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