Preterm Labor
Definition
Defined as regular contractions of the uterus resulting in changes in the cervix that start before 37 weeks of pregnancy.
Changes in the cervix include effacement (the cervix thins out) and dilation (the cervix opens so that the fetus can enter the birth canal).
Features of Preterm Labor
Backache - felt in the lower back - continuous or intermittent - dull not relieved by change of positions or anyother measures
Contractions every 10 minutes or more often - often painless
Cramping in the lower abdomen or menstrual like cramps - like gas pains in diarrhoea
Fluid leaking from the vagina - watery, mucus or bloody -- increase in amount of discharge - ruptured membranes - gush or trickle
Flu like symptoms such as nausea, vomiting or diarrhea
Increased pressure in the pelvis or vagina or lower abdomen
Inceased vaginal discharge
Vaginal bleeding - even slight bleeding
Cervix starts dilating
Risk Factors for Preterm Birth
Having a previous preterm birth
Short cervix
Cervical incompetence
Uteroplacental insufficiency - hypertension, insulin dependent diabetes,drug abuse, smoking alcohol consumption)
Short intervals between pregnancies
Urinary tract infections, vaginal infections, and sexually transmitted infections
Infection with fever greater than 101
Multiple first trimester abortions or second trimester abortions
Underweight or overweight before pregnancy
Clotting disorders (thrombophilia)
Short time between pregnancies (less than 6-9 months between birth and beginning of the next pregnancy
H/O certain types of surgery on the uterus or cervix
Pregnancy complications such as multiple pregnancy, vaginal bleeding
Life style factors such as low prepregnancy weight, smoking during Pregnancy, and substance abuse during pregnancy.
Low income
Long working hours with long periods of standing
Lack of social support
High levels of stress
Domestic violence, including physical, sexual or emotional abuse
Diagnosis
Changes in the cervix
Transvaginal ultrasound
Fetal fibronectin in the vaginal discharge measured
Midtrimester loss : Rapid plasma reagin test, gonorrheal and chlamydial screening, vaginal pH/wet smear/Whiff test, anticardiolipin angibody (e.g. anticardiolipin immunoglobulin [Ig G and IgM, anti-beta2 microglobulin), lupus anticoagulant antibody, activated partial thromboplastin time, one hour glucose challenge test
TORCH (toxoplasmosis, other infections, rubella, cytomegalovirus virus infection, herpes simplex
Tocodynamometry
FFN
Cervical length measurement
Management
Progesterone supplementation - Week;y infections of 17 alpha-hydroxyprogesterone caproate - 250 mg (1ml) IM in the hip every week until 37 weeks or delivery. initiate between 16 wk and 21 wk
Prophylactic vaginal progesterone
Tocolytic agents - transvaginal cervical length < 25 mm, >50% cervical effacement, - MgSO4, Indomethacin (early preterm labor <30wk or preterm labor associated with polyhydramnios, Nifedipine
Cerclage at 13-17 weeks
Genetic amniocentesis
Appropriate treatment of BV, gonorrheal, chlamydial or trichomonal infection
Tocolysis - delays delivery for 48 hours - helps steroid to improve lung maturity in the fetus
Bedrest
Hydration
Relative contraindications for tocolytic agents
Hostile intrauterine environment such as :
Oligohydramnios
Nonreactive nonstress test results
Positive contraction stress test results
Absent or reversed diastolic flow upon Doppler examination
Repetitive severe variable decelerations
Significant vaginal bleeding consistent with abruption, unless patient is stable and fetal well being is established.
Caution in cardiac disease - CCF, Cardiac surgery, significant pulmonary disease, renal failure, maternal infection (pneumonia, appendicitis, pyelonephritis)
MgSO4 - not used in conjunction with calcium channel blockers, in myasthenia gravis, neuromuscular disorders
Goals of Management
Early identification of risk factors associated with preterm birth
Timely diagnosis of pretermlabor
Identifying the etiology of preterm labor
Evaluating fetal well-being
Providing prpphylactic pharmacologic therapy to prolong gestation and reduce the incidence of respiratory distress syndrome and intra-amniotic infection
Initiating tocolytic therapy when indicated
Establishing a plan of maternal and fetal surveillance with patient education to improve neonatal outcome
Mrs.Sujatha a primigravida is admitted at 30 weeks gestation with regular uterine contractions, pelvic pressure and cervix dilated to 2 cm. A diagnosis of pre-term labor is made.
- Explain the features of perterm labor
- Describe the measures to stop the contractions in order to continue her pregnancy to term
