A growing body of research has linked alcohol consumption with impaired fertility (it can also harm a developing fetus). Alcohol alters estrogen metabolism, which may interfere with egg development, fertilization, and implantation. However, pouring an occasional glass of Pinot with your dinner is unlikely to harm fertility. You should also consider cutting back on caffeine while trying to conceive. Although study results have been mixed, research suggests that excessive caffeine intake may also affect female hormone levels. The bottom line: If you're thinking about getting pregnant, be a teetotaler and limit your daily java fix to 200 mg of caffeine per day (about one or two cups of coffee).