There are several different species of herbs in the ginseng family, some of which may not be appropriate for use during pregnancy. Because of this, there can be some confusion for the consumer, since not all are botanically related to Panax ginseng.

A search of PubMed uncovers no clinical reports or specific documented cases that would support a contraindication of American ginseng during pregnancy. However, the results of a review of the scientific literature regarding ginseng use during pregnancy does mention, red ginseng and panax ginseng, as sometimes contraindicated in the traditional literature due to being considered too stimulating by some herbalists.2

Based on strong scientific evidence from a cohort study, Panax ginseng was not associated with adverse effects when used during pregnancy. Panax ginseng was misreported in the literature as causing androgenization, when, in fact, the case reported was due to an adulterant. There is in vitro evidence of teratogenicity with exposure to ginsenosides; however, this evidence is derived from animal embryos and is based on exposure to isolated ginsenosides at much higher levels than achievable through normal consumption in humans. There is also conflicting evidence as to whether or not Panax ginseng has estrogenic properties. In lactation, there are no human studies on the safety of Panax ginseng, only in vitro evidence based on three animal studies reporting minimal risk.2
The most authoritative sources3 on traditional Chinese herbal use do not contraindicate American ginseng for use during pregnancy.

1 McGuffin, M., Hobbs, C., Upton, R. and Goldberg, A. Botanical Safety Handbook, American Herbal Product Association. CRC Press. 1997.
2 Seely et. Al. Can J Clin Pharmcol Vol 15 (1) Winter 2008:e87-e94.
3 Bensky et al. Chinese herbal Medicine, Materia Medica, 3rd Edition. 2004. Seattle: Eastland Press.

The Upper Levels for a pregnant woman age 14-18 are 1,200 IU, and for pregnant women age 19+ the Upper Levels are established at 1,500 IU.