First, I am saddened by your loss. Second, I suggest you listen to your doctor or midwives advice, given your past history. Third, and this is ONLY because you are asking under the "Mythology and Folklore" section, there are certain practices considered 'safe' or condusive for a successfull pregnancy. Some of these are:
-no knots; in your hair or clothing (like a knotted sash);
-find and keep holed stones in the home, threaded with red ribbon;
-acquire water from sacred wells that promote fertility, or visit sacred sites that do the same;
-keep your mind free from any negative thoughts - which means not watching horror movies, the evening news, violent films, etc.
-find a big-breasted / big-bellied goddess figurine to wear as an amulet;
-above all else ... Above All Else .. eat healthy, rest much, be mindful of the precious life growing within you, ask your Mother Ancestors for help, and listen to your care providers!
Best of Luck!