A nurse is reviewing the laboratory results of a client who is at 29 weeks of gestation and has pre-term labor.

Which of the following results indicates an infection that can trigger pre-term labor?

Nitrazine paper test.

This test involves putting a drop of fluid obtained from the vagina onto paper strips containing nitrazine dye.

The strips change color depending on the pH of the fluid.The strips will turn blue if the pH is greater than 6.0, which indicates the presence of amniotic fluid.This test can help confirm rupture of membranes (ROM) in pregnancy, especially when preterm labor is suspected.

Choice B. Ferning test.This test involves examining a sample of vaginal fluid under a microscope and looking for a fern-like pattern that is formed by dried amniotic fluid crystals.This test can also help confirm ROM, but it is less reliable than the nitrazine test because other substances such as cervical mucus, semen, or blood can also cause ferning.

Choice C. Amniotic fluid index.This test involves measuring the amount of amniotic fluid in the uterus using ultrasound.This test can help assess the fetal well-being and detect conditions such as oligohydramnios (low amniotic fluid) or polyhydramnios (high amniotic fluid).This test cannot confirm ROM by itself, but it can be used in combination with other tests to evaluate the status of the pregnancy.

Choice D. Biophysical profile.This test involves using ultrasound and a fetal monitor to assess the fetal heart rate, breathing, movement, muscle tone, and amniotic fluid volume.

Betamethasone is a corticosteroid that is given to pregnant women who are at risk of preterm delivery to enhance fetal lung maturity.Betamethasone stimulates the production of surfactant, a substance that lubricates the lungs and prevents them from collapsing when the baby breathes.This reduces the risk of respiratory distress syndrome and other complications in preterm infants.

Choice A is wrong because betamethasone does not reduce inflammation in the uterus.

Choice C is wrong because betamethasone does not prevent infection in the amniotic fluid.

Choice D is wrong because betamethasone does not increase blood flow to the placenta.

Normal ranges for gestational age are 37 to 42 weeks.

Preterm birth is defined as delivery before 37 weeks of gestation.Antenatal corticosteroids are recommended for women between 24 and 34 weeks of gestation who are at risk of preterm delivery within 7 days, and may be considered for women at 23 weeks of gestation or between 34 and 37 weeks of gestation depending on the clinical scenario.