Notes

Treatment with an antihypertensive is indicated for blood pressures persistently greater than 160 systolic and 105 diastolic. First-line agents include hydralazine (a direct vasodilator) 5 mg IV followed by 5-10 mg doses IV at 20-minute intervals (maximum dose = 40 mg); or labetalol (combined alpha & beta-adrenergic antagonist) 10-20 mg IV followed by 20 mg, then 40 mg, then 80 mg IV every 10 minutes (maximum dose = 220 mg). The goal is not a normal blood pressure, but to reduce the diastolic blood pressure into a safe range of 90-100 mmHg to prevent maternal stroke or abruption, without compromising uterine perfusion.
Noninvasive diagnosis of fetal anemia can be performed with Doppler ultrasonography. The use of middle cerebral artery peak systolic velocity in the management of fetuses at risk for anemia because of red cell alloimmunization has emerged as the best test for the noninvasive diagnosis of fetal anemia.
Rh disease: Fetal hydrops is easily diagnosed on ultrasound. It develops in the presence of decreased hepatic protein production. It is defined as a collection of fluid in two or more body cavities, such as ascites, pericardial and/or pleural fluid and scalp edema.
In the presence of a severely erythroblastotic fetus, the amniotic fluid is stained yellow. The yellow pigment is bilirubin.
Values in Zone 3 of the Liley curve indicate the presence of severe hemolytic disease, with hydrops and fetal death likely within 7-10 days, thus demanding immediate delivery or fetal transfusion. At 30 weeks gestation, the fetus would benefit from more time in utero. An attempt should be made to correct the underlying anemia. Intravascular transfusion into the umbilical vein is the preferred method.
Ultrasound markers suggestive of dizygotic (non-identical) twins include a dividing membrane thickness greater than 2 mm, twin peak (lambda) sign, different fetal genders and two separate placentas (anterior and posterior). The two different placental types in twin gestation are monochorionic and dichorionic. Dizygotic conceptions always have dichorionic placentas. Monozygotic conceptions may have either monochorionic or dichorionic placentation, depending upon the time of division of the zygote. Diamniotic dichorionic placentation occurs with division prior to the morula state (within three days post fertilization). Diamniotic monochorionic placentation occurs with division between days four and eight post-fertilization. Monoamniotic, monochorionic placentation occurs with division between days eight and 12 post fertilization. Division at or after day 13 results in conjoined twins.
Twin-twin transfusion syndrome is the result of an intrauterine blood transfusion from one twin to the other. It most commonly occurs in monochorionic, diamniotic twins
The risk of developing microcephaly and severe intellectual disability is greatest between eight and 15 weeks gestation
Severe hypertension and active APAS is often associated with oligohydramnios and intrauterine growth restriction
A maternal blood type should be checked on all women with vaginal bleeding during pregnancy, unless it was documented earlier in the pregnancy. If the patient’s blood type is Rh-negative, RhoGAM would be indicated to prevent Rh sensitization.
Uncontrolled glucose is associated with adverse fetal outcome. A patient with type 1 diabetes is at risk for many pregnancy complications, including fetal death and fetal macrosomia, although fetal growth restriction may also occur. Diabetics also have increased risk for polyhydramnios, congenital malformations (cardiovascular, neural tube defects, and caudal regression syndrome), preterm birth, and hypertensive complications.
This is important to recognize to help the couple through these stages: Denial, Anger, Bargaining, Depression, Acceptance.
This patient has a missed abortion and should be offered uterine evacuation. Ultrasound criteria for a missed abortion are a Crown Rump Length of > 7 mm with no cardiac activity.
Fetal macrosomia, maternal obesity, diabetes mellitus, postterm pregnancy, a prior delivery complicated by a shoulder dystocia, and a prolonged second stage of labor are all associated with an increased incidence of shoulder dystocia.
Amniotomy (also referred to as artificial rupture of membranes [AROM]) is the procedure by which the amniotic sac is deliberately ruptured so as to cause the release of amniotic fluid. Amniotomy is usually performed for the purpose of inducing or expediting labor or in anticipation of the placement of internal monitors (uterine pressure catheters or fetal scalp electrodes). It is typically done at the bedside in the labor and delivery suite.
