Introduction
Methods
Sources
Study selection
Data extraction and analysis
Results
Characteristics of the studies
Study | Study design | sPTD (n) | Control (n) | Range of GA at sampling (wk) | Mean GA at sampling (wk) | GA at delivery (wk) | Maternal age at sampling (yrs) | BMI at sampling (kg/m2) | State of blood sampling | Biochemical factor(s) determined | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
sPTD | Control | sPTD | Control | sPTD | Control | ||||||||
Harville et al. [21], Finland | Retro. Cohort | 67 | 67 | – | 384.8 ptp | – | 39.8 ± 1.9 | – | – | – | F | TC, TG, HDL-c, LDL-c | |
Catov et al. [20], USA | Prosp. Cohort | 72 | 792 | – | 312 ptp | – | – | 23.7 ± 3.8 | 24.2 ± 3.7 | 23.6 ± 4.9 | 23.4 ± 4.8 | F | TC, TG, HDL-c, LDL-c |
Magnussen et al. [22], Norway | Prosp. Cohort | 172 | 4718 | – | 208 ptp | – | 39.9 ± 2.1 | 26.3 ± 4.4b
| 24.4 ± 3.9b
| NF | TC, TG, HDL-c | ||
Chatzi et al. [13], Greece | Prosp. Cohort | 45 | 145 | <15 | 12.0 ± 1.5 | – | – | 29.45 ± 0.2b
| – | – | F | TG, HDL-c | |
Vrijkotte et al. [14], The Netherlands | Prosp. Cohort | 144 | 3912 | <13 | – | – | – | – | – | – | – | NF | TG |
Catov et al. [12], USA | Case–control | 90 | 199 | <15 | 8.4 ± 2.5 | – | – | 24.6 ± 5.5 | 25.2 ± 6.1 | 25.6 ± 6.7 | 26.7 ± 6.3 | NF | TC, TG, HDL-c, LDL-c |
Edison et al. [18], USA | Retro. Cohort | 70 | 1058 | 13–23 | 17.6 ± 1.5 | – | – | – | – | – | – | – | TC |
Alleman et al. [19], USA | Prosp. Cohort | 153 | 2499 | <26 | – | 33.7 ± 3.6 | 39.1 ± 1.1 | – | – | – | – | NF | TC, TG, HDL-c, LDL-c |
Mudd et al. [15], USA | Prosp. Cohort | 221 | 988 | 15–27 | – | – | – | – | – | – | – | NF | TC, TG, HDL-c, LDL-c |
Niromanesh et al. [16], Iran | Prosp. Cohort | 19 | 161 | 16–20 | – | – | 38.5 ± 2.1 | 28.1 ± 4.5 | 23.2 ± 1.3b
| F | TG | ||
Kramer et al. [25], Canada | Case–control | 207 | 444 | 24–26 | – | – | – | – | – | – | – | NF | TC, HDL-c, LDL-c, Hct |
Knudtson et al. [24], USAa
| Case–control | 99 | 99 | 24–32 | – | 29.1 ± 2.9 | 39.4 ± 1.3 | 25 ± 6 | 24 ± 6 | – | – | – | Hct |
Bartha et al. [17], Spain | Case–control | 40 | 50 | 24–36 | 31.3 ± 2.1 | 33.9 ± 2.6 | 39.6 ± 2.3 | 27.7 ± 6.5 | 29.6 ± 6.5 | 21.7 ± 3.0 | 23.6 ± 3.8 | F | TC, TG, HDL-c, LDL-c |
Dhoble et al. [23], India | Case–control | 67 | 76 | During delivery | – | 39.3 ± 1.1 | 34.3 ± 2.2 | 23.0 ± 3.1 | 22.6 ± 3.0 | 20.1 ± 3.1 | 22.0 ± 2.9 | – | Hct |
Period | Study | Case vs. control | Triglycerides | LDL-c | HDL-c | Homocysteine | Total cholesterol | Adjustment for confounders |
---|---|---|---|---|---|---|---|---|
First trimester | Alleman et al. [19] | sPTD | – | – | – | – | 177.9 ± 35.7 | Crude |
Control | – | – | – | – | 173.8 ± 30.4 | |||
