Addressing delegates at the Association of Directors of Children's Services (ADCS) annual conference in Manchester, Spielman said she is "not wedded" to the controversial grading under the single inspection framework, which replaced the "adequate" rating from the previous inspection regime.
Children's services departments that receive a requires improvement grade often come in for criticism from local and national politicians and media. Directors of children's services argue that the rating gives the impression of a struggling department rather than emphasising that they are delivering services satisfactorily.
The new, lighter-touch inspection system, which is set to start in early 2018, is to retain the four-tier graded judgments, but Ofsted has yet to say what these are.
In addition to a shorter initial inspection that all children's services will be subject to, inspectors will also conduct more in-depth visits at authorities where there are concerns.
Ofsted has already said it is considering scrapping overall effectiveness judgments. Instead of giving children's services an overall rating from "outstanding" through to "inadequate", the change could mean only specific service areas being graded.
Dave Hill, former ADCS president and director of education in Essex, said requires improvement should be scrapped and replaced with "fair".
In a question and answer session at the conference, he asked Spielman whether Ofsted would reconsider the rating. He said: "All the other judgments are a description of a state of being.
"I wondered whether there was any chance of making requires improvement more indicative of what it means?"
In response Spielman said: "I am not absolutely wedded to the requires improvement wording, but every time you change something like this it has repercussions that you don't quite envisage.
"The replacement of satisfactory with requires improvement had bigger consequences than anybody probably expected. So any change needs to be thought about very carefully."
Alison Michalska, president of ADCS, said while she supported scrapping requires improvement she was unsure what should replace it.
"I don't know what the solution is," she said. "We need to stop being defined by that one-word judgment."
Spielman also said the new inspection framework, which has been piloted with a handful of councils this year, will place greater emphasis on how leaders "allow good social work to flourish".