The primary objective of this study is to compare the efficacy of Diclegis for the treatment of nausea and vomiting of pregnancy (NVP) in pregnant adolescents aged 12 to 17 years with placebo.

The secondary objective of this study is to compare the safety of Diclegis in pregnant adolescents aged 12 to 17 years with placebo by assessing differences in the severity and occurrence of maternal adverse events (AEs).

This is a multicenter study in the treatment of NVP that will actively recruit pregnant adolescents from approximately 14-16 study sites in the United States. After obtaining informed consent on Day 1, a medical examination will be conducted to ensure eligibility. Participants will be randomized to receive Diclegis or placebo. On Day 1, all participants will take 2 tablets of study drug at bedtime. On Days 2 to 14, participants will take 2 tablets of study drug at bedtime. The minimum dosage will be 2 tablets daily at bedtime, increasing, when indicated, to the maximal dosage of 4 tablets per day on Days 3 to 14. Participants will be required to complete a diary daily to assess the severity of their NVP by using the validated Pregnancy Unique Quantification of Emesis (PUQE) and to record any AEs experienced; the Global Assessment of Well being scale will be completed only on Days 1, 8 and 15. Participants will receive telephone calls daily to assess whether the current dosing regimen is sufficient at relieving NVP symptoms, to review study procedures, and to address her questions/concerns. Participants will return to the clinic for evaluation on Day 4 (±1 day) and Day 15 (±1 day) for an end of study visit.

Eligible participants are those between 12 and 17 years of age, pregnant with a gestational age of 7 to 15 weeks + 0 days, suffering from NVP, with a PUQE score ≥6, and who have not responded to conservative management consisting of dietary/lifestyle advice according to the 2004 American College of Obstetrics and Gynecology (ACOG) Practice Bulletin.

Inclusion Criteria:

1. The participant is a pregnant female between the following ages: at least 12 years on the day of recruitment (ie, Day 1) and not yet 18 years on the last day of the study (ie, Day 15).
2. The participant must provide written informed consent and/or assent to participate in the study, and agrees that she will follow dosing instructions and complete all required study visits.
3. The participant's entry ultrasound indicates a viable pregnancy and confirms gestational age of the fetus is 7-15 weeks + 0 days at the anticipated time of the first dose of study drug provided that her NVP symptoms began \