The corpus luteum is formed from the granulosa cells that surround the egg before ovulation. After ovulation, the corpus luteum continues to secrete progesterone. Usually 8 to 10 days after ovulation, if the egg is not fertilized, the corpus luteum begins to shrink.
In women with insufficient corpus luteum function, the corpus luteum begins to shrink 4 to 5 days after ovulation, and the second half of menstruation is shortened accordingly. Usually, this menstrual cycle is also relatively insufficient in estrogen, and the endometrium is underdeveloped, so the fertilized egg cannot implant.
Recurrent spontaneous abortion can lead to luteal insufficiency. In the first 3 months of pregnancy, the function of the corpus luteum is particularly important. At this stage, the corpus luteum secretes high levels of hormones, which can cause endometrial hyperplasia and hypertrophy, providing a favorable environment for embryo implantation.
Corpus luteum insufficiency means that the corpus luteum secretes insufficient estrogen and progesterone, and the secretory changes of the endometrium are insufficient. Luteal corpus function will not cause luteal phase bleeding, fertilized egg implantation failure, infertility, or habitual miscarriage. The maintenance of normal luteal function depends on the improvement of the function of the hypothalamus-pituitary-ovarian gonadal axis. Abnormalities in not only the luteal phase but also the follicular phase can also cause luteal dysfunction.
It is generally believed that luteal insufficiency is related to the following factors:
① Insufficient secretion of follicle-stimulating hormone in the follicular phase, and low values of follicle-stimulating hormone and estradiol in the follicular fluid.
②The peak of luteinizing hormone during ovulation is insufficient.
③Insufficient secretion of luteinizing hormone in the luteal phase or insufficient pulse secretion.
④ Abnormal steroid hormone receptors in endometrial cells and low responsiveness to hormones secreted by the corpus luteum can lead to normal luteal function and poor endometrial development.
Infertility caused by insufficient luteal function is not the inability to fertilize, but the inability to maintain pregnancy. In the second half of the menstrual cycle and the first 3 months of pregnancy, vaginal insertion of progesterone-containing suppositories can help improve luteal function. Low-dose human chorionic gonadotropin and clomiphene have been successfully used to maintain luteal function, but synthetic progestins must be avoided. For example, the use of medroxyprogesterone and norethindrone in early pregnancy may be harmful to the fetus.
This article is provided by Baidu Reading and is excerpted from \”The Clear \”Conception\” Plan\” Author: Sun Jianqiu and Xie Yingbiao