Weeks 15 & 16

Furthermore, researchers who have devoted their careers to the neuroscience of pain have concluded that fetal pain is possible from a very early age. Two medical professionals, one pro-choice and one pro-life came to the following conclusion:

“Overall, the evidence, and a balanced reading of that evidence, points towards an immediate and unreflective pain experience mediated by the developing function of the nervous system from as early as 12 weeks.¹⁰”

 

Similarly, European neurologists and embryologists came to a similar conclusion in 2016:

“…the fetus is exposed to rudimentary painful stimuli starting from the 15th gestation week and … it is extremely sensitive to painful stimuli.¹¹“

By 15 weeks, the unborn baby is developing senses that will connect him to the world. The early pathways for smell, taste, touch, sight, and hearing have already taken shape. Most of the smell system is in place,^{20 21} and the nose can respond to irritating chemicals and touch.²² Early tastebuds have formed connections with nerves that process flavor.²³ The majority of the skin is sensitive to light touches.²⁴ The eyes have formed and the light-sensitive cells are growing in the retina.²⁵ The ears have formed and the delicate hairs in the cochlea that will one day detect sound are forming.²⁶

These senses start guiding behavior. By week 15, if something tickles the unborn baby’s lips, he closes his mouth and swallows. If something tickles his palm, he closes his fingers, and he can move each finger separately.²⁷ By 15 weeks, every sensory system is actively being developed, quietly preparing this small human being for life beyond the womb.

The bones of the unborn child’s skeleton are made in one of two ways. Some bones, like the skull and collarbone, form directly from sheets of tissue rather than cartilage.²⁸ Other bones start as cartilage, the same tissue that gives the outer ear its structure. As development continues, the cartilage is slowly replaced by bone cells. In a single long bone, the middle of the bone starts to harden first, and the ends keep growing longer and longer by adding cartilage. This cartilage, too, is later replaced by bone.²⁹ By 15 weeks, if a doctor took an X-ray this week, the baby’s skeleton would be visible.³⁰

By 15 weeks gestation, in the fourth month of pregnancy, the unborn baby is seen as a distinct little patient. Fetal surgery to save the life of the baby or his twin has been performed at weeks.^{31 32}

By 15 weeks, the unborn baby can suck his thumb, and already shows a preference for his right or left hand.³³ Fingerprints start forming at the center and tip of each finger, then expand across the skin.³⁴ At 15 weeks, the basic patterns of whorls, loops, and arches of the fingerprints are established on each finger.³⁵

The baby’s brain is still mostly smooth, but at 16 weeks, the first evidence of bumps can be seen.⁴⁴ Grooves have already begun to form at this point as well.⁴⁵ The corpus callosum, which connects the right and left sides of the brain, also begins developing as early as 15 weeks.^{46 47}