heart medication during pregnancy

[Hajnalka]

I am a 31 year old female, in relatively good physical shape and of normal weight. During my pregnancy two years ago I started to have ‘episodes’ of PSVT (with symptoms of a heart rate of around 220 beats per minute, dizziness, sudden pressure in my chest, near-fainting experience.) A few months after giving birth, these episodes became an everyday occurrence sometimes lasting a whole day. I was put on Metoprolol (25 mg twice a day). In hopes of not having to take medication, 2 months ago I had an ablation but a week later my episodes returned (with around 190 bpm). I was put back on Metoprolol (same Toprol XL, just one 25 mg/day).
My husband and I are planning on having another baby but I am worried that having to take a heart medication throughout the pregnancy would have harmful effects on the unborn baby (too slow of a heart beat, low birthweight?). Is Toprol XL safe during pregnancy? What is considered still a 'safe dose' (in case 25 mg will not be enough later)? Since the medication slows down the heartbeat, due to same circulation can it also slow down the baby’s heartbeat? Can I only start taking the medication after the critical first 3 months have passed, will that lower the risk of problems with the baby’s health? My cardiologist said that it would have no harmful effects on me or the baby if I didn’t take the medication due to my worries even if I had the episodes again. I know I feel much better when I take the medication, but I would ‘stick it out’ if it meant a pregnancy without harmful medication that may have permanent effects on a baby. Thank you.

[Cleveland Clinic]

hajnalka,

thanks for the post.

Generally the discussions of safety and need for particular mediciations should be a team effort between your OB-Gyn and your Cardiologist.  This way the risk and benefits of each can be discussed with regards to the specifics of your case.

Metoprolol is a pregnancy class C drug, meaning there are no adequate and well-controlled studies in pregnant women but animal studies have shown potential detriment.

Practically, beta-blockers may cause fetal bradycardia and possibly result in intrauterine growth retardation if used in the third trimester.

Any use of medications should be used with the guidance of your OBgyn and cardiologist.

good luck

[mjseattle]

"Practically, beta-blockers may cause fetal bradycardia and possibly result in intrauterine growth retardation if used in the third trimester."

I thought the risks of fetal bradycardia and slowed fetal growth were greatest in the first trimester. Is that not the case?

(I have a bunch of questions about Atenolol, SVT, and pregnancy, but for 3 weeks have been unable to post a question. Is it just my timing?)