Introduction
In 10–30% of women, vaginal birth results in levator ani tears (‘avulsion’) that are associated with pelvic floor dysfunction in later life. We hypothesised that women notice reduced pelvic floor muscle strength after childbirth, especially those with avulsion.

Methods
This is a secondary analysis of two perinatal studies. At 3–6 months postpartum, women were asked to estimate pelvic floor muscle strength relative to antepartum strength. Translabial ultrasound was performed to determine pelvic floor structure and function.

Results
Five hundred and thirteen primiparous women were seen at a median of 129 days after delivery of a singleton at a mean gestation of 40 weeks. At follow‐up, 481 were able to rate pelvic floor strength (mean 89%). This reduction was associated with delivery mode (P < 0.001), episiotomy (P = 0.01), perineal tears (P = 0.025) and avulsion (n = 45, P = 0.04). Conclusion After the birth of a first child, women notice a significant reduction in pelvic floor muscle strength, which is associated with delivery mode as well as perineal and pelvic floor muscle trauma. Summary Many women notice reduced pelvic floor function after childbirth, especially those who have suffered an avulsion of the puborectalis muscle.