Alpha-fetoprotein in vaginal blood: a promising novel marker for early pregnancy failure that needs further validation

Miscarriage determination in first trimester based on alpha-fetoprotein extracted from sanitary pads

OBJECTIVE

To determine if high alpha-fetoprotein (AFP) level in vaginal blood collected on a sanitary pad can assist with detecting an active miscarriage.

DESIGN

A prospective cohort study.

SETTING

Academic medical center.

PATIENT(S)

Five groups were evaluated: women with active miscarriage, pregnancy of unknown location, completed miscarriage or extrauterine pregnancy (EUP), ongoing pregnancy, and undergoing elective dilation and curettage (D&C).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

For each patient, AFP level in the vaginal blood collected on a sanitary pad was quantified.

RESULT(S)

The vaginal blood AFP median levels (and their ranges) were 3.7 IU/mL (0.5-739.2) and 4,542 IU/mL (15.6-100,000) in the active miscarriage (n = 16) and the elective D&C (n = 24) groups, respectively. Alpha-fetoprotein was detected in all elective D&C and active miscarriage cases except in 1 case. In the ongoing pregnancy group (n = 35), only 2 of 35 specimens showed detectable AFP levels. In the pregnancy of unknown location (n = 12) and the completed miscarriage or EUP (n = 10) groups, no AFP was detected. Receiver operating characteristic analysis demonstrated 93.7% sensitivity and 97.8% specificity for the detection of an active miscarriage (cutoff 0.61 IU/mL; area under the curve 0.96).

CONCLUSION(S)

Alpha-fetoprotein can be extracted from vaginal blood collected on sanitary pads. A high level of vaginal AFP can assist with the same-day detection of an active miscarriage. This novel test is useful in differentiating active miscarriages from ongoing pregnancies, completed miscarriages, and EUPs and, therefore, it reduces uncertainty, anxiety level, and number of repeat office visits.