The maternity nurse understands that vascular volume increases 40% to 45% during pregnancy to:

Choice A reason: Vibroacoustic stimulation is a technique that uses sound to stimulate the fetus and elicit a response. It is sometimes used in conjunction with the nonstress test (NST), not the CST. The NST measures the fetal heart rate (FHR) in response to fetal movement, while the CST measures the FHR in response to uterine contractions.

Choice B reason: A negative CST result means that the FHR does not show any late decelerations during at least three contractions in a 10-minute period. Late decelerations are decreases in the FHR that begin after the peak of a contraction and return to the baseline after the contraction ends. They indicate uteroplacental insufficiency, which means that the placenta is not delivering enough oxygen and nutrients to the fetus. A negative CST result is reassuring and suggests that the fetus is well-oxygenated and can tolerate labor².

Choice C reason: The CST is not an invasive test, as it does not involve inserting any instruments or devices into the uterus or the fetus. However, it does require stimulating contractions, either by giving the pregnant woman oxytocin (a hormone that causes uterine contractions) or by having her rub her nipples (which also releases oxytocin). The contractions can be uncomfortable and may trigger preterm labor in some cases.

Choice D reason: The CST is not more effective than the NST if the membranes have already been ruptured. In fact, the CST is contraindicated (not recommended) in women who have ruptured membranes, as it can increase the risk of infection and bleeding. The NST is a safer and simpler alternative to the CST, as it does not require stimulating contractions. However, the NST may not be as reliable as the CST in detecting fetal compromise.

The correct answer is: B. 3-1-1-0-3.

Choice A reason:

This option suggests the woman has been pregnant four times, which is incorrect. She has had three pregnancies: one set of twins (counted as one pregnancy) and two singletons.

Choice B reason:

This is the correct option. The woman has had three pregnancies (Gravida = 3), one full-term delivery (Term = 1), one preterm delivery (the twins, Preterm = 1), no abortions (Abortions = 0), and three living children (Living = 3).

Choice C reason:

This option incorrectly suggests two preterm deliveries and one abortion, neither of which is indicated in the woman's history.

Choice D reason:

This option incorrectly suggests two preterm deliveries (the twins are counted as one preterm delivery) and does not accurately reflect the woman's history.

GTPAL stands for Gravida (total number of pregnancies), Term births (deliveries after 37 weeks), Preterm births (deliveries between 20-36 weeks), Abortions (losses before 20 weeks), and Living children. Normal ranges: Term (≥37 weeks), Preterm (20-36 weeks)