Why do babies cry when they are born

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Last updated: April 8, 2026

Quick Answer: Babies cry at birth primarily to clear fluid from their lungs and establish breathing, as the transition from the womb requires them to take their first breaths. This crying helps expand the lungs by creating pressure that pushes out amniotic fluid, with about 10% of newborns needing some assistance to start breathing effectively. The first cry typically occurs within 30-60 seconds after birth, and medical professionals assess it using the Apgar score at 1 and 5 minutes to evaluate the baby's health.

Key Facts

The first cry usually happens within 30-60 seconds after birth, marking the start of independent breathing.
Approximately 10% of newborns require some form of resuscitation or stimulation to initiate breathing and crying.
Medical staff use the Apgar score, developed in 1952 by Dr. Virginia Apgar, to assess newborns at 1 and 5 minutes after birth.
Crying helps expel amniotic fluid from the lungs, with the average newborn having about 80-100 mL of fluid in their respiratory system at birth.
Persistent crying beyond the initial minutes can indicate distress, affecting about 3-5% of births where additional medical intervention is needed.

Overview

The phenomenon of babies crying at birth has been observed throughout human history, with ancient cultures often interpreting it as a sign of life and vitality. In medical terms, this first cry is crucial for transitioning from fetal to neonatal life, where the baby shifts from receiving oxygen via the placenta to breathing air independently. Historically, midwives and healers recognized crying as a positive indicator, but it wasn't until the 20th century that the physiological mechanisms were fully understood. The development of modern obstetrics in the 1900s, particularly with the introduction of the Apgar score in 1952, standardized the assessment of newborn health, including respiratory effort. Today, this initial cry is monitored in delivery rooms worldwide, with approximately 140 million births occurring annually globally, each involving this critical adaptive response.

How It Works

When a baby is born, the process of crying initiates breathing by clearing the respiratory tract of amniotic fluid and expanding the lungs. During gestation, the fetus's lungs are filled with fluid, and at birth, the pressure changes during delivery help squeeze some fluid out. The first breaths involve strong inspiratory efforts, generating negative pressure that draws air into the lungs, while crying creates positive pressure to expel remaining fluid. This mechanism relies on the activation of the respiratory center in the brainstem, triggered by sensory stimuli like cold air, touch, and changes in oxygen levels. Hormonal changes, such as a drop in prostaglandins and a surge in catecholamines, also prepare the lungs for air breathing, with crying serving as a natural way to achieve functional residual capacity in the lungs.

Why It Matters

The first cry is a vital sign of neonatal health, indicating successful adaptation to extrauterine life and reducing risks like respiratory distress syndrome, which affects about 1% of newborns. In clinical settings, delayed or absent crying can signal complications such as birth asphyxia, impacting around 4 million infants annually worldwide and requiring immediate intervention. This crying response also has long-term implications, as effective lung clearance helps prevent infections and supports cognitive development by ensuring adequate oxygen supply. Beyond medicine, the sound of a baby's first cry holds emotional significance for families, symbolizing the start of a new life and often being recorded in birth announcements or memories.