The COC has different degrees of therapeutic effect on AUB caused by various causes without structural changes; on the other hand, the COC can lead to AUB in the early stage of drug administration or inappropriate methods of drug administration. On the other hand, COC can lead to the occurrence of AUB at the early stage of drug administration or inappropriate drug administration.
Concept of abnormal uterine bleeding
The normal values for each parameter of normal menstruation in women of reproductive age as defined by the International Federation of Gynecology and Obstetrics (FIGO) are: menstrual cycle of 24-38 d, variation between cycle lengths of 2-20 d over 12 months, duration of menstruation of 4.5-8.0 d, and average blood loss of 5-80 ml. The normal values for menstruation in China are: menstrual cycle of 21-35 d, variation between cycle lengths of 12 months The range of variation between menstrual cycle lengths is <7 d, the menstrual period lasts 3-7 d, and the average blood loss is 5-80 ml. Anyone who does not meet these criteria is considered to have AUB.
Classification of abnormal uterine bleeding
There are various etiologies of AUB, which are divided into AUB with structural changes and AUB without structural changes (2011 FIGO PALM-COEIN etiology classification of AUB specifically)
1. Etiology of structural changes.
(1) AUB due to endometrial polyps (polyp)
(2) AUB due to adenomyosis
(3) AUB due to leiomyoma (uterine fibroids)
(4) AUB due to malignancy and hyperplasia of the endometrium.
2. Etiology without structural changes.
(1) AUB due to coagulation-related diseases (coagulopathy)
(2) ovulatory dysfunction-related AUB.
(3) AUB due to endometrial local abnormalities (endometrial)
(4) AUB of medical origin (iatrogenic)
(5) not yet classified AUB.
Treatment of abnormal uterine bleeding with oral contraceptives
COC can reduce menstrual flow, regularize the menstrual cycle with periodic use, and suppress menstruation for a long time with continuous use. There is no evidence of differential therapeutic effects of different COCs; both cycle- and continuous-use COCs are effective, while cycle-use produces regular withdrawal bleeding and continuous-use COCs prolong the intermenstrual period; continuous-use COCs are more effective than cycle-use COCs in reducing the duration and volume of bleeding, but with increased symptoms of breakthrough and spotting bleeding.
COC for hemostatic treatment is recommended to be taken 1-2 tablets at a time, repeated every 8-12 hours, and tapered to 1 tablet daily for maintenance until the end of the cycle after 3 d of hemostasis. In patients who develop moderate to severe anemia, the number of days of COC may be increased to delay menstruation and withdrawal of menstruation may occur when the anemia improves and the drug is discontinued. To regulate the menstrual cycle, COC is generally administered periodically for 3 cycles after withdrawal bleeding with hemostatic drugs, and may be extended to 6 cycles if appropriate for recurrent conditions.
The effectiveness of COC in treating AUB associated with ovulatory dysfunction has been found in clinical studies to have higher rates of hemostasis and shorter time required for hemostasis compared to estrogen-only or progestin-only medications. However, there are fewer relevant randomized controlled clinical studies, and no conclusions can be drawn regarding which treatment or which agent is more effective. Low-dose COC (20-35 μg ethinyl estradiol) is recommended for those with AUB associated with ovulatory dysfunction in adolescents, especially in those with hirsutism and hyperandrogenism. COC inhibits the production of androgens by the ovaries and adrenal glands, increases sex hormone-binding globulin (SHBG), further reduces free androgens, improves acne and hirsutism symptoms, and helps restore the menstrual cycle.
AUB due to localized endometrial abnormalities manifests as regular menstrual cycles but excessive menstrual flow or intermenstrual bleeding. Systematic evaluation showed that COC reduced bleeding by 35% to 69%, which was inferior to levonorgestrel intrauterine extended-release system (which reduced by 71% to 95%) but superior to NSAIDs (which reduced by 10% to 52%).
AUB due to coagulation-related disorders manifests as excessive menstrual flow; treatment should first correct coagulation and the use of COC may reduce uterine bleeding.
Factors leading to medical AUB include the use of exogenous hormones, IUDs, non-sex hormonal drugs that affect sex hormone levels and drugs that interfere with coagulation, etc. The use of exogenous hormonal contraceptive preparations and IUDs are the main causes of medical AUB. The use of COC needs to be evaluated for improper use and for drug malabsorption due to interaction with other drugs, etc. If necessary, a pregnancy test should be performed to exclude pregnancy and to confirm that the bleeding originates from the uterus. AUB is more common during the first 3 months of use of sex hormonal contraceptive preparations and is likely to improve spontaneously after at least 3 months of continued use of the same preparations; for persistent bleeding after 3 months, the COC can be switched to a higher dose of estrogen. mechanical irritation of the endometrium by the IUD (without hormonal components) leads to increased intrauterine fibrinogen activator and fibrinolytic enzyme activity and is an important cause of AUB is an important cause of AUB. Randomized controlled studies have shown that COC is effective in treating AUB due to IUD placement.