A nurse is caring for a client who is in her first trimester of pregnancy and asks the nurse if she can continue to exercise during pregnancy. Which of the following responses by the nurse is appropriate?

"exercise during pregnancy is not recommended."

"Daily jogging for up to 30 minutes is fine throughout pregnancy."

"Activities that raise the body temperature, such as saunas and hot tubs, are safe until the third trimester."

"It is recommended that pregnant clients limit their exercise routine to stretching activities on a mat several times a week."