During pregnancy a woman's body changes dramatically; what was once beneficial could now be potentially harmful; what was once adequate may not be enough anymore, etc. Below are some of the guidelines currently recommended regarding what pregnant women should avoid when it comes to food and over the counter (OTC) medicines.
Foods to avoid while pregnant:
Fish with a high content of mercury, like swordfish, marlin and shark, as this may adversely affect the baby's developing nervous system.
Soft cheeses (especially imported ones, as they may not be pasteurized like most American-made cheeses are. Examples of imported soft cheeses include Brie and Feta).
Alcohol.
Undercooked meat or fish.
Large amounts of soda or caffeinated drinks like tea and coffee.
Raw eggs and anything containing them, because of the risk of salmonella (unless they are pasteurised).
OTC medicines to avoid while pregnant (unless taken under the supervision of a health-care practitioner):
Ibuprofen, naproxen and other non-steroidal anti-inflammatory drugs (NSAIDs).
Decongestants like pseudoephedrine and phenylphrine.
Herbal preparations.
Antacids containing sodium bicarbonate.
Antihistamine products.
For more information visit the Mayo Clinic's page on what foods to avoid during pregnancy and Netdoctor's page on OTC medicines during pregnancy.