Manic Depression (Bipolar Disorder)
The impact of pregnancy on the course of manic depressive disorder is unclear; thus, the management of affected women who plan to conceive or are already pregnant poses a significant challenge for clinicians.  Some reports document an improvement of manic depressive symptoms in this population.^26,27 On the other hand, data from 186 women and 141 men with manic depression²⁸ were collected as part of the National Institute of Mental Health Genetics Initiative,  a multisite collaborative molecular genetic study. Almost half of the women with manic depression who had been pregnant reported experiencing severe emotional disturbances related to childbearing, and almost one third reported episode onset during pregnancy.
The medication status of these women was unavailable.

Discontinuation of mood-stabilizing medications may significantly increase the risk for relapse in nongravid patients with manic depressive illness.⁷ However, relapse rates are not well defined in pregnant women with manic depressive disorder who discontinue their mood-stabilizing medications. Recent retrospective data^4,29 indicate that rates of recurrence during the first 40 weeks after lithium discontinuation were similar for gravid and nongravid patients, and there was less risk of relapse with gradual discontinuation of the drug. Other case reports²⁷ suggest that some manic depressive patients remain emotionally stable during pregnancy despite medication discontinuation.

Panic Disorder
The course of panic disorder during pregnancy is variable. Some women do poorly when attempts are made to discontinue their antipanic medications during pregnancy.

Other women experience a diminution of symptoms that allows them to tolerate medication discontinuation.

The characteristics that distinguish these patient groups remain to be elucidated. A retrospective study³⁰ of 20 pregnant patients with active panic symptoms at the time of conception described a marked symptomatic improvement in most of the patients despite the fact that a majority of the women had discontinued their medications at conception.

Another retrospective case series³¹ of 49 women with pregravid panic disorder noted that 38 patients (78%) were noted to have insignificant change in anxiety status or to have clinical improvement;  10 women (20%)  evinced more severe panic symptoms during pregnancy. A more recent prospective study³² found no diminution in panic symptoms in 9 of 10 women during pregnancy. Finally, a computerized search of the impact of pregnancy and the puerperium on panic disorder³³ identified 8 relevant studies; none were controlled studies, and all but 1 were retrospective. Of the total 215 pregnancies described in the studies, 89 (41%) were associated with improvement of panic symptoms during pregnancy.

Physiologic changes during pregnancy may contribute to the amelioration of panic symptoms in some women.

Hormonal changes in pregnancy have been speculated to have anxiolytic affects.³⁰  Progesterone metabolites possess barbiturate-like activity and may also be anxiolytic.³⁴

In addition, pregnancy has been found to decrease sympathetic arousal to a variety of physiologic stimuli; for example, 2 studies reported an attenuation of heart rate and norepinephrine release in response to postural changes in pregnant women.^35,36