Latent phase of labor

A 20-year-old G1 woman at 40 weeks gestation presents to labor and delivery complaining of painful contractions every 3-4 minutes since midnight. Her examination on admission was 2 centimeters dilated, 90% effaced and 0 station. Three hours later, her exam is unchanged. What's the next step of management?

This is a common scenario seen in triage. Patient is in the latent phase of labor and has not yet reached the active phase (more than 4 cm). 

A prolonged latent phase is defined as >20 hours for nulliparas and >14 hours for multiparas, and may be treated with rest or augmentation of labor. 

Artificial rupture of membranes is not recommended in the latent phase as it places the patient at increased risk of infection. Cervical dilation or laminaria placement are not indicated.

Indication of labor induction
Benefits of delivery outweighs the risks of continuing the pregnancy

• Maternal: fetal demise, prolonged pregnancy, chorioamnionitis, severe preeclampsia, eclampsia
• Fetal: IUGR, abnormal fetal testing, infection

Fetal heart tracing

Late decelerations are a symmetric fall in the fetal heart rate, beginning at or after the peak of the uterine contraction and returning to baseline only after the contraction has ended. Late decelerations are associated with uteroplacental insufficiency. 

Variable decelerations show an acute fall in the FHR with a rapid downslope and a variable recovery phase. They are characteristically variable in duration, intensity, and timing, and may not bear a constant relationship to uterine contractions. Variable decelerations are due to cord compression. 

Early decelerations are physiologic caused by fetal head compression during uterine contraction, resulting in vagal stimulation and slowing of the heart rate. This type of deceleration has a uniform shape, with a slow onset that coincides with the start of the contraction and a slow return to the baseline that coincides with the end of the contraction. Thus, it has the characteristic mirror image of the contraction. 

The true sinusoidal pattern is a regular, smooth, undulating form typical of a sine wave that occurs with a frequency of two to five cycles/minute and an amplitude range of five to 15 beats/minute. It is also characterized by a stable baseline heart rate of 120 to 160 beats/minute and absent beat-to-beat variability.

Preeclampsia

Preeclampsia: hypertension and proteinuria with or without edema which develop during the third trimester

W/U:

All women who present with new-onset hypertension should have the following tests:

• CBC
• AST/ALT
• Serum creatinine
• Uric acid
• 24-hour urine collection for protein and creatinine (criterion standard) or urine dipstick analysis
• Mild: 300mg
• Severe: 5g

Additional studies to perform if HELLP syndrome is suspected are as follows:

• Peripheral blood smear
• Serum lactate dehydrogenase (LDH) level
• Indirect bilirubin

Management 

• Deliver the baby if severe

Perineal lacerations

First degree: fourchette, perineal skin, and vaginal mucosa

Second: first + vaginal fascia and muscle of the perineal body

Third: second + anal sphincter

Fourth: external and internal anal sphincters and the rectal mucosa

Spalding sign

Ultrasound finding of overlapping of the fetal skull bones. 
This finding was originally described for abdominal radiographs and is indicative of fetal demise.

Pyelonephritis in pregnancy

Renal infection is the most common serious medical complication of pregnancy. 

1. Why pregnant women are more likely to have renal infection?
• Ureters are more dilated
• Uterus can compress the ureter, leading to stagnant urine
2. Presentation: fever, chills, CVA tenderness, UTI symptoms may be present 
3. W/U: urine analysis
4. Management
• Initially aggressive intravenous hydration is given to ensure adequate urinary output
• Antimicrobials are begun promptly after diagnosis (cephzolin)
5. Outcome:
• The majority of patients are afebrile by 72 hours. If there is no clinical improvement by 72 hours, further evaluation is warranted including sonography to look for urinary tract obstruction (abnormal ureteral or pyelocaliceal dilatation) or calculi. 
• Obstruction can be relieved by cystoscopic placement of a double-J ureteral stent unless long-term stenting is foreseen, then percutaneous nephrostomy is indicated. 

• Surgical exploration is required in up to 2% of women if other conservative therapies are not successful

PROM and PPROM

Premature rupture of membrane
Definition = ROM before onset of labor
Management

• Confirm ROM w/ speculum exam 
• Avoid too many vaginal exams (prevent infection)
• Evaluate for chorioamnionitis (fever, leukocytosis, maternal/fetal tachycardia, uterine tenderness, malodorous vaginal discharge)
• If there is chorioamnionitis, deliver despite GA + antibiotics

Preterm PROM

• Admit the patient
• Administer steroids to prevent RDS (if <32 weeks)
• US to assess GA, anomalies, AFI (is there enough fluid)

The time from premature rupture of membranes to labor is inversely related to gestational age. At term, 90% will spontaneously go into labor within 24 hours of PROM. At 28 weeks to 34 weeks, 50% will go into labor within 24 hours and 80% within 48 hours.

Rupture of membrane

Rupture of membrane presents as a gush of fluid

To determine that the fluid is amniotic fluid: sterile speculum exam

• Pooling: fluid collection @ posterior fornix
• Valsalva: bear down to see if there's fluid
• Ferning: place a thin layer of fluid on a slide
• Nitrazine (not used that often); Amnisure is used 

DDx of ROM: urine, vaginal discharge

When you do the speculum exam, do three slides

1. KOH for Candida
2. Saline for BV (clue cells)
• For BV (caused by Gardnerella vaginalis proliferation, not necessarily an STD; treat pt w/ metronidazole)
3. Check ferning 

Intrapartum cervical exam

Five parameters are assessed:

1. Dilation
2. Effacement 
3. Station
4. Consistency 
5. Position

Report: cm dilation/ % effacement/ -3 to +3 (or high, low)/ thick or thin/ posterior or anterior 

Dilation: size of opening (0-10cm)

• Index and middle fingers are inserted in the cervical opening and are separated as far as the cervix will allow

• Don't stick your fingers in w/o making sure that the pt does not have placenta previa, vasa previa

Effacement: length of the cervix

• Cervix shortens with labor (when it's shortened by 50% = 50% effacement, about 2cm)
• Palpate w/ finger to estimate the length from internal os to external os

Station: descent in relation to ischial spine

Consistency: firm to soft

Position: location of the cervix w/ respect to the fetal presenting part

• Posterior: difficult to palpate (high in pelvis)
• Anterior: easy to palpate
• During labor, cervical position progresses from posterior to anterior 

BISHOP SCORE

Scoring system that helps to determine the status of the cervix for vaginal delivery based on these 5 parameters 

• Score >= 6: probability of vaginal delivery w/ induction of labor is similar to that of spontaneous labor

Normal labor

Normal labor management is observe w/o intervention

Change in the cervix per time dictates normalcy in labor (not contraction patterns)

There are three stages:

1. Onset to complete dilation (@10cm)
• Active: >4cm, more rapid dilation
• Arrest of active phase: cervix does not dilate for 2 hours
• >=1.2cm/hr for nullipara, >=1.5cm/hr for ultipara
• Latent: <4cm
• Prolonged latent phase (> 18-20 hr for nullipara/ >14 hr for multipara)
2. Complete dilation to delivery of infant (<2-3 for nullipara, <1-2 for multipara)
3. Delivery of infant to deliver of placenta (less than 30 minutes)

When a labor abnormality occurs, assess powers, passenger and pelvis 

Adequate contraction = every 2-3 minutes, firm on palpation, lasting for 40-60 seconds

Passenger - cephalopelvic disproportion, consider C-section

Power - give IV pitocin