Final answer:
A macrocosmic infant is likely to cause difficulty in passing through the birth canal, which is the most probable complication at the end of pregnancy from the options provided.
Step-by-step explanation:
The question relates to the difficulties that a macrocosmic infant, likely meaning a larger-than-average baby, may create at the end of pregnancy. The most probable complication from the options provided is c) Difficulty in passing through the birth canal. A large fetus may face challenges fitting through the mother’s pelvis, potentially leading to a prolonged labor or the need for a caesarian section. Moreover, it could lead to complications such as birth trauma for the infant or severe perineal tears for the mother.
Maternal stress is indeed increased due to the physical and emotional demands of carrying and potentially delivering a large baby, but it is not the primary complication. Difficulty in breastfeeding could arise postpartum but is not directly related to the size of the infant at birth. An enhanced maternal immune response is typically downregulated during pregnancy to prevent the mother's immune system from attacking the fetus. The concern would be increased vulnerability to infections like Listeria monocytogenes, which could cross the placenta and harm the fetus but is not directly caused by the size of the infant.