“Test tube babies” are not that rare these days.
The Centres for Disease Control and Prevention estimates that 1.5% of babies born in the US are conceived using what’s called Assisted Reproductive Technology (ART), of which the most common procedure is in vitro fertilization (IVF).
IVF is a procedure in which eggs are taken from a woman’s ovaries and fertilised with sperm in a petri dish. Then one or more fertilised embryos are placed in the woman’s uterus, where one will hopefully implant and grow into a baby.
Though thousands of IVF cycles are done every year in the US, it’s tricky to get a sense of an individual woman’s chance of conceiving with the procedure. The graphs below, from the CDC, show exactly how often IVF resulted in a baby for women who went through the costly treatment using their own eggs, not donor eggs. A single IVF cycle costs an average of $US12,400, according to the American Society for Reproductive Medicine (ASRM), and women often need multiple tries to get pregnant.
About 36% of IVF cycles result in pregnancy, and 29.4% of cycles result in a baby:
A live birth rate of about 30% for IVF cycles is really pretty respectable. A healthy, fertile 30-year-old woman has about a 20% chance of getting pregnant without assistance every month that she tries, according to the ASRM. That decreases to 5% chance each month for women aged 40.
To put that IVF success data in a slightly different frame, however, a majority of IVF cycles do not result in pregnancy:
The flip side of a 35.9% pregnancy rate for IVF cycles is that 63.4% of cycles don’t result in pregnancy.
A woman doing IVF may have a better chance of getting pregnant that she would without the procedure, but it’s nowhere near a sure thing.
The data in the graphs above group women of all ages together in reporting IVF outcomes, which can be somewhat misleading. A woman’s age is the most important factor influencing the success of IVF when she uses her own eggs, according to the Society for Assisted Reproductive Technology (SART), the professional organisation for IVF clinics.
When the success of IVF cycles is plotted by women’s age, it becomes clear why SART says age is so important:
Around 40% of IVF cycles result in babies for women aged 32 and younger. Not even 10 years later, for women aged 40, that success rate is cut in half to less than 20%.
A live birth rate of about 20% for 40-year-old women is not quite as bad as it sounds — remember it’s about the same chance a healthy, fertile 30-year-old woman has of becoming pregnant every month she tries, and far more than a 40-year-old woman’s chance without IVF.
Still, a 40-year-old woman considering IVF doesn’t have the 30% chance of having a baby she might expect if she just saw average IVF success rates reported, and many people underestimate the effect age will have on their fertility. Of eight top misconceptions about infertility specialist Dr. Joshua Klein identified in a column for CNN, two were related to ageing.
As with any medical procedure, the costs, risks, and discomfort of IVF have to be weighed as well as potential benefits. IVF isn’t cheap and isn’t always covered by insurance — a recent survey found that 70% of women who used fertility treatments like IVF went into debt doing so.
Besides the financial cost, women have to deal with the discomfort of injecting themselves with hormones daily to stimulate the uterus. The possible side effects of the hormone treatment include bloating, nausea, throwing up, diarrhoea, soreness, and weight gain. In rare cases, the ovaries are overstimulated and swell suddenly, which throws off the body’s fluid balance and can cause potentially life-threatening blood clots.
For couples who try to conceive through IVF, a lot more is at stake financially, emotionally, and physically, even if the success rate is often better than the traditional method.
While looking at the national averages for IVF success rates is a good start for dispelling misconceptions, pregnancy and live birth rates differ from clinic to clinic, and the data don’t tell the whole story. There are many different causes of infertility, and IVF does not address the direct problem for every cause. Only a doctor can say what chance IVF has of success for a particular couple.
Even though the data is there, SART discourages using success rates to compare fertility clinics. Data can give women a clear picture of what average success rates for IVF actually are, but can’t possibly predict what will happen for each individual patient.