Table 2.

Distribution of Selected Characteristics of Exposed and Unexposed Pregnancies^a

	Exposed				Unexposed
	Losses		Livebirths		Losses		Livebirths
	n	%	n	%	n	%	n	%
Characteristic
Year of pregnancy
Before 1968	0	0.0	0	0.0	55	12.3	347	11.0
1968–1974	25	11.7	264	15.1	129	28.9	851	26.9
1975–1980	93	43.7	749	43.0	137	30.7	1097	34.7
After 1980	95	44.6	730	41.9	125	28.0	870	27.5
Gestational duration
Up to 13 weeks	170	79.8	0	0.0	350	78.5	0	0.0
14–26 weeks	24	11.3	9	0.5	79	17.7	12	0.4
> 26 weeks	19	8.9	1734	99.5	17	3.8	3153	99.6
Maternal age (n, mean)	211	29.0	1730	27.7	442	26.7	3147	26.0
Paternal age (n, mean)	202	31.2	1729	30.9	417	29.4	3109	29.0
Race
White	197	92.5	1662	95.4	419	93.9	3021	95.5
Non-White	14	6.6	77	4.4	22	4.9	132	4.2
Missing	2	0.9	4	0.2	5	1.1	12	0.4
Educational level
< High school	7	3.3	27	1.5	6	1.3	70	2.2
High school graduate	24	11.3	324	18.6	85	19.1	649	20.5
Some college	71	33.3	602	34.5	164	36.8	1091	34.5
College graduate	109	51.2	785	45.0	188	42.2	1348	42.6
Missing	2	0.9	5	0.3	3	0.7	7	0.2
Paternal occupation
White collar	114	53.5	888	50.9	207	46.4	1457	46.0
Blue collar	63	29.6	566	32.5	141	31.6	1064	33.6
Other	36	16.9	255	14.6	90	20.2	602	19.0
Missing	0	0.0	34	2.0	8	1.8	42	1.3
Number of prior livebirths
0	54	25.4	534	30.6	150	33.6	1354	42.8
1	81	38.0	674	38.7	175	39.2	1012	32.0
2+	74	34.7	534	30.6	121	27.1	796	25.2
Missing	4	1.9	1	0.1	0	0.0	3	0.1
Prior pregnancy losses before PCE exposure or index yearb
Yes	34	16.0	147	8.4	94	21.1	254	8.0
No	177	83.1	1595	91.5	352	78.9	2908	91.9
Missing	2	0.9	1	0.1	0	0.0	3	0.1
Cigarette smoking during first trimester
Some	48	22.5	430	24.7	136	30.5	953	30.1
None	164	77.0	1306	74.9	308	69.1	2183	69.0
Missing	1	0.5	7	0.4	2	0.4	29	0.9
Alcohol consumption during first trimester
Some	68	31.9	639	36.7	178	40.0	1182	37.3
None	142	66.7	1093	62.7	265	59.4	1949	61.6
Missing	3	1.4	11	0.6	3	0.7	34	1.1
Marijuana use during pregnancy
Yes	8	3.8	57	3.3	14	3.1	128	4.0
No	201	94.4	1665	95.5	429	96.2	2997	94.7
Missing	4	1.9	21	1.2	3	0.7	40	1.3
Cervical Incompetence	7	3.3	34	2.0	16	3.6	61	1.9
Occupational exposure to solvents
Yes, before or during pregnancy	29	13.6	186	10.7	63	14.1	284	9.0
Yes, unknown when 1	0.5	26	1.5	9	2.0	46	1.5
No	178	83.6	1503	86.2	368	82.5	2784	88.0
Missing	5	2.3	28	1.6	6	1.3	51	1.6
Use of solvent-based spot removers
Yes	148	69.5	1127	64.7	313	70.2	2060	65.1
No	60	8.2	581	33.3	127	28.5	1026	32.4
Missing	5	2.3	35	2.0	6	1.3	79	2.5
Use of professional dry cleaning
Yes	187	87.8	1495	85.8	377	84.5	2703	85.4
No	13	6.1	188	10.8	41	9.2	312	9.9
Missing	13	6.1	60	3.4	28	6.3	150	4.7
Use of self-service dry cleaning
Yes	32	15.0	233	13.4	78	17.5	526	16.6
No	174	81.7	1456	83.5	361	80.9	2549	80.5
Missing	7	3.3	54	3.1	7	1.6	90	2.8
Surface water supply during LMP year	71	33.3	601	34.5	22	4.9	166	5.2

^aExposure status during LMP year of each pregnancy

^bPrior losses before exposure for PCE exposed pregnancies or a comparable index year for unexposed pregnancies