Physiological Perspective, the First Trimester of Pregnancy

¶ … physiological perspective, the first trimester of pregnancy is when the majority of fetal development occurs, and also when the full development of the placenta occurs. The first twelve weeks or so after conception see the transformation of a fertilized egg cell into a fetus that shares blood flow with the placenta through the umbilical arteries and vein. As a result, these twelve weeks are particularly crucial for the health and development of the fetus at its most vulnerable stage. Among numerous other physiological changes, the mother's nutritional intake needs (which include vitamins and minerals) increase substantially, so nutrition is crucial. The avoidance of alcohol is necessary to avoid birth defects caused by the substance: as Blackburn notes, "drinking alcohol at any stage of pregnancy can affect the brain and other areas of development" (Blackburn 2007, 221).

Zoey's preganancy undergoes what is termed induced labor, in which she is given a dose of Pitocin, a synthetic form of the naturally occurring hormone oxytocin. Oxytocin has a number of functions in humans (including a sense of bonding during orgasm) but its functions in pregnancy are incredibly important. The normal release of oxytocin by the brain's pituitary gland is what triggers the contractions during labor, and it also seems to play a role in decreasing inflammation and promoting wound healing (suggesting its usefulness in repairing the damage done to the uterus and birth canal during parturition). Hence the introduction of synthetic oxytocin through an IV drip helps to efface and dilate Zoey's cervix and causes her contractions to speed up.

3. The membrane that breaks when Zoey's "water breaks" is the amniotic sac. The amnion forms around the embryo in the earliest stages, as it attaches to the placenta, then fills with amniotic fluid (forming the sac) for the period of fetal development.

Tissues from a fetus might be useful for replacing diseased and damaged cells particularly in cases where the generation of new cells by the body itself does not happen. It is generally held, for example, that brain cells do not regenerate: as a result, diseases of progressive neurological impairment such as Parkinson's or Alzheimer's, or diseases involving other defects in the nervous system like epilepsy or spinal cord injuries, are faced with a human body that is not capable of reproducing new brain cells to replace the damaged ones. After embryonic development, the human organism has nerve cells that are capable of dying or being damaged but not capable of being regenerated. Likewise the pancreatic beta-cells that produce insulin -- damage to which causes type 1 diabetes -- are also not self-regenerating. As a result, embryonic stem cells may present the best means of regenerating these types of cells in affected adults and reversing the course of disease. The ethics of medical use of embryonic stem cells are complicated in the United States by those who are morally opposed to abortion. Stem cells used for medical research cannot be obtained without destroying the embryo. Miscarriage represents an available source of embryonic stem cells that does not require the embryo to be killed by the researcher. Legal abortion represents an available source of embryonic stem cells as well. The ethical question here does not seem to be the use of the stem cells themselves. Childress (1997) notes the "well-established social practice of using cadaveric human tissue in research, transplantation, and education…cadaveric fetal tissue has already been used in all these ways, too (though not widely for transplantation)" (323). What would be preferable, of course, is regular laboratory production of non-viable embryos that serve purely as a source of stem cells -- this seems to raise no ethical questions unless one's ideas about the ethics of fertilizing an egg derive exclusively from Thomas Aquinas.