Güncel Obstetride Alfa-Fetoprotein Hastane Tecrübelerimiz ve Literatürün Gözden Geçirilmesi

Abstract

Amaç: Önemli bir glikoprotein olan Alfa-fetoprotein (AFP), gebelik boyunca fetal karaciğer ve yolk kesesinden salınmaktadır. Günümüzde halen, erken 2. trimesterde açık nöral tüp defektlerinin taranmasında kullanılan en önemli biyokimyasal belirteçtir. Trizomi tarama testlerinin bir bileşeni olarak ve ayrıca klinik çalışma düzeyinde olumsuz gebelik sonuçlarının öngörülmesinde kullanılmaktadır. AFP, maternal karaciğer tümörleri gibi birtakım nadir hastalıklarda da yükselebilmekle birlikte, AFP yüksekliği genel olarak feto-plasental kaynaklı nedenlere bağlanır. Bu yazıda, AFP’nin güncel obstetride kulanımı ile ilgili detaylar gözden geçirilecek ve AFP kullanımı ile ilgili hastanemizin tecrübeleri paylaşılacaktır. Yöntemler: Bu retrospektif tanımlayıcı çalışmaya, hastanemize ilk trimesterde başvuran 525 gebe dahil edildi. USG’ de CRL ölçümüne göre NT MoM (Multiple of Median) değeri 99. persantil üzerinde olan veya herhangi bir haftada 3 mm ve üzerinde olan veya kombine tarama test sonucu 1/ 270 ve üzerinde gelen (yüksek riskli grup) hastalara invaziv tanı testi önerildi. Düşük riskli gruba 2. trimesterde (BPD ölçümü 27 ile 49 mm arasında ve 15-21. gebelik haftaları arasında iken) sadece AFP ölçümü yapıldı. Hastaların gebelik ve doğum ile ilgili diğer bilgileri (doğum ağırlığı, doğum haftası vb.) hastane kayıtlarından geriye dönük olarak elde edildi. Bulgular: Ortalama AFP MoM değeri 1,2± 0,45 idi. AFP MoM değeri 2.5 ve üzeri olan hasta sayısı 7, 2-2,5 MoM arası olan hasta sayısı 19 idi. Bu gebelerin hiçbirinde ayrıntılı USG taraması sonrasında açık nöral tüp defekti (NTD) saptanmadı. Preterm doğum oranı AFP MoM değeri 2,5 ve üstü olan grupta %14,2, 2-2,5 MoM arası olan grupta %15,7 ve 2 MoM altı olan grupta %14,7 idi ve gruplar arasında istatistiksel olarak anlamlı fark saptanmadı (her grup için p>0.05). Sonuç: Anöploidi tarama testleri tüm gebelere önerilmelidir. Tarama testlerinin kısıtlılıkları, yanlış pozitif ve negatiflikleri hakkında hastanın aydınlatılması gerekmektedir. Tarama testlerinin aynı anda veya ardışık kullanımı önerilmemektedir. Anöploidi tarama testlerinin bir parçası olan AFP, NTD riskinin taramasında da tek başına başarıyla kullanılmaktadır. AFP yüksekliği durumunda tüm gebelere genetik danışmanlık verilmeli, ayrıntılı USG taraması ve gerekli durumlarda invaziv test önerilmelidir.

Keywords

• Trizomi 21,anöploidi,serum tarama testi,alfa-fetoprotein

The Use of Alpha-Fetoprotein in Current Obstetrics; Our Hospital Experiences and Review of the Literature

Abstract

Objective: Alpha-fetoprotein (AFP) is an important glycoprotein that is released from fetal liver and yolk sac during pregnancy. AFP during the early second trimester remains the most important biochemical marker for fetal open neural defects (NTD). Maternal serum AFP is also a component in the biochemical screening for fetal aneuploidy as well as adverse gestational outcomes. Although AFP may be elevated in a number of rare diseases such as maternal liver tumors, the elevation of AFP is generally attributed to feto-placental origin. In this paper, the details of the use of AFP in current obstetrics will be reviewed and the experiences of our hospital will be shared. Methods: In this descriptive-retrospective study, 525 healthy pregnant women who admitted to our hospital at first trimester were included. Invasive diagnostic tests were recommended for patients with increased nuchal translucency (NT) value or with combined screening test result 1/270 and above (high-risk group). An increased NT was described as a measure greater than 99th percentile according to gestational age or exceeds a set threshold of 3 mm. Low-risk group underwent only AFP testing in the second trimester. Information on birth weight, birth week and as well as pregnancy complications was obtained from hospital records. Results: The mean AFP MoM value was 1.2 ± 0.45. The number of patients with AFP MoM 2.5 and above was 7, between with 2-2.5 MoM was 19. Open neural tube defect (NTD) was not detected in any of these pregnant women after a detailed ultrasound scan. Preterm delivery rate was 14.2% in the group with AFP MoM 2.5 and over, 15.7% in the group with between 2-2.5 MoM and 14.7% in the group with less than 2 MoM and no statistically significant difference was found between the groups (p> 0.05 for each group). Conclusions: Aneuploidy screening tests should be offered to all pregnant women. The pregnant should be informed about the limitations, false positive and negative rates of the screening tests. Simultaneous or sequential use of screening tests is not recommended. Single AFP value may be used alone successfully in the screening of NTD. Detailed USG screening, genetic consultation and (if indicate) diagnostic testing should be recommended to all pregnant women complicated with increased AFP values.

Keywords

• Trisomy 21,aneuploidy,serum screening test,alpha-fetoprotein

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