Prenatal drinking-water exposure to tetrachloroethylene and ischemic placental disease: a retrospective cohort study

Table 2 Characteristics of 2,110 index pregnancies, by PCE exposure during the LMP year and occurrence of ischemic placental disease ^a

Characteristic		Ischemic placental disease		No ischemic placental disease
Characteristic	% Exposed (N = 92)	% Unexposed (N = 104)	% Exposed (N = 999)	% Unexposed (N = 915)
Year of pregnancy^b
Before 1974	15.2	21.2	15.7	18.3
1975-1980	51.1	44.2	49.8	49.4
After 1980	33.7	34.6	34.5	32.4
Maternal age (y)^c, mean (SD)	26.2 (4.3)	26.6 (4.4)	27.5 (4.5)	27.0 (4.6)
Paternal age (y), mean (SD)	29.5 (5.8)	29.5 (5.5)	30.7 (5.6)	29.9 (5.6)
White	91.3	95.2	95.7	97.4
Maternal education^b
Less than high school	3.3	1.9	1.1	1.1
High school graduate	22.8	25.0	19.2	18.4
Some college	32.6	35.6	33.9	34.8
Four-year college graduate or more	41.3	37.5	45.8	45.8
Paternal occupation^b
White collar	40.2	39.4	53.7	46.0
Blue collar	34.8	42.3	31.6	32.0
Other	21.7	15.4	13.2	20.4
Number of prior livebirths and prior ischemic placental disease^b
Nulliparous	43.5	58.7	35.5	41.0
Previous pregnancy, no prior ischemic placental disease	45.7	35.6	60.1	56.7
Previous pregnancy, prior ischemic placental disease	10.9	5.8	4.4	2.3
Diabetes before or during pregnancy	1.1	4.8	2.3	2.2
Hypertension before or during pregnancy	10.9	18.3	5.2	5.8
Gestational weight gain <20 lb	30.4	21.2	13.8	12.4
Cigarette smoking during first trimester	41.3	36.5	24.8	27.2
Alcohol consumption during first trimester	32.6	40.4	37.2	37.6
Occupational exposure to solvents^b
No	76.1	86.5	86.3	87.2
Yes, before or during pregnancy	17.4	11.5	10.9	9.8
Yes, unknown when	2.2	1.0	1.7	1.3
Use of solvent-based spot removers	63.0	57.7	67.3	64.0
Use of professional dry cleaning	82.6	86.5	87.7	85.8
Use of self-service dry cleaning	21.7	13.5	13.8	16.7

Abbreviations: LMP last menstrual period, PCE tetrachloroethylene, SD standard deviation.
^aIncluding placental abruption, preeclampsia, small for gestational age, and stillbirth at ≥27 weeks gestation.
^bPercentages do not sum to 100 due to rounding or missing values.
^cMissing: paternal age (N = 18), paternal occupation (N = 35), diabetes (N = 20), hypertension (N = 23), gestational weight gain <20 lb (N = 62), alcohol consumption (N = 4), occupational exposure to solvents (N = 31), use of spot removers (N = 40), use professional dry cleaning (N = 79), use of self-service dry cleaning (N = 56).

ISSN: 1476-069X