Adding my uneducated guess:

- there's some evidence that healthcare in general can benefit from deliberate less intervention by patients and medical staff [0]

- maternity intervention is notorious for intervention (historically for good reasons) yet, today, so much extra can be profited by just pre-planning interventions that are distorting incentives [1]

- pandemic has raised the stakes of leaving home, particularly visiting hospitals so people think twice before deciding to go for intervention - patients preserveer more. That includes expecting mothers.

[0] this an opinion https://www.theguardian.com/commentisfree/2014/jul/19/patien...

[1] https://www.wilsoncenter.org/event/too-much-too-soon-address...