The Science Behind Maternal Instinct: It’s More Than Culture

MADRID, 10 Feb. – The concept of “maternal instinct” is not simply a cultural construct, according to scientists. Significant changes occur in the brain and hormonal systems during pregnancy and early parenthood that predispose individuals to care for a newborn. However, experts emphasize this process is neither automatic nor universal, varying between individuals and being influenced by prior experiences, the birthing process, mental health, and overall life circumstances.

Psychiatrist Bianca Granados, specializing in reproductive and perinatal mental health, family, and couples therapy, explained that the brain undergoes changes during pregnancy designed to foster nurturing behavior. “It’s a mechanism that ensures the baby’s survival – the mother’s desire to care for the child. This happens in all women, and it’s the maternal instinct, drawing mothers to provide care due to these cerebral changes,” she said.

Granados, writing in her recently published book, ‘Matrescencia,’ notes that a physiological birth, coupled with a typical hormonal response, facilitates a state of love, surrender, and connection with the baby, potentially even leading to euphoria.

However, Granados cautioned that external factors can impact the development of maternal instinct. Past experiences, particularly those involving trauma, can interfere with the biological process. “Sometimes this biological aspect can be overshadowed by painful experiences, hindering the need for connection or causing discomfort with motherhood. A mother might even experience shock upon becoming a parent,” she stated.

Pregnancies following previous losses are often particularly challenging, with women sometimes avoiding emotional connection with the developing fetus for fear of further loss. This can make bonding after birth more challenging. Granados noted that even after a smooth delivery, some individuals may not immediately feel a strong emotional connection, experiencing instead a sense of strangeness or confusion – reactions she described as normal.

Granados stressed that there is no prescribed way to feel, and a lack of an immediate “spark” does not indicate a woman will be a less effective mother. The bond develops over time through interaction with the baby. She added that responses vary widely, with some women feeling overwhelmed with love, others with tenderness, and still others experiencing shock, neutrality, or surprise.

Scientific research confirms that the female brain undergoes demonstrable changes during pregnancy, and motherhood. Endocrinologist and nutritionist Paloma Gil, explained that hormones have a neuroprotective effect during gestation, safeguarding brain cells and promoting neuronal plasticity, which enhances the brain’s ability to adapt to the demands of childcare and protection.

“The female brain changes during pregnancy, focusing on caring for the growing being within. Before birth, hormonal shifts prioritize bonding with the baby, and after birth, everything else fades into the background,” Gil said.

In her book, ‘El poder invisible de tus hormonas,’ Gil details how a little area of the brain, the medial preoptic area, becomes saturated with receptors for estrogen, prolactin, and oxytocin during pregnancy. However, progesterone initially blocks these hormones from binding. Only towards the conclude of pregnancy, as progesterone levels decline, can the hormones activate this area, effectively deactivating the brain’s rejection circuit and activating the reward circuit, thus awakening the maternal instinct. She cited cases of women who report not experiencing this instinct until becoming pregnant.

A Spanish study led by Susana Carmona found that pregnant women experience a reduction in gray matter volume in brain areas associated with social cognition and empathy. This reduction appears to be linked to brain specialization and optimization for motherhood, potentially improving a mother’s ability to care for her infant. These changes in gray matter have been observed up to two years postpartum, suggesting the maternal brain retains these modifications to facilitate prolonged infant care.

Gil also noted that the brains of fathers also change, though to a lesser extent and driven more by environmental factors related to childcare than by hormonal shifts. The more time fathers spend caring for their children, the more their brains and hormones adapt to support parental behavior. While significant progress has been made in understanding how pregnancy transforms the brain, Gil emphasized the need for further research to fully grasp the extent and nature of these changes.