Fertility and Immunosuppressants: What You Need to Know About Medication Risks and Preconception Counseling

Planning a baby when you’re on immunosuppressants isn’t something you can wing. These drugs keep your immune system from attacking your own body-or a transplanted organ-but they don’t care if you’re trying to conceive. The risks are real, the data is complex, and waiting until you’re pregnant to ask questions can put both you and your baby in danger.

Not All Immunosuppressants Are Created Equal

Some immunosuppressants are safe to use while trying for a baby. Others are not. The difference isn’t subtle-it’s life-changing. Take azathioprine. It’s been studied in over 1,200 pregnancies with no increase in birth defects, miscarriages, or developmental issues. That’s why it’s often the go-to choice for women with lupus or rheumatoid arthritis who want to get pregnant. It’s not perfect, but it’s the safest option in its class.

Now compare that to cyclophosphamide. This drug, often used for severe autoimmune diseases, doesn’t just pause fertility-it can end it. In women, cumulative doses over 7g/m² cause permanent ovarian damage in 60-70% of cases. In men, it can lead to irreversible azoospermia in 40% of users. If you’re on this drug and thinking about kids, you need to talk to your doctor before you start. Fertility preservation-like freezing eggs or sperm-isn’t optional here. It’s essential.

Methotrexate is another red flag. It’s a known teratogen, meaning it can cause serious birth defects. Even small doses can harm a developing embryo. The rule? Stop it at least three months before trying to conceive. Don’t guess. Don’t hope. Stop it. And get a blood test to confirm it’s fully out of your system.

Steroids and Hormones: The Hidden Disruptors

Prednisone and other corticosteroids are often seen as harmless because they’re used for so many things-from asthma to eczema. But when it comes to fertility, they’re sneaky. These drugs mess with the signals your brain sends to your ovaries and testes. In women, that can mean irregular or absent ovulation. In men, it can lower testosterone and reduce sperm production.

And it doesn’t stop there. Pregnant women on steroids face a 15-20% higher risk of premature rupture of membranes. That’s when the amniotic sac breaks too early, leading to early labor or infection. It’s not common, but it’s common enough that your OB-GYN needs to know you’re on these meds.

What About Men? The Male Side of the Story

Most people assume fertility issues are a woman’s problem. That’s not true here. Men on immunosuppressants face real risks too. Sulfasalazine, often used for ulcerative colitis or ankylosing spondylitis, cuts sperm count by 50-60%. The good news? It’s reversible. Once you stop the drug, sperm counts bounce back in about three months. But you can’t just stop cold turkey. Your doctor needs to help you switch to a safer alternative first.

And then there’s the big blind spot: most of these drugs were approved decades ago, before regulators required testing for male reproductive toxicity. The FDA didn’t start requiring semen analyses before and after exposure until recently. So if you’re on an older drug, your doctor might not even know what it does to sperm. Ask for a baseline semen analysis. It takes 74 days for a full sperm cycle to renew, so test after that time. And test again 13 weeks after stopping the drug to see if recovery is happening.

The Newer Drugs: Hope With Caveats

There’s new hope. Belatacept, a newer drug used in kidney transplants, has shown promise. Only three pregnancies have been documented so far, but all resulted in healthy babies with no birth defects. That’s encouraging-but it’s not enough to call it safe. We need more data.

On the flip side, sirolimus is a hard no during pregnancy. Early reports show a 43% miscarriage rate among women who took it-more than double the normal rate. There were also cases of serious birth defects. Even though animal studies didn’t show harm, human data is too alarming to ignore. If you’re on sirolimus and want to get pregnant, switching to azathioprine or another safer option is non-negotiable.

Preconception Counseling Isn’t Optional-It’s Critical

You wouldn’t drive across the country without checking your oil, tire pressure, and route. Why would you try to get pregnant without checking your meds?

Preconception counseling means sitting down with your rheumatologist, transplant team, and OB-GYN-at least three to six months before you start trying. This isn’t a quick chat. It’s a full review: your disease activity, your current meds, your fertility status, and your backup plan if things go wrong.

Your doctor needs to know:

• Which drugs you’re on and for how long
• Your last menstrual cycle (if you’re female)
• Your sperm count (if you’re male)
• Whether your disease is stable
• What your kidney or liver function looks like (high creatinine levels raise preeclampsia risk)

And here’s something most people don’t realize: stopping immunosuppressants can make your disease flare. That’s dangerous too. A flare during pregnancy can be worse than the meds. The goal isn’t to stop everything-it’s to switch to the safest option that still keeps your disease under control. For many, that’s azathioprine or sometimes hydroxychloroquine. For others, it’s tapering steroids to the lowest possible dose.

What Happens After You Get Pregnant?

Getting pregnant is just the first step. Now you need to monitor.

Monthly blood tests for creatinine are standard. If your levels are above 13 mg/L before pregnancy, your risk of preeclampsia shoots up. Your OB will watch your blood pressure, urine protein, and fetal growth like a hawk.

Babies born to moms on immunosuppressants often have lower B-cell and T-cell counts. That means they’re more prone to infections in their first year. Your pediatrician needs to know about your meds so they can watch for signs of illness early. Vaccines? They’re still safe-but timing matters. Live vaccines like MMR may be delayed until the baby’s immune system recovers.

And breastfeeding? It’s complicated. Chlorambucil is a hard no-don’t breastfeed if you’re on it. Azathioprine? Probably safe. Small amounts pass into breast milk, but studies show no harm to babies. Still, talk to your doctor. Don’t assume.

The Big Picture: Progress, But Not Perfection

Twenty years ago, doctors told women with lupus or kidney transplants to avoid pregnancy. Now, thanks to better drugs and better science, most can have healthy babies. That’s huge progress.

But we’re still missing pieces. We don’t know the long-term effects on children exposed to newer drugs like belatacept or voclosporin. We don’t have enough data on paternal exposure. And we still don’t have mandatory fertility testing for new drugs until after they’re on the market.

The bottom line? You can have a baby on immunosuppressants. But only if you plan ahead. Only if you work with your team. Only if you treat this like the medical emergency it is-because it is.