From the Guidelines
Induction of labor at 38 weeks gestation in a woman with a suspected large-for-gestational-age (LGA) fetus poses a significant risk of cesarean delivery without reducing the risk of shoulder dystocia or newborn morbidity 1.
Key Considerations
- The patient's short stature of 5 feet 1 inch may increase the risk of shoulder dystocia and other complications associated with fetal macrosomia.
- The fetus's estimated weight of 8 pounds and the patient's 1 cm cervical dilation with a soft cervix may not necessarily require cervical ripening agents such as misoprostol.
- Oxytocin administration, typically initiated at a dose of 1-2 mU/min and titrated to achieve adequate contractions, may be considered to induce labor, but careful monitoring of fetal heart rate and uterine activity is essential to minimize the risk of complications 1.
Potential Complications
- Cesarean delivery: current evidence suggests that induction of labor at least doubles the risk of cesarean delivery without reducing the risk of shoulder dystocia or newborn morbidity 1.
- Shoulder dystocia: a significant risk associated with fetal macrosomia, particularly in patients with a short stature.
- Newborn morbidity: induction of labor may not reduce the risk of newborn morbidity, and careful consideration should be given to the potential risks and benefits of induction.
From the Research
Induction of Labor at 38 Weeks Gestation
- The decision to induce labor at 38 weeks gestation in a woman with a suspected large-for-gestational-age (LGA) fetus, weighing approximately 8 pounds, and 1 cm cervical dilation with a soft cervix, given her height of 5 feet 1 inch, should be made with caution.
- According to a study published in the Australian & New Zealand journal of obstetrics & gynaecology 2, the rate of vaginal birth following induction of labor at 38 or 39 weeks gestation varies widely according to the indication for induction, ranging from 54% when the indication is suspected large fetus to 82% when the indication is suspected fetal compromise.
- Another study published in the same journal 3 found that induction of labor at 38-39 weeks pregnancy was associated with a higher risk of cesarean delivery for suspected fetal compromise among young women (<30 years), potentially due to uterine hyperstimulation.
Risks and Benefits
- A study published in the American journal of obstetrics and gynecology 4 found that elective induction of labor at 39 weeks gestation was associated with a decreased likelihood of cesarean birth in nulliparous women, but an increased rate of operative vaginal birth.
- The same study found that elective induction at 39 weeks gestation was associated with a decreased likelihood of pregnancy-related hypertension in both nulliparous and multiparous women.
- However, another study published in the New England journal of medicine 5 found that induction of labor at 39 weeks in low-risk nulliparous women did not result in a significantly lower frequency of a composite adverse perinatal outcome, but it did result in a significantly lower frequency of cesarean delivery.
Considerations for Induction of Labor
- The American journal of obstetrics & gynecology MFM 6 study found that the use of mid-to high-dose oxytocin regimens for induction of labor in nulliparas at ≥39 weeks of gestation was not associated with a lower cesarean delivery rate or improved neonatal outcomes compared with the use of low-dose oxytocin regimens.
- The study also found that the use of mid- to high-dose oxytocin regimens was associated with a shorter duration of labor, but an increase in self-limited neonatal respiratory support.
- Therefore, the decision to induce labor at 38 weeks gestation should be individualized and based on the specific circumstances of each patient, taking into account the potential risks and benefits of induction, as well as the patient's preferences and values 5, 3, 2, 4.