Placental somatomammotropin (lactogen) is released during pregnancy only by the placenta. In non-pregnant women and men, there is no placental lactogen in norm. This peptide hormone, similar in structure to prolactin of the pituitary gland, but much more active. Under its influence, maturation and preparation of the mammary glands for the production of milk occurs. And, like prolactin, it has a stimulating effect on the yellow body of the ovaries. Under the influence of placental lactogen, it produces progesterone, which ensures the maintenance of pregnancy until 16 weeks.
In different terms of pregnancy the placenta produces placental lactogen in different amounts:
- begins to be determined from 10 weeks;
- the maximum reaches 38 weeks;
- up to 40 weeks decreases due to aging of the placenta.
The rate of placental lactogen during pregnancy for a particular period is determined by the table.
How is the placental lactogen assay performed?
For the study on placental lactogen, blood is taken in the morning, on an empty stomach, from the vein of a pregnant woman, since 90% of its quantity enters the woman's blood and only 10% is in the fetal fluid. Indications for analysis:
- diagnosis of the placenta during pregnancy (together with free estradiol);
- diagnosis of bladder skidding and chorion carcinoma (a decrease in the level of placental lactogen at high rates of chorionic gonadotropin).
In case of death of the fetus, frozen pregnancy, placental dysfunction, delayed pregnancy, fetal development retardation syndrome, late pregnancy gestosis, a decrease in the level of placental lactogen will be observed. And its increase is possible in case of multiple pregnancy , diabetes mellitus (with thickened placenta), Rh-conflict of mother and fetus, fetal macrosomia, trophoblast tumors.