Our purpose is to determine whether ondansetron, a commonly used antiemetic, is equivalent in efficacy to the combination of pyridoxine and doxylamine, the currently recommended first line therapy for nausea and vomiting in pregnancy by the American Congress of Obstetricians and Gynecologists (ACOG). Since both treatments are safe in pregnancy, many physicians are using ondansetron as first line in practice. Despite this practice and the recommendations from ACOG, there is not data to suggest that ether practice is superior. This will be the first prospective, randomized, double blind, controlled trial comparing the two treatments. We hypothesize that ondansetron will be equally efficacious in reducing nausea and episodes of emesis. By alleviating nausea and vomiting associated with pregnancy, patients will likely benefit from less Emergency Department visits, urgent clinic visits, and admissions for progression to hyperemesis gravidarum.

Inclusion Criteria:

• Women who are less than 16 weeks pregnant by last menstrual period or ultrasound
• Greater than 18 years of age
• English speaking
• No significant visual or hearing impairment
• Requesting treatment for nausea associated with pregnancy

Exclusion Criteria:

• If nausea or vomiting preexisted the pregnancy
• Requires hospitalization at the time of initial enrollment
• Already taking anti-emetics to include metoclopramide, ondansetron, doxylamine, pyridoxine, or promethazine
• The patient has an allergy to either study regimen
• If they are unable to return for a follow up visit in 1 week