Understanding IVF Success Rates
When patients ask "what are the success rates?", they deserve an honest, nuanced answer. IVF success is not a single number — it varies dramatically based on patient age, diagnosis, treatment protocol, embryo quality, and clinic expertise. This article provides a comprehensive overview of what the evidence shows about IVF success in South Africa.
How Success is Measured
IVF success can be measured in several ways, each telling a different part of the story:
- Clinical pregnancy rate per transfer — The percentage of embryo transfers that result in a pregnancy visible on ultrasound (heartbeat at 6-7 weeks). This is the most commonly reported metric.
- Live birth rate per transfer — The percentage of transfers resulting in a baby born alive. This is the most meaningful outcome but accounts for pregnancy losses.
- Cumulative live birth rate per cycle start — The total chance of a live birth from one complete IVF cycle including all fresh and frozen embryo transfers from that retrieval. This is the most realistic measure of what one IVF cycle offers.
Age-Related Success Rates
Female age is the single most significant predictor of IVF success. Based on South African registry data and international benchmarks:
Clinical Pregnancy Rates per Embryo Transfer (approximate)
- Under 30: 50-55%
- 30-34: 45-50%
- 35-37: 35-40%
- 38-39: 25-30%
- 40-41: 15-20%
- 42-43: 8-12%
- Over 43: <5% with own eggs
Cumulative Live Birth Rates (per complete cycle including frozen transfers)
- Under 35: 55-65%
- 35-37: 45-55%
- 38-40: 30-40%
- Over 40: 15-25% with own eggs
With donor eggs, success rates are consistently 50-60% regardless of recipient age, because the egg quality reflects the young donor's age.
Factors Affecting IVF Success
Patient Factors
- Female age — Most important predictor (affects egg quality and chromosomal normality)
- Ovarian reserve — AMH level and antral follicle count predict response to stimulation
- Body weight — BMI 19-30 associated with best outcomes
- Smoking status — Smoking reduces success by up to 50%
- Previous pregnancies — Previous live births associated with better prognosis
- Diagnosis — Tubal factor and male factor generally have better IVF outcomes than diminished ovarian reserve or endometriosis
- Duration of infertility — Longer duration associated with lower success
Treatment Factors
- Number of eggs retrieved — Optimal range is 10-15 eggs (fewer limits selection; more increases OHSS risk)
- Embryo quality — Blastocyst transfer generally has higher success than day 3 transfer
- PGT-A (genetic testing) — Selecting euploid embryos improves per-transfer rates but requires sufficient embryo numbers
- Frozen vs fresh transfer — Comparable or slightly better outcomes with frozen transfer in many scenarios
Clinic Factors
- Laboratory quality — Air quality, incubation systems, and embryologist experience significantly impact embryo development
- SASREG accreditation — Accredited clinics undergo regular audits and meet defined quality standards
- Specialist experience — Volume and years of practice correlate with outcomes
South African Context
South Africa's SASREG-accredited clinics report outcomes comparable to international benchmarks (UK HFEA, Australian ANZARD data). However, several factors are unique to the South African context:
- Cost barriers — Limited medical aid coverage means many patients can only afford 1-2 cycles, reducing cumulative success opportunities
- Late presentation — Some patients present later due to cost or awareness barriers, reducing age-related success rates
- Diverse population — Genetic diversity may influence some outcomes (e.g., AMH norms vary by ethnicity)
- Egg donation excellence — South Africa has a well-established, regulated egg donation system with excellent outcomes
Interpreting Success Rates
When comparing clinics, be cautious about raw success rate comparisons. Clinics with stricter patient selection (refusing difficult cases) may report higher rates. True quality is better reflected by cumulative live birth rates per cycle start, and by willingness to treat challenging cases.
At PTA Fertility Centre, we believe in transparent, honest communication about expected outcomes. During your consultation, we provide individualised success estimates based on your specific age, reserve, and diagnosis — not clinic-wide averages that may not apply to you.
Improving Your Chances
While you cannot control your age or genetics, evidence-based strategies to optimise IVF success include:
- Stop smoking (at least 3 months before treatment)
- Achieve optimal weight (BMI 19-30)
- Limit alcohol and caffeine
- Take folic acid and vitamin D supplementation
- Address thyroid or other endocrine issues
- Consider PGT-A if over 37 or with recurrent failure
- Don't delay — earlier treatment generally means better outcomes