Cannabis use and cannabis use disorder (CUD) are associated with mental health disorders, however the extent of this matter among pregnant and recently postpartum (e.g., new moms) women in the US is unknown. Associations between cannabis use, DSM-5 CUD and DSM-5 mental health disorders (mood, anxiety, personality and post-traumatic stress disorders) were examined among a nationally representative sample of pregnant and postpartum women. The 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions-III was used to examine associations between past-year cannabis use, CUD and mental health disorders. Weighted logistic regression models were used to estimate unadjusted and adjusted odds ratios (aORs). The sample (N=1316) included 414 pregnant and 902 postpartum women (pregnant in the past year), aged 18-44 years old. The prevalence of past-year cannabis use and CUD was 9.8% and 3.2%, respectively. The odds of cannabis use (aORs range 2.10-3.87, p-values<0.01) and CUD (aORs range 2.55-10.44, p-values< 0.01) were higher among women with versus without any past-year mood, anxiety or posttraumatic stress disorders or any lifetime personality disorder. aORs for the association of cannabis use with specific mood, anxiety or personality disorders ranged from 1.95 to 6.00 (p-values<0.05). aORs for the association of CUD with specific mood, anxiety or personality disorders ranged from 2.36 to 11.60 (p-values<0.05). From pregnancy up to one year postpartum is a critical period where women may be particularly vulnerable to mental health disorders, cannabis use and CUD. Treatment and prevention are essential.