22/07/2026
MYTH: Your placenta begins to fail after 40 weeks.
❌ Not true.
Your placenta doesn’t have an expiry date, and it doesn’t suddenly stop working when you reach 40 weeks.
Every pregnancy is unique. Some placentas may become less efficient earlier in pregnancy, while many continue to function well beyond 40 weeks.
One reason this myth persists is that we can’t directly measure how well an individual placenta is functioning during pregnancy. While there is research into the placenta, there is limited evidence on accurately assessing placental function in real time, particularly in healthy pregnancies at term. Instead, healthcare professionals assess your baby’s wellbeing using factors such as your baby’s movements, growth, amniotic fluid levels and, where appropriate, fetal monitoring.
So why is induction often offered after 41 weeks?
It’s because research shows that the overall risk of complications gradually increases as pregnancy continues beyond 41 weeks—not because every placenta starts to fail.
📊 Understanding the statistics
You may have heard that the risk of stillbirth increases by 64% between 40 and 41 weeks. This is the relative risk.
But what does that actually mean?
* At 40 weeks, the risk of stillbirth is approximately 1.5 in 1,000 pregnancies.
* At 41 weeks, the risk is approximately 2.4 in 1,000 pregnancies.
This is a 64% relative increase, but the absolute increase is around 0.9 additional stillbirths per 1,000 pregnancies (or approximately 1 extra stillbirth for every 1,449 pregnancies that continue from 40 to 41 weeks).
Both ways of presenting the data are correct, but understanding both relative and absolute risk gives a much clearer picture and supports informed decision-making.
✨ Knowledge, not fear, empowers informed choices.
This information is intended to support informed decision-making and is not a substitute for personalised advice from your maternity care team.