You will need
  • - to do an ultrasound during pregnancy;
Pregnancy starts from the first day of the menstrual cycle. So I think the obstetric period. Approx 1 to day 14 for a 28 day cycle so-called luteum exists in the ovary.
The formation of the corpus luteum in the menstrual cycle
By 15-18 days of the menstrual cycle, or after 2 weeks from the onset of menstruation, ovulation occurs: the dominant follicle bursts and leaves ripe, ready to fertilize the egg. From the cells of the follicle under the influence of luteinizing hormone (LH) is the formation of new gland – yellow body, which will assume the role of the future placenta, that is, will produce the hormone progesterone and small amounts of estrogen. At this stage, the progesterone prepares the endometrium of the uterus for a possible pregnancy and implantation of the ovum. This is an early luteal phase and the normal size of the corpus luteum during this period is in the range of 15 – 20 mm.
Yellow body
In the cycle in which conception occurred or interrupted the development of the embryo at a very early stage – yellow body is exposed to extinction and disappearance.
Regression of the corpus luteum
In pregnant cycle luteum, under the influence of human chorionic hormone produced by the embryo continues to develop and to operate for 12 weeks on the obstetric maturity or three months from the beginning of menstruation. The corpus luteum continues to secrete progesterone and inhibits the formation of new Mature oocytes, the onset of menstruation, thus preventing miscarriage. On ultrasound it appears as a heterogeneous soft yellow rounded education. Starting in the mid-luteal phase of the menstrual cycle, and over the next few weeks, the corpus luteum reaches 25 – 27 mm.
Yellow body photo
To the 12th week of pregnancy in the uterus completes its development of the placenta, the organ that provides the embryo with all the necessary throughout the period of fetal development. It is designed to displace a yellow body and become a monopolist in the production of progesterone. Thus, the corpus luteum gradually decreases and finally disappears. In the period of the extinction of the size of the yellow body reaches 10 to 15 mm.
Yellow body photo