Is it safe to detox in pregnancy?

I was discussing this question recently with a colleague who pointed me to:


J Subst Abuse Treat. 2003 Jun;24(4):363-7.
Is opiate detoxification unsafe in pregnancy?
Luty J, Nikolaou V, Bearn J.
PMID: 12867211

This group in London treated 101 pregnant women for opiate withdrawal with a 21 day methadone taper.  This was  a retrospective case series of all admissions from 1988 to 1999. 

They noted 1 miscarrage out of 5 women in the 1st trimester, at 9 weeks gestation. The authors estimated with this tiny sample that the relative risk for miscarriage was 6.87 "compared to population norms."

There were no adverse events noted for the 54 women in the 2nd trimester.

There was one preterm delivery in the remaining women who were in 3rd trimester.  The authors believe this was within "population norms".  There is no comment about the gestational age or the baby's weight.  The authors state this was out of 57 "treatment episodes" suggesting several women were seen for more than one attempt.   

Of the 101 women who started the detoxification treatment, only 42 completed and only 8 were discharged to residential rehabilitation.

The authors tracked down delivery records for 28 women, out of 50 women who delivered in the 3 large obstetric centers associated with the study.  Mean weight at delivery was 2564 g (5 lbs 10 oz) with 7 babies less than 2500 grams.  Mean gestational age was 37.5 week.   None of these 28 women had entered a rehab program after discharge from the detox.   Of the 28 only 10 women had in fact completed the detox procedure and only 1 was abstinent at the time of delivery.

What can we conclude from this study?

A 21 day inpatient taper of methadone had dismal results.  Of the original 101 patients, only 42 women remained in treatment until the time of discharge. Only 8 were discharged to residential treatment. One of 5 first trimester women miscarried during the procedure.  One of 57 third trimester women delivered early during the procedure although the birth weight and gestational age is not given.

Of the small sample who's birth records they reviewed, the average birth weight was 5 lbs 10 oz and gestational age 37.5 weeks. Seven of the 28 babies were  below 2500g.  Only one woman was abstinent at the time of delivery.

The authors conclude "Methadone detoxification treatment was not associated with any increased risk of miscarriage in the second trimester or premature delivery in the third trimester." but it would be more reasonable to note that in this study methadone detoxification was not effective in promoting sobriety or abstinence and lead to poor birth weights.