USUHS MSIII Ob/Gyn Clerkship Self Directed Studies Diagnostic Techniques for Pre-Term Labor Ch Academic Year MSIII Ob/Gyn Clerkship Self-Directed Study

USUHS MSIII Ob/Gyn Clerkship Self Directed Studies Diagnosis of PTL Objectives - Understand the diagnostic techniques for PTL –Definition –Cervical Length –FFN

USUHS MSIII Ob/Gyn Clerkship Self Directed Studies Definition Between 20 and 37 weeks EGA Documented uterine contractions (4 per 20 minutes or 8 per 60 minutes) Documented cervical change

USUHS MSIII Ob/Gyn Clerkship Self Directed Studies Normal Cervical Length Bladder Cervix Intrauterine

USUHS MSIII Ob/Gyn Clerkship Self Directed Studies Cervical Length Measure length of cervix using trans- vaginal ultrasound Greater than 2.5 to 3 cm is considered normal (references differ) Best PPV if use 3 cm as cutoff. Normal Cx Length No Funneling

USUHS MSIII Ob/Gyn Clerkship Self Directed Studies Shortened Cervix Less than 2 cm with high PPV for PTL Can be affected by bladder (full vs. empty), want empty Change vs. stability over time - if 2.5 cm but no change, may not be PTL 9mm is not normal for CL

USUHS MSIII Ob/Gyn Clerkship Self Directed Studies Funneling and PTL Funneling Present when patient valsalva’s or with fundal pressure by sonographer Residual length is important Funneling present

USUHS MSIII Ob/Gyn Clerkship Self Directed Studies Fetal Fibronectin (FFN) Very good NPV (Neg test result consistent with no delivery within 7 days) PPV not as good (can be false positive) Blood can give false positive. If speculum, cervical exam, intercourse (anything in vagina) in past 24 hours, can give false results, so cannot be done in those circumstances. Posterior Fornix FFN is presesnt when cervix starts to change. No gel on speculum