But Barnhart said she understands the hesitations of parents who don't want to let their children cry.
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"Sometimes he'll pretend he's crying and I'll just do the same exact routine," Barnhart said. "If they're crying more than 10 minutes, I just don't like that, but I will let him cry for a little bit. "
A friend of hers is struggling with the same problem, and her pediatrician suggested she let the baby cry for 15 minutes, comfort her, and try again.
"My one friend's doctor said leave them cry 15 minutes, try again. What do you do when the third 15 minutes didn't work? You just have to try something totally different," Barnhart said.
That friend ended up staying in the room with the baby until she fell asleep, and the baby girl was comforted enough by her presence that she is able to fall asleep, Barnhart said. Another friend tried letting her daughter cry, but when she started crying at the top of her lungs, she ended up bringing her back into bed with her.
Barnhart said it can be hard for parents to figure out what to do, and the only advice she's sure of is to follow a bedtime routine that will make the babies feel safe and loved.
For instance, her son looks up at stars projected on the ceiling with her, and her new three-month-old son, Colt, also has his own projector.
Sajankila, or "Dr. Van" as her patients call her, said the study makes her more confident recommending the techniques to parents for babies older than 6 months, as the five-year timeframe is a good long-term measurement for the well-being of the child's emotional development.
"Medicine is all evidence-based now," Sajan-kila said. She has been practicing for six years at The Children's Doctor, which is the largest pediatrics practice in Hagers-town, she said.
The study found that allowing babies to cry as part of a consistent, structured behavioral training technique resulted in no difference for emotional health or chronic stress levels compared to a control group.
And other studies show that following these guidelines consistently will result in a better sleeping child within two weeks — even though the first week may be exhausting for parents, Sajankila warned.
Sajankila said she does not recommend just letting the baby cry it out, because studies have shown that parents could miss medical problems affecting the baby.
Both Sajankila and Shuster recommend that parents take other steps in addition to helping babies learn how to fall asleep by themselves. For instance, they both said that older babies do not need to feed in the middle of the night, as that can disrupt sleep. They also recommend a bedtime routine like the one Barnhart uses.
And while it is a common concern, Sajankila said that babies will eventually learn how to sleep well — some just take longer than others.
"Most of the babies do learn how to sleep on their own," Sajankila said. "I have a 13-year-old son who didn't sleep for a year. I don't know what was that one-year magic, but after that, I never had a problem."