The night Marta Salzberg gave up was a Wednesday in October, in a flat off Easter Road in Edinburgh, at about eleven minutes past two in the morning. Her daughter Esme, then twenty months old, was standing in her crib calling for her, and Marta was sitting in the hallway in a wool cardigan over her nightgown, doing the calculation that every sleep-deprived parent eventually does.
The calculation has two columns. In one column, you write the costs of continuing to enforce the sleep arrangement you have chosen. In the other, you write the costs of abandoning it.
Most of us do this calculation over and over without realizing it, in small increments, throughout the months. The night you finally let it go is the night the columns come out the other way.
Marta had been doing some version of sleep training, the gentle kind, for eleven weeks. Her daughter had been resisting it, the persistent kind, for the same eleven weeks. The pediatrician had been kind but unhelpful. The books had been unkind and also unhelpful. Marta had not slept more than four consecutive hours since August.
She got up from the hallway floor and went into Esme's room and picked her up and carried her into the family bed. Esme stopped crying within about thirty seconds. She was asleep in two minutes. Marta was asleep in four.
In the morning, when she told her husband Owen what she had done, he said, with what she described later as a startling degree of relief, that he had been hoping for months that she would do it.
This is one of the small secrets of the sleep question. Often the two parents have arrived at the giving-up point at slightly different times, and one of them has been waiting, quietly, for the other to break first.
There is no shame in this. It is, in fact, a reasonable distribution of labor. One parent holds the line of the original plan; the other parent holds the line of the alternative. When the costs of the original plan exceed its benefits, the parent holding the alternative line is ready to receive the change.
Marta and Owen have told me, in the small kitchen of their flat, that the night Marta gave up was the night their marriage started to recover from the previous eleven weeks. They had not realized, until they slept again, how much sleep deprivation had been costing them as a couple.
I want to be careful here. I am not arguing that every family should give up on every sleep plan. I am arguing that there is, in most families, a night on which the current plan stops working, and that the willingness to recognize that night, and to change course, is itself a form of competent parenting.
We tend to talk about giving up as a failure. In the context of family sleep, it is often the only path back to a workable life.
Esme slept in the family bed, on Owen's side, for another fourteen months. She moved to her own room, on her own schedule, at three years and one month. Her parents did almost nothing to bring this about. She just, one Saturday morning, asked to sleep in the small bed her grandparents had bought her, and that was that.
The grandparents, incidentally, had bought the bed almost a year earlier, hoping it would speed the transition. It had sat in Esme's room unused, the duvet still folded at the foot. Marta says now that she should not have been surprised that the child made the decision herself. The child usually does, eventually.
The literature on what is sometimes called child-led sleep transitions is thin, because it is hard to research the absence of an intervention. The studies that do exist suggest that most children, given a stable bed of their own and a parent who does not push, will move into it on their own between the ages of two and four.
This is not, again, a recommendation. It is an observation about the wider distribution. Some families need to push. Some families do not.
What seems to matter, more than the method, is whether the parents have given themselves permission to change course when the current course is not working.
The permission is the hard part. Most of us are trying to be good parents, which we have learned to define as parents who have a plan and stick to it. We have not been told that there is a kind of goodness that consists in noticing when the plan has stopped serving the family and adjusting.
The night you finally let it go is not the night you stopped being a good parent. It is, in many families, the night you became one.
Marta is in the kitchen with a cup of tea on a Saturday afternoon in April, and Esme, now four and a half, is at the table drawing a picture of a horse. She does not remember sleeping in the family bed. She remembers her own bed, and her quilt, and her stuffed seal named Buster.
Marta remembers everything. She does not regret any of it. She has saved the wool cardigan from that October night, folded in a drawer. She does not know why.


