Infertility in humans and animals by Prof. Oladapo Ashiru
This new year, it is important to focus on conception procedures. As done in the past, I wish to give our people the opportunity to once again benefit from this topic, which covers both the old and newer protocols that have been established to address assisted conception.
Infertility is the inability to get pregnant after a year of unprotected intercourse. Both men and women can be infertile. According to the Centre for Disease Control, one-third of the time, the diagnosis is due to female infertility and one-third of the time it is linked to male infertility. The remaining cases of infertility are due to a combination of factors from both partners.
For approximately 20 per cent of couples, the cause cannot be determined (unexplained infertility). When the overall statistics are done, they project that the male factor is 50 per cent and the female factor is also 50 per cent. This is very important as in the African environment the shift of blame is always to the female partner.
There is a worldwide emotional epidemic of infertility. As of today, about 25 per cent of couples are infertile. Even in India, which has severe overpopulation, the most common reason for a visit to the doctor is infertility.
In Nigeria, infertility, which used to be a small area of gynaecology practice, has now become a huge discipline with several doctors devoting their clinic solely to the practice of infertility.
Human ability to get pregnant decreases with age, which explains why only one per cent of teenagers are infertile, while a large majority of infertile couples are in their thirties. It is well documented that from our teenage years when the last thing we wanted was a child to our mid-thirties when we are finally secure enough to start our family, our ability to conceive decreases almost by twenty-five percent.
Research shows that in the past 30 years, infertility has increased and those over 30 have the most problems.
If you are in your 30s, and have been working to establish yourself in your profession and you are now just casually reading this write-up, you should realise that there is a 25 per cent chance you will not be able to do so without medical intervention.
Other factors that may make it difficult for you to get pregnant include abnormal organs, immunological factors and malfunctioning of the body system. The dramatic increases in infertility over the last 30 years have been blamed on various factors, including the increases in sexual transmitted diseases, environmental toxins in our food such as heavy metals in fish, environmental pollution particularly in the oil-producing geographical zones, declining sperm counts from absorption of toxic substances and even the increased tension and anxiety of the modern life.
The level of reproductive toxins in the oil-producing regions is worrisome, especially when it affects those who are even in the office or the spouse at home when her partner is in the oil fields.
In all other animals except humans, the desire to have sexual intercourse is timed to correspond exactly to that moment when the female is ovulating or producing eggs that can be fertilised. Take for instance, a dog or a rabbit. Once the female is ovulating she seeks out the male and, after intercourse, the female is usually pregnant with multiple pregnancies. Humans, however, desire to have sex at any time, regardless of whether there is an egg that can be fertilised in the woman. This makes us reproductively more inefficient than other animals.
We know that in all species, there is a very short window, in fact, a matter of days during each month that the female is fertile and can get pregnant with intercourse. The timing of sex is, therefore, very important if a species is to have an efficient and high fertility rate.
In humans, women go through a period of 14 days when the follicle in the ovary develops. This starts from the day one of the menstruation until the egg is sufficiently matured and ready for ovulation. Once the egg is released at ovulation, there is another 14-day period that it can be fertilised. If intercourse occurs at the right time, then the embryo grows and implants in the uterus or womb. But, if intercourse occurs at another time other than the ovulating period, it is very unlikely that the woman will get pregnant in that cycle /month.
Animals go through what is described as an “estrus” cycle or “heat.” Humans go through a menstrual cycle. Apart from other hormonal variations, one significant difference between humans and animals is that the female sex hormone, estrogen, which increases just before ovulation in animals, is the trigger factor for their sex drive. This hormone is responsible for producing eggs.
In other words, animals do not desire to have sex unless there is an egg to be fertilised in the female’s womb. In humans, sex desire is much more complex and is not driven by the female sex hormone estrogen, but by the male sex hormone testosterone. This is unique in the animal kingdom and it is especially a human phenomenon.
The small amount of testosterone that the female makes is enough to generate a sexual drive in her. It is only a few females that recognise the slight increase in testosterone around the ovulation period to enable them deliberately initiate sex at the appropriate time to get pregnant.
From sociological studies, the fact that humans make love facing each other indicates a communication of direct sexual interest and development of love, permanent mating and a family system. On the contrary, throughout the animal kingdom, the female squats in her position of “heat” and the male mounts her, facing her rear end.
The animals never get to look at each other and do not need to know each other or get emotionally involved for intercourse to take place. In other words, in animals, sex is not emotional but for procreation. For humans, having sex is about expressing emotions and not just for the purpose of having babies. This makes us less reproductively efficient which makes infertility common in humans because the human reproductive system was never that efficient, to begin with.