Preterm labor: regular uterine contractions with cervical effacement, dilation, or both before 37 weeks’ gestation
Preterm birth
- Live birth between 20 0/7 weeks’ and 36 6/7 weeks’ gestation
- WHO subcategories
  - Extremely preterm (< 28 weeks)
  - Very preterm (28 to < 32 weeks)
  - Moderate to late preterm (32 to < 37 weeks)

Epidemiology

Etiology

Prior spontaneous PTB (single strongest risk factor).
Short cervical length (CL <25 mm on TVUS prior to 24 wks). c
Multiple gestations (uterine overdistension).
Cervical trauma/surgery (e.g., LEEP, cold knife conization).
Infections: Intra-amniotic infection, STIs, asymptomatic bacteriuria, BV.
Uterine anomalies or large leiomyomas.
Low SES, maternal age <18 or >35, cigarette/substance use, short interpregnancy interval (<18 mos).

Definition: Bleeding into the ventricles from the germinal matrix, a highly vascularized region within the subventricular zone of the brain from which cells migrate out during brain development.
Etiology: associated with a number of risk factors
- Birth weight < 1500 g and delivery before 32 weeks’ gestation due to the fragility of the germinal matrix and/or impaired autoregulation of blood pressure
- Maternal chorioamnionitis
Pathophysiology
- Immaturity of the basal lamina and lack of astrocytic glial fibrillary acidic protein within the germinal matrix leads to abnormal cerebral autoregulation.
- Alterations in an infant’s blood pressure (e.g., during birth, intubation) → failure of cerebral autoregulation to compensate for the change in blood pressure → rupture of and bleeding from vessels in the germinal matrix → rupture of ependyma → blood flows into the ventricles
Clinical features
- Usually occurs within the first days of life (up to day 5)
- Most infants are asymptomatic, but saltatory (for several days) or, more rarely, catastrophic (over minutes to hours) courses are also possible.
- Lethargy, hypotonia, irregular respirations, seizures, bulging anterior fontanelle
- Cranial nerve abnormalities (e.g., pupils react sluggishly to light) and changes in eye movement (e.g., roving eye movements)

tags	—
aliases	Preterm labor, Preterm birth