9 months in, 9 months out

Me, five months pregnant and me with my 2-month-old daughter

Pregnancy is also known as endogestation (endo, from Latin, means “inside”), and as we all know, it lasts 9 months, or to be more accurate 266 days, counting from conception to birth.

What maybe some of you don’t know is that there are other 266 days important for the development of children. This period is called exogestation (“exo”, from Latin eso, means “outside”). The exogestation lasts from birth to crawling, a period of about 266 days.

Human babies are born too early to complete their development. This is an evolutionary adaptation to the standing position of humans. Due to standing, the pelvic outlet of women narrowed and it is now too small for a completely developed child’s head. When a baby is born, his/her brain is only 25% of the adult size.

Birth is a shocking process for children. The life as they knew it until that moment, is gone. Now they have to breath by themselves, food is no longer always available, their gastrointestinal system needs to start working.

In 2011, Morgan and collaborators measured the heart rate variability (HRV) in 2-day-old sleeping babies during skin-to-skin contact with their own mother and during alone rest (in maternal-neonate separation MNS context). HRV is a way to quantify autonomic nervous system activity and it is influenced by the level of arousal. Results show that during MNS there is a 176% increase in autonomic activity and an 86% decrease in quiet sleep. Results clearly indicate how stressful MNS is for infants.

The contact with the mother for the first 266 days of life is fundamental for children’s correct development outside the maternal womb.


Morgan et al., “Should Neonates Sleep Alone?”, Biological Psychiatry Journal,(2011), 70:817-825, https://doi.org/10.1016/j.biopsych.2011.06.018

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