First, about going out and doing picnic.
Modest Clothing is required for women to go out otherwise, it'll be like 'not obeying' what Allaah Subhanahu wata'ala prescribed for women to wear for their modesty in Quran.
Second, about iron bangle.
That's a total rubbish. (Harsh comment but I just can't constrain myself)
Wearing iron bangle or anything like that is not prescribed in anywhere in Quran and Hadith (As far as I know).
And, as you are pregnant, you must take precaution about going out and doing picnic.
From Islamic Context, I would advice you to recite Quran (in your leisure time or, after the Fajr Prayer) in a silent portion in your room with full devotion to our Lord, Allaah Rabbul 'Alameen.
Reciting Quran, (Specific Chapter, like, Chapter al-Yaseeen, Chapter al-Kahf, Chapter Ar-Rahman) will be beneficial to you and your child who isn't yet born because reciting Quran brings about the attention of Our Lord, himself. A special kind of Tranquillity are brought down with Angels upon the reciter.
So, rather than acting upon those kinds of foolish superstition, I would suggest you stay with more tranquillity by reciting Quran and last and all, never miss prayers 5 times a day.
From my opinion, A pious woman will surely be rewarded by our Lord.
And Allaah knows best.