A 30-year-old G1P0 at 25 weeks presents to labor and delivery complaining of irregular uterine contractions and back pain. She reports no leakage of fluid from her vagina, but says that earlier in the day she had some very light vaginal bleeding, which has now resolved. She has had no prenatal care. She is dated by a sure LMP. On arrival to labor and delivery, she is placed on an external fetal monitor, which demonstrates uterine contractions every 2 to 4 minutes. She is afebrile and her vital signs are all normal. Her gravid uterus is nontender and measures 25 cm, consistent with her gestational age by LMP. The nurse calls you to evaluate the patient.
Which of the following is the most appropriate first step in the evaluation of vaginal bleeding in this patient?
The concern with this patient who presents with symptoms of back pain, cramping, and vaginal bleeding is preterm labor. Before performing a digital examination on this patient to determine her cervical status, an ultrasound should be performed to rule out placenta previa in light of her history of vaginal bleeding without a prior ultrasound to document placental location. Intravenous hydration is appropriate in the setting of contractions, because dehydration may cause preterm contractions and uterine irritability. Urinary tract infections can be associated with uterine contractions and preterm labor, and therefore a urinalysis and/or urine culture should be obtained. The type of bleeding described is unlikely to have been caused by coagulopathy. The blood is unlikely to be fetal given the reassuring fetal heart tracing.
A 30-year-old G1P0 at 28 weeks’ gestation is being evaluated for vaginal bleeding and uterine contractions. A bedside ultrasound demonstrates a cephalic fetus with an anterior placenta and no evidence of placenta previa. The fetal heart rate tracing is reactive, and uterine contractions are seen every 2 to 3 minutes. A sterile speculum examination is negative for ruptured membranes. A digital examination indicates that the cervix is 3 cm dilated and 50% effaced, and the presenting part is at -3 station. Tocolysis with magnesium sulfate is initiated and intravenous antibiotics are started for group B streptococcus prophylaxis.
Which of the following statements correctly describes the benefits of betamethasone in the treatment of preterm labor?
The patient is in preterm labor, because she has a dilated and effaced cervix in the presence of regular uterine contractions. Therefore, treatment is aimed at delaying delivery to allow continued fetal growth and maturity. The administration of tocolytic therapy to treat the preterm contractions is indicated. In addition, from 24 to 34 weeks, management also includes the administration of steroids, such as betamethasone, to promote fetal lung maturity. These steroids increase fetal surfactant production. RDS is a sequela of preterm neonates and occurs less often in infants given betamethasone in utero, because the surfactant increases pulmonary compliance and decreases surface tension. If delivery seems likely, intravenous antibiotics are administered to prevent possible neonatal sepsis. If the patient’s contractions subside and there is no evidence of infection, then the antibiotics can be discontinued. It is advantageous to obtain a neonatology consult on any patient who appears to be in preterm labor so the parents know what to expect if they give birth to preterm infants. There is no need to prepare for a cesarean delivery in this patient at this time. Attempts are made to stop the labor first. If the patient continues to progress, then a vaginal delivery is preferred since the fetus is cephalic.
A 30-year-old G1 at 28 weeks’ gestation is admitted to the hospital for preterm labor with painful contractions every 2 minutes. She is 3 cm dilated with membranes intact and a small amount of bloody show. Her pregnancy has been complicated by chronic hypertension, which has been well controlled on oral antihypertensive therapy. Ultrasound demonstrates a cephalic fetus with appropriate growth for gestational age and oligohydramnios.
Which of the following statements correctly describes the potential benefits of tocolysis?
According to ACOG, in the United States, the rate of preterm birth is 12%, and approximately 50% of these births were preceeded by preterm labor. Preterm births account for approximately 70% of neonatal deaths, 36% of infant deaths, and 25% to 50% of cases of long-term neurologic impairment in children. Tocolysis does not provide neuroprotection; however, several studies have shown that predelivery administration of magnesium sulfate reduces the incidence of cerebral palsy when it is given with neuroprotective intent. Tocolysis has not been shown to work longer than 48 hours, and has not been shown to decrease the incidence of preterm birth. There is no evidence that tocolysis has any direct favorable effect on neonatal outcomes, or that any prolongation of pregnancy afforded by tocolytics translates into a statistically significant neonatal benefit.
Which of the following is a contraindication to the use of indomethacin as a tocolytic in this patient?
Indomethacin would not be an appropriate tocolytic agent in this patient. Indocin is a prostaglandin synthetase inhibitor that can decrease fetal urine production and cause oligohydramnios. Since this fetus already has oligohydramnios it is best to avoid this therapy. Nifedipine is used for tocolysis and is thought to work by preventing entry of calcium into muscle cells. It can be associated with hypotension, so blood pressure must be followed carefully. Ritodrine and terbutaline are tocolytic agents that are b-adrenergic agents. They work by increasing cAMP in cells, which decreases free calcium. These agents can be associated with tachycardia, hypotension, and pulmonary edema. Magnesium sulfate is a tocolytic agent that works by competing with calcium for entry into cells. At high levels, it can cause respiratory and cardiac depression. Magnesium sulfate is contraindicated in patients with myasthenia gravis.
A healthy 32-year-old G2P1001 presents to labor and delivery at 30 weeks’ gestation reporting a small amount of bright red blood per vagina which occurred shortly after intercourse. It started off as spotting and then progressed to a light bleeding. By the time the patient arrived at labor and delivery, the bleeding had completely resolved. She reports no contractions, but admits to occasional abdominal cramping. She was dated by an 18-week ultrasound, and her pregnancy has been uncomplicated. Her obstetric history is significant for a previous low transverse cesarean at term. Vital signs are normal. Tocodynomometer shows contractions every 10 to 15 minutes, and the fetal heart rate tracing is reactive.
Which of the following diagnoses may be excluded as the most likely cause for her vaginal bleeding?
Vasa previa occurs when fetal vessels overlie the cervical os from velamentous insertion of the umbilical cord. They are susceptible to compression and laceration with rupture of membranes. Bleeding from a vasa previa causes fetal exsanguination, and since only a small amount of bleeding is necessary to kill a fetus, death is almost instantaneous if it goes unrecognized. Since the fetal heart tracing is normal, vasa previa is an unlikely diagnosis. Cervical inflammation (cervicitis) can render the cervix friable and prone to bleeding, especially after intercourse. Placental abruption occurs when there is a premature separation of the placenta from the uterine wall. While vaginal bleeding can be observed, the hemorrhage can be completely concealed, with the blood being trapped between the detached placenta and the uterine wall. Labor can be associated with vaginal bleeding caused by cervical dilation. Placenta previa occurs when the placenta is located over or in close proximity to the internal os of the cervix. When the lower uterine segment is formed or cervical dilation occurs in the presence of placenta previa, a certain degree of spontaneous placental separation and hemorrhage from disrupted blood vessels will occur.
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