Chapter 11: Preterm Labor Flashcards
What is Preterm Labor (PTL)?
cervical changes and regular uterine contractions occurring between 20 and 37 weeks of pregnancy
>many present with preterm contractions, but only those who demonstrate changes in the cervix are diagnosed with PTL
Short term neonatal morbidities associated with premature birth
- respiratory distress syndrome
- intraventricular hemorrhage
- periventricular leukomalacia
- necrotizing enterocolitis
- bronchopulmonary dysplasia
- sepsis
- patent ductus arteriosus
Long-term morbidities associated with premature birth
- cerebral palsy
- intellectual and developmental disabilities
- retinopathy of prematurity
Risk for short-term and long-term morbidities is related to?
the infants gestational age and birth weight
Risk Factors Associated with Preterm Labor and Birth
- hx of preterm birth, especially in second trimester
- preterm premature rupture of the membranes (PROM)
- uterine or cervical anomalies
- multiple gestation
- hypertensive disorders of pregnancy
- diabetes (especially inadequately controlled)
- low pre-pregnancy weight
- clotting disorders
- bacterial infections
- fetal anomalies
- uterine overdistension (e.g. multiple gestation, hydramnios)
- vaginal bleeding, especially in the second trimester or in more than one trimester
- late or no prenatal care
- alcohol or drug use
- smoking
- cervical injury (e.g. related to surgery or elective abortion)
- Diethylstilbestrol (DES) exposure
- trauma including intimate partner violence (IPV)
- non-Hispanic African American race
- maternal age extremes (less than 16 years or greater than 40 years)
- low socioeconomic or educational status
- stress
- long working hours with long periods of standing
- periodontal disease
Risk Screening for Preterm Birth
- Fetal Fibronectin Testing
- Assessment of Cervical Length and Funneling
Fetal Fibronectin (fFN)
Fetal fibronectin (fFN) is a glycoprotein produced by the fetal membranes; normally present in the cervicovaginal fluid until 16 to 20 weeks of gestation
- described as the “glue” that attaches the fetal membranes to the underlying uterine decidua
- when uterine contractions occur, the adherence is disrupted and fFN is released
- fFN is a marker for the disruption of the chorioamnion and underlying decidua caused by inflammation with or without infection
Fetal Fibronectin Testing
-a positive fFN test result between 24 and 34 weeks has been associated with subsequently diagnosed maternal and fetal infection
>this test is done when the membranes are not ruptured and the patient is not bleeding
>the patient should not have a pelvic exam, vaginal ultrasound, or vaginal intercourse within the 24 hours prior to the collection
Fetal Fibronectin Testing: how to test for the presence of fFN
a sterile cotton-tipped swab is placed in the posterior vaginal fornix or in the ectocervical region of the external cervical os for a minimum of 10 seconds
-the collection swab is then removed, placed in a manufacturer-supplied medium, and sent to the lab
-results reported in 24 to 48 hours
>if test is negative (no fFN detected), the likelihood of giving birth in the following week is less than 1%
Assessment of Cervical Length and Funneling
association of cervical shortening (less than 15 to 25 mm, depending on gestational age) with preterm birth, particularly if associated with a positive fFN test result
- cervical length (CL) measurements are performed, with TVU or FDA-approved CervilLenz CL measuring device
- the risk of preterm delivery increases as the CL in the second trimester declines
Interventions to possibly prevent Preterm Labor
- preconception control of chronic medial conditions (e.g. diabetes, seizures, asthma, hypertension)
- smoking cessation
- routine prenatal screening and treatment for asymptomatic bacteriuria
- the use of laminaria for woman undergoing second trimester pregnancy termination via dilation and evacuation
- progesterone supplementation; Micronized progesterone vaginal gel or suppositories may reduce preterm labor, especially in woman with a history of preterm birth and a short CL verified by vaginal ultrasound
Micronized Progesterone Vaginal Gel or Suppositories
may reduce preterm labor, especially in woman with a history of preterm birth and a short CL verified by vaginal ultrasound
>progesterone supplementation should be offered to all women with a singleton pregnancy and a prior spontaneous preterm birth because of spontaneous preterm labor or premature rupture of the membranes
Diagnosis of PTL is diagnosed with this criteria is met
- a gestation of 20 to 37 weeks
- documented persistent uterine contractions (4 every 20 minutes or 8 in 1 hour)
- documented cervical effacement of 80% or greater
- cervical dilation of more than 0.4 in (1 cm) or a documented change in dilation
Signs and Symptoms
can be subtle
- backache
- pelvic aching
- menstrual-like cramps
- increased vaginal discharge
- pelvic pressure
- urinary frequency
- intestinal cramping with or without diarrhea
What has been implicated as a contributing factor in PTL
Infection
-prostaglandin production by the amnion, chorion, and decidua is stimulated by cytokines (extracellular factors) that are released by activated macrophages
>Group B streptococci, chlamydia, and gonorrhea have been associated with PTL and preterm premature rupture of the membranes
>important for nurse to obtain a clean-catch, midstream, or catheterized urine specimen to identify and treat infection if the patient presents with signs of PRL or premature rupture of the membranes
