Because your senses are heightened and in the first 3 months, when you are experiencing morning sickness, the smells and noises around you will be particularly disturbing to you. If you work in a loud office or at a school where bells are ringing and children are laughing and screaming, you may want to go to a park or quiet place during your lunch break to get some quiet, rest your ears and be able to go on with your day. Make it a daily practice so that you can ensure that you aren't too affected by the loud noises and hustle and bustle and that you can take some time to breathe deeply and relax amidst the chaos. You will not suffer any damage to your hearing if you opt to stay in the environment, but because your senses are heightened you may begin to feel sick or nauseous amidst the loud noises and activity. In many respects, it is similar to having a migraine where every sound and every movement can grate on your nerves in a way that no one else in the room will understand.
Also, be sure to make regular appointments with your doctor so that he can monitor your health and the health of your baby, but also so that you can regularly get a hearing test and make sure that nothing has been affected. It is always better to err on the side of caution so stop into your doctor's office every so often and make sure that you and your baby are staying healthy. Many mothers also like to expose their baby to soothing sounds in the womb and will put headphones over their stomach so that the baby can listen to relaxing music. This is a common practice and has been proven to soothe the baby but be sure to put the volume at an audible but moderate volume as you can damage your baby's hearing if it is too loud. A safe bet is to put it one module lower than what is comfortable to you that way you are sure that the sound is pleasant and not overbearingly coming through the headphones.