Maybe

She only had one child because time ran out.
She only had one child because she had no time.
She only had one child because she feared what came next.
She only had one child because she feared she hadn’t enough love for more.
She only had one child because she feared she hadn’t enough love to start.
She only had one child because she didn’t know how she’d pay the bills.
She only had one child because one was all her money could buy.
She only had one child because one of herself was enough.
She only had one child because one was all her body could bear.
She only had one child so she could still hear herself think.
She had no children so she could hear herself think.
She had no children because even one was more than she could bear.
She had no children because her body would not bear even one.
She had no children because she couldn’t trust herself.
She had no children because the cost was too great.
She had no children because he chose to have none.
She had no children because she chose him instead.
She had no children because she didn’t meet him in time.
She had no children because she met her instead.
She had no children because there had never been the time.
She had many children because all she had had was time.
She had many children so she would have no time.
She had many children because they could afford many children.
She had many children because she’d been one of many children.
She had many children because she saw herself in each of them.
She had many children because her body bore the burden well.
She had many children because they required it.
She had many children because he required it.
She had many children because she imagined it would make him stay.
She had many children because she never imagined anything else.