Pregnancy and Childbirth

Authors: Flaherty, Alice W.; Rost, Natalia S.

Title: Massachusetts General Hospital Handbook of Neurology, The, 2nd Edition

Copyright 2007 Lippincott Williams & Wilkins

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Pregnancy and Childbirth

A. Neurological complications of pregnancy

• 1. Cerebral hemorrhage: The risk increases with each trimester.

  • a. Causes: AVMs and aneurysms are most common; also DIC, anticoagulants, placental abruption, mycotic aneurysm, metastatic choriocarcinoma, and eclampsia.

  • b. Rx: Hyperventilation, hypothermia, and steroids are safe; try to avoid mannitol. Surgery is based on same criteria as nonpregnant pts.

• 2. Cerebral infarction: About 1 in 3,000 pregnancies. 70% are arterial occlusion, 30% secondary to cerebral venous thrombosis.

• 3. Cerebral venous thrombosis.

• 4. Chorea gravidarum: Rare. Usually starts after first trimester, remits after delivery. See Choreoathetosis, p. 76, for DDx. Haloperidol is a relatively safe rx.

• 5. Eclamptic encephalopathy: Associated with hypertension, proteinuria, edema, oliguria, hyperreflexia, and seizures. Usually young primigravidas, >20 wk gestation. Give magnesium 4 g IV over 15 min, then 1-2 g/h, along with Ringer's lactate. Seizures may also be treated with diazepam or DPH.

• 6. Neuropathies of pregnancy: Bell's palsy, carpal tunnel syndrome, and meralgia paresthetica are most common.

• 7. Obstetrical palsies: From fetal head, forceps, or leg holders. Most common is L4-5 palsy, compressed by fetal brow as it crosses the pelvic rim.

• 8. Pseudotumor cerebri: Usually presents around week 14 and spontaneously resolves in 1-3 mo.

B. Effects of pregnancy on neurological conditions

• 1. Migraine: Most migraineurs improve during pregnancy, but migraines may also begin during pregnancy, especially in the first trimester. Acetaminophen, barbiturates, and low-dose opiates are the safest analgesics. Avoid serotonin agonists, ergots, and propranolol. Amitriptyline may be acceptable but should be stopped 2 wk before delivery.

• 2. Multiple sclerosis: Flares are less likely during pregnancy but more likely postpartum. Epidural anesthesia is okay in MS.

• 3. Myasthenia: Avoid magnesium sulfate, scopolamine, large amounts of procaine. Watch for neonatal myasthenia for 72 h. Myasthenia often flares postpartum.

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• 4. Neuropathy: CIDP and Charcot-Marie-Tooth dz may worsen.

• 5. Tumors: Most enlarge during pregnancy and shrink a little afterwards. Increased ICP may be an indication for termination of the pregnancy. ICP generally does not increase during labor, however.

• 6. Seizures: ACDs may harm the fetus, although so may seizures. Birth defect rate is as high as 10%.

  • a. Before pregnancy: Give all young women folate 1 mg qd. Carbamazepine decreases oral contraceptive levels.

  • b. During pregnancy: Keep ACD doses as low as possible. Monitor free levels since plasma proteins change in pregnancy.

  • c. Postpartum: Seizure incidence increases 10-fold during the first 24 h after delivery. If doses are increased in pregnancy, return them to initial postpartum levels to avoid toxicity.