The first IVF baby was born in 1978. Since then, more than 10 million babies have been born through IVF worldwide. In the US alone in 2024, over 100,000 babies were conceived through IVF, roughly 1 in 36 children. It’s one of the most performed, best studied, and most successful medical procedures in reproductive medicine.
Consent forms list every complication that has ever occurred without saying how often any of it happens. Most are mild, the serious ones have grown rarer as protocols improved, and a few of the widely repeated fears rest on studies that compared the wrong groups.
At a glance
- Common and mild: bloating, cramping, spotting after retrieval — gone within a few days.
- Uncommon but serious: severe OHSS, significant bleeding or infection after retrieval.
- Largely solved: multiple pregnancy (which was once the defining risk of IVF).
- Mostly overstated: birth defects and childhood cancer (the underlying infertility explains most of the gap).
Ovarian hyperstimulation syndrome (OHSS)
OHSS is the risk most specific to IVF, since it comes from the stimulation itself rather than from anything that follows. Hormones push the ovaries to grow many follicles instead of the usual one. In OHSS, the ovaries respond too strongly, enlarge, and fluid shifts out of the blood vessels into the abdomen.
Mild OHSS is relatively common, showing up in about 20-30% of cycles, and causes bloating, nausea, and abdominal discomfort in the days after retrieval.
Serious OHSS is much rarer and continues to get rarer. US surveillance data show moderate OHSS falling from 1.05% of cycles in 2006 to 0.42% in 2015, and severe OHSS from 0.38% to 0.11% over the same period. Serious cases involve enough fluid buildup to make breathing difficult, along with severe vomiting and a raised clotting risk.
Most at risk are patients with PCOS, a high follicle count, people who produces a very large number of eggs (roughly fifteen or more), or has high estrogen levels at the time of the trigger shot.
Clinics now prevent most severe cases with gentler stimulation protocols, a different type of trigger shot (GnRH agonist instead of hCG), dosing set from individual ovarian reserve testing, and freezing all embryos for a later transfer since pregnancy itself worsens OHSS.
The retrieval
Egg retrieval is a short outpatient procedure under sedation. A thin needle guided by ultrasound passes through the vaginal wall into the ovaries to collect eggs from the follicles.
The usual aftermath is mild cramping and spotting that resolves quickly. Severe complications are extremely rare, around 0.08%, including significant bleeding, infection, or injury to a nearby organ.
Overall, serious harm from retrieval is uncommon, and clinics manage risk with antibiotics, ultrasound guidance, and post-procedure monitoring.
Multiple pregnancy
Historically, the biggest risk of IVF wasn’t the procedure. It was twins.
Clinics used to transfer several embryos to raise the odds of a pregnancy, but that also raised the odds of a multiple pregnancy. While that might sound like a positive bonus, twins carry substantially higher rates of premature birth, low birth weight, perinatal mortality, and cesarean delivery. About 12.5% of IVF births are multiples, compared to roughly 3.2% of births overall.
This is the risk the field has done the most to fix. In 2024, more than 97% of IVF births were singletons. Twins accounted for about 2.6% and triplets for 0.04%, putting IVF roughly in line with the general population. About 79% of embryo transfer cycles now use elective single embryo transfer.
Fears that are mostly overstated
Birth defects. The baseline rate of major birth defects in any pregnancy is around 3%. IVF itself doesn’t significantly raise this risk. Older studies would say otherwise, citing a 30% higher risk among ART-conceived children. But these studies compared IVF children to the general population. When factoring in underlying parental infertility, the gap narrows considerably when researchers compare ART children to children of parents who also struggled to conceive. The increased risk comes from the infertility itself, not from IVF.
Childhood cancer. The evidence splits along the same line. Meta-analyses comparing ART-conceived children to the general population find a modest increase, around 20%. A 2025 systematic review pooling 18 studies found no significant increase in childhood cancer among ART-conceived children. Any increased risk is from whatever made conception difficult in the first place, not the lab or procedure.
Emotional toll
IVF is hard. The hormones, monitoring, waiting, cost, and the possibility that a cycle fails all take a toll. It’s not a complication in the medical sense, but it’s often the hardest part. Among insured women who stopped fertility treatment, 40.2% named the stress of it as their reason. More on this in Emotions.
Bottom line
IVF is a common, well-studied procedure with a good safety record. The risk most worth understanding is OHSS, and modern protocols have made its serious form rare. Retrieval complications are uncommon. The multiple-pregnancy risk is shrinking as single-embryo transfer becomes standard. And the two biggest fears, cancer and birth defects, are mostly due to the underlying infertility, not the IVF treatment itself. If you have any concerns regarding your own situation, always discuss that with your clinic directly.
Sources
- American Society for Reproductive Medicine, “For the First Time, More Than 100,000 Babies Born Through IVF in the U.S. in a Single Year”
- American Society for Reproductive Medicine, “Prevention of moderate and severe ovarian hyperstimulation syndrome: a guideline”
- National Library of Medicine, “Ovarian Hyperstimulation Syndrome (OHSS) requiring Intensive Care Unit (ICU) admission between 1996-2020 in England, Wales, and Northern Ireland”
- Fertility and Sterility, “Clinical complications after transvaginal oocyte retrieval in 7,098 IVF cycles”
- ACOG, “Perinatal Risks Associated With Assisted Reproductive Technology”
- JMIR Cancer, “Assisted Reproductive Technology and Risk of Childhood Cancer Among the Offspring of Parents With Infertility: Systematic Review and Meta-Analysis”
- National Library of Medicine, “Cumulative temporal association between assisted reproductive technology and childhood cancer: a systematic review and meta-analysis of observational studies”
- ScienceDirect, “Infertility-related stress, quality of life, and reasons for fertility treatment discontinuation among US women”