I did my L&D training in the East Bay Area of San Francisco.
One of the routine practices, although not approved by the FDA, was the "off label" use of Terbutaline or "Brethine" (bronchodilator) to treat pre-term Labor.
We gave sub-q injections, followed by oral pill form when stable, as routine practice.
I never really questioned it at the time because that was the standard protocol we would follow for preterm labor in those days.
When I moved back to Canada, I noticed the
glaring absence of Terbutaline on the labor units. In fact, none of the gals I worked with had even
heard of it.
I asked one of the OB docs why it wasn't used in Canada. At the time, his reply shocked me.
"
Because" he stated, "
it isn't proven to be effective in stopping labor."
I can only speak for British Columbia, but as a practice, the primary treatment for preterm labor seventeen years ago when I moved back to Canada, was the administration of fluids and
Indomethacin or perhaps
nifedipine -
in the five different hospitals I worked. We may have even used MgS04 a time or two before it went by the wayside. "Bedrest" was a joke, really.
I remembered back to my California days when we would care for pregnant moms-to-be in what was classified as "Preterm labor". The monitor recorded "contractions" would quickly smooth out with the administration of Terbutaline. So really, what was it doing, if it wasn't stopping preterm labor?
I suppose a clue can be found in this question -
What is the definition of preterm labor?
True Preterm Labor is gauged
only by the progressive change in the cervix by contractions (between 20 and 36 weeks gestation) -
not by the contractions alone.
When a health care worker is assessing contractions, it is necessary to palpate contraction strength with
hands on the abdomen and actually
feel them. The appearance of the bumps on the monitor isn't an indication of their strength - and yet how often do we see this as the sole determination of contractions?
There is debate that the contractions appearing on the monitor that were "smoothed out" by the terbutaline were even strong enough to do anything in the first place. Basically, what we were actually doing with the "Terb", is getting rid of the irritability that was appearing so the mom didn't have to be kept in the hospital any longer than necessary. No contractions = discharge = less expense.
The truth about terbutaline is that there is a lack of controlled studies that support the use and it may even do harm.
So how do we treat preterm Labor?
In B.C. there has been an increase in the number of preterm births - especially noted in the 33 to 36 wk age group, immature lung development being the most challenging problem as a result.
Because of the advanced maternal age of the women giving birth in recent years, and also the fact that older moms have a higher instance of multiple births which in turn are also are more susceptible to preterm birth... it makes sense that the statistics have been on the rise.
But - guess what?
"
Clinical trials have not been able to demonstrate a reduction in preterm births from the following prevention strategies: home uterine activity monitoring, frequent digital cervical exams, bedrest for twin pregnancies, tocolytics, and education about the signs of preterm labor among women with identifiable risks."
So, as far as tocolytics go, according to our province's policy for Perinatal Services in B.C., "
there is no evidence demonstrating that the use of tocolytics to arrest preterm labor results in a reduction of preterm mortality" - both long and short term administration.
In our province, the only tocolytic recommended is Indomethacin - and only up to 32 weeks gestation - and the primary aim in its administration is to give Betamethasone a chance to mature a baby's lungs and to ensure a safe transfer to a facility that can adequately care for the premature infant.
I can remember a brief time when Magnesium Sulphate (MgS04) was given for pre term labor. It has since been shown to not only be an ineffective tocolytic, but its use is associated with an increase in mortality for the infant. It is strongly advised by BC Perinatal Services
not to use MgS04 as a tocolytic.
Another medication I have seen used is nitroglycerin. Apparently there is no evidence supporting the use of nitro as a tocolytic either.
When I worked south of the border, every woman who walked in through the door in preterm labor had an IV started. Surprisingly, there is no evidence supporting IV hydration to prevent or arrest preterm labor.
Definitely it can benefit a woman who is dehydrated, which, when I lived in a very hot area of Canada in the summer, we would see plenty of those. In the hospitals I worked in North of the border, we were more likely to hand them fluid to drink rather than an IV infusion.
One will find that bedrest is still recommended for those singleton moms in preterm labor, both sides of the border - either at home or in the hospital. Interestingly, there is no evidence for or against bedrest in the prevention of preterm births.
Even for twin pregnancy - there is no evidence supporting routine hospitalization for bedrest in the prevention of preterm birth - and until there is a study that shows otherwise, BC perinatal policy states there is no indication for this practice as routine.
So, what is left if nothing really works?
Basically, the use of cervical ultrasound and the use of fibromectin test are useful in
identifying those moms in preterm labor who need to be stabilized and transported (with infant in utero) to a facility that can adequately care for a premature infant and the results can possibly be used to reduce the number of interventions done to the woman - such as the unnecessary use of tocolytics for those not at risk and more appropriate identification of those who can benefit. Read
here for the discussion on this (5.3 and 7.2).
So - what do we do when we know that evidence based medicine is
best ? When what we have done in the care of pregnant woman for
since forever is not what research shows we should be doing?
Why are clinical trials and research done if it isn't going to change the way we do things?
*********************************
Thanks to the BC Perinatal Health Program for the information online.
