As already mentioned, there is still no actual pregnancy at this time. All changes that occur in the female body correspond to the normal menstrual cycle. So, 1 week of pregnancy begins with the fact that on the 1st day of menstruation, the pituitary gland secretes follicle-stimulating hormone (FSH), under the influence of which a follicle begins to develop on the ovary. In the blood of a woman, the concentration of the hormones estrogen and progesterone decreases and the amount of prostaglandin, a substance that causes uterine contractions, increases. Thanks to them, the surface of the uterus becomes loose, the layer of the endometrium exfoliates and comes out with menstrual bleeding.
After the end of menstruation, the hormonal background changes again. At the end of the first week of pregnancy, the growing follicle stimulates the production of estrogen. Under its influence, a new endometrium begins to grow in the uterus. In about ten days, he will be ready to receive a fertilized egg.
If there is a need to do an ultrasound, it is prescribed at the end of the first week of pregnancy (usually on the 5th or 6th day of the cycle), when menstrual bleeding has already stopped. The doctor will see the growing follicle and will be able to accurately predict the date of ovulation (the release of the egg from the follicle). Sexual intercourse on the eve of ovulation and on this day increases the chances of getting pregnant, so the results of an ultrasound scan will be useful for couples planning a baby.
Another way to calculate your ovulation date is to measure your basal body temperature. On the day of ovulation, it will rise sharply, the difference can be up to half a degree. Further temperature measurement will help determine the date of implantation and the fact of pregnancy.
When planning a pregnancy, pay attention to the following interesting point. Spermatozoa, which are carriers of the “girl” chromosome, are quite tenacious: they can wait for an egg up to 7 days. Spermatozoa-"boys" live not so long - from several hours to 1-2 days. If you want to try to conceive a girl, it's worth trying somewhere three or more days before ovulation. If a boy, the day of conception should fall directly on the period of ovulation.