The value of maternal first and second trimester serum data of β-hCG, PAPP-A, AFP and uE3 in the prediction of preeclampsia

Abstract

To discover the value of combined maternal first and second-trimester serum β-hCG, pregnancy associated plasma protein A (PAPP-A), alpha-fetoprotein(AFP)and unconjugated estriol (uE3) in the prediction of preeclampsia. A total of 1 805 pregnant women who had antenatal care at International Peace Maternal and Child Health Hospital Affiliated to Shanghai Jiaotong University between April 2012 and June 2013 were selected prospectively by random method. According to the outcome, they were defined as the control group and the preeclampsia group (including mild and severe cases). PAPP-A and β-hCG level were measured at 10-14 gestational weeks. AFP, β-hCG and uE3 were measured at 15-20 gestational weeks. The relevance between the serological indicators and outcomes was analyzed. The value of the indicators was judged by receiver operating characteristic (ROC) and Youden index, and the relevant predictive boundary values were identified. (1) Among the 1 805 cases, 1 739 women did not have hypertension(the control group), while 66 women had preeclampsia (the preeclampsia group). The incidence of preeclampsia was 3.66% (66/1 805), including 43 mild cases and 23 severe cases. (2) At 10-14 gestational weeks, the mean value of PAPP-A in the control group was (3 972 ± 2 311) mU/L, while in the preeclampsia group it was (2 837 ± 1 849)mU/L. The difference between the two groups had statistical significance (P < 0.01). The mean value of β-hCG of the control group was 55(37∼83) U/L, while in the preeclampsia group it was (57 ± 35)U/L. There was no statistical significance (P > 0.05). PAPP-A, β-hCG and AFP of mild preeclampsia cases were (3 249 ± 1 877) mU/L, (61 ± 38) U/L and (35 ± 11) µg/L respectively, and in severe cases they were(1 758 ± 1 297)mU/L, (47 ± 23)U/L and (47 ± 22)µg/L, respectively. There was statistically significant difference in PAPP-A (P < 0.05). (3) At 15-20 gestational weeks, β-hCG, AFP and uE3 in the preeclampsia group were (47 909 ± 31 396 )U/L, (38 ± 15)µg/L and (0.98 ± 0.31)µg/L respectively, and in the control group they were (39 267 ± 25 054 )U/L, (47 ± 18)µg/L and (1.17 ± 0.39) µg/L, respectively. AFP and uE3 of the preeclampsia group were lower than those in the control group and the difference was statistically significant (P < 0.05). However, β-hCG and uE3 of the mild preeclampsia cases and the severe cases had no statistical difference (P > 0.05). (4)At 10-14 gestational weeks, PAPP-A demonstrated positive relevance to the newborn weight (r = 0.068, P = 0.011) and gestational weeks at delivery (r = 0.057, P = 0.048). At 15-20 weeks, positive relevance was found between AFP and the newborn weight (r = 0.149, P = 0.000), while negative relevance was found between β-hCG and Apgar scores (r = -0.085, P = 0.024), and positive relevance was found between uE3 and gestational weeks at delivery (r = 0.086, P = 0.036). (5) PAPP-A, AFP and uE3 data were used as testing parameters to obtain the boundary values of preeclampsia prediction as follows: PAPP-A 1 831 mU/L, AFP 41 µg/L and uE3 1.04 µg/L. The specificity was 97.82% , 98.54% and 98.80% , respectively. (6) ROC was drawn and Youden index was calculated based on the joint predicative factor of PAPP-A, AFP and uE3. Youden index reached its peak (0.41) when the joint predictive factor was 0.032, meaning that the factor had the highest prediction value. The prediction value of the PAPP-A, AFP and uE3 was 0.032, with the specificity and sensitivity of 98.93% and 70.59%, respectively. The odds ratio was 2.37. Both the individual parameter (PAPP-A, AFP and uE3) and the combined data have prediction value for preeclampsia, but the latter is more effective than any of the single parameter.