Table 3

Results, stratified analyses and adjusted OR

Fibroids before pregnancy
no operation
group 2
odds ratio (95% CI)
Odds ratio (95% CI)Fibroids after pregnancy
group 3
odds ratio (95% CI)
Odds ratio (95% CI)Operation before pregnancy
group 4
odds ratio (95% CI)
Odds ratio (95% CI)
No fertility treatment
n=75/81 836
Fertility treatment
n=17/5522
No fertility treatment
n=869/81 836
Fertility treatment
n=94/5522
No fertility treatment
n=140/81 836
Fertility treatment
n=91/5522
Preterm birth (week)
 ≤371.74 (0.75─4.02)1.37 (0.39─4.76)1.04 (0.77─1.41)0.93 (0.51─1.72)1.05 (0.49─2.25)1.06 (0.59─1.92)
 ≥34 to <370.37 (0.05─2.69)Empty1.02 (0.71─1.47)1.20 (0.62─2.33)1.24 (0.55─2.80)0.97 (0.47─2.02)
 ≥28 to <342.45 (0.60─10.02)3.37 (0.77─14.85)0.94 (0.48─1.81)0.55 (0.13─2.25)0.64 (0.09─4.61)1.47 (0.59─3.60)
 ≥22 to <2825.60 (7.95─82.43)8.36 (1.08─64.50)2.13 (0.68─6.69)EmptyEmptyEmpty
 ≥22 to <345.57 (2.24─13.85)4.5 (1.28─15.76)1.09 (0.62─1.93)0.46 (0.17─1.87)1.09 (0.6─1.93)1.22 (0.49─3.04)
Singleton pregnancy
n=119/89 338
Multiple pregnancies
n=5/1964
Singleton pregnancy
n=925/89 338
Multiple pregnancies
n=38/1964
Singleton pregnancy
n=292/89 338
Multiple pregnancies
n=25/1964
Preterm birth (week)
 ≤371.90 (0.32─11.45)2.18 (1.17─4.05)0.66 (0.34─1.30)1.02 (0.75─1.39)1.17 (0.53─2.59)1.33 (0.81─2.16)
 ≥34 to <370.76 (0.24─2.40)Empty0.99 (0.68─1.42)0.99 (0.49─2.03)1.26 (0.68─1.42)0.77 (0.31─1.95)
 ≥28 to <343.41 (1.25─9.28)4.40 (0.73─26.48)0.96 (0.50─1.86)0.37 (0.09─1.53)1.71 (0.70─4.15)2.09 (0.82─5.27)
 ≥22 to <2822.32 (8.18─60.92)12.95 (1.41─118.77)2.08 (0.66─6.56)EmptyEmptyEmpty
 ≥22 to <346.11 (2.99─12.51)8.4 (1.41─50.93)1.11 (0.63─1.98)0.31 (0.75─1.31)1.48 (0.61─3.59)1.78 (0.71─4.50)