Table 2.

Unadjusted and adjusted∗ odds ratio (OR) for spontaneous preterm birth at different gestations for women conceiving after IVF/ICSI compared to women conceiving spontaneously, Slovenia, 2002–2015.

Gestation (weeks)	Unadjusted odds ratio	Confidence interval	p value	Adjusted∗ odds ratio	Confidence interval	p value
< 32	2.801	2.292 – 3.424	< 0.001	1,555	1.256 – 1.925	< 0.001
32 to 36 and 6/7	1.705	1.526 – 1.904	< 0.001	1,300	1.159 – 1,459	< 0.001

∗ Adjusted for 11 covariates: maternal age, maternal education, maternal BMI, parity, smoking during pregnancy, history of cervical excision procedure, history of hysteroscopic resection of uterine septum, presence of other congenital uterine malformations, bleeding in pregnancy, preeclampsia or HELLP in pregnancy and maternal heart, and pulmonary or renal illness.