Preterm Labour: Pathogenesis & Maternal Complications

Preterm Labour: Pathogenesis & Maternal Complications
Cervical Procedures
Removing part of the cervix
Ex. Cone biopsy, cervical LEEP
Genitourinary Infections
E.g. Urinary tract infection, bacterial vaginosis, chorioamnionitis, abnormal vaginal flora
↑ bacterial colonization of fetal membrane
↑ bacterial enzymes and immune reactions
Antepartum Hemorrhage
↑ risk placental abruption
↑ decidual tissue factor release
Activates coagulation cascade
↑ thrombin ↑ proteases
Substance Use
Smoking or cocaine use
Vasoconstriction in uterine circulation, endothelial dysfunction
Placental hypoperfusion and ischemia
↑ fetal ACTH
↑ placental prostaglandins
Maternal Stress
Malnutrition, depression, trauma- related disorders, work-related stress
↑ cortisol
↑ placental corticotropin releasing hormone
Uterine Abnormalities
Mullerian duct anomalies: congenital abnormalities in uterine shape
Septate uterus: ridge of tissue dividing uterus into two horns
Intracavitary leiomyoma: benign mass inside uterus
↑ Uterine volume
Maternal Genome
Family hx or personal hx of preterm birth, previous preterm premature rupture of membrane
↓cervical stroma & ↑cervical scarring
↓ cervical glandsà ↓ mucous production
↑risk of infection ↑ inflammation
Cervical collagen degradation
Rapid growth exceeds blood supply
Ischemia & necrosis of fetal tissue
↑prostaglandins and cytokines
↓ functional volume of uterine cavity
Multifetal pregnancy, poly- hydramnios
↓tensile strength and plasticity
Uterine stretch
Upregulation of oxytocin receptors
Genes for ↑ risk
Mechanism unknown
Cervical Insufficiency
Pathologic cervical dilation and/or effacement (thinning)
Authors: Skye Russell Reviewers: Danielle Chang, Crystal Liu, Yan Yu*, Nicholas Papalia*
*MD at time of publication
Digest and weaken amniotic membrane
Preterm Premature Rupture of Membranes
↑ myometrial sensitivity to oxytocin
Uterine contractions Preterm Labour
Uterine contractions and cervical change occurring <37wk gestational age ↑ Risk of future preterm labour and preterm birth Abbreviations: • LEEP – Loop electrosurgical excision procedure • ACTH – adrenocorticotropic hormone Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published July 12, 2020 on