Choice A rationale:
Constipation is a common complaint during pregnancy, especially in the later stages. It is caused by hormonal changes that relax the muscles of the intestines, as well as the pressure of the growing uterus on the rectum.
It is generally not a cause for concern, and can be managed with dietary changes, increased fluid intake, and exercise. However, if constipation is severe or persistent, it is important to rule out other potential causes, such as intestinal obstruction or hypothyroidism.

Choice C rationale:
Leukorrhea is a white, milky discharge that is common during pregnancy. It is caused by increased production of cervical mucus, and is generally harmless.
However, if leukorrhea is accompanied by other symptoms, such as itching, burning, or a foul odor, it may be a sign of an infection and should be evaluated by a healthcare provider.

Choice D rationale:
Blurred vision can be a symptom of several different conditions, including preeclampsia, gestational diabetes, and migraines. It is important to report any changes in vision to a healthcare provider so that the underlying cause can be identified and treated.

Choice B rationale:
Low back pain is a common complaint during pregnancy, especially in the later stages. It is caused by a number of factors, including:
The weight of the growing uterus, which puts strain on the muscles and ligaments of the back. The relaxation of the joints and ligaments in the pelvis in preparation for childbirth.
Changes in posture to accommodate the growing belly.
While low back pain is often a normal part of pregnancy, it can sometimes be a sign of a more serious problem, such as preterm labor or placental abruption.
Therefore, it is important to report any new or worsening back pain to a healthcare provider.