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Table 1 Characteristics of the study population (N = 814)

From: Associations between maternal risk factors of adverse pregnancy and birth outcomes and the offspring epigenetic clock of gestational age at birth

Maternal characteristics

Mean (SD) or N (%)

Pre-pregnancy risk factorsa

Maternal age at delivery, years

33.3 (5.8)

 Below 20 years, yes

22 (3.0%)

 Above 40 years, yes

115 (14.1%)

Pre-eclampsia in previous pregnancy, yes

178 (21.9%)

Intrauterine growth estriction in previous pregnancy, yes

85 (10.4%)

Gestational diabetes in previous pregnancy, yes

84 (10.3%)

 Diet treated

75 (9.2%)

 Insulin treated

9 (1.1%)

Pre-pregnancy body mass index kg/m2

27.4 (6.4)

 ≥30 kg/m2

287 (35.3%)

Pre-pregnancy chronic hypertension, yes

109 (13.4%)

Pre-pregnancy type 1 diabetes, yes

12 (1.5%)

Pre-pregnancy systemic lupus erythematosus, yes

2 (0.3%)

Sjögren’s syndrome, yes

11 (1.4%)

Previous pregnancy with fetal demise (>22 gestational weeks or over 500 g), yes

28 (3.4%)

Number of known pre-pregnancy risk factors

 

 No known pre-pregnancy risk factors

79 (9.7%)

 1 or 2 pre-pregnancy risk factors

696 (85.5%)

 3 or more pre-pregnancy risk factors

31 (3.8%)

 Data not available

8 (1.0%)

Pregnancy disorders

 

Gestational diabetes, yes

183 (22.5%)

 Diet treated

147 (18.1%)

 Insulin treated

36 (4.4%)

 Data not available on gestational diabetes treatment

2 (0.2%)

 Data not available on gestational diabetes diagnosis

1 (0.1%)

Hypertension spectrum pregnancy disorders, yes

 

 Gestational hypertension

80 (9.8%)

 Pre-eclampsia

61 (7.5%)

  Early pre-eclampsia (diagnosis <34 weeks of gestation)

53 (6.5%)

  Late pre-eclampsia (diagnosis ≥34 weeks of gestation)

8 (1.0%)

  Non-severe pre-eclampsia

42 (5.2%)

  Severe pre-eclampsia

19 (2.3%)

 Chronic hypertension

134 (16.5%)

 Data not available

1 (0.1%)

Other characteristics

Education level

 

 Lower secondary or less

359 (44.1%)

 Upper secondary

184 (22.6%)

 Tertiary

248 (30.5%)

 Data not available

23 (2.8%)

Parity

 

 Primiparous

247 (30.3%)

 Multiparous

566 (69.5%)

 Data not available

1 (0.1%)

Smoking during pregnancy

 

 Non-smoker

780 (95.8%)

 Quit during first trimester

26 (3.2%)

 Smoked throughout the pregnancy

8 (1.0%)

 Data not available

0

Alcohol use during pregnancy

 

 No

588 (72.2%)

 Yes

117 (14.4%)

 Data not available

109 (13.4%)

Mode of delivery

 

 Vaginal

640 (78.6%)

 Cesarean

173 (21.3%)

 Data not available

1 (0.1%)

Antenatal betamethasone treatment

 

 No

750 (92.1%)

 Yes (n = 1 for 12 mg/24 h, n = 22 for 24 mg/24 h, n = 1 for 48 mg/24 h, n = 11 for no information on dose)

35 (4.3%)

Timing of antenatal betamethasone treatment, number of days before birth

33.4 (27.1)

 30 days or less before delivery

14 (1.7%)

 30 days or more before delivery

13 (1.6%)

 Data not available

29 (3.6%)

Neonatal characteristics

Sex

 

 Girls

384 (47.2%)

 Boys

430 (52.8%)

 Data not available

0

Gestational age at birth, weeks

39.76 (1.60)

 Data not available

0

DNA methylation gestational age, weeks

38.45 (2.05)

 Data not available

0

Raw epigenetic gestational age difference, DNA methylation gestational age-gestational age

−1.32 (1.85)

 Data not available

0

Absolute epigenetic gestational age difference, DNA methylation gestational age-gestational age in absolute values

1.78 (1.41)

 Data not available

0

Horvath DNA methylation age at birth, weeks

9.77 (19.51)

 Data not available

0

Birth weight, g

3549 (546)

  Small for gestational age, yesb

23 (2.8%)

 Data not available

1 (0.1%)

Birth length, cm

50 (2)

 Small for gestational age, yesb

21 (2.6%)

 Data not available

1 (0.1%)

Head circumference, cm

35 (2)

  Small for gestational age, yesb

14 (1.7%)

 Data not available

2 (0.3%)

Ponderal index, kg/m3

27.8 (2.7)

 Data not available

1 (0.1%)

Placenta weight, g

615 (134)

Cord blood pH

 

 Arterial

7.26 (0.09)

 Venous

7.31 (0.08)

Apgar score

 

 9–10

611 (75.1%)

 7–8

145 (17.8%)

 ≤6

47 (5.8%)

 Data not available

11 (1.4%)

  1. aPre-pregnancy risk factors served as inclusion criteria for the study as described [39]
  2. bSmall for gestational age indicates birth size for sex and gestational age SD ≤ −2 according to Finnish growth references [23]