As an earlier intervention, DTP (Diphteria, Tetanus, and Pertussis) vaccines, should be best shot to 28-38 weeks pregnant women for helping them protect their infant from a "deadly" whooping cough. Whooping cough (pertussis) is contagious and is not too dangerous for adult, but it is so highly lethal for newborn and infant less than 1 year-old.
Some women may argue that they have ever had DTP vaccination when they were infant. Based on that statement, some studies has been done to all adults who have ever got DTP vaccination when they were child, and you know what? Nothing left. There were no more spesific antibody found in their bodies to attack whooping cough.
Some clinical data showed that DTP/whooping cough vaccine only persisted for 6 - 8 years after shot.
Most pregnant women may not show any signs and symptoms of whooping cough, but they are susceptible to re-infection or they can be a "healthy carrier" of pertussis bacteria for their future child.
Other issue that women who have ever got whooping cough will have their antibody automatically. Well, it's only half-right. You created your own antibody automatically, but it does not cover you for life. It only covers you for 10 - 15 years after its first onset.
Nowaday, this DTP shot urgently required for pregnant women in America and Europe, but it could be also required next in Asia, Africa, and other countries around the world. Yes!! All pregnant women whole the world should warn themselves and their family member around her for every possibilities of pertussis bacteria spread, since it's easy to spread when you breath.
For more peace of mind, all women should re-taken the DTP/whooping cough vaccine before they pregnant, and if you are a pregnant women, go consult to your doctor before taking your whooping cough shot.