Final answer:
Nitrazine paper is used to assess amniotic fluid pH to confirm membrane rupture during childbirth, as amniotic fluid has a higher pH than vaginal secretions.
Step-by-step explanation:
We test a membrane rupture with nitrazine paper primarily to assess the pH of amniotic fluid. Amniotic fluid typically has a pH range of 7.0 to 7.5, which is more alkaline compared to the normal pH of vaginal secretions which is between 4.5 and 6.0. When the amniotic membranes rupture, fluid may leak from the vagina, and by using nitrazine paper, which changes color in response to different pH levels, healthcare providers can distinguish between amniotic fluid and normal vaginal secretions. A positive nitrazine test, indicated by the paper turning blue (pH > 6.5), suggests that the membranes have ruptured, which is a critical step in the process of childbirth, particularly in the case of Preterm premature rupture of membranes (PPROM) where the membrane ruptures before 38 weeks of gestation. This test does not check for infection, determine the baby's blood type, nor measure cervical dilation directly, but it helps clinicians manage labor and delivery more effectively by confirming the rupture of membranes.