Final answer:
By the 12th week of gestation, the uterus should be palpable at the pubic symphysis, indicating normal fetal and uterine development.
Step-by-step explanation:
By the 12th week of gestation, the uterus should have increased in size to be palpable at the pubic symphysis. During this time, fetal development is significant; the brain continues to expand, the body elongates, and ossification of the bones occurs. Moreover, the fetus becomes active and may begin to show movements, though they are not yet well-coordinated. The placenta now fully assumes the critical roles of nutrition, waste elimination, and production of important hormones like estrogen and progesterone, since the corpus luteum has degenerated by this stage of pregnancy.
The uterus, which begins pregnancy about the size of a fist, experiences remarkable growth to accommodate the developing fetus, leading it to be detectable above the pelvic rim. By 12 weeks, the uterus has grown enough to be felt through the abdominal wall at the pubic symphysis, signaling a normal progression of pregnancy.