ACOG updates its recommendations for estimating gestational age and due date: May 2017

http://www.ultrasoundpaedia.com/normal-1sttrimester/

Accurate gestational dating of pregnancy is very important for optimal maternal and fetal outcome.Throughout pregnancy decisions like ordering and interpreting lab tests, determining fetal growth and performing intervention to prevent preterm births or post-term pregnancies and associated morbidities are based on accurate dating.

Estimated Due Date (EDD)and current gestational dating should be documented on medical records and discussed with the patient as early as possible based on dates of Last Menstrual Period(LMP) and earliest available ultrasound in pregnancy.

A first trimester ultrasound can improve the accuracy of predicted EDD, even if date of LMP is known. Many women have irregular cycles, or falsely recall the date of LMP or have irregular ovulation, which is not considered when calculating the EDD by traditional method.

The American College of Obstetricians and Gynecologists, the American Institute of Ultrasound in Medicine, and the Society for Maternal–Fetal Medicine make the following recommendations regarding the method for estimating gestational age and due date:

A first trimester ultrasound of the embryo (up to and including 13 6/7 weeks of gestation) is most accurate for calculating or confirming the gestational age. Measuring the crown–rump length (CRL) is accurate up to ±5–7 days and it should be the mean of three discrete CRL measurements when possible.

If the pregnancy is the result of successful ART procedure, then the EDD is calculated based on age of embryo and day of transfer.

As soon as LMP and results of first trimester ultrasound are known, EDD should be calculated and recorded in medical records. It should also be told to patient and discussed with her.

Second trimester ultrasound for gestational dating (14 0/7 weeks to 27 6/7 weeks of gestation) is more complex and introduces more complexities and variability. It incorporates multiple parameters like the biparietal diameter and head circumference, the femur length and the abdominal circumference. The accuracy decreases as we progress further into second trimester, with a variability of ± 10–14 days at the end of second trimester.

Gestational age assessment by ultrasonography in the third trimester (28 0/7 weeks of gestation and beyond) is the least reliable method, with an accuracy of ± 21–30 days.

Pregnancies without an ultrasound examination that confirms or revises the EDD before 22 0/7 weeks of gestational age should be considered suboptimally dated and managed accordingly.

This document replaces the Committee Opinion Number 611, (October 2014).

The full text of the committee opinion can be accessed here. 

Choosing wisely and ACOG advises against non-medical indicated elective induction or C-section before 39 completed weeks.

choosing wisely, USA

Choosing Wisely campaign[1] was launched in April 2012 by the American Board of Internal Medicine Foundation, Consumer Reports, and nine medical specialty societies in guiding physician towards wise management of healthcare resources and to encourage patients to have conversation with physician about unnecessary tests, procedures and care.

Saving Healthcare Resources 

The campaign released a list of “Top Five” lists from nine founding specialty societies. Today More than 70 societies comprising over one million clinicians are now partners of the Choosing Wisely campaign.[2]

American College of Obstetricians and Gynecologists (ACOG)released a list of 10 ‘ Do’ and ‘Don’t’ for the physicians in February 21, 2013 and updated it again on August 24, 2016.

The first in the list is “Don’t schedule elective, non-medically indicated inductions of labor or Cesarean deliveries before 39 weeks 0 days’ gestational age.”

ACOG and Choosing Wisely strongly advises against elective delivery before 39 weeks as it is associated with increase in cognitive disorders and morbidity in the newborn. It further adds that delivery before 39 weeks should be only carried out based on clear indication that favors positive outcome for mother and fetus. A fetal lung maturity in the absence of clear indication is not the reason for delivering the baby.

The '39 weeks rule'

The 39-week rule is now a strict clinical guideline that is enforced by professional organizations, governmental agencies and the medical insurance industry in US. 

In November 2013, ACOG and Society for Maternal and Fetal medicine(SMFM) made a recommendation of replacing the use of “term” pregnancy which accommodated gestations between 37 wks to 42 wks with the following designations:[3]

•  Early term: 37 weeks through 38 weeks and 6 days

 •  Full term: 39 weeks through 40 weeks and 6 days

 •  Late term: 41 weeks through 41 weeks and 6 days

 •  Postterm: 42 weeks and beyond

These changes were made by growing research evidence, a part of which has been led by Eunice Kennedy ShriverNational Institute of Child Health and Human Development, indicating that key developmental process for the fetus continue well beyond 37 weeks till 39 weeks. They also advocated that “Babies born at or after 39 weeks have the best chance at healthy outcomes compared to those born before 39 weeks.”

It was seen that the percentage of infants born preterm declined for the seventh straight year in 2013. The NIH also published a report that shows a decline in induction of labor for singleton birth in year 2011 (23.7%) and 2012 (23.3%), after 20 years of consecutive increases. There was also a decline in Early Elective Deliveries across the UnitedStates, from 17% of babies in the United States were delivered before 39 weeks in 2010 to a sharp decline to 4.6% in 2013. 

But many researchers and clinicians across US are not in favor of strict implementation of the ‘39 weeks rule.’

Dr. Baxi from New York University Langone Medical Center in New York City opined that timing of delivery is refined decision depending on many variable and it should be individualized per the circumstances and not governed by a rule.

