Continuous fetal monitoring is essential for the evaluation of a mother and fetus during the second half of a woman's pregnancy and should be implemented when assessing all the conditions discussed in this chapter.
Abruptio placentae, placenta previa, and preterm labor are the most common causes of vaginal bleeding during the second half of pregnancy.
Abruptio placentae, the premature separation of the placenta from the uterine wall, must be considered in all pregnant females near term who present with painful vaginal bleeding. Clinical features include vaginal bleeding, abdominal pain, uterine tenderness, hypertonic contractions, increased uterine tone, fetal distress, and, in severe cases, disseminated intravascular coagulation (DIC), and fetal and/or maternal death. Vaginal bleeding may be mild or severe, depending on whether the area of abruption communicates to the cervical os. Abruption of greater than 50% of the placenta usually results in fetal demise.
Placenta previa is the implantation of the placenta over the cervical os. Clinical features include painless, bright red vaginal bleeding. The amount of bleeding is frequently large as opposed to normal “bloody show,” when a small amount of bright red blood and mucous are passed.
Diagnosis and Differential
Transabdominal ultrasound should be obtained to prior to performing speculum or digital pelvic examination to differentiate abruption placenta from placenta previa as it is contraindicated in previa. Ultrasound is very sensitive in detecting placenta previa but has limited sensitivity in diagnosing abruption placenta.
Emergency Department Care and Disposition
Hemodynamic instability is managed with IV normal saline or leukoreduced packed red blood cells.
Obtain emergent obstetric consultation, CBC, type and crossmatching, baseline coagulation studies, electrolyte studies on all patients.
Obtain a DIC profile on patients with suspected abruptio placentae.
Give Rh (D) immune globulin 300 micrograms IM to Rh-negative patients.
Patients with abruptio placentae or placenta previa may need emergent caesarean delivery.
Tocolytics should not be used in patients with suspected abruption.
Premature Rupture of Membranes
Premature rupture of membranes (PROM) is rupture of membranes before the onset of labor. Clinical presentation is a rush of fluid or continuous leakage of fluid from the vagina. Diagnosis is confirmed by finding a pool of fluid in the posterior fornix with pH greater than 7.0 (dark blue on Nitrazine paper) and ferning pattern on smear. Sterile speculum examination may be done; however, digital pelvic examination should be avoided because it increases the rate of infection. Tests for chlamydia, gonorrhea, bacterial vaginosis, and group B Streptococcus should be performed. Management of PROM depends on gestational age and maturity of the fetus, condition of the fetus, concern for infection, and presence of other complicating factors. An obstetrics consultation should be obtained to assist with treatment and admission decisions.