pregnancy is associated with an increased risk of various maternal and fetal complications, and the risk is further amplified when pre-eclampsia is superimposed on it.

4. Pathophysiology: The exact pathophysiology of pre-eclampsia is not fully understood, but it is believed to involve abnormal placentation, immune maladaptation, genetic factors, and endothelial dysfunction. In the case of chronic hypertension, the pre-existing vascular disease may exacerbate these pathophysiological changes. The abnormal placentation is thought to cause placental ischemia, which in turn releases factors into the maternal circulation that cause widespread endothelial dysfunction and inflammation.

5. Risk factors for developing superimposed pre-eclampsia Renal disease. Maternal age >40 years. Pre-existing diabetes. Multiple pregnancy. Connective tissue disease (e.g. antiphospholipid syndrome). Coarctation of the aorta. Blood pressure ≥160/100 mmHg in early pregnancy. Prepregnancy BMI >35. Previous pre-eclampsia. Antiphospholipid syndrome.

6. Diagnosis: To diagnose superimposed pre-eclampsia, there must be an exacerbation of hypertension (typically systolic blood pressure >160 mmHg or diastolic blood pressure >110 mmHg on two occasions at least 4 hours apart) and one or more of the following new-onset conditions after the 20th week of gestation: - Proteinuria is often quantified as the excretion of 300 mg or more of protein in a 24-hour urine sample. - A sudden increase in proteinuria or blood pressure in a woman with chronic hypertension.

7. The development of signs of end-organ dysfunction, such as thrombocytopenia (platelet count less than 100,000 per microliter), impaired liver function, the new development of renal insufficiency, pulmonary edema, or new-onset cerebral or visual disturbances. However, preeclampsia can be difficult to diagnose in a chronically hypertensive woman. First, blood pressures may increase during pregnancy in women with chronic hypertension alone and without superimposedpreeclampsia. This is most commonly encountered near the end of the secondtrimester.

8. In the absence of other supporting criteria for superimposed preeclampsia, this likely represents the higher end of the normal blood pressure. In such women, if preeclampsia is excluded, it is reasonable to begin or to increase the dose of antihypertensive therapy.

9. Management: The management of pre-eclampsia superimposed on chronic hypertension includes: Close monitoring of blood pressure and urine protein. Use of antihypertensive medications to maintain blood pressure at safe levels to prevent maternal end-organ damage while avoiding fetal hypoperfusion. Corticosteroids may be administered to enhance fetal lung maturity if preterm delivery is anticipated.

10. Delivery is the definitive treatment for pre-eclampsia. The timing of delivery in superimposed pre-eclampsia is a balance between the benefits of prolonging the pregnancy for fetal maturation and the risks of worsening maternal and fetal conditions. Magnesium sulfate may be used for seizure prophylaxis in severe cases.

11. Risks and Complications: Superimposed pre-eclampsia carries risks for both the mother and fetus including: 1) Increased risk of placental abruption, acute renal failure, hepatic rupture, eclampsia, disseminated intravascular coagulation (DIC), and cardiovascular complications for the mother. 2) For the fetus, there is an increased risk of intrauterine growth restriction (IUGR), preterm birth, and stillbirth.

12. REFERENCES 1. American College of Obstetricians and Gynecologists, Task Force on Hypertension in Pregnancy. Hypertension in pregnancy. Report of the American College of Obstetricians and Gynecologists’ Task Force on Hypertension in Pregnancy. Obstet Gynecol. 2013 Nov. 2. OBSTETRICS 20th EDITION by Ten Teachers. 3. Williams OBSTETRICS 6TH EDITION.