Currently, the USA as a whole does not give any maternity leave. Unless you fall in the 9 percentile based on a 2008 calculation by the US Department of Labor's Bureau of Labor Statistics.
While the US gives generally 0 weeks of maternity leave, one of the highest amount of time given in the world is a whopping 50 weeks. One of the lowest, other than us, is 12 weeks.
Though we do have the option of FMLA, you must have worked with your company for 12 months. Additionally, you must live in a 75 mile radius of 50 or more of your co workers.
Based on this, if you have only been working at a job for a few months and have a baby or adopt, you cannot leave to take care of it unless you take personal time. It is very hard though to take any personal time if you are at the beginning of a job.