Dr J.Nicholson is a strict opponent of  ’39 weeks rule’ and  says “the 39-week rule is not supported by high-quality evidence, its strict application unjustifiably obstructs patient autonomy, and it may actually cause harm in the form of early-term stillbirth. Because of these problems, the 39-week rule should be modified, made optional, or withdrawn. Patients should be able to request and receive early-term labor induction if they believe that such an intervention is in the best interest of themselves and/or their fetus.”[4]

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[1] http://www.choosingwisely.org/about-us/

[2] http://www.choosingwisely.org/about-us/history/

[3] http://www.acog.org/About-ACOG/ACOG-Departments/Deliveries-Before-39-Weeks

[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4402696/

Combination of labor induction agents almost halves the time to delivery.

The cascade of spontaneous events that sets the wheels of labor in motion has remained a mystery despite all the recent advances in the field of maternal and fetal medicine. Researchers hypothesize that it’s blend of physiology and magic that sets the ball rolling. Maternal and fetal signals both play a part in starting the process.

The history of labor induction dates to time of Hippocrates' when mammary stimulation and mechanical cervical dilatation was used to bring about uterine contraction.[1]

Induction of labor for singleton births has seen a slight decline from 23.8% in 2010 and 23.3% in 2012 after seeing a steady increase in past 20 years. [2]  This translate to 932,000 women undergoing induction of labor for various maternal and fetal indication.

Various mechanical and chemical methods singly or in combination have been in use since long. The choice of method depends on state of cervix, previous obstetric history, indication of induction and gestational age at induction. Foley’s balloon catheter, Prostaglandin E2 and misoprostol are common methods used for cervical ripening. Amniotomy and oxytocin are used when the cervix is already ripened.[3]

A recent paper published on November 03, 2016 in Journal of Obstetrics & Gynecology evaluated the effectiveness of the four most commonly used method. [4] The paper was also presented at the Pregnancy Meeting, the 2016 Annual Meeting of the Society for Maternal-Fetal Medicine (SMFM).

Dr. Lisa Levine, MD, University of Pennsylvania’s Perelman School of Medicine, Philadelphia, Pennsylvania, and colleagues said in their presentation “This randomized trial is one of the first of its kind to compare 4 different induction methods in a head-to-head trial. We found that combination induction methods resulted in delivery in half the amount of time as single agents with no difference in caesarean delivery rates.”

The study called as Foley or Misoprostol for the Management of Induction (FOR MOMI) trial was a 4-armed randomized trial conducted between May 2013 and June 2015. The study recruited 492 women with singleton full-term pregnancy (37 weeks of gestation or greater), vertex-presentation, with no contraindication to vaginal delivery, intact membranes, Bishop score 6 or less, and cervical dilation 2 cm or less. These women were assigned to receive either misoprostol alone; or Foley catheter alone; Foley catheter and Pitocin concurrently or misoprostol and cervical Foley catheter concurrently.

The primary outcome measured was reduction in time to delivery with a reduction of more than 4 hours considered significant. Numerous secondary outcomes like time to vaginal delivery, rate of caesarean deliveries, time in active labor, defined as cervical dilation of 5 cm or more, delivery within 12 or 24 hours, and maternal length of stay were also looked at.

The demographics and clinical characteristics of the study participants were quite similar with a mean age of 27 years, 72% being nullipara, mean gestational age at induction being 39 weeks with mean bishop score 3 and mean cervical dilatation 1.

The median time to delivery for nulliparous and multiparous women in various arms of the study are (P<.001):

misoprostol–Foley group       13.1 hours

oxytocin–Foley group            14.5 hours

misoprostol only                    17.6 hours

Foley-only group                   17.7 hours

When the data was adjusted for parity and only vaginal deliveries analyzed, women in the misoprostol-Foley group where twice as likely to deliver earlier (HR=1.92) with reference to misoprostol only or Foley-only group.

  

Women in the combination arms of the study also had the maximum chance of delivering in 24 hours. (88% of women in the misoprostol/Foley group and 84% in the oxytocin/Foley group).

Rates of cesarean section and other maternal morbidities like perineal lacerations, endometritis, wound infection and dehiscence, readmission or length of stay were comparable in all the groups. No significant difference was found in neonatal morbidities too.

The authors opined that “This study has significant clinical implications for obstetric care. The ability to shorten the length of time women spend in labor without increasing morbidity has large clinical and financial implications given the cost and known maternal–neonatal risks associated with both prolonged labor and cesarean delivery."

The only study limitation was lack of blinding, because women had to be examined for application of different methods in 4 study arms. Also, individual arm lacked the statistical power to compare the cesarean section, maternal and neonatal morbidities across different groups.

In all, the findings could help millions of women and shorten thousands of hours in labor across the world. It is estimated that nearly 20% or 932,000 women undergo induction of labor in USA. If combination method is used in all of them, then there would be more than 3 million fewer hours, or more than 125,000 fewer days that women spend in labor in the United States alone. 

This has huge financial and health care utilization implications.

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[1] www.glowm.com/section_view/heading/Induction%20of%20Labor/item/130

[2] http://www.cdc.gov/nchs/data/databriefs/db155.pdf

[3] https://sogc.org/wp-content/uploads/2013/08/September2013-CPG296-ENG-Online_REV-D.pdf

[4] http://journals.lww.com/greenjournal/Abstract/publishahead/Mechanical_and_Pharmacologic_Methods_of_Labor.98564.aspx