Catov et al. [12] | sPTD <34#
| 100.2 ± 60.2 | 118.3 ± 44.8 | 65.0 ± 18.7 | – |
203.3 ± 50.5*
| † | |
sPTD 34–37#
|
102.6 ± 43.8*
| 110.2 ± 37.9 | 65.7 ± 16.2 | – | 196.5 ± 43.7 | |||
Control | 90.6 ± 41.5 | 104.7 ± 28.6 | 65.1 ± 16.2 | – | 188.0 ± 33.6 | |||
Second trimester | Kramer et al. [25] | sPTD | – | 116.0 ± 30.9 |
61.9 ± 15.5*
|
4.0 ± 1.4*
| 235.9 ± 42.5 | ‡ |
Control | – | 119.89 ± 30.9 | 69.6 ± 15.5 | 3.7 ± 0.9 | 232.0 ± 42.5 | |||
Mudd et al. [15] | sPTD |
171.1 (163.5–179.0)*
| 70.3 (68.2–72.4) | 116.4 (111.1–122.0) | – |
226.8 (220.9–232.8)*
| § | |
Control | 161.1 (157.3–164.9) | 68.2 (67.2–69.2) | 113.5 (111.0–116.0) | – | 219.7 (217.1–222.4) | |||
Third trimester | Bartha et al. [17] | sPTD | 189.4 ± 77.9 |
125.7 ± 35.6*
|
53.4 ± 18.2*
| – |
219.6 ± 32.3*
| – |
Control | 175.0 ± 64.1 | 142.2 ± 36.1 | 68.3 ± 18.4 | – | 240.4 ± 40.0 | |||
During delivery | Dhoble et al. [23] | sPTD | – | – | – |
12.2 ± 4.4*
| – | – |
Control | – | – | – | 10.7 ± 8.7 | – |
Period | Study | Triglycerides (95 % CI) | LDL-c (95 % CI) | HDL-c (95 % CI) | Homocysteine (95 % CI) | Total cholesterol (95 % CI) | Adjustment for confounders | |
---|---|---|---|---|---|---|---|---|
Pre-pregnancy | Harville et al. [21] | sPTD | 0.98 (0.74–1.30) | 1.17 (0.89–1.54) | 0.92 (0.73–1.17) | – | 1.13 (0.84–1.49) | † |
Catov et al. [20] | Q1 | 1.44 (0.78–2.67) | 1.40(0.77–2.54) | 0.98 (0.53–1.82) | – | 1.66 (0.89–3.09) | ‡ | |
Q2 | Reference | Reference | Reference | – | Reference | |||
Q3 | 1.41 (0.77–2.58) | 1.05 (0.56–1.98) | 0.72 (0.39–1.36) | – | 1.57 (0.84–2.94) | |||
Q4 | 1.02 (0.53–1.94) | 1.30 (0.70–2.41) | 1.32 (0.76–2.30) | – | 1.55 (0.82–2.93) | |||
Magnussen et al. [22] | 0–20 % | Reference | – | 1.4 (0.9–2.2) | – | Reference | § | |
20–40 % | 1.3 (0.8–2.1) | – | 1.2 (0.7–1.9) | – | 0.8 (0.5–1.3) | |||
40–60 % | 1.6 (1.0–2.5) | – | 1.0 (0.7–1.8) | – | 0.9 (0.6–1.4) | |||
60–80 % |
2.1 (1.3–3.2)*
| – | 1.1 (0.7–1.8) | – | 1.1(0.7–1.6) | |||
80–100 % | 1.3 (0.8–2.2) | – | Reference | – | 1.3 (0.9–2.0) | |||
First trimester | Alleman et al. [19] | Q1 | 1.12 (0.79–1.60) | 1.02 (0.72–1.45) | 1.16 (0.82–1.62} | – | 0.90 (0.62–1.30) | Crude |
Q2–Q3 | Reference | Reference | Reference | – | Reference | |||
Q4 | 1.20 (0.85–1.69) | 1.06 (0.75–1.51) | 0.89 (0.62–1.29) | – | 1.14 (0.81–1.61) | |||
Vrijkotte et al. [14] | sPTD | 0.87 (0.62–1.23) | – | – | – | – | || | |
Chatzi et al. [13] | sPTD | 1.09 (0.52–2.29) | – | 1.54 (0.84–2.82) | – | – | ¶ | |
Second trimester | Alleman et al. [19] | Q1 | 1.10 (0.78–1.56) | 1.25 (0.88–1.76) | 1.21 (0.86–1.70) | – | 1.00 (0.7–1.42) | Crude |
Q2-Q3 | Reference | Reference | Reference | – | Reference | |||
