By Cristina Mestre Ferrer BSc, MSc (embryologist).
Last Update: 08/08/2014

Before going over the definition of secondary sterility, it is worth pointing out that infertility and sterility do not mean the same. They are commonly taken as synonyms, but there are significative differences between each other.

Sterility refers to the impossibility of getting pregnant. The spermatozoid somehow does not reach the egg to fertilise it. Sterility also implies that the embryo has failed to settle in the endometrium (implantation usually takes place in the 6-7th day of embryonic development). Infertility, on the other hand, is the inability to produce a full-term pregnancy and give birth to a healthy baby. Conceptions are feasible despite being infertile, but they are not completed because of miscarriages or the aforementioned incapcity.

Failing to conceive again

Therefore, secondary sterility is the failure to conceive following previous succesful pregnancies. To label the condition as secondary sterility, the couple has to be the biological parents of a previous child.

Socially, since these couples already have offspring, secondary sterility is regarded as a problem less serious than the primary type. Nonetheless, for those that have never had difficulties to conceive, being unable to conceive again can be very stressful. These patients feel that physicians and relatives do not understand what they are going through, as they do not perceive the problem as something to be worried about.


Primary and secondary sterility normally share the same causes. Fertility problems can be caused by him, her or both. An optimum reproductive potential has to be achieved in order to get pregnant; that is the summation of the male and female’s reproductive capacity.

Fertility problems aggravate as the couple gets older and the root causes of sterility persist. Most of the cases of secondary sterility are caused by alterations in the fertility of the woman. Time is harsher on female fertility, so advanced maternal age, sexually transmitted diseases and health alterations due to a previous pregnancy should be considered within the frequent causes of sterility. Examples of the latter are diabetes, hyperprolactinaemia (abnormally high levels of prolactin in the blood), hormonal imbalances caused by the thyroid gland, ovulation disorders, endometriosis, uterine myomas

Female fertility problems

Sometimes, this type of sterility is a consequence of sustaining unrecommended life habits, like not controlling weight after pregnancy, smoking, stress, extreme physical exercise…These factors may decrease semen quality in men or women’s reproductive potential.

When to look for help

Couples that have had offspring do not think they are going to have problems to conceive again, as their fertility was put to the test and they passed it, so they do not really know when to visit a doctor. If after a year of attempts, conception is not achieved, they must head to a fertility clinic. Nonetheless, the age of the woman is an important factor. For instance, a 38 year-old woman should visit a doctor if she has failed to get pregnant in the last 6 months. Since the ovarian reserve is not the same at the early thirties than at the late thirties, the chances of conceiving get slimmer as years go by. Physiologically, egg quality starts to fade away, though gradually, at 27 years old. Eight years later, at 35, female fertility is drastically diminished; the quality of the oocytes decreases at a faster rate.

In light of the outlined above, the cutoff age will be 35 years old. Women younger than 35 should visit a doctor after a year trying to get pregnant. On the other hand, those older than 35 should also see a doctor if they have not conceived after a six-month period.

Authors and contributors

 Cristina Mestre Ferrer
BSc, MSc
Bachelor's Degree in Biological Sciences, Genetics & Human Reproduction from the University of Valencia (UV). Master's Degree in Biotechnology of Human Assisted Reproduction from the UV and the Valencian Infertility Institute (IVI). Embryologist at IVI Barcelona. More information