TABLE 2.

Perinatal outcomes by maternal fertility status and plurality, 2004 through 2008, live births and fetal deaths in Massachusetts

			Fertile as reference		Subfertile as reference
		%	AOR	95% CI	AOR	95% CI
Singletons
Preterm	Fertile	6.4	1.00	Reference	0.80a	0.72–0.89a
	Subfertile	8.1	1.24a	1.12–1.38a	1.00	Reference
	IVF	10.2	1.53a	1.40–1.67a	1.23a	1.08–1.41a
Low birthweight	Fertile	5.4	1.00	Reference	0.83a	0.74–0.94a
	Subfertile	5.7	1.20a	1.06–1.36a	1.00	Reference
	IVF	7.8	1.51a	1.37–1.67a	1.26a	1.08–1.47a
Small for gestational age	Fertile	8.1	1.00	Reference	1.05	0.94–1.17
	Subfertile	6.5	0.95	0.85–1.06	1.00	Reference
	IVF	8.1	1.05	0.96–1.16	1.10	0.96–1.27
Perinatal death	Fertile	0.43	1.00	Reference	0.66a	0.46–0.95a
	Subfertile	0.58	1.51a	1.05–2.17a	1.00	Reference
	IVF	0.42	1.00	0.67–1.50	0.66	0.40–1.11
Twins
Preterm	Fertile	53.0	1.00	Reference	0.74	0.31–1.76
	Subfertile	56.5	1.35	0.57–3.20	1.00	Reference
	IVF	53.8	0.89	0.68–1.18	0.66	0.23–1.90
Low birthweight	Fertile	53.0	1.00	Reference	0.99	0.83–1.18
	Subfertile	50.5	1.01	0.85–1.20	1.00	Reference
	IVF	50.3	0.98	0.89–1.09	0.98	0.82–1.17
Small for gestational age	Fertile	20.6	1.00	Reference	1.25a	1.02–1.52a
	Subfertile	16.9	0.80a	0.66–0.98a	1.00	Reference
	IVF	17.9	0.85a	0.75–0.96a	1.06	0.86–1.30
Perinatal death	Fertile	2.57	1.00	Reference	0.27a	0.17–0.42a
	Subfertile	6.15	3.73a	2.37–5.87a	1.00	Reference
	IVF	1.15	0.55a	0.34–0.89a	0.15a	0.09–0.25a

Adapted.⁶¹

Models adjusted for maternal age, race/ethnicity, marital status, education, payer status, smoking, prenatal care, preexisting conditions (diabetes mellitus and chronic hypertension), parity, and infant sex. Sample based on live births for preterm birth, low birthweight, and small for gestational age; sample based on live births and fetal deaths for perinatal death.

AOR, adjusted odds ratio; CI, confidence interval; IVF, in vitro fertilization.

^aSignificantly different than reference group.