Normal Labor and Delivery Bridgett Casadaban July 25

Normal Labor and Delivery Bridgett Casadaban July 25, 2007

Definitions • Labor – Uterine contractions that result in effacement and dilatation of the cervix. • Braxton-Hicks – Uterine contractions NOT associated with cervical change. – – Shorter in duration Less intense Over lower abdomen and groin Resolve with ambulation • Lightening – Descent of the fetal head into the pelvis

Definitions • • Preterm labor – Prior to 37 weeks Term – 37 to 42 weeks Post term – After 42 weeks Post dates – After 40 weeks

UVA Labor and Delivery • 22 yo G 2 P 1 at 39 wks comes into L&D complaining of RUC’s q 5 minutes x 2 hours. Diana has hooked the patient up to the monitor and brings the patient’s chart to you to further evaluate the patient. What to do next?

UVA Labor and Delivery • Talk with the patient – – Confirm ctx history LOF? Vaginal bleeding? Feeling baby move? – Desires an epidural? – Distance from home to hospital? – GBS status? q 5 minutes x 2 hours Yes No No

UVA Labor and Delivery • Examine patient – Rule out rupture – Check cervix Negative pooling, nitrazine, ferning 2/50/-1

UVA Labor and Delivery • Formulate a plan – You decide to allow the patient to walk around the hospital for 2 hours then return for a cervical check. What steps must you take next before the patient can leave L&D? *Ultrasound to confirm fetal presentation *Confirm a reactive/reassuring strip

UVA Labor and Delivery • Patient returns in 2 hours with continued, uncomfortable ctx’s q 5 minutes. Now what? • Recheck cervix Now what? 5/90/0

UVA Labor and Delivery • Admit patient to Labor and Delivery – Complete H&P • *Obtain EFW by Leopold’s – Consents signed for delivery and potential blood transfusion – Orders entered into MIS • • • Clear diet IVF’s T&S/CBC GBS prophylaxis? Continuous EFM vs. intermittent – Intermittent = FHTs q 30 min to include a ctx and immediately after » Membranes intact or SROM and well-engaged – Continuous » NRFHTs, SROM and poorly engaged, augmented labor, epidural?

UVA Labor and Delivery • In order to maximize the patient’s chance at a vaginal delivery it is important to understand the basics of labor and delivery: – Stages of labor – Mechanics of labor – Cardinal movements of labor – Delivery

Stages of Labor • 1 st Stage – Interval between onset of labor and full cervical dilatation – 2 phases: • Latent – period between onset of labor and point at which a change in slope of rate of cervical dilatation is noted. • Active – Greater rate of cervical dilatation and usually begins around 2 -3 cm

Stages of Labor • 2 nd stage – Interval between full cervical dilatation and delivery – Duration • Nulliparous – 3 hrs w/ epidural; 2 hrs w/o epidural • Multiparous – 2 hrs w/ epidural; 1 hr w/o epidural • 3 rd stage – Delivery of the placenta and membranes – Duration – maximum of 30 minutes

Normal Labor and Delivery • In order to maximize the patient’s chance at a vaginal delivery it is important to understand the basics of labor and delivery: – Stages of labor – Mechanics of labor – Cardinal movements of labor – Delivery

Mechanics of Labor • The Powers – Forces generated by uterine musculature – Frequency, amplitude, and duration of ctx’s – Observation, manual palpation, tocodynamometry, intrauterine pressure catheter (IUPC) – Measured in Montevideo units • Average strength of ctx’s (mm. HG) x no. of ctx’s in 10 minutes • Adequate 200 -250 MVUs

Mechanics of Labor • Passenger – Fetal size • Abdominal palpation or Ultrasound • Macrosomia (>4500 g) associated w/ failure to progress – Lie • Longitudinal axis of fetus relative to longitudinal axis of uterus • Longitudinal*, transverse or oblique – Presentation • Fetal part that directly overlies pelvic inlet • Cephalic, breech, or shoulder • Compound – presence of >1 fetal part overlying the pelvic inlet • Funic – umbilical cord presenting at pelvic inlet • Malpresentation – any presentation that is not cephalic with occiput leading

