Can gestational dates routinely derived from very early ultrasound be used to interpret maternal serum alpha-fetoprotein measurements? |
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Authors: | Dr James E. Haddow Mary S. Holman Glenn E. Palomaki |
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Affiliation: | Foundation for Blood Research, P.O. Box 190, Scarborough, ME 04070-0190, U.S.A. |
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Abstract: | This study assesses the reliability of estimating gestational age via crown-rump or gestational sac measurements obtained at 8 weeks' gestation or earlier as part of routine physician office practice. To accomplish this, we studied 88 pregnancies managed at 45 different sites in which both an early first-trimester ultrasonically-derived gestational age estimate and a second-trimester biparietal diameter (BPD) estimate were available. The first-and second-trimester determinations were highly correlated, but the first-trimester determinations were, on average, 0.43 weeks earlier than the second. The first-trimester estimates were satisfactory for use in interpreting maternal serum alpha-fetoprotein (MSAFP) screening measurements, but second-trimester BPD measurements obtained prior to MSAFP screening should be the method of choice for interpreting MSAFP values, due to the increased sensitivity for detecting open spina bifida. |
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Keywords: | Gestational dating Early ultrasound MSAFP screening |
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