Our purpose was to investigate the effect of proteinuria associated with pre-eclampsia on intrapartum fetal heart rate patterns. A retrospective study was performed involving 79 pregnant women with pre-eclampsia and 19 pregnant women with gestational hypertension (GH). Pre-eclampsia was then classified into two groups according to the degree of proteinuria (> or = or < 3 + dipstick), which was classified as severe urinary protein (UP; n = 35) and mild UP (n = 44) at delivery. Intrapartum fetal heart rate (FHR) monitoring was classified as either no deceleration, moderate variable deceleration, severe variable deceleration (sVD), prolonged deceleration (PD), occasional deceleration or recurrent late deceleration (rLD). We evaluated the prevalence of non-reassuring FHR (sVD, PD or rLD), the prevalence of intrauterine growth restriction (IUGR), and cord blood gas status in the three groups. The prevalence of non-reassuring FHR and cord blood gas status of these three groups was also compared with their prevalence in 65 women with low-risk pregnancies. Multiple logistic regression analysis was performed to determine the association between rLD and maternal-fetal parameters. Levels of systolic and diastolic blood pressure were similar among the three groups. Severe UP was diagnosed significantly earlier, was associated with significantly lower gestational age, and infants with lighter birth weight (P < 0.05) compared with GH and mild UP. The prevalence of IUGR in severe UP was higher than in GH (54%v. 21%, P < 0.05); however, no differences were found in the prevalence of IUGR between mild and severe UP (43%v. 54%, P = 0.33). The prevalence of non-reassuring FHR in GH was not statistically significant in the low-risk pregnancies (5%v. 9%, P = 0.58). In mild and severe UP, the non-reassuring FHRs were more predominant (30% and 43%, respectively) than in low-risk pregnancies and GH (P < 0.05). The rLD was more common in the group with severe UP and accounted for 40% of all FHR patterns. There was no difference in the incidence of low pH among the groups. However, fetuses in pregnancies involving severe UP were significantly hypoxemic when compared with others. Multiple logistic regression analysis showed that worsening proteinuria (odds ratio [OR], 5.5; 95% confidence interval [CI], 2.4-12.9) and IUGR (OR, 3.8; 95% CI, 1.2-11.5) increased the risk of rLD. Rates of preterm birth at less than 32 weeks (OR, 0.7; 95% CI, 0.2-2.5) and severe hypertension (OR, 0.5; 95% CI, 0.2-1.3) were not significant. In pre-eclampsia, the presence of severe proteinuria is associated with an increased likelihood of rLD.