The effect of offering a third-trimester routine ultrasound on pregnancy-specific anxiety and mother-to-infant bonding in low-risk women: A pragmatic cluster-randomized controlled trial.

Background: Third-trimester routine ultrasounds are increasingly offered to monitor fetal growth. In addition to limited evidence for its clinical effectiveness, little is known about its importance for pregnancy-specific anxiety and mother-to-infant bonding.

Methods: 1275 low-risk women participated in a Dutch nationwide pragmatic cluster-randomized trial and answered questionnaires on pregnancy-specific anxiety (PRAQ-R) and prenatal mother-to-infant bonding (MAAS) before and after a third-trimester routine ultrasound was offered to the intervention group. Linear mixed model regression analyses were performed to examine the effect of offering a third-trimester routine ultrasound on pregnancy-specific anxiety and mother-to-infant bonding. In addition, we examined whether the effect depended on maternal background characteristics and level of satisfaction with the ultrasound procedure.

Results: We found no effect of offering a third-trimester routine ultrasound on pregnancy-specific anxiety and mother-to-infant bonding. However, interaction analyses showed that women with high levels of depressive symptoms at baseline and women who were very satisfied with the ultrasound procedure benefited somewhat more from offering a third-trimester routine ultrasound in terms of mother-to-infant bonding compared with women with low or no depressive symptoms, or less satisfied women.

Conclusions: The relationship between offering a third-trimester routine ultrasound with pregnancy-specific anxiety and mother-to-infant bonding is limited. A beneficial effect only applies to some subgroups of women. This implies that, in terms of psychological outcomes, there are no counterarguments to implementing a third-trimester routine ultrasound. Strong evidence for offering all pregnant women a third-trimester routine ultrasound for psychological reasons, however, is lacking.