In my research I found no reference to problems in pregnancy from exposure to poison oak. Actually, about one in every three people are immune to the effects.

The most common allergens inducing "allergic contact dermatitis" are the toxicodendrum plants, poison ivy, poison oak and poison sumac. These agents usually produce an acute eczema with linear lesions, which represent the areas of direct contact with the leaves of the plants. The eruption is generally localized to exposed areas, but can be transferred by hands or clothing to other body sites. Direct contact with the above mentioned plants is probably the most common cause of this type of dermatitis, although severe cases have occurred from the smoke of burning plants.

For additional information:

• Poison Ivy Allergy