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Saving Lives with Better Gestational Age Estimation

November 14, 2014

Complications from prematurity are now the number one cause of death in children under five.  While great strides have been made in reducing deaths from infectious causes—such as pneumonia, diarrhea and measles—progress has been slow in improving outcomes from preterm birth.

In developed countries, most pregnant women can rattle off their gestational age (GA) to the week, and their health practitioners estimate and record it to the day at every antenatal visit.  It’s reflex for health care workers in these settings to find out the GA of a patient presenting in triage or on the labor ward as one of their first courses of action.  This is because GA greatly impacts how maternal and newborn care providers team up to manage their patients and what treatment options they will consider. 

By contrast, when USAID’s flagship Maternal and Child Health Program (MCHIP) began a research project in Cambodia aimed at increasing the use of dexamethasone[1] in the management of preterm birth, staff discovered that many records didn’t include GA, and those that did estimated it to the month—not the week, let alone the day.  We found this trend repeated in country after country when we looked: at worst, no GA; at best an entire month given.

Unlike their counterparts in developed countries, women in these settings rarely know their GA to the week, and their health care providers may or may not estimate and record it at all.  This is in part because, until recently, they have had little reason to, as many of the interventions long in use in developed countries have been unavailable to them. Therefore, knowing a woman’s GA would not change their management plan.  The baby would come when it would come, and there was little they could do to help prepare it for life prematurely. 

However, as greater focus is being placed on addressing mortality in the neonatal period, that story is changing.  National health systems and development partners are collaborating to improve quality of care for prematurity by strengthening the use of certain key interventions in the management of preterm birth—including antenatal corticosteroids (ACS) for fetal lung development; continuous positive airway pressure to support inflation of underdeveloped preterm baby lungs; magnesium sulphate for neuroprotection; and antibiotics in the case of preterm, prelabor rupture of membranes to prolong pregnancy.

These lifesaving interventions will enable maternal care providers to reduce the complications of prematurity in newborns in low-resource settings, just as their counterparts do in the developed world.  In fact, MCHIP’s follow on project—the USAID-funded Maternal and Child Survival Program—is already leading an effort with the Survive and Thrive Global Development Alliance to create a clinical training package for the management of preterm birth under the Helping Babies Survive series. 

Yet a critical element necessary for the correct use of interventions for preterm birth management is accurate GA estimation, as highlighted by findings from the recent [2]  The authors found significantly higher mortality among infants given ACS and born with an estimated gestation ≥37 weeks.  This study does not negate the previous 21 randomized controlled trials, which found a 30% reduction in neonatal mortality when steroids are given to women at risk of imminent preterm delivery between 24 and 34 weeks gestation; rather it points, in part, to the need for careful and improved gestational dating. When an intervention is beneficial at 34 weeks, and potentially harmful at 36 weeks, estimation of GA as “eight months” simply isn’t accurate enough.

(Please see the statement from the UN Commission of Life Saving Commodities ACS Working Group for more details regarding the ACT trial and the programmatic and research implications.)

When used appropriately, ACS are still one of the most beneficial interventions to improve mortality in premature infants.  However, GA dating must be improved to ensure their judicious use.  Improving GA dating worldwide requires:

  • A clinical behavior shift among maternal and newborn health care providers to actively seek accurate GAs, and diligent recording of this information at each antenatal care visit (driven by the understanding that accuracy of dating is crucial for good clinical decision making in the effort to help save premature babies);
  • Better dating techniques and/or algorithms to support providers in estimating GA with imperfect information (driven by a combination of clinical and implementation research);
  • Judicious use of ultrasound to assist GA assessment when other techniques are not sufficient (driven by an understanding of the correct combination of clinical assessment and technology); and
  • A cultural behavior shift among pregnant women to seek antenatal care earlier and to take careful note of the date of their last menstrual period (driven by the knowledge and belief that early care in pregnancy and accurate knowledge of their gestational age may help their baby survive).

As we turn the spotlight to prematurity, we must also focus on better dating. This will ensure our interventions reach those who need them most, while upholding the most central tenet in medicine: do no harm.

[1] The most commonly used antenatal corticosteroid

[2] Althabe et al.  (Lancet, October 2014)

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