Q4 | 1.03 (0.72–1.47) | 1.08 (0.76–1.54) | 0.93 (0.64–1.34) | – | 1.00 (0.7–1.42) | |||
Edison et al. [18] | <10 % | – | – | – | – |
2.93 (1.54–5.56)*
| # | |
10–90 % | – | – | – | – | Reference | |||
≥90 % | – | – | – | – |
2.66 (1.39–5.09)*
| |||
Kramer et al. [25] | Q1 | – | Reference | Reference | Reference | Reference | ** | |
Q2 | – | 1.0 (0.5–2.2) | 0.6 (0.3–1.2) | 0.8 (0.4–1.4) | 0.8 (0.4–1.7) | |||
Q3 | – | 0.8 (0.4–1.8) | 0.6 (0.3–1.2) | 1.2 (0.7–2.0) | 1.0 (0.4–2.2) | |||
Q4 | – | 0.9 (0.4–2.0) | 0.2 (0.1–1.6) | 2.2 (1.3–3.7) | 1.1 (0.5–2.3) | |||
Mudd et al. [15] | <10 % | – | 1.37 (0.85–2.21) | 1.17 (0.70–1.95) | – | 1.10 (0.67–1.82) | †† | |
10–70 % | – | Reference | Reference | – | Reference | |||
≥70 % | – | 1.17 (0.99–2.04) | 1.10 (0.78–1.55) | – | 1.51 (1.06–2.15)* | |||
Q1 | Reference | – | – | – | – | |||
Q2 | 1.27 (0.81–2.01) | – | – | – | – | |||
Q3 |
1.90 (1.21–2.97)*
| – | – | – | – | |||
Q4 |
1.72 (1.06–2.78)*
| – | – | – | – | |||
Niromanesh et al. [16] | sPTD |
10.9 (1.6–74.4)*
| – | – | – | – | Crude | |
Third trimester | Knudtson et al. [24] | >75 % | – | – | – | 0.81 (0.4–1.6) | ‡‡ | |
>90 % | – | – | – | 1.7 (0.7–4.5) | ||||
>95 % | – | – | – | 2.5 (0.7–8.7) |
Study
|
Ottawa Quality Assesment*
Selection/ Comparability/ Exposure
|
In- and exclusion criteria of study
|
---|---|---|
Alleman et al. [19], USA | 3/0/3 | In: PTD with spontaneous labour or PROM. Gestation age >20 weeks, singleton gestations |
Ex: congenital anomaly, any serious infection (gonorrhoea, syphils, hepatites), a term births with treatment tocolysis | ||
Bartha et al. [17], Spain | 2/0/3 | In: threatened spontaneous PTD between 24 and 36 weeks gestational age, preterm labor was based on the clinical diagnosis of at least four painful uterine contractions per 20 minutes and evidence of cervical change |
Ex: maternal or fetal condition needing delivery (including symptoms or signs of chorioamnionitis), multiple gestations, PROM, intrauterine fetal demise or suspected lethal fetal anomalies, cervix dilated > 4cm, treatment with either tocolytics or corticosteroids within 24 hourspreviously, food intake within 8 hours previously | ||
Catov et al. [12], USA | 2/2/3 | In: PTD with PROM, spontaneous labor |
Ex: hypertension (chronic, transient, PE), diabetes, growth restriction, small for gestational age (<10% percentile) | ||
Catov et al. [20], USA | 4/2/3 | In: first birth with PTD< 37 weeks gestation (no distinction between indicated and spontaneous PTD) |
Ex: diabetes mellitus or hypertension at baseline based on self-report or medication use, pregnant within 3 months of the baseline assessment, hysterectomy at baseline, no births between baseline and yr 20 of follow-up, twin births, a first term birth but subsequent PTD | ||
