Head Lag in Infant Development

It takes a few months, but most babies begin holding their heads up on their own during the first half of the first year of life.

The inability to hold the head up is referred to as head lag, and it is evident when a baby can't seem to control his head and neck movements.

Head lag that lasts for a prolonged amount of time can be a signal for other medical or physical development problems. If you're worried because your baby isn't holding his head up on his own, make an appointment to see a pediatrician.

Head Lag Defined

Holding the head up is a gross motor skill that babies aren't born with.

Head lag occurs in newborn babies because their neck muscles are not quite strong enough to support the weight of their head. When you pick up your infant and his head seems to flop around or tip backward, he has head lag -- which is completely normal in tiny babies. It is the reason why doctors caution new parents to support the infant's head.

Doctors test head lag by gently pulling a baby's arms to bring him into a sitting position. If the head falls backward during this process, head lag is still present.

Head Lag Timeline

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Newborn babies have complete head lag. During the second month of life, a baby's head still tends to tip forward when in a sitting position.

At the age of about 12 weeks, head lag starts to disappear as a baby gains better head control. For babies developing normally, head lag usually disappears at about 20 weeks of age, which is approximately the fourth or fifth month of life, according to Tufts University.

Reasons for Head Lag

Head lag is used as one indicator for autism, according to a 2012 article published in the "American Journal of Occupational Therapy." The study in the journal discovered a positive correlation between babies with head lag at 6 months of age and an autism diagnosis at 3 years of age.

Head control can also be impacted by the amount of time a baby is handled as an infant, according to a 2012 article published in "Physical Therapy." In other words, allowing babies to "practice" their head control skills, such as with tummy time, can help them develop normally.

When Parents Should Worry

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If your baby is around 20 weeks of age and seems to have no neck or head control, make an appointment with his pediatrician. Hypotonia is the medical term for a baby who has low muscle tone, including the muscles in his neck that allow him to hold his head up on his own.

The condition can cause a baby to miss gross motor acquisition milestones, according to Boston Children's Hospital. Head lag can also be caused by other medical problems, so if your baby is missing several milestones or if you feel like something just isn't right, seek medical attention.