Exercise & Pregnancy: Safety Considerations for Triathlons & Running

Question
I have been running for 5 years.  I just completed my first Olympic distance tri on Saturday and found out I am pregnant on Tuesday.  I just finished nursing my 15m old and my periods have not returned.  Therefore I have NO idea where I am in this pregnancy.  I am traveling to Hawaii next week to complete another 1/2 marathon.  I have no problem dialing down the pace and just doing the 1/2 for "fun".  I am more concerned about other activities while in Hawaii.  Should I be concerned about hiking?  Paddle boarding? Kayaking?  I am a VERY fit person and thinking that if I keep my perceived exertion level moderate, I should be fine?  Also we had talked of going to the summit of Mauna Kea - 14,000 feet, but I am reading that it isn't recommended for pregnant women.  If I am in my first trimester and in excellent health, is this a concern?

Answer
Because of your very high fitness level, a "fun" run 1/2 marathon will not overly tax your body. When doing all ocean activities, play it safe, always wear a life vest.
Driving to the summit of Mauna Kea will not be a problem. But I don't advise any exercise at altitudes higher than 5,000 feet, as this is the one activity that your body is not acclimated to.