Sonja is pregnant during the year she is taking human physiology. At each check-up, she expects to be told that her blood pressure has increased. Yet into the final weeks of her pregnancy, her blood pressure is unchanged from its pre -pregnancy value. Why did she expect her blood pressure to increase? Propose some explanations for why it didn't. (Hint: Sometimes women adopt healthier habits

Question

during pregnancy, there are large blood-filled sinuses in the maternal portion of the placenta, and there are many hormonal effects that are unique to pregnancy.)

What will be an ideal response?

Answer 1

(Note to instructor: You may want to alter the hint, providing more or less help, depending on what you have covered in class.)
Sonja assumes that her pressure will elevate with the increased blood volume and increased peripheral resistance that accompany the tissue growth she experiences. It is possible that she has adopted healthier diet and exercise habits during her pregnancy, offsetting an increase in pressure. It is also possible that the changing hormonal environment includes regulation of blood pressure so that it remains normal. It is also the case that the placenta forms a low-resistance reservoir for the maternal blood, offsetting the expected increase in total peripheral resistance and blood pressure.