Metrorrhagia, or 'infant's periods': no need to worry! We explain everything to you.

After giving birth to a baby girl, as you learn or relearn how to care for her, you might notice traces of blood in her diaper during a change. While this can be unsettling or even worrying for parents, it is completely normal and physiological. In many newborns, the amount of blood lost is so minimal that it often goes unnoticed. This phenomenon usually occurs a few days after birth. These small drops of blood, known as metrorrhagia or "newborn periods," are the result of normal physiological changes in your baby's body. No need to worry—we explain everything!

What Are Infant Metrorrhagia or Newborn Periods?

Newborns can experience a type of hormonal surge at birth, known as the neonatal hormonal crisis. Their bodies suddenly produce more sex hormones, particularly estrogen. In baby girls, the uterine lining begins to form under the influence of these hormones, which can cause light bleeding. This hormonal crisis can also result in other temporary signs such as breast swelling and baby acne, which are also linked to this "mini-puberty."
For baby boys, this hormonal shift can cause a temporary increase in the size of the penis and testicles, as they too undergo a similar hormonal adjustment.

What Should You Do If Your Baby Has Newborn Periods?

Although it may seem alarming, these small traces of blood are harmless and painless, lasting only a few days. This hormonal surge will subside and remain dormant until puberty, when it naturally resumes.

When it comes to care, there is nothing special to do—simply continue your regular hygiene routine using a mild soap.

However, if the bleeding does not stop or seems excessive, consult your pediatrician or midwife, who will assess the situation and provide appropriate guidance.