Summary
Highlights
The video is a continuation of a series on pregnancy complications, shifting focus to the intrapartum phase, which specifically addresses labor and delivery. The first complication discussed is preterm labor.
Preterm labor is defined as the onset of labor between 20 to 37 weeks of gestation. Various factors can predispose a woman to preterm labor, including conditions affecting the placenta, such as pre-eclampsia, diabetes, cardiac disease, and adolescent pregnancy. Infections, particularly UTIs, can also trigger preterm labor due to bladder spasms stimulating uterine contractions. Over-distension of the uterus from multiple gestations, polyhydramnios (excess amniotic fluid), or a large gestational age baby can also lead to preterm labor. Psychosocial factors like stress, having multiple young children, financial stress, or lack of support are also implicated. Smoking and substance use (cocaine) cause vasoconstriction, impacting placental blood supply, leading to intrauterine growth restriction and potentially preterm labor. Other factors include short cervix and placental bleeding (placenta previa, abruptio placentae).
The chances of survival for neonates in preterm labor are best if the baby weighs over 2000 grams or is more than 32 weeks gestational age. Babies born prematurely often face significant medical issues, primarily cardiorespiratory problems like respiratory distress syndrome, due to immature lungs. Even if these immediate issues are overcome, long-term neurodevelopmental problems, such as autism or mental retardation, can manifest later in childhood. Preterm labor is defined as more than five contractions per hour with cervical changes, indicating that intervention is required.
Prevention of preterm labor involves early recognition and diagnosis, addressing lifestyle factors like smoking and stress, and activity restrictions, including complete bed rest and sexual activity restrictions. In the hospital, IV hydration can sometimes stop contractions. Tocolytics like terbutaline (which can cause maternal tachycardia) and magnesium sulfate (a CNS depressant requiring careful monitoring of urine output, respiratory rate, reflexes, and blood pressure) are used to halt contractions. Steroids, such as betamethasone and dexamethasone, are administered to accelerate fetal lung maturity, especially when the lecithin-sphingomyelin (LS) ratio indicates immature lungs. Steroids can increase the mother's risk of infection due to immunosuppression and hyperglycemia.
Induction of labor means initiating contractions when none are present, while augmentation means strengthening existing contractions that are not progressing adequately. Indications for induction/augmentation include intrauterine growth restriction (IUGR), uteroplacental insufficiency (like post-term pregnancy where the placenta ages), prolonged pre-rupture of membranes (PROM) without labor onset, chorioamnionitis (uterine infection), hypertension in pregnancy (PIH/eclampsia), and intrauterine fetal death (IUFD) to prevent disseminated intravascular coagulation (DIC) in the mother.
Before induction, the cervix must be 'ripe' (soft and ready), as assessed by the Bishop Score. Cervical ripening can be achieved using prostaglandins like Cytotec (misoprostol) and Cervidil (dinoprostone), which are inserted intravaginally. Other methods include stripping membranes (manual separation of membranes from the uterine wall), nipple stimulation (to release natural oxytocin), and artificial rupture of membranes (AROM), followed by oxytocin (Pitocin) administration.
When administering Pitocin for induction, it is given via IV infusion (typically in D5 LRS with 10 units of oxytocin). Crucially, the nurse must constantly monitor fetal heart rate (watching for decelerations) and uterine contraction characteristics (duration, frequency, interval). Contractions lasting over 90 seconds or occurring too frequently (less than 2-3 minutes apart) are dangerous and may indicate uterine tachysystole or hyperstimulation, which can lead to fetal distress and uterine rupture. Maternal vital signs must be checked every 15 minutes. Pitocin should be delivered using an infusion pump for precise titration. If uterine hyperstimulation or fetal distress occurs, immediate interventions include stopping Pitocin, repositioning the mother (preferably left side-lying), administering oxygen by face mask (8-10 L/min), and increasing IV fluid flow. Oxytocin also has an antidiuretic hormone (ADH) effect, so monitoring urine output (30-60 ml/hour) is important to prevent water intoxication and hyponatremia. All actions must be documented on the monitor strip.