Instrument selection in assisted vaginal delivery: Reassessing its role in maternal fear of childbirth

We read with great interest the recently published study by Grindheim et al. (2025) titled “Influence of Instrument Choice on Fear of Childbirth After Assisted Vaginal Delivery: A Secondary Analysis of the Bergen Birth Study.”¹ While the study aims to evaluate the association between instrument choice in assisted vaginal delivery (AVD) and secondary fear of childbirth (FOC), we would like to highlight several critical concerns regarding the study's methodology, statistical power, and interpretation of findings.

The study does not account for preexisting maternal FOC, a well-established risk factor for postpartum FOC. Previous research, by Li et al. (2025), has demonstrated that antenatal FOC significantly influences postpartum perceptions of childbirth.² The authors' failure to adjust for this variable limits the ability to attribute FOC development solely to the mode of delivery.

The study reports no significant differences in FOC prevalence between spontaneous vaginal delivery and AVD. However, given the relatively small sample size, the study may be underpowered to detect a clinically meaningful difference. A recent study by Märthesheimer et al. (2025) has identified significant associations between instrumental deliveries and FOC.³ A post hoc power analysis would be necessary to confirm the robustness of the findings.

The study assessed FOC within 1 week postpartum. However, literature suggests that childbirth experiences evolve over time, with recall bias potentially underestimating FOC prevalence. Khademi et al. (2024) demonstrated that assessments performed later in the postpartum period yield more stable and reliable data on birth-related psychological outcomes.⁴ The lack of longitudinal follow-up weakens the conclusions drawn.

While the study discusses perineal trauma and obstetric anal sphincter injuries, it does not adequately analyze their impact on FOC. A study by Muraca et al. (2023) found that forceps deliveries were significantly associated with maternal trauma and long-term psychological distress.⁵ Given the higher rate of episiotomies and perineal trauma in AVD cohorts, it is crucial to explore whether these factors contribute to FOC rather than attributing it solely to the choice of instrument.

While the study by Grindheim et al. contributes to an important area of obstetric research, the aforementioned limitations call into question the reliability and generalizability of its conclusions. Future studies should employ larger, multicenter cohorts; incorporate preexisting maternal fear factors; and utilize a longitudinal follow-up design to more accurately assess the psychological consequences of AVD.