During a 3-year period, a total of 22 pregnant women with vulvar oedema were observed in a high-risk antenatal clinic (ANC) in Maputo. They were compared with 22 unselected normal ANC attenders, matched for age, parity, gestational length and area of living. Reported and observed genital ulcers were more prevalent in the oedema group than in the referent group. Reported and observed vaginal discharge was also significantly more common in the oedema group. Syphilis screening by VDRL was positive in 61.9% of oedema cases while positivity reached 5.0% in referents (p < 0.005). Cases found seropositive on screening were confirmed using Wassermann reaction (WR) in a reference laboratory, in which WR-positive cases underwent FTA-ABS analysis and IgM assay with solid-phase haemadsorption. IgM-positive individuals were significantly more prevalent among WR-positive oedema cases than among WR-positive referents (p < 0.05). It is concluded that among antenatal attenders in Maputo presenting with vulvar oedema, a significant proportion is associated with recent syphilis. Vulvar oedema should be considered as an important marker for seropositive syphilis during pregnancy.