Final answer:
The nurse should recommend that the pregnant patient can travel by air, automobile, or train during the 21st week of pregnancy, with air travel often being preferred, provided there are no health complications or contraindications, and that the chosen airline's policies permit it. The patient should ensure regular movement and stay hydrated, and should avoid places with limited medical services.
Step-by-step explanation:
When advising a pregnant patient on the best method of travel during the 21st week of pregnancy, it's important to consider travel safety as well as the comfort and well-being of the mother and fetus. Generally, at this stage of pregnancy, women can still travel safely, given no other health concerns or complications. The safest method of travel recommended by most health professionals is by air; however, all forms of travel have their own risks and benefits. Airlines often allow pregnant women to fly up to the 36th week of pregnancy, but it is recommended to check with the specific airline for their policies. Regardless of the method chosen, pregnant women should practice regular movement and stretching to reduce the risk of deep vein thrombosis, and stay hydrated. It's also important to have access to medical care and avoid traveling to places where it would be difficult to receive prompt medical attention.