Final answer:
The correct understanding about physiological changes during pregnancy is that alternative positions for sexual intercourse may be required due to anatomical changes. Gaining more than 15 to 20 pounds is common, breast enlargement can occur despite reduction surgeries, and stretch marks can appear regardless of complexion.
Step-by-step explanation:
The statement indicating an understanding of the physiological changes that occur during pregnancy would be: "I will likely need to use alternative positions for sexual intercourse." This consideration addresses the anatomical changes of the mother's body that could affect comfort and physical ability. The misconceptions presented in other options, such as not gaining more than 15 to 20 pounds and not expecting breast enlargement after breast reduction or stretch marks due to light complexion, do not reflect the typical physiological changes. During pregnancy, BMI WDL (Body Mass Index Within Desired Limits) does not prevent typical pregnancy weight gain, which primarily occurs in the breasts and abdominal region, with the total weight gain usually exceeding the 15 to 20 pounds over the course of the entire pregnancy if the BMI is normal to begin with.
Pregnancy involves an increase in blood volume by 30 percent and respiratory minute volume by 50 percent. Skin changes like stretch marks can occur regardless of one's complexion, and they are related to the rapid stretching of the skin. Moreover, breasts typically enlarge during pregnancy due to hormonal changes, even if there has been a previous breast reduction. Lastly, the idea that weight gain during pregnancy will be limited to only 5 pounds from fat storage is a misconception, as the weight also comes from the growing fetus, amniotic fluid, and placenta.