Harmful effects of Brethine

Specialties Ob/Gyn


Gotta que. We have a doc that swears the adverse effects on the fetus/neonate are far worse than the benefits of giving it for PTL. Says it causes brain hemorrhage and seizures. Been giving brethine all my yrs of OB..never had a fetus to seize after giving it. We think he is crazy..but i need info from you to confirm it or exonerate him for good.

Also besides tachycardia and the routine flushed, sweaty, dyspnea, weak feelings brethine can give you..anyone know any other side effects to mom or fetus?


231 Posts

I have given it in practice and had it as a pt in both of my pregnancies. Thankfully this stuff worked without resulting in me ending up on MgSo4. So my thought is that it is good stuff, tachycardia and palps, are a small price to pay for stopping PTL, esp. if it is firstline. The MDs concerns are odd, what about the effects of MgSo4 on both fetus and mom? Is that what he goes to as firstline?

I have however read about the intercranial hemorrhage in the neonate in something a while ago. From what I recall it had to do with the gestation of the pregnancy. Something along the lines of under 20 wks, when the brain developement is in full force. Since it does cause tachycardia in mom/fetus, maby it has to do with the early brain developement, high heart rate=high pressures on the arterio-venous system in the early brain. That I could possibly rationalize, but on a 28 wker? Never heard of any problems and have seen it given in 24+ wks. Wish I could remember the source of the article, it was awhile ago..

What do you all think???


32 Posts

Specializes in Labor and Delivery.

thanks for your input..he doesnt want to use mag or brethine. but brethine is his big kick. takes everyone off it that his partners puts on it prenatally. wish you knew the source of that article. would enjoy reading about it.

Jolie, BSN

6,375 Posts

Specializes in Maternal - Child Health.

What in the world does he put them on?

I went into pre-term labor at 25 weeks with my first, and 22 weeks with my second. Both OB groups were hesitant to start Brethine too early, for fear that it would quit working too soon, leaving only MgSO4, but because my cervix was changing, we felt we had no choice. I used po Brethine with my first, and the pump with my second, and much preferred the pump. No waking up every 2 hours for meds, and with a lower continuous dose, the side-effects were much less.

I did require several MgSO4 "washouts" with each pregnancy, and based on the side-effects of that miserable drug, I'd take Brethine any day!

I was referred to a perinatologist who sounds like your colleague. He advised me to go off all my meds, and just have my cervix checked once a week to monitor my progress. I was 28 weeks at that point, 4cm dilated, and a +1 station. What a b**b! I wouldn't have needed my cervix checked. We would have known what it was when the baby delivered in the car on the way to the hospital!

At any rate, I carried my girls to 37 and 36 weeks respectively, fully aware that there were potential side-effects, but willing to accept them, as they were preferable to all the complications of prematurity.

I sure hope your doctor is giving his patients beta-methasone, at the very least!


350 Posts


brethine....& its side effects...........


preterm baby in NICU............



1,804 Posts

I don't know about the neonatal article w/ intracranial hemmorhage, but I did take care of a woman in her late 30's or early 40's who had some pulmonary edema and possibly needed a new (pulmonic-I think) valve related to an arrhythmia caused by terb. She had a pre-existing defect and the pregnancy and fast HR caused by the terb were too much for her. She had to have a swan-ganz in for delivery and was told no more kids. At one time, I remember reading that older gravidas should have an EKG before terb is started, but docs almost never seem to do this.


195 Posts

that's why getting a good history BEFORE giving terb is a good idea, any hx of heart problems, we don't give it......


1,378 Posts

Sounds like he and his partners need to be on the same page. Are you all aware that there is a new test for preterm labor so that much LESS brething can be used? It's called FETAL FIBRONECTIN. If negative, there is little to no chance of preterm labor (for a given amount of time, which I cannot remember right now). It has DECREASED our use of brethine and terb greatly. maybe you should ask that doctor about that.


82 Posts

We use fetal fibronectin but it has not been 100% accurate either. We start with Brethine and move into Mag if not successful. Our biggest issue is poor compliance by the patients when they go home. "I didn't like how it made me feel". Maybe they'd like to spend months in NICU instead. Drives me crazy that how "I" feel is more important than the health of my baby.


20,964 Posts

Specializes in Specializes in L/D, newborn, GYN, LTC, Dialysis.

Ffn is not 100%, like said above, but we do use it to try to "predict" who will likely go into PTL or not....

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