Labor induction is a medical procedure that artificially stimulates the uterus to begin contractions before labor starts naturally. A pregnancy at 35 weeks is categorized as “late preterm,” spanning 34 weeks through 36 weeks and six days of gestation. While babies born at 35 weeks have a high chance of survival, doctors generally seek to delay delivery to allow for further fetal maturation. Induction at this stage is never performed electively or for convenience. It is undertaken only when continuing the pregnancy poses a greater, immediate danger to the health of the mother or the fetus than the risks of early delivery.
Medical Reasons for Induction at 35 Weeks
Induction at 35 weeks is reserved for serious medical conditions where the intrauterine environment is no longer safe. Primary indications include severe hypertensive disorders, such as severe preeclampsia or HELLP syndrome, which threaten the mother’s organ systems. These conditions involve dangerously high blood pressure and can rapidly progress to seizures or liver failure, making immediate delivery the only treatment.
Another serious concern is the compromise of placental function, leading to Fetal Growth Restriction (FGR) or Intrauterine Growth Restriction (IUGR). When the placenta fails to supply adequate oxygen and nutrients, the fetus is considered safer outside the womb. Similarly, a placental abruption, where the placenta prematurely separates from the uterine wall, causes severe maternal hemorrhage and acute fetal distress, demanding urgent delivery.
Other conditions, such as uncontrolled maternal diabetes or severe oligohydramnios (dangerously low amniotic fluid), can also necessitate early delivery. When these severe conditions are present, the potential for complications is lower with a late preterm birth than with continued management. The goal shifts from maximizing gestational age to minimizing the immediate risk of harm.
Understanding Fetal Development at Late Preterm
While 35 weeks is close to full term, a baby born at this stage is still medically premature and may face unique challenges. The primary concern is lung maturity; the lungs may lack sufficient surfactant to prevent Respiratory Distress Syndrome (RDS). RDS requires the baby to receive breathing support and is the most common reason for a Neonatal Intensive Care Unit (NICU) admission for late preterm infants.
Babies born at 35 weeks also have less coordinated neurological function, affecting feeding and temperature regulation. They often struggle to coordinate the suck, swallow, and breathe reflexes required for successful oral feeding. Additionally, late preterm infants have less body fat and an immature central nervous system, making it difficult to maintain a stable body temperature without assistance.
These infants are at a higher risk for other transitional problems, including hypoglycemia (low blood sugar), jaundice, and apnea (pauses in breathing). Although survival rates are high, the risk of serious medical complications and a prolonged hospital stay is greater compared to babies born after 39 weeks.
Monitoring Instead of Immediate Delivery
When a complication is identified but is not immediately life-threatening, the medical team may opt for expectant management. This approach involves intensive surveillance to safely prolong the pregnancy, allowing the fetus more time to mature. This is important when the risk of early delivery temporarily outweighs the manageable risk of continuing the pregnancy.
Expectant management protocols involve frequent, detailed testing to monitor fetal well-being. These tests include the Non-Stress Test (NST), which records the fetal heart rate response to movement, indicating adequate oxygenation. Another element is the Biophysical Profile (BPP), a scoring system using ultrasound to assess fetal breathing, body movements, muscle tone, and amniotic fluid volume.
The BPP is typically performed once or twice a week, depending on the underlying condition. This close monitoring allows clinicians to detect subtle signs of fetal compromise before a medical emergency occurs. If monitoring results deteriorate, it signals that the benefits of intervention now outweigh the benefits of continuing the pregnancy.
Weighing Risks and Informed Consent
The decision to induce labor at 35 weeks requires a thorough risk-benefit discussion with the expectant parents. This process mandates informed consent, ensuring parents understand the risks of immediate delivery (e.g., respiratory issues) versus the risks of continuing the pregnancy (e.g., stillbirth or maternal organ failure). The conversation must clearly delineate whether the induction is primarily for maternal or fetal benefit, as this influences the urgency and management plan.
In anticipation of induction, a single course of antenatal corticosteroids, such as betamethasone, may be administered. This medication accelerates the production of surfactant in the fetal lungs, reducing the likelihood and severity of respiratory distress after birth. Although the strongest evidence for corticosteroids is for earlier preterm births, a benefit is still considered for those delivering between 34 and 36 weeks and six days.
The medical team must document a compelling reason for delivery before 39 weeks, adhering to established clinical guidelines. This ensures that the intervention is a necessary response to a dangerous situation and not an elective choice. The informed consent process reconciles the medical necessity of intervention with the potential developmental risks to the late preterm infant.