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

Planning a pregnancy while taking immunosuppressants isn’t something most people expect to face. But for those managing autoimmune diseases like lupus, rheumatoid arthritis, or who’ve had organ transplants, it’s a real and urgent question: Can I safely get pregnant while on these drugs? The answer isn’t yes or no-it’s complex, personal, and depends on which medication you’re taking, how long you’ve been on it, and whether you’ve had time to plan ahead.

Not All Immunosuppressants Are Created Equal

The big mistake people make is treating all immunosuppressants the same. They’re not. Some are safe during pregnancy. Others can cause permanent damage to fertility or serious birth defects. Knowing the difference can mean the difference between a healthy baby and a preventable tragedy.

Azathioprine is one of the safest options. Over 1,200 pregnancies in women taking this drug have been tracked since the 1990s. No increase in birth defects, miscarriages, or developmental issues has been found. It’s the go-to choice for many doctors when someone wants to conceive. If you’re on something else, switching to azathioprine before pregnancy might be the smartest move you make.

On the other end of the spectrum is cyclophosphamide. This drug is used for severe autoimmune conditions and some cancers. It’s brutal on the ovaries. In women who take more than 7 grams per square meter of body surface, 60-70% experience permanent ovarian failure. That means no more eggs, no more natural pregnancy. For men, it can cause irreversible azoospermia-no sperm at all-in up to 40% of cases. If you’re on this drug and thinking about kids, fertility preservation (freezing eggs or sperm) needs to happen before you start, not after.

What About Steroids Like Prednisone?

Corticosteroids like prednisone are common. They’re often used alongside other immunosuppressants. Many people assume they’re harmless because they’re “just steroids.” But they’re not. Prednisone can interfere with ovulation and reduce sperm production. It also raises the risk of premature rupture of membranes by 15-20%. That means your water breaks too early, increasing the chance of preterm birth.

Here’s the good news: you usually don’t need to stop prednisone completely during pregnancy. Your doctor can adjust the dose to keep your disease under control while minimizing risks. But you can’t just keep taking the same dose you were on before pregnancy. Monitoring is critical.

Drugs That Require a Head Start

Some medications need to be cleared from your system months before you try to conceive. Methotrexate is one of them. It’s a powerful drug used for rheumatoid arthritis and psoriasis. It’s also highly toxic to developing embryos. Even small amounts can cause severe birth defects. The rule? Stop methotrexate at least three months before trying to get pregnant. Some doctors recommend waiting six months to be extra safe.

Sulfasalazine is another one that catches people off guard. It doesn’t cause birth defects, but it cuts sperm counts by 50-60%. The good news? That drop is reversible. Once you stop taking it, sperm counts bounce back in about three months. But you can’t just stop cold turkey and expect to get pregnant next month. Plan ahead.

Sirolimus and Belatacept: The New Players

Newer drugs like sirolimus and belatacept are changing the game-but not always for the better. Sirolimus is linked to a 43% miscarriage rate in early case reports. That’s more than double the normal rate. Because of this, it’s still considered contraindicated during pregnancy. No exceptions.

Belatacept, on the other hand, is promising. Only three pregnancies have been documented in women taking it after kidney transplants. All three babies were born healthy, with no birth defects. That’s encouraging, but it’s not enough data to call it safe. Doctors may consider it in rare cases, but only after careful discussion and with close monitoring.

Male Fertility Is Often Overlooked

Most people think fertility issues are a woman’s problem. That’s not true. Immunosuppressants affect men too. Sulfasalazine lowers sperm count. Cyclophosphamide can wipe it out permanently. Even azathioprine, which is safe for women, hasn’t been studied enough in men to say it’s risk-free.

The FDA recommends semen analysis for men on these drugs: once before starting, once after one full sperm cycle (about 74 days), and again 13 weeks after stopping. Most men never get tested. They assume they’re fine. They’re not. If you’re trying to conceive and your partner is on immunosuppressants, ask your doctor about sperm testing. It’s simple, non-invasive, and could save months of frustration.

What Happens After the Baby Is Born?

Breastfeeding is another layer. Some drugs pass into breast milk. Chlorambucil? Absolutely no breastfeeding. It’s too toxic. Azathioprine? Probably safe, but only in low doses and with monitoring. The baby’s immune system is still developing, and even small amounts of immunosuppressants can increase infection risk.

Studies show babies born to mothers on immunosuppressants have 2.3 times higher risk of infections in their first year. That doesn’t mean you can’t breastfeed-but it does mean you need to work with your pediatrician. Watch for fever, poor feeding, or unusual fussiness. Don’t assume every cold is just a cold.

Preconception Counseling Isn’t Optional

This is the most important point: Don’t wait until you’re pregnant to talk to your doctor. Waiting is dangerous.

Preconception counseling means meeting with your rheumatologist, transplant specialist, and a reproductive endocrinologist-at least three to six months before you start trying. This isn’t a quick chat. It’s a full review of your medications, disease activity, organ function, and fertility status.

For example, if your creatinine level (a kidney function marker) is above 13 mg/L before pregnancy, your risk of preeclampsia skyrockets. That’s not a number you want to find out after you’re already pregnant. Same with your disease activity. If your lupus is flaring, getting pregnant could make it worse. You need to get your condition stable first.

And yes, this means you might have to stop your current meds and switch. It’s inconvenient. It’s scary. But it’s better than risking your baby’s life.

The Bottom Line: Plan, Don’t Guess

Twenty years ago, doctors told women with autoimmune diseases not to get pregnant. Now, thanks to better drugs and better science, most can. But only if they plan.

You can’t rely on old advice. You can’t assume your drug is safe because it’s been around for years. Some of the oldest drugs-like chlorambucil-are still linked to kidney and heart defects in babies. Others, like azathioprine, have decades of safety data.

The goal isn’t to avoid pregnancy. It’s to have a healthy one. That means:

• Knowing exactly which drug you’re on and what it does to fertility
• Stopping dangerous drugs months before conception
• Getting sperm and egg health checked
• Switching to safer alternatives if needed
• Working with a team, not just one doctor
• Monitoring your baby after birth

If you’re on immunosuppressants and thinking about having a child, your first step isn’t buying a pregnancy test. It’s calling your doctor and asking: “What do I need to do to get pregnant safely?” Don’t wait. Don’t assume. Plan.