Vaginal alpha-fetoprotein a red flag for miscarriage

21 Jan 2021

High alpha-fetoprotein (AFP) levels from vaginal blood aid in the same-day detection of an active miscarriage, a study has found.

The study included five groups of women, as follows: active miscarriage, pregnancy of unknown location, completed miscarriage or extrauterine pregnancy (EUP), ongoing pregnancy, and undergoing elective dilation and curettage (D&C). All of them had AFP levels measured in the vaginal blood collected on a sanitary pad.

Median AFP levels in the vaginal blood were 3.7 IU/mL (range, 0.5–739.2) in women with active miscarriage (n=16) and 4,542 IU/mL (range, 15.6–100,000) in those with elective D&C (n=24). AFP was detected in all women in these two groups, with the exception of one.

In the group of women with ongoing pregnancy (n=35), only two out of 35 specimens had detectable AFP levels. There was no trace of AFP in the samples collected from women with pregnancy of unknown location (n=12) and those with completed miscarriage or EUP (n=10).

Receiver operating characteristic analysis showed that at a cutoff of 0.61 IU/mL, AFP levels were able to detect an active miscarriage (area under the curve, 0.96) with sensitivity of 93.7 percent and specificity of 97.8 percent.

The findings indicate the utility of measuring AFP levels in vaginal blood for differentiating active miscarriages from ongoing pregnancies, completed miscarriages, and EUPs. This should help reduce uncertainty, anxiety level, and number of repeat office visits.

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