Did you know that there are two categories of infertility? This is important for you
to understand. Many people believe that if they were able to get pregnant once
then they will be able to again. This is not necessarily true. Stay tuned and I will explain.
Primary infertility describes people that are having difficulty becoming pregnant
and have never been pregnant before. Secondary infertility
describes people that are having trouble becoming pregnant but they have been pregnant
before. The previous pregnancy was often a successful delivery or it might have been a
miscarriage or even an ectopic pregnancy. You can further divide people with secondary infertility
into those that also had trouble conceiving their first pregnancy and those who did not.
This last category, people who had no trouble getting pregnant the first time but now are
having trouble conceiving again, is the one that causes the most anxiety for my patients. People
have trouble wrapping their heads around the fact that they became pregnant so easily before and now
are seemingly unable to get pregnant again. They will frequently say to me, “I don’t get it” or
“Nothing has changed.” It is likely however, that much has changed but they just don’t realize it.
Some people with secondary infertility actually had fertility issues before
but they just got lucky and were able to conceive and deliver anyway.
They are only now seeing the impact of those long standing problems. It may also have been that the
issues interfering with fertility in the past may have been milder and they became worse over time.
One of those issues is aging. As we have talked about numerous times on this channel,
people with ovaries will see their fertility decrease as they get older. In any given month,
the chance for a 25 year old to become pregnant is much higher than it is for a 35 year old.
This is usually a gradual decline for most but there may be times when fertility
declines more rapidly. Watch this episode for information about that. By definition,
people with secondary infertility are always older than people with primary infertility. As a result,
age related infertility is going to be more common in people with secondary infertility.
Another factor is weight. Fertility doctors look at weight in relation to height
by using a number called BMI. People with a higher BMI have more trouble becoming and staying
pregnant until delivery. Watch this video for more information about the impact of BMI on fertility.
As people get older, they ARE more likely to become overweight. For example,
the average BMI for a 20 year old living in the US today is 27.1 which is considered overweight.
The average BMI for a 35 year old is 30.2 which is in the obese range.
People with secondary infertility are therefore more likely to have issues
with their weight when trying for a second pregnancy that they did during their first.
Tubal blockage is a relatively common cause for infertility in both primary
and secondary infertility. However, this study found tubal blockage in about one in
five people with primary infertility but in nearly one in three people for those with secondary
infertility. The reasons why tubal blockage is more common are not clear. For instance,
the rate of past infection with chlamydia, a bacteria known to cause tubal blockage,
was the same in both groups in this study. There may be some aspects of a pregnancy or
a delivery that make it more likely for tubes to get blocked. This is the reason, for my patients,
we will repeat an HSG after a delivery before starting fertility treatment again.
Finally, any of the problems which can cause primary infertility can also cause
secondary infertility. Ovulation problems, for example, are the most common cause for primary
infertility. But, we still see ovulation problems commonly in people with secondary infertility.
Because of the cumulative effect, secondary infertility is actually more common than
primary infertility. For example, when I look at new patients who come to my office
for infertility treatment, 40% have primary infertility but 60% have secondary infertility.
Our infertilityTV Bottom Line is this. Infertility is a common problem today in the United States.
Don't assume that because you were able to get pregnant easily the first time that you
will be able to get pregnant easily again. There are a number of problems that can arise
or worsen even though it seems to you that nothing has changed.