This patient likely is experiencing a placenta abruption. Her biggest risk factor is polyhydramnios with rapid decompression of the intrauterine cavity. While oxytocin is used to augment labor, in a nulliparous patient, the difference between her two exams is extreme. Typically, normal labor progresses about 1 cm per hour in the active phase of labor (multiparous woman about 1-2 cm/hour). While there may be some vaginal bleeding (bloody show, or light bleeding with cervical dilation) it is not normal to have a large amount of bleeding.
This patient is near term with a third episode of active bleeding from a placenta previa. The appropriate next step would be to move towards delivery via Cesarean section. Catastrophic bleeding could occur due to disruption of blood vessels as the cervix dilates if a vaginal delivery is pursued, and induction of labor would therefore be contraindicated.
Placenta accreta occurs when the placenta grows into the myometrium. This patient is at risk for this condition due to her history of four previous Cesarean deliveries, and the low anterior placenta. The scar tissue from the previous surgery prevents proper implantation of the placenta and it subsequently grows into the muscle. Vasa previa is a rare condition where the umbilical cord inserts into the membranes.
placental abruption - Common presenting signs of an abruption include abdominal pain, bleeding, uterine hypertonus and fetal distress. Risk factors for abruption include smoking, cocaine use, abdominal trauma, chronic hypertension, multiparity and prolonged premature rupture of membranes.
Cervical incompetence is usually diagnosed earlier in the second trimester and is associated with painless cervical dilation.
This patient is in preterm labor. Ampicillin is indicated for this patient as her Group B Strep status is unknown and should be continued until a culture result is negative or her labor stops. Nifedipine is a tocolytic used to delay the progression of labor to allow for the benefit of betamethasone to hasten pulmonary maturation. Both prostaglandin E1 and E2 are uterotonic agents and would likely increase the rate of this patient’s contractions.
This patient has a fever, a tender fundus, and elevated white blood cell count, which are concerning for an intra-amniotic infection. Delivery is warranted and in the case of reassuring heart tones, there are no contraindications for labor induction and a Cesarean section is not indicated at this time. Tocolytics should not be used in the case of an intra-amniotic infection.
Magnesium sulfate is contraindicated in myasthenia gravis. Indomethacin is contraindicated at 33 weeks due to risk of premature ductus arteriosus closure.
Terbutaline is a beta-adrenergic agent. Side effects include tachycardia, hypotension, anxiety and chest tightening or pain. Tachypnea and headaches are not usual side effects. The FDA made a formal announcement in 2011 warning against using terbutaline to stop preterm labor stating that terbutaline is both ineffective and dangerous if used for longer than 48 hours. The drug may still be used on a short-term basis in patients with active contractions, such as those being transferred to another hospital for tertiary care. Alternative tocolytic agents should be used for longer term treatment of preterm labor. Non-steroidal anti-inflammatory agents, such as indomethacin can be used as a tocolytic agent, but would have the side effect of premature closure of the ductus arteriosus if used beyond 32 weeks gestation. Magnesium sulfate can also be used as a tocolytic and has the potential side effect of respiratory depression.
Treatment with betamethasone from 24 to 34 weeks gestation has been shown to increase pulmonary maturity and reduce the incidence and severity of RDS (respiratory distress syndrome) in the newborn. It is also associated with decreased intracerebral hemorrhage and necrotizing enterocolitis in the newborn.
Fibronectin is an extracellular matrix protein that is thought to act as an adhesive between the fetal membranes and underlying decidua. It is normally found in cervical secretions in the first half of pregnancy. Its presence in the cervical mucus between 22 and 34 weeks is thought to indicate a disruption or injury to the maternal-fetal interface. - Good negative predictive value
Magnesium sulfate works by competing with calcium entry into cells. Beta-adrenergic agents work by increasing cAMP in the cell, thereby decreasing free calcium. Prostaglandin synthetase inhibitors, such as Indomethacin, work by decreasing prostaglandin (PG) production by blocking conversion of free arachidonic acid to PG. Calcium channel blockers prevent calcium entry into muscle cells by inhibiting calcium transport.