A nurse is reviewing the ultrasound report of a client who is at 31 weeks of gestation and has pre-term labor.

Which of the following findings indicates oligohydramnios?

Betamethasone is a corticosteroid that is given to pregnant women who are at risk of preterm delivery to enhance fetal lung maturity and prevent respiratory distress syndrome.It is usually given in two doses, 24 hours apart, and takes effect within 24 hours of administration.

Choice B.Magnesium sulfate is wrong because it is used to prevent seizures in women with severe preeclampsia or eclampsia, not to prevent respiratory distress syndrome.

Choice C.Nifedipine is wrong because it is a calcium channel blocker that is used to inhibit uterine contractions and prolong pregnancy in women with preterm labor, not to prevent respiratory distress syndrome.

Choice D.Indomethacin is wrong because it is a nonsteroidal anti-inflammatory drug that is used to inhibit prostaglandin synthesis and reduce uterine activity in women with preterm labor, not to prevent respiratory distress syndrome.However, it can also cause premature closure of the ductus arteriosus in the fetus and should be avoided after 32 weeks of gestation.

Normal ranges for gestational age are 37 to 42 weeks.

Preterm labor is defined as regular uterine contractions with cervical changes.

According to the search results, magnesium sulfate can have a negative effect on the fetal heart rate (FHR) by lowering the baseline, decreasing the variability, and reducing the reactivity or acceleration pattern.Absent variability means that there is no fluctuation in the FHR and it indicates fetal hypoxia or acidosis.

This is a potential adverse effect of magnesium sulfate on the fetus and requires immediate intervention.

Choice A.Accelerations is wrong because accelerations are transient increases in the FHR that indicate fetal well-being.They are not affected by magnesium sulfate.

Choice B.Early decelerations is wrong because early decelerations are decreases in the FHR that occur with uterine contractions and are caused by fetal head compression.They are benign and do not indicate fetal distress.They are not associated with magnesium sulfate.

Choice C.Variable decelerations is wrong because variable decelerations are abrupt decreases in the FHR that vary in shape, duration, and timing and are caused by umbilical cord compression.

They may or may not indicate fetal compromise.