EGA >42°/7 2.85% 0.62%
Stillbirths 9/1000 5/1000 0.018
Neonatal deaths 13/1000 811000 .033
Vacuum delivery 11.3% 10.2% <0.001
Induction 28% 43% <0.001 aNational guidelines changed between epochs as described in text.
NS = not significant.
Data from Zizzo, 201n7.
at 41 weeks is from the randomized Canadian and American investigations cited earlier. No randomized studies have specifically assessed intervention at 41 weeks versus an identical intervention used at 42 weeks. A large Swedish multicenter randomized trial of more than 10,000 women at 41°1 weeks has been designed to address the question (Elden, 2016).
he American College of Obstetricians and Gynecologists (2016a) deines postterm pregnancies as having completed 42 weeks, namely, beyond 42°/7 weeks. There is insuicient evidence to mandate a management strategy between 40 and 42 completed weeks. hus, although not considered mandatory, initiation of fetal surveillance at 41 weeks is a reasonable option. After completing 42 weeks, recommendations are for labor induction as summarized in Figure 43-6.
When gestational age is uncertain, the American College of Obstetricians and Gynecologists (2017b) recommends delivery at 41 weeks' gestation using the best clinical estimate of gestational age. he College also recommends against amniocentesis for fetal lung maturity.
At Parkland Hospital, based on results from the trials just discussed, we consider 41-week pregnancies without other
FIGURE 43-6 Algorithm for management of postterm pregnancy. (Summarized from American College of Obstetricians and Gynecologists,o201o6d.) complications to be normal. hus, no interventions are practiced solely based on fetal age until 42 completed weeks. With complications such as hypertension, decreased fetal movement, or oligohydramnios, labor induction is carried out. It is our view that large, randomized trials should be performed before otherwise uncomplicated 41-week gestations are routinely considered pathologically prolonged. In women in whom a certain gestational age is known, labor is induced at the completion of 42 weeks. Almost 90 percent of such women are induced successfully or enter labor within 2 days of induction. For those who do not deliver with the first induction, a second induction is performed within 3 days. lmost all women are delivered using this management plan, but in the unusual few who are not delivered, management decisions involve a third-or even more-induction versus cesarean delivery. Women classiied as having uncertain postterm pregnancies are managed with weekly nonstress fetal testing and assessment ofamnionic luid volume. Women with an AFI ;5 cm or with reports ofdiminished fetal movement undergo labor induction.
Labor is a particularly dangerous time for the postterm fetus.
Therefore, women whose pregnancies are known or suspected to be postterm ideally come to the hospital as soon as they suspect labor. While being evaluated for active labor, we monitored electronically for variations consistent with fetal compromise.
During labor, the decision to perform amniotomy is problematic. Further reduction in luid volume following amniotomy can enhance the possibility of cord compression. Conversely, after membrane rupture, a scalp electrode and an intrauterine pressure catheter can be placed. These usually provide more precise data concerning fetal heart rate and uterine contractions. Amniotomy also aids identification of thick meconium.