There’s an old saying that if a pregnant woman has heartburn, her baby will be born with a full head of hair. Interestingly enough, there is a correlation between heartburn and baby hair growth, according to the New York Times. Still, a baby born with hair might not keep that hair. In fact, it is hard to predict just when your baby’s hair will grow, how fast it will grow or how much she will have.

Baby Hair Growth

In Utero

Your baby’s hair starts growing before he is even born. In fact, by the fifth month of pregnancy, your baby has started to grow hair, according to Sutter Health. During the last four weeks of pregnancy, your baby’s hair grows thicker as he prepares to be born.

Cause

Hair growth in utero is thought to be caused by estrogen, along with other hormones. In fact, pregnant women with elevated levels of estrogen had babies with more hair than women with lower levels. Those same hormones also cause the sphincter to relax, which allows stomach acids to rise into the esophagus and cause heartburn.

Hair Loss

Hair loss in newborns is common, so don’t whip out the bows if your daughter has a full head of hair when she is born. You might have to save them for later. Hormone levels in babies drop dramatically after they are born, which results in hair loss. In addition, hair can be lost in certain areas on the head that are frequently in contact with a mattress, such as on the back of the head.

Time Frame

Some babies immediately grow new hair after losing their newborn locks. Others stay bald until well after their first birthday. A few babies are born bald and do not get a full head of hair until well into their second year. In addition, the hair can grow in unusual patterns. Some babies develop a fringe around the edges, while others sport a look reminiscent of a mohawk.

Considerations

The hair your baby is born with may not resemble the hair he eventually grows. In many cases, the hair your baby grows ends up looking a lot different than his newborn locks. It can grow back lighter, darker, curlier or straighter. Usually, baby hair is fine in texture and does not thicken and become coarse until a child reaches the age of 6 or 7.