The American Congress of Obstetricians and Gynecologists has recently updated two Practice Bulletins and a Committee Opinion on interrelated topics: Premature Rupture of Membranes, preterm labor management, and the use of magnesium sulfate to stop preterm labor. We have provided a summary of each highlighting the new recommendations as well as background on the topic.
All three documents have been updated to reflect a very specific change in the recommendations for the administration of corticosteriods to support lung development in the baby before birth. ACOG recommends a single course of corticosteriods between 24 and 34 weeks gestation. This change comes in part following the joint Obstetric Care Consensus document from ACOG and the Society for Maternal-Fetal Medicine on Perviable Birth released last year.
Premature Rupture of Membranes – Practice Bulletin Interim Update
ACOG states that the course of care when a woman’s water breaks before labor begins (the definition of PROM) should be determined based on an accurate assessment of gestational age, the status and progression of labor, infection and risks to mother and baby. Evaluation and counseling are the first course of action. The Practice Bulletin notes that Premature Rupture of Membranes occurs in approximately 8% of pregnancies and labor generally begins quickly after the water breaks. Infection is the most common complication of Premature Rupture of Membranes occurring in 15 -20% of cases. ACOG recommends hospitalization and surveillance (their word) of both mom and baby with PROM citing insufficient research to support “outpatient management”. Additional care guidelines include an initial period of fetal heart and contraction monitoring followed by periodic fetal heart tone monitoring. Induction of labor has been shown to reduce the length of labor, incidence of infection and admission to the Neonatal Intensive Care unit without increasing the risk of cesarean or vaginal operative delivery the Bulletin notes. Expectant management (allowing labor to progress on its own) may be acceptable, according to ACOG, if “clinical and fetal conditions are reassuring” and the mother is adequately counseled on the associated risks of prolonged PROM. There is insufficient evidence to support the administration of prophylactic antibiotics except in the case of patients who are GBS positive.
ACOG has issued an Interim Update to this Practice Bulletin “to reflect a limited, focused change”. In this update, the guideline has been changed regarding:
Antenatal coricosteroids are now recommended for the following gestational ages:
- Between 24 weeks, 0 days and 34 weeks, 0 days
- May be considered as early as 23 weeks, 0 days for those at risk of preterm birth
Course of care in previable period (before 23 weeks, 6 days):
- Antibiotics not recommended except to prolong the pregnancy when the patient has chosen expectant management
- Tocolysis (medications to stop premature labor such as magnesium sulfate) not recommended
Management of Premature Labor – Practice Bulletin Interim Update
Preterm labor is defined as contractions which create cervical change between 20 and 37 weeks of pregnancy. Preterm labor does not always lead to preterm birth, with 50% of women hospitalized with preterm labor giving birth after 37 weeks (term). Preterm birth is associated with a number of risk factors including long-term impairment, neonatal and infant death. While bed rest has historically been recommended for preterm labor, ACOG notes that evidence does not support its effectiveness. The suggested course of treatment includes tocolytic drugs such as magnesium sulfate to stop contractions and corticosteriods to support the baby’s lung development. Magnesium sulfate is also administered for its benefits in supporting the baby’s brain health. Antibiotics are not recommended without clinical indication of infection.
In this Interim Update, changes have been made to align with the PROM Practice Bulletin Interim Update:
- Single course of antenatal corticosteriods for pregnancies between 24 and 34 weeks gestation at risk of preterm birth within 7 days
- Antenatal corticosteriods may be considered as early as 23 weeks
The Management of Premature Labor Practice Bulletin has also been updated to recommend:
- Considering an additional course of antenatal corticosteriods if the first course was given at least seven days ago, the risk of preterm birth remains and the pregnancy is less than 34 weeks along
Magnesium Sulfate Use in Obstetrics – Committee Opinion Interim Update
Magnesium Sulfate offers two benefits in the case of preterm labor – stopping contractions and reducing the incidence of cerebral palsy in babies. Magnesium sulfate and other tocolytic medications are often used to stop labor long enough for the administration of corticosteriods before birth. ACOG and the Society for Maternal-Fetal Medicine support the use of magnesium sulfate for up to 48 hours. The U.S. Food and Drug Administration advises against providing magnesium sulfate for more than five to seven days out of concern that long term exposure to magnesium sulfate can lead to neonatal bone demineralization and fractures. The Committee Opinion notes that these risks are associated with cases where the averaged exposure to magnesium sulfate was 9.6 weeks which is considered nonstandard use of this medication.
The Committee Opinion on magnesium sulfate has been updated to reflect the changes to the Practice Bulletins on preterm labor and Premature Rupture of Membranes:
Magnesium Sulfate is recommended:
- Between 24 and 34 weeks of pregnancy
- When there is a risk of preterm birth within 7 days
Note: Practice Bulletins and Committee Opinions are guidelines for practitioners about specific conditions and care options for treatment. ACOG is clear that these recommendations do not dictate a specific course of care and that care providers should create a course of treatment based on the patient’s unique needs, the resources available to the provider, and any limitations based on where or how they practice.
— Adrianne Gordon, CD(DONA), MBA
Premature rupture of membranes. Practice Bulletin No. 160. American College of Obstetricians and Gynecologists. Obstet Gynecol 2016;127:e39–51.
Management of preterm labor. Practice Bulletin No. 159. American College of Obstetricians and Gynecologists. Obstet Gynecol 2016;127:e29–38.
Magnesium sulfate use in obstetrics. Committee Opinion No. 652. American College of Obstetricians and Gynecologists. Obstet Gynecol 2016;127:e52–3.
Periviable birth. Obstetric Care Consensus No. 3. American College of Obstetricians and Gynecologists. Obstet Gynecol 2015;126:e82–94.