Best route for domestic partner?

My partner is pregnant and very early stages. Only  4 weeks. I am starting a new job next week and can add her as a DP since we have been living together for almost 4 years. 

im scared of losing a lot of income on this as she does not work currently, so I am sole provider. 

is the best option to add her as a DP and as a dependent since she hasn’t made any money yet this year? 

is it better for her to just pursue Medicaid?

 

thanks for any info!