Chapter 007. Medical Disorders during Pregnancy (Part 4)

Marfan Syndrome (See also Chap. 357) This is an autosomal dominant disease, associated with a high risk of maternal morbidity. Approximately 15% of pregnant women with Marfan syndrome develop a major cardiovascular manifestation during pregnancy, with almost all women surviving.
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Chapter 007. Medical Disorders during Pregnancy (Part 4) Chapter 007. Medical Disorders during Pregnancy (Part 4) Marfan Syndrome (See also Chap. 357) This is an autosomal dominant disease, associatedwith a high risk of maternal morbidity. Approximately 15% of pregnant womenwith Marfan syndrome develop a major cardiovascular manifestation duringpregnancy, with almost all women surviving. An aortic root diameter (See also Chap. 244) Maternal mortality in the setting of severe pulmonaryhypertension is high, and primary pulmonary hypertension is a contraindication topregnancy. Termination of pregnancy may be advisable in these circumstances topreserve the life of the mother. In the Eisenmenger syndrome, i.e., thecombination of pulmonary hypertension with right-to-left shunting due tocongenital abnormalities (Chap. 229), maternal and fetal death occur frequently.Systemic hypotension may occur after blood loss, prolonged Valsalva maneuver,or regional anesthesia; sudden death secondary to hypotension is a dreadedcomplication. Management of these patients is challenging, and invasivehemodynamic monitoring during labor and delivery is generally recommended. In patients with pulmonary hypertension, vaginal delivery is less stressfulhemodynamically than cesarean section, which should be reserved for acceptedobstetric indications. Deep Venous Thrombosis and Pulmonary Embolism (See also Chap. 256) A hypercoagulable state is characteristic of pregnancy, and deep venousthrombosis (DVT) occurs in about 1 in 2000 pregnancies. Pulmonary embolism isone of the most common causes of maternal death in the United States. Inpregnant women, DVT occurs much more commonly in the left leg than in theright leg, due to the compression of the left iliac vein by the iliac artery and theuterus. Activated protein C resistance caused by the factor V Leiden mutationincreases the risk for DVT and pulmonary embolism during pregnancy.Approximately 25% of women with DVT during pregnancy carry the factor VLeiden allele. The presence of the factor V Leiden mutation also increases the riskfor severe preeclampsia. Additional genetic mutations associated with DVT duringpregnancy include the prothrombin G20210A mutation (heterozygotes andhomozygotes) and the methylenetetrahydrofolate reductase C677T mutation(homozygotes). Deep Venous Thrombosis: Treatment Aggressive diagnosis and management of DVT and suspected pulmonaryembolism optimize the outcome for mother and fetus. In general, all diagnosticand therapeutic modalities afforded the nonpregnant patient should be utilized inpregnancy. Anticoagulant therapy with low-molecular-weight heparin (LMWH) orunfractionated heparin is indicated in pregnant women with DVT. LMWH may beassociated with an increased risk of epidural hematoma in women receiving anepidural anesthetic in labor. One approach to this problem is to switch fromLMWH to unfractionated heparin before the anticipated delivery date. Warfarintherapy is contraindicated in the first trimester due to its association with fetalchondrodysplasia punctata. In the second and third trimesters, warfarin may causefetal optic atrophy and mental retardation. When DVT occurs in the postpartumperiod, LMWH therapy for 7–10 days may be followed by warfarin therapy for 3–6 months. Warfarin is not contraindicated in breast-feeding women. Endocrine Disorders Diabetes Mellitus (See also Chap. 338) In pregnancy, the fetoplacental unit induces majormetabolic changes, the purpose of which is to shunt glucose and amino acids tothe fetus while the mother uses ketones and triglycerides to fuel her metabolicneeds. These metabolic changes are accompanied by maternal insulin resistance,caused in part by placental production of steroids, a growth hormone variant, andplacental lactogen. Although pregnancy has been referred to as a state ofaccelerated starvation, it is better characterized as accelerated ketosis. Inpregnancy, after an overnight fast, plasma glucose is lower by 0.8–1.1 mmol/L(15–20 mg/dL) than in the nonpregnant state. This is due to the use of glucose bythe fetus. In early pregnancy, fasting may result in circulating glucoseconcentrations in the range of 2.2 mmol/L (40 mg/dL) and may be associated withsymptoms of hypoglycemia. In contrast to the decrease in maternal glucoseconcentration, plasma hydroxybutyrate and acetoacetate levels rise to two to fourtimes normal after a fast.