ACOG recommendations for management of suboptimally dated pregnancies.

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The American College of Obstetricians and Gynecologists (ACOG) recently published its recommendations regarding management and delivery of pregnancies in whom the best clinical estimation of gestational dates is not confirmed in forthcoming March 2017 issue of Obstetrics and Gynecology Journal. 

ACOG has always strived to curb elective deliveries before 39 weeks of pregnancy and spread awareness among obstetricians about the negative effects of elective delivery before 39 weeks, which increases neonatal respiratory and nonrespiratory morbidities.[1] 

The article can be accessed here.

This topic was also debated at the ACOG Annual Clinical and Scientific Meeting 2016.[2]

The most accurate method of gestational dating is a first trimester sonography. As the woman advances into second and third trimester the reliability of USG for the purpose of dating decreases linearly.  Pregnancies without an USG performed to confirm or revise the gestational dating before 22 0/7 weeks are labeled as suboptimally dated.

The guidelines for management are:

1. The decision about timing the delivery in a suboptimally dated pregnancy should be based on the best clinical estimate of the gestational age.
2. There is no role for elective delivery in suboptimally dated pregnancies to avoid the neonatal morbidity because the pregnancy may be earlier in gestation than believed to be. Decision to administer antenatal corticosteroids should be based on the best clinical judgement if a woman with suboptimally dated pregnancy is identified to be at risk for preterm delivery.
3. Amniocentesis to determine fetal lung maturity should not be used to decide the time of delivery in suboptimally dated pregnancies because  it is not reliable in predicting pulmonary maturity and other non-respiratory outcomes.
4. A follow-up sonography after 3-4 weeks of the initial one is always advisable in women with suboptimally dated pregnancies. It helps to support the prediction of gestational dating as well as fetal well-being in terms of weight gain. If IUGR is suspected, a close surveillance with umbilical cord Doppler should be considered.
5. It is always difficult to manage a presumably late-term pregnancy that lacks accurate dating because of the risk of overlooking post maturity and associated fetal morbidity and mortality. Therefore, is advised to begin antepartum fetal surveillance at 39–40 weeks of gestation and to deliver at 41 weeks using the best clinical judgement because it could be more postdated than it is believed to be.
6. In women with suboptimally dated pregnancy with a previous history of low transverse C-section incision a trial of labor can be given based on the clinical assessment of gestational age. If a woman requests a repeat elective C-section, it should be planned around 39 weeks based on best clinical judgement.
7. Women with suboptimally dated pregnancy should be well informed about the risks of neonatal morbidity and mortality because of inaccurate dating.

The full text of the  journal article can be accessed here.  

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[1] https://obgynupdated.blogspot.com/2017/01/choosing-wisely-and-acog-advises.html

[2] https://obgynupdated.blogspot.com/2016/05/elective-induction-of-labor-iol-at-39.html

Vaginal fluid Interleukin-6 seems to be a promising non-invasive marker for the prediction of inflammation in amniotic cavity in PPROM.

Preterm PROM complicates 3% of all pregnancies and is responsible for one third of preterm labors which leads to significant fetal morbidity and mortality. [1]Once the membrane ruptures the protective and sterile environment of the amniotic cavity is breeched linking it to bacterial cervicovaginal flora. This increases the risk of amniochorial infection which in turn is responsible for fetal inflammatory response syndrome.

Obstetricians have to weigh the benefits of prolonging the pregnancy at the risk of intrauterine infection. vs active induction of  labor. Numerous biomarkers have been studied in predicting the occurrence of infection and decide the clinical course of the pregnancy.

Maternal serum markers are not much useful in prediction of the fetal inflammatory response; hence researchers have studied various biomarkers from vaginal fluid like tumor necrosis factor-α, metalloproteinase-8 (MMP-8), soluble HLA-G (sHLA-G) and interleukin-6.

A recent paper published ahead of print in July issue of American Journal of Perinatology concluded that MMP-8, IL-6, glucose, and lactate concentrations in vaginal fluid did predict poor neonatal outcome but it was not reach statistical significance. Only increased levels of metalloproteinase-8 (MMP-8) were associated with poor neurological outcome. [2]

A recent study published in the forthcoming issue of American Journal of Obstetrics and Gynecology aimed to determine the diagnostic indices and predictive value of vaginal fluid interleukin-6 concentration as a point of care tool(POCT) in predicting microbial invasion of the amniotic cavity(MIAC), intra-amniotic inflammation, and microbial-associated intra-amniotic inflammation in patients with preterm PROM.[3]

The researchers also intended to know the relationship between vaginal and amniotic fluid interleukin-6 concentrations in fresh unprocessed samples obtained simultaneously.

This prospective cohort study recruited 153 women with singleton pregnancy who had PROM at between 24+0 and 36+6 weeks. Preterm PROM was confirmed by examination with a sterile speculum to verify the pooling of amniotic fluid in the vagina.

Samples of vaginal and amniotic fluids were collected from posterior fornix and transabdominal. IL6 assessment was done in both fluids by lateral immunoassay.

The cut-off level to define Intra-amniotic inflammation for IL6 was ≥745 pg/mL.

Out of 153 women in the study, samples of vaginal fluid were obtained in 141 women. It was possible to predict the microbial invasion of the amniotic cavity, intra-amniotic inflammation or microbial-associated intra-amniotic inflammation by higher vaginal fluid interleukin-6 concentrations.

The levels of vaginal fluid IL-6 were higher than amniotic fluid IL-6 concentrations.

A IL6 level of ≥2500 pg/mL identified patients with MIAC, intra-amniotic inflammation, and microbial associated intra-amniotic inflammation. Levels of IL6 < 2500 pg/mL could 100 % exclude patients with microbial-associated intra-amniotic inflammation. These findings need future corroboration by larger studies and meta-analysis before a clinical recommendation is made.

This finding has very important clinical implications, because in future it can be used as triage, to decide the expectant vs active management of women with preterm PROM.

By using this easy, cheap, noninvasive and rapid method, women will be spared of the invasive procedure of amniocentesis to evaluate the intrauterine environment.

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[1] http://www.aafp.org/afp/2006/0215/p659.html

[2] http://www.ncbi.nlm.nih.gov/pubmed/27120475

[3] http://www.ajog.org/article/S0002-9378(16)30439-2/abstract