Skip to main content

Table 1 Risk Factors preterm birth (PTB). Risk factors for PTB used for sample classification in low/high PTB risk and their definitions

From: A hierarchical procedure to select intrauterine and extrauterine factors for methodological validation of preterm birth risk estimation

Risk factors Definition Uterine environment Study
Short Cervical Length Transvaginal ultrasound cervical length ≤ 25 mm (2nd to 3rd centile) U [19]
Polyhydramnios Severe Single deepest pocket (SDP) ≥ 16.0 cm or amniotic fluid index (AFI) > 35.0 cm U [20]
pPROM Preterm prelabor rupture of membranes U [21]
Medically Assisted Procreation All the methods or techniques based on the manipulation of reproductive cells (gametes) that will allow infertile couples to conceive a child U [22]
Prior PTB Previous delivery that occurs between 20 and 37 weeks of gestation U [4]
Pregnancy Induced Hypertention (PIH) Systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg on at least 2 occasions at least 4 hours apart after 20 weeks of gestation in a previously normotensive patient P [23]
Placenta Previa Placenta that completely or partially covered the internal os on a second- or third-trimester imaging study P [24]
Placental Abruption Partial or complete placental detachment prior to delivery of the fetus P [5]
Preeclampsia, Eclampsia, HELLP New onset of hypertension and proteinuria or hypertension and end-organ dysfunction with or without proteinuria after 20 weeks of gestation in a previously normotensive woman P [23]
Fetal Growth Restriction EFW < 3 centile or EFW < 10 centile with Doppler abnormalities on maternal or fetal side or decline in EFW F [25]
Urinary Tract Infections (UTI) Cystitis (infection of the bladder/lower urinary tract) and pyelonephritis (infection of the kidney/upper urinary tract) n pregnant women E [26]
Complex Autoimmune Diseases With Polytherapy i.e. Systemic lupus erythematosus (LES), Antiphospholipid Syndrome (APS) E [27]