Data issues #2: On underestimating NNMR.

Subject at hand today: neonatal mortality rates (NNMR). Neonatal mortality is one of five infant and child mortality rates reported in Demographic and Health Surveys (DHS).  NNMR is defined as the number of deaths during the first 28 completed days of life per 1,000 live births* in a given year, effectively estimating the rate of infant deaths in the first month of life.

In DHS and other national health surveys, female respondents are asked a series of questions about each child the woman has given birth to in her lifetime, which are reported based on when the birth happened (five year intervals preceding the survey). A woman is able to report if a child she gave birth to passed away, and when the child passed relative to the date of birth.

But what about children born to a woman who dies a maternal death? Given the high maternal mortality ratios (MMR; number of maternal deaths per 100,000 live births) in many developing countries, it would logically follow that at least some neonatal deaths would follow maternal deaths, and would go uncounted.

A coworker of mine picked up on this issue, and, after talking to a few others from BUSPH about it, I found out that it seemed to be common knowledge that these neonatal deaths would go uncounted. In a rough estimation from a professional who works on the DHS, neonatal deaths are underestimated by as much as 10 percent – and while the rate may not seem too different (29 per 1,000 versus 32, perhaps), the percent change is worthy of note.

My question, then, is why, in thirty years of DHS surveys and revising the questionnaire, have we not found a way to count those children? We use the sisterhood method to estimate MMR; could we not ask if a child born by the woman who passed away had died too? These deaths also factor into the infant and under-five mortality rates as well, but have less of an effect on the numbers. I know national surveys are complicated and that this post underestimates the complexity of resolving this issue, but it doesn’t seem right to systematically underestimate NNMR.

If you want to read more from the WHO on NNMR, it can be found here.

*Live births are technically defined as “the complete expulsion or extraction from its mother of a product of conception, irrespective of the duration of the pregnancy, which, after such separation, breaths or shows any other evidence of life – e.g. beating of the heart, pulsation of the umbilical cord or definite movements of voluntary muscles – weather or not the umbilical cord has been cut or the placenta is attached. Each product of such a birth is considered live born.”

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