Table 1 Main characteristics of included studies
From: Inter-pregnancy interval and risk of recurrent pre-eclampsia: systematic review and meta-analysis
Study | Country | Study design | Sample size (women with PE in 1st pregnancy) | Definition of inter-pregnancy interval | Inter-pregnancy interval studied (years) | Elegibility criteria in pregnancy 1 | Outcome in pregnancy 2 | Definition of outcome | Confounders used in the adjustment |
|---|---|---|---|---|---|---|---|---|---|
Basso 2001 | Denmark | Retrospective cohort | 8401 | Interval between birth of the first child and conception date of the second one | ≤1, 1–2, 2-3, 3–4, 4-5, 5–7, > 7. | Danish women with PE that delivered at the hospital, with a 28 weeks or more single pregnancy and whose children were not given in adoption who had subsequently given birth | PE or E | ICD-9 and ICD-10 | Maternal age in the second pregnancy, SES in the first pregnancy and change of SES between the first and second pregnancies. |
Mostello | USA | Retrospective cohort | 17,773 | Interval between birth of the first child and conception date of the second one | ≤1, 1–2, 2-3, 3–4, 4-5, 5–6, 6-7, 7–8, > 8. | Women who delivered their first 2 singleton pregnancies at > 20 weeks gestation | PE or E | PE = HT + proteinuria or edema that is generalized and overt | maternal age, prepregnancy BMI, smoking and SES |
E = PE + convulsion, coma or both | |||||||||
Trogstad | Norway | Retrospective cohort | 19,970 | Time between the dates of the two deliveries | ≤1, 1–5, 6-10, 11-15, > 15 | All women with a first and second singleton pregnancy delivery after 16 weeks gestation in Norway | PE or E | BP > 140/90 after 20 week gestation combined with proteinuria ≥0.3 g/24 h (≥ + 1 dipstick) on at least two occasions. ICD-8 | maternal age in 2nd pregnancy, new father, year of second delivery. |
Hernandez Diaz | Sweden | Retrospective cohort | 31,417 | Difference between dates of last menstrual period | <2, 2-4, 4-6, 6-8, > 8 | Women who had their first delivery on or after 1 January 1987, with reproductive history followed until the end of 2004. | PE or E | ICD-9 and ICD-10 | None |