According to reproductive biologists at the University of Adelaide in South Australia, sex even up to a full year before conception helps guard against a litany of ailments.
The disorders, which range from infertility to high blood pressure during pregnancy, all appear to be linked to the reluctance of the mother's immune system to accept the foetus and placenta. Both which come with foreign protein from the father.
The Adelaide team found sex, early and often with the intended father, may help overcome that reluctance to conceive. Though if the mother's immune system remains unconvinced the consequences will be dire. The mother may immediately and repeatedly reject new embryos- in which case she will be infertile. If the mother's immune system takes a little longer to avoid the foreign tissue she may suffer miscarriages frequently. If the rejection is less severe it may only affect the placenta. This can be disastrous because the placenta is the foetuses lifeline supplying it with oxygen and nutrients from the mother's blood.
If the placenta does not grow the mother's immune system cuts the foetus's supply line and in result the baby is born under weight or stillborn. Immune rejection can even threaten the mother's life.
According to a controversial theory it is the mother's rejection of a placenta that causes pre-eclampsia. Pre-eclampsia also called toxaemia of pregnancy is a condition in which the mother's blood pressure soars this is accompanied by protein in urine or retention of fluid, in some cases triggering convulsions, coma and death. In this case fragments of dead placenta are swept into the mother's circulation damaging vessels and sending her blood pressure soaring.
Some mother's immune systems try to annihilate that developing foetus because of foreign genes and the brutish way the foetus behaves in the womb.