Outcome of pregnancies with elevation of both maternal serum alpha-fetoprotein and human chorionic gonadotropin.

We evaluated the pregnancy outcome of all patients with elevations of both maternal serum alpha-fetoprotein and human chorionic gonadotropin since institution of combined serum screening at our program. After analysis of 34,404 samples, 99 patients were found to have significant elevations of both maternal serum alpha-fetoprotein and human chorionic gonadotropin. The ultrasound findings, amniocentesis results, and pregnancy outcomes were determined in each case. Sixty-six patients with singleton gestations met entry criteria. Pregnancy outcome information is available for 63 of these patients, 60% of whom had at least one complication. Thirty-three patients with multiple gestations met inclusion criteria. Pregnancy outcome information is available for 31 of these, 81% of whom had at least one complication. These patients had a high incidence of pregnancy related complications. This group would appear to be at higher risk than women with elevation of either maternal serum alpha-fetoprotein or human chorionic gonadotropin alone.

Role of ultrasound and informed consent in the evaluation of elevated maternal serum alpha-fetoprotein.

Informed consent of medical procedures should include a discussion of both the risk of the procedure and the probability of the malady in question. Many centers in the United States currently recommend amniocentesis for all women with elevated levels of maternal serum alpha-fetoprotein (MSAFP) unexplained by targeted ultrasound examination. Prospective clinical data from our unit support the use of an algorithm that provides for a 90% reduction of the predicted risk of neural tube defect from MSAFP alone. The predicted risk is revised only if the ultrasound shows normal fetal cranial size and shape, normal ventricular size, normal posterior fossa anatomy, and normal spinal anatomy. Preliminary results supported this approach with no reduction in sensitivity, while substantially reducing the need for invasive testing. The additional experience reported here of 20,211 patients resulted in 451 ultrasound examinations for an elevated MSAFP, but only 54 amniocenteses. During this period, nine open neural tube defects were detected among patients with elevated MSAFP using ultrasound; none was missed. All fetuses with defects had ultrasound findings of cranial and intracranial changes first reported by Campbell. These data support the premise that, prior to amniocentesis, informed consent should include discussion of the ultrasound evaluation.

Pitfalls of gestational age reassignment in evaluation of low maternal serum alpha-fetoprotein levels.

Accurate interpretation of low maternal serum alpha-fetoprotein levels depends on confirmation of gestational age by ultrasound. However, revision of gestational age estimations based solely on sonographic fetal biometry may result in excluding the fetus with trisomy from further diagnostic study.