Ms. Lin, 29 years old, has experienced two pregnancies in the past, but both ended in early miscarriages. After several years of unsuccessful attempts to conceive, she underwent artificial insemination and finally confirmed her pregnancy. Due to her previous episodes of vaginal bleeding during early pregnancy, she assumed that bed rest would resolve the issue. However, the bleeding worsened over time, leading her to seek medical help at the obstetrics and gynecology department. Through ultrasound examination, the doctor discovered that the embryo had been expelled, diagnosing it as an incomplete miscarriage possibly caused by progesterone deficiency or chromosomal abnormalities. Consequently, for her current pregnancy, the doctor prescribed progesterone supplementation and advised her to continue taking it until the fetus reaches 8 weeks. What exactly is progesterone deficiency, and can it cause infertility?

 

According to statistics, out of 100 pregnancies, approximately 10 will result in miscarriage, with the majority of cases being caused by chromosomal abnormalities. Some miscarriages, however, are attributed to progesterone deficiency.

 

Progesterone is secreted by the corpus luteum, which is formed by the transformation of granulosa cells in the follicle after ovulation. Progesterone acts on the endometrium of the uterus, promoting glandular proliferation and thickening of the endometrial lining, creating a suitable environment for embryo implantation. It also reduces uterine contractions, facilitating implantation. Once implantation occurs and pregnancy is established, the placenta gradually forms and begins to secrete hormones, gradually replacing the secretion of progesterone by the ovaries. Around 8 weeks of gestation, the placenta fully takes over progesterone production. Therefore, during this period, insufficient progesterone secretion can lead to early miscarriage and may even affect earlier stages by making it difficult for the embryo to implant, resulting in infertility.

 

So, the correct statement would be that insufficient progesterone does not affect fertilization between sperm and egg, but it can potentially impact implantation and even result in early miscarriage.

 

The diagnosis of insufficient progesterone is not difficult. It can be determined by monitoring a woman's basal body temperature. If the luteal phase (the post-ovulation phase) is less than 10 days, there is a high suspicion of progesterone deficiency. Further confirmation can be obtained by conducting a blood test for progesterone levels during the later phase of the menstrual cycle. If the progesterone level is less than 12 ng/ml, it can confirm the diagnosis.

 

Treatment for luteal phase deficiency, especially in anovulatory women, is relatively simple. It involves administering ovulation-inducing medications. For women who have already ovulated but have luteal phase deficiency, supplementation with progesterone is required. Therefore, charting a woman's basal body temperature (BBT) is very useful. By using a BBT chart, it is possible to estimate the occurrence of ovulation, and the medical approach will also vary accordingly.