Act penetrative sex has evolved over millions of years as the mechanism for delivering sperm to the oocytes and early pregnancy. But sex is more than just a clash of two sets of genes. In a series of “Why sex?”, we analyze the biological, physical and social aspects of sex and gender. In today’s article we will look at how the female immune system responds to sexual relations and ensures healthy pregnancy.
Most people think that sperm is needed to fertilize the eggs of the female and ensure a healthy pregnancy. Therefore, it is assumed that the rest of the sperm (and the sex) are excessive in relation to requirements, at least with regard to conception.
Today, however, biologists believe sex is not just a process of delivering sperm, but also a kind of biological communication. Despite whether or not fertilization, sperm and other components of the liquid spewing cause subtle changes in the immune system of women.
This may have further impact on the potential pregnancy. Broadly speaking, sexual activity has implications for the planning of pregnancy for in vitro fertilization and other forms of assisted reproductive technologies, the application of which sexual relationship and their story is usually left out of the equation.
The sperm swims in the “soup” of molecular information
Evidence from studies conducted on animals, and clinical studies have led scientists to the conclusion that the seminal fluid (one in which there is sperm in the subsequent ejaculation) plays an important role in fertility.
Seminal fluid contains a small molecule that performs the function of biological signals. When injected into the vagina and into the cervix, they “persuade” the immune system of a woman to accept the status-tolerant proteins of sperm, known as “transplantation antigens”.
Tolerance is important if the process of fertilization. Immune cells recognize the same transplantation antigens on the developing child and thus supporting a process in which the embryo attaches to the uterine wall and form a healthy placenta and fetus.
Therefore, over time, in constant contact with the same male partner stimulates and strengthens the tolerant immune response to its transplantation antigens. The immune system responds to women semen partner to gradually increase the chances of a healthy pregnancy, at least for a few months of regular sexual relations.
Some forms of infertility and disorders of pregnancy are caused by the rejection of the immunity when the process tolerance was not properly run.
The pregnancy is going better after a few months of sex
The condition, known as preeclampsia, gives us valuable information about how interaction with seminal fluid affects a successful pregnancy. Preeclampsia is an inflammatory violation of the pregnancy threatening the development of the fetus and often causes premature births. It can threaten the mother’s life if left untreated.
Preeclampsia occurs more frequently when the number of sexual contacts with the child’s father before the conception was limited, this condition is associated with insufficient development of immune tolerance from the mother.
The length of time during which the couple had sexual relations, is more important than frequency of contact. A study of first pregnancies in 2057 women in Australia, showed that about 5% suffered from preeclampsia. In women with this disorder compared with women whose pregnancies took place without violations, twice as often had a short sexual relationship with partner (less than six months).
In women, sexual activity with a partner in the conception lasted less than three months, was 13% probability of preeclampsia, that is twice higher than the average. Among the few women conceive during the first sexual contact with the father of the child, the likelihood of pre-eclampsia was 22%, was three times higher. The low weight of babies at birth are also more frequently observed in this group.
None of the relationships are not analyzed in connection with sexual activity during pregnancy and risk of developing preeclampsia, therefore, the greatest importance is the interaction time before conception.
Formation of tolerance of the immune system, promoting healthy pregnancy, is characteristic of a partner involved in the conception. Women changing partner, return to their original state, they have to re-develop immune tolerance with a new partner.
In women who use barrier contraceptives, e.g., condoms or cervical caps (which reduce the interaction of the vagina and cervix with the seminal fluid and sperm), and subsequently conceive soon after the rejection of contraception, there is an increased risk of developing preeclampsia.
On the contrary, those women who use before conception intrauterine devices, there is a lesser risk of developing this condition.
Sex during IVF can increase the chances of conception
The importance of sex in creating the right conditions for a healthy pregnancy it is also noted in clinical studies in IVF and other assisted reproductive technologies. Fertility can be improved with the sexual relationship in couples during the period of infusion of the embryo in the uterus.
Combined data on more than 2,000 patients collected in the course of the seven studies showed that chances of pregnancy increase by 24% after vaginal contact with seminal fluid during the period of egg collection and replanting of the embryo. A study conducted with the participation of Australian and Spanish couples, showed that sex in the days that immediately precede the planting of the embryo, increased the percentage of pregnancy by 50%.
These studies have focused on early stages of pregnancy, which require further research in order to argue that sexual relationships affect the whole pregnancy after assisted reproductive technologies.
The lack of interaction with seminal fluid may be one factor explaining why preeclampsia occurs more frequently after the use of donor eggs or donor sperm, when no contact women with donor transplantation antigens occurred. Increased risk when using a donor of semen can be reduced, if in the previous cycles, insemination using the same donor.
In pairs using the conception with the modified version of IVF known as Intracytoplasmic sperm injection, the frequency of formation of pre-eclampsia is also more common in women who minimally interacted with the transplantation antigens of their partners due to the very low content of sperm.
Some of the couples to the imbalance in the composition of the seminal fluid or the characteristics of the immune system can reduce or slow the formation of immune tolerance in women. Other couples may be immunological incompatibility, preventing tolerance, despite the time spent together.
Perhaps some couples needed a longer period of sexual relations for the occurrence of pregnancy.
The immune system works during pregnancy as a gatekeeper
It is interesting to consider why the immune system is so closely connected with reproduction.
One theory is that women in the process of evolution developed the ability to perceive signals in the seminal fluid and react to them to determine the quality or “suitability” genetics of a male partner. Scientists are now trying to identify the key signals from the male and female sides, which provides transparency.
In addition, because male Smoking, being overweight and other factors can affect how a woman responds to sex in the biological sense. This helps to explain why dad’s health is just as important as the mother’s health in preparation for pregnancy.