Brattleboro Retreat Psychiatric Review
June 1996
Sarah K. Lentz - Dartmouth Medical School - Class of 1997

Introduction

Psychiatric illness during pregnancy often presents a clinical dilemma. Pharmacologic interventions that are usually effective for these disorders have teratogenic potential and are therefore contraindicated during pregnancy. However, for depression, mania, catatonia, and schizophrenia, an alternative treatment exists: electroconvulsive therapy (ECT), the induction of a series of generalized seizures.

Psychiatric Treatment during Pregnancy

Pharmacologic therapies pose risks to the fetus in pregnant patients. Antipsychotics, particularly phenothiazines, have been noted to cause congenital anomalies in babies born to women treated with these medications during pregnancy (Rumeau-Rouquette 1977). Congenital defects have also been associated with the use of lithium, especially when administered during the first trimester (Weinstein 1977). However, in a recent study by Jacobson et al. (1992), no association between lithium and congenital anomalies was found. Tricyclic antidepressants have been associated with limb reduction deformities (McBride 1972) and, moreover, take four to six weeks to affect depression. During this time, risk to the fetus and woman may be substantial, depending on the mental and psychologic condition of the mother, her ability to care for herself, and possible suicidality. In a crisis situation in which the risks of untreated symptoms are extreme, the patient is known to be refractory to medications, or the medication represents a substantial risk to the fetus, ECT represents a valuable alternative in the pregnant patient. When administered by trained staff, and when precautions germane to pregnancy are taken into account, ECT is a relatively safe and effective treatment during pregnancy.

ECT: The History

Electroconvulsive therapy was first introduced as an effective treatment option for psychiatric illness in 1938 by Cerletti and Bini (Endler 1988). Several years earlier in 1934, Ladislas Meduna introduced the induction of generalized seizures with the pharmacological agents camphor and then pentylenetetrazol as effective treatment in a number of psychiatric illnesses. Prior to this time, no effective biological treatment for psychiatric illness was in use. The work of Meduna therefore, opened a new era of psychiatric practice and was quickly accepted throughout the world (M. Fink, personal communication). With the discovery that more predictable and effective seizures could be induced by ECT, the pharmacological method fell into disuse. ECT persisted as a mainstay of therapy until the 1950s and 1960s, when effective antipsychotic, antidepressant, and antimanic drugs were discovered (Weiner 1994). ECT was largely replaced by medications from this point until the early 1980s, when its usage level stabilized. However, a renewed interest in ECT in the medical community, prompted by failures of pharmacotherapy, has led to an increase in its judicious use in treatment-refractory patients with several psychiatric illnesses, including depression, mania, catatonia, and schizophrenia and also in circumstances in which psychopharmacological treatment is contraindicated, such as during pregnancy (Fink 1987 and personal communication).

ECT: The Procedure

Standard procedure. During the procedure, the patient is administered a short-acting barbiturate, typically methohexital or thiopental, which puts the patient to sleep, and succinylcholine, which induces paralysis. Paralysis suppresses the peripheral manifestations of the seizure, protecting the patient from fractures caused by muscular contractions and other injuries induced by the seizure. The patient is ventilated with 100% oxygen through a bag and hyperventilated before the electrical stimulus is administered. An EEG should be monitored. The stimulus is applied either unilaterally or bilaterally, inducing a seizure that should last at least 35 seconds by EEG. The patient is asleep for 2 to 3 minutes and awakens gradually. Vital signs are monitored throughout (American Psychiatric Association 1990).

Systemic changes that may occur during ECT include a brief episode of hypotension and bradycardia, followed by sinus tachycardia and sympathetic hyperactivity with an increase in blood pressure. These changes are transient and typically resolve over the course of minutes. The patient may experience some confusion, headache, nausea, myalgia, and anterograde amnesia following the treatment. These side effects generally clear over the course of several weeks following completion of the treatment series but can take up to six months to resolve. In addition, the incidence of side effects has been decreasing over the years as ECT technique has improved (American Psychiatric Association 1990). Finally, the mortality rate associated with ECT is approximately only 4 per 100,000 treatments and is generally cardiac in origin (Fink 1979).

During pregnancy. ECT has been found safe during all trimesters of pregnancy by the American Psychiatric Association. However, all ECT on pregnant women should occur in a hospital with facilities to manage a fetal emergency (Miller 1994). During pregnancy, several recommendations are added to the standard procedure to decrease potential risks. An obstetric consultation should be considered in high-risk patients. Vaginal exam is not obligatory, though, since it is relatively contraindicated during pregnancy. Furthermore, nothing about the vaginal exam would affect ECT. In the past, external fetal cardiac monitoring during the procedure was recommended. However, no alteration in fetal heart rate has been observed. Therefore, fetal monitoring as a routine part of the procedure is not warranted given its expense and lack of utility (M. Fink, personal communication). In high-risk cases, the presence of an obstetrician during the procedure is recommended.

If the patient is in the second half of pregnancy, intubation is the standard of anesthetic care to reduce the risk of pulmonary aspiration and resultant aspiration pneumonitis. During pregnancy, gastric emptying is prolonged, increasing the risk of aspiration of regurgitated gastric contents during ECT. Pneumonitis may result following aspiration of particulate matter or acidic fluid from the stomach. Standard procedure requires the patient to take nothing by mouth after midnight the night preceding ECT. However, in the pregnant patient this is often insufficient to prevent regurgitation. In the second half of pregnancy, intubation is performed routinely to isolate the airway and reduce the risk of aspiration. In addition, administering a nonparticulate antacid, such as sodium citrate, to raise gastric pH, may be considered as optional adjuvant therapy, but its usefulness is debated (Miller 1994, M. Fink, personal communication).