Table 2

Crude associations (OR and 95% CI) of parity (parous vs nulliparous) with other potential risk factors in the Piedmont Birth Registry (PBR) population and among the NINFEA participants

Potential risk factorsParity (1+ vs 0)
PBRNINFEA
OR (95% CI)OR (95% CI)
Alcohol during pregnancy0.92 (0.87 to 0.97)1.08 (0.78 to 1.49)
Folic acid intake0.77 (0.74 to 0.82)0.89 (0.59 to 1.33)
Maternal education (graduate)1.11 (1.05 to 1.17)1.24 (0.92 to 1.68)
Maternal age (>32)2.45 (2.35 to 2.56)3.17 (2.27 to 4.45)
Low pregnancy weight gain (<10 kg)1.33 (1.26 to 1.40)1.26 (0.89 to 1.79)
Previous miscarriages1.67 (1.58 to 1.76)1.59 (1.12 to 2.26)