It is difficult to provide accurate, scientific advice about the effects of herbs on an unborn child. Many herbs are safe, and many are potentially dangerous. In general, unless the herb is widely known to be safe (such as herbal cough drops), it is safer to avoid them while pregnant.
True homeopathic remedies involve highly dilute solutions, so these are considered generally safe during pregnancy.
Nutrasweet, Sweet’N’Low, Equal, Splenda
These are food additives, and have no known risk when taken in normal amounts.
Caffeine intake should not to exceed one coffee, two teas, or two colas daily (chocolate is so low in caffeine, it is not a significant source). According to the website Mother to Baby: "Most experts agree that moderation and common sense are the keys for consuming caffeinated items during pregnancy. “Moderate” caffeine consumption is approximately 200-300 mg/day, which is similar to 1-3 cups of coffee a day. It is also important for pregnant women to drink enough water, milk and juice. These fluids should not be replaced with caffeinated beverages."
Absolutely strongly discouraged, leads to low birth weight, premature labor. This is so universally agreed on that we do not feel a need to write more about this.
This is strongly discouraged. Overuse can lead to fetal alcohol syndrome, mental retardation and birth defects. Minimal safe levels of intake have not been established.