If you are an expectant, first-time or veteran mom, you’ve likely heard this so-called advice: Sleep when the baby sleeps. Despite the vast popularity of this adage, I would like to tell you why it is quite possibly the worst “tip” in the parenting world. Here are four reasons.

It assumes the baby actually sleeps

OK, I know there’s no such thing as a truly sleepless baby. But there are plenty of babies who will sleep only if someone is holding them. You know the type – they are sound asleep on Mom or Dad’s chest, but as soon as you put them in a bassinet or crib, forget it. The squirming starts, and their eyes pop open. For moms of these tinies, restorative sleep in a horizontal position is rare because they are probably cradling their babies – perhaps while sitting up or maybe lying on their side. (Disclaimer: I am not advocating these sleeping positions, just being realistic.) In this situation, breaking out the ol’ “sleep when the baby sleeps” makes Mom feel terrible. She questions herself, “What am I doing wrong? Why won’t my baby take a nap?” For the record, I know your tendency is to blame yourself, but you’re doing nothing wrong, Mama. (Speaking to myself, too, here.)

It doesn’t take into account older children

Especially toddlers, who cannot be trusted to play alone or watch a TV show while Mom naps. Let’s say Mom does get the baby to sleep. Relief, sure. But rest? Not likely when there’s another small human who needs a meal or is begging for some alone time with her.

Sleeping during the day can be difficult for adults

I know it is for me. Even if I am tired, I prefer darkness to sleep, and I struggle to achieve a restful state during daytime hours. This is the part of the human body’s circadian timing system, sometimes called circadian rhythms. In his book “Healthy Sleep Habits, Happy Child,” Marc Weissbluth, M.D., explains this phenomenon as a “dedicated regulatory program that switches specific genes on and off in response to the light-dark cycle.” Dr. Weissbluth adds:

“This regulatory apparatus built to turn on and off is a molecular clock that is genetically specified and is set to the proper time by sunlight. This mechanism automatically tries to ensure that the body is sleeping at the right time, and that when you are asleep, the timing and amounts of different stages and types of sleep are correct. Signals come from a specific area within the brain to make us feel sleepy or wakeful.”

Consider this: Have you ever stayed up all night? If so, despite exhaustion, you likely experienced a refresh about the time you normally wake up in the morning. Again, circadian rhythms. Richard Ferber, M.D., author of “Solve Your Child’s Sleep Problems,” gives a very detailed, scientific explanation of this scenario. I’m not going to regurgitate the whole thing. I will say, though, that Dr. Ferber’s “key point” is to “remember that it is hard to sleep in your wake phase and hard to stay awake in your sleep phase.” So while sleeping when the baby sleeps may sound like a great idea, it is probably going to be physically challenging. Again, there’s nothing wrong with you, Mama. It’s just biology.

Life happens

The last reason I propose for dismissing the “sleep when the baby sleeps” advice is because of, well, life. If you are lucky enough to have a baby who sleeps, you may want to do something for yourself. Eating and showering are usually pretty high on the list. Or you may want to accomplish something around the house, like laundry or dishes. Or perhaps you’re like me, and you’re dying to read the book on your nightstand or you’re about to burst because you have a story that you need to write. All good choices. Be warned, though: It will be difficult to choose just one.

All that said, if you are one of the lucky ones whose baby sleeps and you want to (and can) sleep, please do. Don’t feel like you have to eat or shower or fold laundry. Another warning: Even if you choose sleep and you feel physically sleepy in your wake phase, your brain may not turn off so easily. For me, when I lie down, inevitably the thoughts and tasks come like an avalanche. One of the primary trains of thought – why is the baby being so quiet? Is he OK? Is he breathing? Maybe I should check on him before I take a nap?

And if you check on the baby, you know what happens! He wakes up. Back to square one.