A popular argument in favor of abortion is that the unborn cannot breath. Because they do not inhale and exhale air with their lungs in the same way as those who are born, it’s something that is used to disconnect the unborn from humanity and treat them as non-persons. Some argue that a fetus becomes a baby when it takes it’s first breath of air.
My problem with this argument is that the unborn can’t breath because they aren’t supposed to. The womb is an aquatic environment where the unborn are growing and developing, their bodies and organs are preparing for life outside the womb which they are not yet ready for. That’s kind of the whole point of pregnancy — that’s the purpose of the entire process — the womb is the place where we begin and where we develop until we are capable of life outside the womb, then we are born and we continue to develop outside the womb.
The circulatory system of unborn humans works differently from that of born humans, mainly because the lungs aren’t in use: the unborn obtain oxygen and nutrients from the mother through the placenta and the umbilical cord. Highly oxygenated and nutrient-enriched blood returns to the fetus from the placenta via the left umbilical vein. Some blood percolates through the hepatic sinusoids; most of the blood bypasses the sinusoids by passing through the ductus venosus and enters the inferior vena cava, and then enters the right atrium where most of the blood bypasses the right ventricle through the foramen ovale to enter the left atrium, and from the left atrium the blood enters the left ventricle and is delivered to the fetal tissue via the aorta. This method of circulation is different from born humans, but the purpose is the same: to supply the unborn with oxygen and nutrient-rich blood. It’s a shared requirement to sustain life of the unborn and born.
We’ve long known that a mammal’s lungs are the last organ to develop in utero before it is baby’s time to exit. At the University of Texas Southwestern Medical Center at Dallas, researchers have found that it is in fact the fetal lungs themselves which provide the signal to initiate labor. Drs. Carole Mendelson, Jennifer Condon and Pancharatnam Jeyasuria published findings that the initiation of term labor is carefully timed to begin only after the fetus is sufficiently mature to survive outside the womb. In this study, researchers found that the key labor triggering substance, surfactant, is essential for normal breathing outside the womb. The surfactant serves as a hormone of labor that signals to the mother’s uterus when the fetal lungs are sufficiently mature to withstand the critical transition from life in fluid to air breathing.
As adults, we actually have fibrous remnants of our fetal circulatory structures. The right and left umbilical arteries we had as a fetus become our medial umbilical ligament as an adult. The left umbilical vein as a fetus becomes our ligamentum teres as an adult. The ductus venosus becomes the ligamentum venosum, the foramen ovale becomes the fossa ovalis, and the ductus arterosus becomes the ligamentum arteriosum. Our hearts still carry pieces from our previous state of development.
After birth, all of the baby’s blood must pass through the lungs to be re-oxygenated and to release carbon dioxide. This process requires that a number of changes occur at birth. With the first few breaths, the baby’s lungs expand, and more and more alveoli inflate. Blood flow to the lungs increases substantially. But that’s not where the lungs stop developing and growing — just as they were growing and developing in the unborn in the womb, they also continue to grow and develop in the born baby outside the womb. As the baby grows, the lungs continue to recruit and expand more alveoli and to grow new lung tissue, which develops and multiplies to accommodate the growing lungs. The airway and vascular structures continue to grow, as does the entire thoracic space where the lungs reside. As a child grows, so does his lung volume.