Final answer:
The accurate statement about pregnancy is that nausea and vomiting typically occur during the early stages due to increased levels of certain hormones and usually do not harm the fetus, subsiding by the 12th week. The correct option is D.
Step-by-step explanation:
Considering the provided information, the correct statement about a condition of pregnancy is that nausea and vomiting are common during the first few weeks to months of pregnancy and rarely have harmful effects on the fetus. Nausea, often termed 'morning sickness', is mostly caused by the increased levels of estrogen, progesterone, and hCG hormones. Though uncomfortable, this condition generally subsides by about week 12 of pregnancy.
Gastrointestinal complaints such as acid indigestion or heartburn (pyrosis) tend to not decline throughout pregnancy but can increase due to the growing uterus exerting pressure on the stomach and the relaxation of the lower esophageal sphincter, further exacerbated by decreased intestinal peristalsis.
As for changes in thyroid function, it is true that the anterior pituitary increases hormone production during pregnancy which in turn raises thyroid hormone levels enhancing the maternal metabolic rate, but this does not typically result in hyperthyroidism.