Preterm labor occurs after 20 and before 37 weeks’ gestation. Patients in preterm labor usually present with irregular, mild contractions, pressure in the pelvis, and vaginal discharge or spotting. However, the contractions often progress to become severe and regular, causing cervical dilation.

is regular, painful contractions leading to cervical change at <37 weeks gestation.

Common obstetric complication and a leading cause of neonatal morbidity and mortality

Risk factors include prior preterm deliveries, maternal diabetes, extremes of age, placenta previa or abruption, cervical insufficiency, multiple gestations, and maternal tobacco use. The risk for complications in the fetus increases the earlier the preterm labor begins, with these complications including respiratory distress syndrome, hypothermia, hypoglycemia, intraventricular hemorrhage, and necrotizing enterocolitis. Treatment of preterm labor includes tocolytic therapy, hydration, and bed rest. Corticosteroids are also given to promote fetal lung maturation if the gestational age is less than 34 weeks, and magnesium is added for neuroprotection in patients with a gestational age less than 32 weeks. For patients with a history of or at high risk for preterm labor and delivery, such as this patient, progesterone supplementation (eg, 17a-hydroxyprogesterone therapy) has been used with some success to prevent preterm labor. Progesterone supplementation is typically started at 16 to 20 weeks' gestation and continued until term. It is thought to inhibit uterine contractility in support of the developing fetus.

Preterm birth prevention

• Risk factors
• Fetal fibronectin

Evaluation includes the assessment of maternal and fetal vital signs, a speculum examination to determine whether the amniotic membrane has ruptured, and a digital cervical examination to assess cervical dilatation and effacement. Ultrasonography may also be performed to evaluate amniotic fluid volume and fetal positioning, in addition to testing for group B streptococcus (GBS), bacteriuria, drug use, and sexually transmitted infections. The risk to fetal survival is greater the earlier preterm labor occurs, with complications including respiratory distress, bronchopulmonary dysplasia, retinopathy of prematurity, intraventricular hemorrhage, neurodevelopmental delay, and a propensity for infections. Therefore, for patients at less than 34 weeks’ gestation, treatment includes a course of betamethasone to increase fetal lung maturity, tocolytics to delay delivery, magnesium for fetal neuroprotection, and prophylactic antibiotics against GBS.

Management of preterm labor depends on gestational age, with increased intervention required at earlier gestations due to the risks of neonatal prematurity.

In patients at <34 weeks gestation, management includes attempts to delay delivery and minimize neonatal morbidity and mortality associated with preterm delivery.

Preterm labor at ≥34 weeks gestation who have no contraindications to vaginal delivery (eg, placenta previa), receive expectant labor management.  In addition, patients in preterm labor may benefit from administration of antenatal corticosteroids (eg, betamethasone) to decrease the risk of neonatal respiratory distress syndrome; however, the use of corticosteroids after 34 weeks gestation is not universal.  Patients who are either group B Streptococcus positive or unknown require penicillin prophylaxis.

• IM betamethasone to promote fetal lung maturity (prevention of NRDS).

• Magnesium sulfate to decrease the risk of cerebral palsy (ie, fetal neuroprotection).

• Tocolysis details

• GBS intrapartum prophylaxis

• Inappropriate things to do in patient in preterm labor

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