Is the function of the core muscles affected during pregnancy?

Introduction and hypothesis The aim of our study is to examine the changes in core muscle functions during pregnancy. Methods Our study was carried out in 67 primigravida pregnant women. Superficial electromyography (EMG) and non-invasive 2D/3D ultrasonography (USG) were used to evaluate core muscle (diaphragm, transversus abdominus [TA], internal oblique [IO]–external oblique [EO] muscles, pelvic floor muscles, multifidus) function during pregnancy. Pelvic floor muscle strength was also measured by a digital palpation method (PERFECT system). USG was used to measure expected fetal weight and the diastasis recti (DR) distance. Mann–Whitney U test was used to show changes in trimesters in the core muscles, and Spearman correlation analysis was used to determine the relationship. Results In the third trimester, an nonsignificant increase in EMG parameters was observed in all of the core muscles. Although a statistically significant decrease was observed in muscle thickness values measured by EO and IO USG in the third trimester, DR was found to increase at all levels ( p < 0.005). When we evaluated both trimesters and all pregnant women together, no relationship was found between all core muscles and pelvic floor muscles in the data evaluated by EMG and USG. We found a negative correlation in USG values between fetal weight and IO and the upper part of the rectus abdominus muscle, and a positive correlation between the EMG data of the EO and rectus abdominus muscles. Conclusions In women, the coactivation relationship between the core muscles may disappear during pregnancy. As the trimesters progress during pregnancy, a decrease in thickness and an increase in muscle activity can be observed in the core muscles. Pregnant women can be given exercise training for core muscles for protection in both the prenatal and postnatal periods. But more research needs to be done.