There are a number of markers that are heavily affected by pregnancy, many practitioners are unaware of these, and it makes interpreting a pregnant person's blood test very challenging. Below are the main markers that will commonly be affected in a standard blood test, most of these are normal changes and are not concerning observations:

Hemoglobin decreases (due to increase in blood volume)

MCV increases slightly (due to increased production of red blood cells)

HCT decreases slightly (due to changes in blood volume)

Neutrophils increase (partly due to increased physiological stress and partly due to slower cell death)

Lymphocytes fluctuate (decrease initially, then increase)

Platelets decrease (due to increased platelet activation and clearance)

Albumin decreases (due to increased blood volume)

Creatinine decreases (due to increased kidney function)

Urea decreases (due to increased kidney function)

Sodium slightly decreases (due to increased blood volume)

Uric acid decreases (due to increased kidney function)

ALP increases significantly (due to high activity in the placenta)

Cholesterol increases (supports growth of the fetus)

Triglycerides increase (supports growth of the fetus)