Maternal serum alpha-fetoprotein level and the relationship to ventriculomegaly in fetal neural tube defect: A retrospective cohort study

Abstract

ObjectiveTo estimate the significance of the association between mid-trimester maternal serum alpha-fetoprotein (MSAFP) level and fetal neuroanatomic findings in cases of open neural tube defect (ONTD). MethodsRetrospective study of patients referred for prenatal ONTD repair between 2012 and 2018. Cases were classified into three groups based on their MSAFP level: 1)High MSAFP (>3.8MoM – n = 22), 2)Moderately high MSAFP (≤3.8 and ≥2.5MoM – n = 28), 3)Normal MSAFP (<2.5MoM – n = 18). MRI scans at the time of referral were used to assess the relationship between MSAFP and: A)Type of ONTD; B) Ventriculomegaly; C) Size of the myeloschisis lesion; D) Volume of myelomeningocele; E) Anatomical level of the lesion (LL). ResultsHaving a high MSAFP level was more likely to be associated ventriculomegaly at mid-gestation than a moderately high or normal MSAFP level (OR = 8.4;CI95[0.9–73.4];p = 0.05 and OR = 2.8;CI95[0.9–8.8];p = 0.07). There were no differences between the three groups regarding type of lesion, size of the myeloschisis lesion, anatomic LL, or volume of the myelomeningocele sac. Myeloschisis cases with normal MSAFP had a larger surface area when compared to myeloschisis cases with moderately high MSAFP (219.8[104.4−551] vs 155.4[38.5−502.4] mm², p = 0.04). ConclusionA 2nd trimester MSAFP level >3.8MoM in a fetus with ONTD is associated with mid-gestation ventriculomegaly.