Tying a mother’s drug use to death of her fetus is complicated

Friday, June 1, 2018 8:34 PM

One of my colleagues asked for advice after an unnamed “outside agency” requested an autopsy on a fetus stillborn to a mother who used illegal drugs. The implication was that someone within the agency was eager to charge the mother with a crime.

Like most medical examiners, such a request makes me uncomfortable – partly because the person making the request probably has unrealistic expectations.

Did a mother’s drug use cause the death of her fetus or not? That’s a difficult question to answer. Maternal drug use is widely touted as a statistical risk factor for fetal complications and death, but statistics don’t prove a connection in a given case. And even the statistics are uncertain. A 2012 journal article reporting on 412 mother/infant pairs found that babies of drug-using mothers were more likely to have relatively mild developmental issues. But this series, as well as several others, found no correlation between maternal drug use and fetal death.

Even after an autopsy, the cause of a stillbirth is often tough to figure out. Some drug-using mothers deliver normal infants. Some women who have never used illicit drugs deliver babies stillborn. Known or unknown genetic abnormalities of the fetus or mother, problems with the uterus or placenta, maternal illnesses whether recognized or not and lots of other factors can precipitate stillbirth. Some abnormalities can be identified at autopsy or through ancillary tests, but not all.

I was often left without a definitive cause of death after performing a fetal autopsy. So if I can’t identify or rule out other possibilities, how could I pin the death of a fetus on maternal drug use beyond a reasonable doubt? In most cases, there’s simply no way to achieve the level of certainty required for a court conviction.

It’s true that when a high level of drugs is found in the body of an adult who also has a potentially fatal disease, medical examiners comfortably assume that the drugs at least contributed to death. But for the death of a fetus, that assumption rests on shakier ground.

Would a fetus be more susceptible to a given drug level than an adult because of immaturity? Or less susceptible because the mother’s body assumes or assists some of her baby’s vital functions? Nobody really knows.

Medical examiners can prove whether drugs were present when an adult died. But the death of a fetus usually isn’t discovered until hours or days later, and delivery may not occur for days after that. There’s no way to tell exactly when the fetus died and therefore no way to correlate death with the timing and amount of maternal drug use.

At the federal level, the Unborn Victims of Violence Act, known as Laci and Conner’s Law, makes it a crime to harm a fetus during an assault on a pregnant woman. The “unborn child” is recognized as a potential homicide victim in 38 states.

But only a relatively small number of drug-addicted women have been prosecuted for the deaths of their fetuses. Presumably this is at least in part because many medical examiners, mindful of the scientific uncertainties, are reluctant to consider such deaths homicides or to testify in support of such prosecutions.

This reluctance has little or nothing to do with political or philosophical persuasions. It has a great deal to do with the fact that, when it comes to fetal death, medical examiners can be sure of far less than most politicians, prosecutors and parents think.

Dr. Carol J. Huser, a forensic pathologist, served as La Plata County coroner from 2003-12. She now lives in Florida and Maryland. Email her at