A common cause of waist pain in pregnancy is round ligament pain caused by changes in hormones, according to Mayo Clinic. Waist pain can also be the result of general weight gain, which places a strain on the lower back, and stress, as stated by WebMD.
Though waist and back pain may increase throughout a pregnancy, it usually improves after giving birth. To relieve pain, an individual should continue her exercise routine to strengthen muscles and improve flexibility, as stated by WebMD. Applying heat and cold to sore muscles, improving posture, acupuncture treatments and chiropractic manipulation have also been shown to decrease pain. If back pain is related to stress, counseling may also help relieve it. Having a soak in a tub or getting into a swimming pool to relieve pregnancy-related pain are other ways to reduce pain symptoms, suggests Mayo Clinic.