1. You may request the immigrant visa application process be expedited. Given the case is currently at the U.S. Embassy, you would need to make a request to that office. The NVC no longer has jurisdiction. However, please note your pregnancy may not be sufficient reason for expediting. Expediting is usually reserved for humanitarian situations.
2. If your request is approved, your parents could be interviewed within 2-4 weeks. It will really depend upon interview availability at the U.S. Embassy.
3. No. It is highly unlikely yor parents would be issued visitor visas given the stage in processing they are for their immigrant visas.
You can read more about family-based immigration at http://myattorneyusa.com/family-immigration.
Answered on Apr 21st, 2016 at 3:00 PM