At a prenatal visit at 12 weeks gestation a 38-year-old gravida 3 para 2 has a pulse rate of 110 beats/min and has lost 2 kg (4 lb) since her previous visit. At age 26, she was treated for Graves’ disease with radioactive iodine and has been euthyroid on no medication for over 10 years. A CBC shows a mild anemia. Her hematocrit is 34% (N 35-45) and her TSH level is 0.00 U/mL (N 0.5-5.0).
Which one of the following would be most appropriate at this time?
Correct Answer A:
Graves disease is an autoimmune disease characterized by hyperthyroidism due to circulating autoantibodies. Mild hyperthyroidism (slightly elevated thyroid hormone levels, minimal symptoms) often is monitored closely without therapy as long as both the mother and the baby are doing well. When hyperthyroidism is severe enough to require therapy, anti-thyroid medications are the treatment of choice, with propylthiouracil (PTU) being the drug of choice. PTU is usually prescribed in the first trimester (up to week 14), and Methimazole (MMI) for the rest of the pregnancy. Thyroid surgery is rarely an option for pregnant women.
→ The combination of propylthiouracil and levothyroxine is frequently used for hyperthyroidism in nonpregnant patients, but transplacental passage of the levothyroxine would be harmful to the developing fetus.
→ Methimazole (MMI) crosses the placenta more readily than propylthiouracil and is associated with aplasia cutis. In areas where PTU is not available, or when a woman is allergic to PTU, methimazole and carbimazole are used during pregnancy.
→ Radioactive iodine therapy is contraindicated in pregnancy, and immediate surgery might present hazards to both the mother and the fetus.
→ Propranolol would control the patient’s heart rate, but would do nothing about the underlying hyperthyroidism.
A 28-year-old gravida 2 para 1 successfully delivers a full-term infant vaginally. Her first child was delivered by cesarean section. With this delivery there are no signs of maternal pain, significant bleeding, or hemodynamic compromise during the first two stages of labor. However, 30 minutes after delivery of the infant there is still no umbilical cord elongation or contraction of the uterus, and the placenta is not at the cervical os. Manual exploration of the uterus reveals that the placenta is attached in a low anterior position and there is no easily discernible plane of separation. During this procedure, uterine bleeding becomes brisk and continues despite bimanual massage and administration of oxytocin (Pitocin), 10 U intra-muscularly.
Vital Signs: Temperature:
Which one of the following should be done next?
Correct Answer D:
This case demonstrates the clinical outcome of abnormal placental attachment. In this situation, the placenta has either partially or completely attached to the myometrium instead of the endometrium, which normally sloughs after birth, thus resulting in detachment of the placenta. The three forms of abnormal attachment (accreta, increta, and percreta) are difficult to differentiate by examination and are treated as the same condition, sometimes generally referred to as “placenta accreta”. No conservative mode of management will definitively treat these conditions when a significant portion of the placenta is abnormally attached. Therefore, if bleeding becomes profuse and the patient’s condition is unstable, prompt hysterectomy is required.
This patient has low blood pressure and an elevated pulse, likely due to significant blood loss. It is inappropriate to await spontaneous delivery of the placenta, which may never occur. Trying further to remove the placenta will only result in increased bleeding. Pulling on the umbilical cord may result in uterine inversion. There is no indication for any other manual maneuver.
You see a 24-year-old obstetric patient late in her third trimester for mild dysuria and urinary urgency. Microscopic examination of the urinary sediment is notable for bacteria and you make a presumptive diagnosis of cystitis.
Which one of the following antibiotics would be contraindicated?
Correct Answer B:
Trimethoprim/sulfamethoxazole is a pregnancy category C antibiotic which is contraindicated in the third trimester of pregnancy because its sulfonamide component displaces bilirubin from albumin binding sites and thus can increase the free bilirubin concentration in the newborn’s blood. This theoretically could increase the risk of the infant developing kernicterus, particularly preterm infants. The remaining antibiotics listed are pregnancy category B agents, which can be used safely throughout pregnancy.
Which one of the following intravenous agents given to the mother during labor is the drug of choice for prophylaxis of neonatal group B streptococcal disease?
Correct Answer E:
Intravenous penicillin G is the drug of choice for prophylaxis of neonatal group B streptococcal disease, although shortages during 1999 required the interim use of broader-spectrum antibiotics. Group B streptococci have remained sensitive to penicillin, but they may be resistant to clindamycin and erythromycin, the drug recommended for women allergic to penicillin.
An 18-year-old gravida 1 para 0 at 40 5/7 weeks gestation presents stating that she “thinks her water broke 12h ago”. A sterile speculum examination confirms rupture of the membranes. There are no signs of active labor. The patient is afebrile, her uterus is nontender, and fetal heart tones are reassuring. The remainder of the prenatal history is unremarkable. A group B Streptococcus culture obtained 4 weeks ago was negative. The patient has no known drug allergies.
In addition to induction of labor, which one of the following is the most appropriate management for this patient?
According to current guidelines, women with negative vaginal and rectal group B Streptococcus screening within 5 weeks of delivery do not require intrapartum antimicrobial prophylaxis. This holds even if certain obstetric risk factors develop (delivery at < 37 weeks gestation, duration of membrane rupture > 18 hours, or temperature > 100.4°F or 38°C). In patients requiring intrapartum antibiotic prophylaxis, penicillin is the first-line agent, with ampicillin as an acceptable alternative. For women who have a known penicillin allergy, cefazolin should be used if the patient is not at high risk for anaphylaxis. If the patient is at high risk for anaphylaxis, clindamycin is an acceptable alternative if prior cultures have shown susceptibility. If the susceptibility is unknown, vancomycin should be used.
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