Chatzi et al. [13], Greece | 4/1/2 | In: PTD<37 weeks, singleton pregnancy, |
Ex: preeclampsia | ||
Dhoble et al. [23], India | 2/0/3 | In: PTD, singleton pregnancy |
Ex: preeclampsia, gestational diabetes, anemia, chorioamnionitis, fetal infections, alcohol, drug abuse | ||
Edison et al. [18], USA | 3/1/3 | In: PTD, aged 21 to 34 |
Ex: history of smoking, type 1 diabetes, or other medical or gestational risk conditions | ||
Harville et al. [21], Finland | 3/2/3 | In: PTD< 37 weeks, limited to primiparous women |
Ex: type 1 diabetes or suspected familial hypercholesterolemia, gestational hypertension, pre-eclampsia, gestational diabetes | ||
Knudtson et al. [24], USA | 3/2/2 | In: PPROM, singleton pregnancy |
Kramer et al. [25], Canada | 2/2/3 | In: PTD<37 weeks gestation with PPROM, age >18 years at the expected date of delivery, singleton gestation. |
Ex: severe chronic illness (other than hypertension, asthma or diabetes) requiring ongoing treatment, placenta previa, history of incompetent cervix diagnosed in a previous pregnancy, impending delivery at the time of initial contact or a fetus affected by a major anomely | ||
Magnussen et al. [22], Norway | 3/2/3 | In: PTD as <37 weeks gestation, singleton pregnancy, at least 1 birth (gestational age 22 weeks or birthweight above 500 g, Ex: pregnant at baseline or delivered within 9 months after participating in, the study, hypertensive disorders in pregnancy (preeclampsia, chronic. and gestational hypertension |
Mudd et al. [15], USA | 2/0/2 | In: Spontaneous preterm birth, singleton pregnancy, no known chromosomal abnormality or birth defect, maternal serum alpha-fetoprotein (MSAFP) screen at 15–22 weeks, maternal age≥15 years, no preexisting diabetes mellitus. All women with high MSAFP levels (i.e.≥2multiplesofthemean) were invited to participate because this biomarker has previously been associated with PTD. |
Ex: medical indicated PTD | ||
Niromanesh et al. [16], Iran | 2/0/2 | In: PTD with age between 20–35 yrs, gravid >2 |
Ex: history of PTD, pre-eclampsia, diabetes or gestational diabetes (GD), primigravida, those with a BMI >25 | ||
Vrijkotte et al. [14], The Netherlands | 3/0/3 | In: spontaneous PTD defined as delivery onset by spontaneous preterm labor or premature rupture of membranes between 24.0 and 36.6 wk gestation |
Ex: multiple gestation or who had no data on the gestational age at blood sampling, women with diabetes (preexistent as well as pregnancy induced), those using lipid-altering medication (e.g. antiepileptic drugs, steroids, insulin, antidepressants, thyroid hormones, or sleep medication), |