Mechanics of Labor • Passenger (cont) – Attitude • Position of head with regard to fetal spine (ie: degree of flexion or extension) • Flexion allows smallest diameter of fetal head to present at pelvic inlet – Position • Relationship of a nominated site of presenting part to denominating location on internal pelvis – Example: cephalic presentation

Mechanics of Labor

Mechanics of Labor • Passenger (cont. ) – Station • Measure of descent of presenting part of the fetus through the birth canal. – Multifetal Pregnancy • Increase probability of abnormal lie and malpresentation in labor

Mechanics of Labor • Passenger (cont. ) – Leopold’s maneuvers • #1 – Correct dextrorotation of the uterus with the back of one hand delineate the fundus with the other to determine gestational age and/or appropriate size. • #2 – Run hands down maternal abdomen on either side of fetus to determine fetal lie, identifying small parts and fetal spine • #3 – Firmly grasp upper and lower poles of fetus by placing fingers at uterine fundus and above symphysis to determine presentation and fetal size. • #4 – Move hands in bilaterally from anterior superior iliac crests to determine whether or not the presenting part of the fetus is engaged in maternal pelvis. – Head regarded as unengaged if examiner’s hands are see to converge below fetal head.

Mechanics of Labor • Passenger (cont. )

Mechanics of Labor • Passage – Bony pelvis + soft tissues – X-ray pelvimetry now rarely used, having been replaced by a trial of labor – 4 types of the female bony pelvis

Normal Labor and Delivery • In order to maximize the patient’s chance at a vaginal delivery it is important to understand the basics of labor and delivery: – Stages of labor – Mechanics of labor – Cardinal movements of labor – Delivery

Cardinal Movements of Labor • Engagement – Passage of widest diameter of presenting part to level below the plane of the pelvic inlet – 0 station – Occurs earlier in nulliparous women (36 wks) • Descent – Downward passage of presenting part through the pelvis. • Flexion – Occurs passively as the head descends due to the shape of the bony pelvis and resistance of pelvic floor soft tissues – Allows smallest diameter of fetal head to pass through the pelvis.

Cardinal Movements of Labor • Internal Rotation – Rotation of presenting part from original position (transverse) to anteroposterior position • Extension – Occurs once fetus has descended to the level of the introitus – Base of occiput in contact with inferior margin of symphysis pubis • External Rotation – Return of fetal head to correct anatomic position in relation to the fetal torso • Expulsion – Delivery of rest of fetus – Anterior shoulder delivered first with rotation under the symphysis pubis

Cardinal Movements of Labor

Normal Labor and Delivery • In order to maximize the patient’s chance at a vaginal delivery it is important to understand the basics of labor and delivery: – Stages of labor – Mechanics of labor – Cardinal movements of labor – Delivery

How to effectively deliver a baby • Prepare for the delivery taking into account parity, progression of labor, presentation of fetus, complications of labor • When head crowns and delivery is eminent, protect the perineum + downward pressure to keep head flexed – Ritgen’s maneuver my help if delay in delivery of the fetal head • Sterile towel used to palpate fetal chin through the rectum to apply upward pressure to facilitate extension of fetal head • After delivery of head – Allow for external rotation (restitution). – Reduce nuchal cord – Suction fetal mouth and nares • After clearing fetal airway – Place a hand on each parietal eminence to apply downward traction to deliver anterior shoulder – Followed by upward traction to deliver posterior shoulder

How to effectively deliver a baby • After complete delivery of infant – Cradle in a single arm below the perineum to allow maximal blood transfer to infant • Delivery of the placenta – 3 classic signs of placental separation: • Lengthening of the umbilical cord • Gush of blood from vagina • Change in shape of the uterine fundus to a more globular appearance – Active management of 3 rd stage has been shown to reduce total blood loss • Brandt-Andrews Maneuver: abdominal hand secures the uterine fundus to prevent uterine inversion while the other hand exerts sustained downward traction on umbilical cord • Crede maneuver – cord is fixed with lower hand while the uterine fundus is secured and sustained upward traction is applied using abdominal hand

How to effectively deliver a baby • Inspect the placenta – Abnormalities of lobulation – Site of insertion of umbilical cord into the placenta • Marginal insertion –inserts into edge of placenta • Membranous insertion – vessels course through the membranes prior to attaching to placental disk – Length (50 -60 cm) – 2 arteries and 1 vein • Single umbilical artery associated with 20% risk of other structural anomalies.