Table 4.

Classification probabilities for the top tertile of average gestational BPA or phthalate concentration according to trimester-specific surrogate categories.^a,b

Urinary metabolite	33rd percentile	66th percentile	Sensitivity	Specificity	PPVc
ΣDEHP (μmol/L)d
First	0.22	0.89	0.69	0.84	0.69
Second	0.17	0.33	0.54	0.76	0.54
Third	0.15	0.45	0.62	0.80	0.62
MBP (μg/L)
First	11	21	0.62	0.80	0.62
Second	12	23	0.73	0.86	0.73
Third	12	22	0.69	0.84	0.69
MBzP (μg/L)
First	2.7	5.4	0.65	0.82	0.65
Second	2.3	5.1	0.62	0.80	0.62
Third	2.3	5.3	0.69	0.84	0.69
MEP (μg/L)
First	20	73	0.62	0.80	0.62
Second	33	85	0.81	0.90	0.81
Third	28	81	0.77	0.88	0.77
BPA (μg/L)
First	1.1	2.1	0.70	0.85	0.70
Second	1.0	1.9	0.60	0.80	0.60
Third	1.0	2.0	0.67	0.84	0.67
aAssumes that the within-woman GM gestational urinary phthalate or BPA concentration is the gold standard. The surrogate measure of low, medium, or high is defined by the first, second, or third tertile of trimester-specific urine samples, respectively. Probabilities are calculated from the top versus bottom two tertiles of trimester-specific and average gestation urinary phthalate metabolite and BPA concentrations. Limited to women with all three urine samples. All concentrations are SG adjusted. bn = 77 for phthalates; n = 91 for BPA. cPPV is the probability of being classified in the top tertile of mean gestational phthalate metabolite or BPA concentration, given that the woman’s trimester-specific urinary phthalate metabolite or BPA concentration is in the top tertile. dΣDEHP metabolites: mono 2-ethyl-5-carboxypentyl phthalate (MECPP), mono 2-ethyl-5-hydroxyhexyl phthalate (MEHHP), mono 2-ethyl-5-oxohexyl phthalate (MEOHP), and mono 2-ethylhexyl phthalate (MEHP).