According to the laws of nature
When the ovary ripens in the follicle of the female ovary, it leaves it and goes to the uterine cavity through the uterine tubes. This process is called ovulation and means the readiness of a woman's organism for conception. Against this background, there are hormonal changes, which are accompanied by painful and aching sensations in the lower abdomen, thick vaginal discharge. It is during the ovulation period that a female egg can be fertilized by a male sperm during sexual intercourse. If this did not happen, conception did not take place, then after a while it is excreted from the body. This is the period of menstruation - the beginning of the menstrual cycle.
When in the ovulation period the egg is impregnated with the sperm, it again moves up the uterine tube, attached to the uterine wall. There comes a pregnancy, the embryo develops. It is logical that the female body directs all its forces to a healthy bearing of the baby. In this case, for 9 months the eggs no longer ripen. So it is arranged by nature that after the onset of an "interesting" position, ovulation can harm a woman and an embryo.
Once the fertilization has already taken place, the development of new eggs is no longer needed by the woman's reproductive system. Her body is rebuilt: the ovaries do not produce eggs, overlapping the cervix with a specific mucosa, and spermatozoa can no longer manifest activity in it.
On exceptions to the rules
If you still assume that ovulation during pregnancy is possible and a new conception may occur, the fetal egg can not simply attach itself to the uterus, because the embryo is already developing there.
There are no rules without exceptions. Therefore, sometimes the process of ovulation with the carrying of the baby occurs. But only in the first month of pregnancy. At its early stage, there is a possibility of an exit from the ovary of the second egg and its fertilization. To date, there are several cases of repeated fertilization after the onset of pregnancy. But these are the rare exceptions to the rules. That is, a woman can not conceive two embryos at the same time with different terms of conception. Multiple pregnancies are the incubation of two or three babies conceived at the same time. They come into the world in the process of one birth, one after another.
Today they help couples who want to have a baby and are trying to determine if the egg is maturing in the female body, to use the optimal day for conception.
All tests for ovulation are based on one principle. Their action consists in changing the color of the indicator strip as a result of the ingestion of luteinizing hormone. His level during the period of ovulation is the highest, which is what the test reacts to. So can it happen that a test for ovulation of a pregnant woman will show a positive result? Practice shows that this is out of the question. It can not be positive such a test in a future mother. However, the same practice confirms that, due to inattention, many of the fairer sexes use another test - for pregnancy. That's why the result is positive. And this is quite natural. After all, the task of this method of diagnosis is to confirm the "interesting" situation. It is confirmed by the presence in the blood of the hormone of pregnancy - the chorionic gonadotropin. At its presence, the test strip for pregnancy tests responds.
The test for ovulation can be false positive, that is unreliable, in some cases. We are talking about kidney failure, hormonal dysfunction of the body, postmenopause. Then, and possibly an increase in the blood level of luteinizing hormone.
So, the onset of ovulation in pregnant women is impossible, so already laid nature. Therefore, in this period, when intimate relationships are no longer used for contraception, they are not necessary.