Ensuring that pregnant women take essential micronutrient supplements can dramatically improve the health of mothers and babies.

But in many parts of rural Ethiopia – where two-thirds of women of reproductive age face micronutrient deficiencies linked to adverse pregnancy outcomes – resource constraints often make it difficult to track whether supplements are taken as prescribed.

Tracking whether women actually take the supplements they receive, known as measuring “adherence,” can be both costly and complicated. Yet without reliable data, it’s hard to know if programs are working – and women are taking the supplements they need during pregnancy.

A new study from the Johns Hopkins Center for Communication Programs, presented at the American Public Health Association Annual Meeting in early November, offers a practical solution, one that balances scientific rigor with the realities of limited resources.

Around the world, the most common way to check whether people are taking their supplements is by counting the pills that remain after they’ve been given out, a method known as the “pill count.” But that approach is difficult to apply in Ethiopia’s rural health system, where time, training, and equipment are scarce.

“Pill count is a better and reliable measure of adherence, but it’s less feasible and less cost-effective, in a context like ours,” says CCP’s Habtamu Tamene, senior director of research, monitoring and evaluation in Ethiopia, “It requires devices and proper training. And, after the count, pregnant women may not feel comfortable consuming pills that have been counted by others due to hygiene concerns.”

To find a more realistic alternative, researchers followed 1,243 pregnant women attending health centers in eight rural districts. Each woman received 180 multiple micronutrient supplement (MMS) pills, enough to last her entire pregnancy. The study was supported by the Gates Foundation’s Optimizing Adherence for Nutrition Supplements in Ethiopia project.

The team compared four recall methods – asking women how many pills they had taken over the past day, week, month, or since they received the pills – against actual pill counts. Using robust statistical analysis, they assessed which method best reflected true adherence.

By pill count, only 49 percent of women took at least 65 percent of their recommended dose. The literature suggests that 65 percent is a reasonable benchmark, given the low adherence to nutrition supplements typically seen among pregnant women in Ethiopia.

When women self-reported, adherence estimates rose from 54 percent to 82 percent, suggesting that recall methods tend to overestimate adherence.

But one option stood out. The 30-day recall method emerged as the most reliable, with what the study called “a fair level of adherence, both sensitivity and specificity.”

Overall, method struck a good balance between being accurate enough to trust and simple enough to use in the field.

Shorter recall periods, like “yesterday” or “last seven days,” didn’t perform as well, likely reflecting normal variations in daily routines and memory.

“Improving maternal nutrition isn’t only about distributing pills,” Tamene says. “It’s about making sure they’re taken consistently. By testing cost-effective ways to track adherence, Ethiopia’s health programs now have new evidence to guide their work.”

The implications are clear, the researchers say. In settings where pill counting is too costly or logistically impossible, the 30-day recall method provides a credible, low-cost way to monitor supplement use.

“This method doesn’t require specialized tools or extensive training, just thoughtful conversations with pregnant women during regular health visits,” said CCP’s Tewabech Tesfalign, a project director in Ethiopia.

“This is a valuable lesson for other organizations. Measuring adherence doesn’t have to be expensive, and it proves to donors and partners that real impact is possible even in low-resource settings.”

“Evaluating the Validity of Adherence Measurement Methods for Multiple Micronutrient Supplementations (MMS) among Pregnant Women in Ethiopia” was written by Habtamu Tamene, Yihunie Lakew, Nandita Kapadia-Kundu, PhD, Simon Heliso, Biruk Melaku and Maria-Elena Figuera, PhD.