Extreme Values of Maternal Serum Analytes in Second Trimester Screening: Looking Beyond Trisomy and NTD's

Abstract

Second trimester maternal serum screening can identify high risk pregnancies and fetuses at risk for birth defects (in addition to those in the standard interpretation). The purpose of this study was to quantify such risks to improve counseling. We compared outcomes of 692 pregnancies that had abnormal levels of at least one analyte with a cohort of 713 pregnancies with normal analytes. Increased risks include: demise with high AFP and low uE3; intrauterine growth restriction with high AFP, high and low hCG, and low uE3; placental abnormalities with high AFP; fetal stress with high AFP and high hCG. Birth defects are increased with high AFP, high hCG, and low hCG. When two or more analytes are abnormal, 46% have a poor outcome. Abnormal levels of maternal serum analytes provide information in addition to the risks for neural tube defects, Down syndrome, and trisomy 18. This information is important for counseling and pregnancy management.

Mid-Trimester Maternal Serum hCG and AFP Levels: Clinical Significance and Prediction of Adverse Pregnancy Outcome

“…In the absence of fetal chromosomal or structural anomalies, mid-trimester ms-AFP levels >2.5 MoM are thought to reflect a defect in placentation [placental abruption, placenta previa, abnormal placental adherence (placenta accreta, increta and percreta)] (3, 36, 37). They also associated with an increased risk for pregnancy complications including: late fetal loss [OR 10.1 (95% CI: 7.5-13.5)], gestational hypertension [OR 1.6 (95% CI: 1.3-2.1)], preeclampsia [OR 0.83 (95% CI: 0.44–1.56)], IUGR [OR 2.3 (95% CI: 1.8-2.9)], preterm delivery [OR 1.8 (95% CI: 1.5-2.3)] and IUFD [OR 5.3 (95% CI: 3.8-7.3)] (3, 4, 17, 23-25, 38, 39). Mechanisms for elevated mid-trimester ms-AFP levels with a structurally normal fetus include: disruption of the fetal-maternal placental barrier, placental vascular damage from early abruption, fetal-maternal bleeding and fetal-placental ischemia (3, 36, 40-42).…”

“…The risk for adverse pregnancy outcome also increases as mid-trimester ms-hCG and/or ms-AFP levels become more extreme. In the absence of fetal chromosomal or structural anomalies, combined mid-trimester elevation in ms-hCG and ms-AFP levels suggest a more complex type of placental pathology which have stronger association with pregnancy complications including: late fetal loss [OR 7.05 (95% CI: 1.18-29.88)], gestational hypertension [OR 0.78 (95% CI: 0.13-3.24)], preeclampsia [OR 6.67 (95% CI: 3.84-11.58)], IUGR [OR 3.54 (95% CI: 1.26-9.14)], preterm delivery [OR 3.20 (95% CI: 1.49-6.61)] and IUFD [OR 6.87 (95% CI: 1.71-22.93)] (3, 4, 23-25, 39, 46, 47). Placental pathology studies suggest that unexplained combined mid-trimester elevation in ms-hCG and ms-AFP levels associated with villitis and placental vascular lesions (48).…”

The relationship between second trimester alpha fetoprotein levels and adverse pregnancy outcome

“…More recent studies have also confirmed these findings [5,[9][10][11]. However, studies by Smith and McPhearson showed no significant increase in IUGR with an elevated AFP [4,12].…”

İkinci Trimester Gebeliklerde Maternal Serum Alfa Feto Protein (AFP) Yüksekliği ve Ultrasonografi Bulguları

“…İkinci trimesterde saptanan yüksek MSAFP değerlerini açıklayacak her hangi bir patolojinin bulunmadığı gebeliklerin yaklaşık %25'inde ilerleyen gebelik dönemlerinde çeşitli komplikasyonlar görüldüğü bildirilmiştir (21). Yüksek MSAFP değeri ile birlikte diğer belirteçlerden birinin de artmış düzeyde saptanması daha fazla oranda kötü gebelik prognozu ile ilişkilidir (22,23). Çalışmamızda da yüksek MSAFP saptanan olgular içerisinde NTD saptanmayanların bir kısmında AFP yüksekliğini açıklayacak fetal anomaliler tespit edilmişken bir bölümünde ise ilerleyen gebelik haftalarında çeşitli komplikasyonlar izlenmiştir.…”