Abstract Objective The purpose of this study was to determine the acute effect of an abdominal hypopressive exercise (AHE) on linea alba morphology among women who are primiparous and to compare this effect with that of other common abdominal exercise modalities. Methods A cross-sectional study of 46 women 3 months after first delivery was conducted. B-mode ultrasound imaging of the interrectus distance (IRD) and linea alba distortion was performed 2 cm below (I-point) and above (S-point) the umbilicus and at the mid-point between the umbilicus and xiphoid process (X-point). Images were recorded at rest and during an AHE performed in a supine position, a semi curl-up (SCU), an abdominal drawing-in maneuver (ADIM), and a SCU performed after an initial ADIM (ADIM+SCU). Results The SCU exercise narrowed the IRD at the X- and S-points. Compared with SCU, AHE and ADIM widened the IRD at the S- and X-points. No significant differences were found when comparing the IRD at rest, during AHE and during ADIM, but AHE tended to narrow I-point IRD more than ADIM but to widen S-point IRD more than ADIM+SCU. No participant showed linea alba distortion during the AHE or ADIM. When compared, SCU increased the occurrence of distortion with respect to AHE and ADIM. The isolated hypopressive posture did not change the IRD or linea alba distortion. Conclusion Among women who were postpartum, AHE seemed to narrow IRD below the umbilicus compared with ADIM without either of these 2 modalities generating linea alba distortion, as SCU or ADIM+SCU does. Thus, although no significant differences were found when comparing the IRD at rest and during AHE, the AHE could improve the tensile response of the linea alba without increasing the IRD. Impact This is believed to be the first study to describe linea alba changes during AHE in women who are postpartum. AHE and ADIM seem to show different effects on infraumbilical IRD. The lack of distortion suggests that linea alba may undergo tensile loading at all levels.