For of the purpose of performing studies, unplanned bleeding is classified by the World Health Organization into 2 categories: 1)
breakthrough bleeding, which requires sanitary protection, and 2) spotting, which does not require sanitary protection.
Breakthrough bleeding may be due to any the following variables: 1) physiologic effects of OCs on the endometrium, 2) OC-related parameters, including dose, formulation, and regimen, 3) patient behavior (including compliance, using concomitant medications, and smoking), and 4) benign or malignant pathology.
Data from another study comparing bleeding patterns of CEE/MPA and ethinyl estradiol/norethindrone acetate (NETA) also demonstrated more
breakthrough bleeding with MPA, although both progestogens produced more initial
breakthrough bleeding than was seen with placebo (7) (FIGURE 2).
It should not be used in pregnancy or in combination with low-dose contraceptives because of a theoretical risk of
breakthrough bleeding and pregnancy.
Compared with oral contraceptives, NuvaRing may reduce the incidence of early
breakthrough bleeding and spotting.
One of the problems with the higher-dose formulations was the incidence of
breakthrough bleeding.
There also appears to be less
breakthrough bleeding with tibolone than with HRT.
Wulf Utian, the principal investigator and executive director of the North American Menopause Society Women should be told that the lower dose takes longer than e higher dose to work--up to 2-3 weeks for maximal effect--but has a lower rate of
breakthrough bleeding, he said.
Breakthrough bleeding occurs in about 3% of tibolone-treated patients, far less than with conventional HRT.
Cullins cited a number of potential advantages with the NuvaRing: The once-monthly change means that patients do not have to remember their birth control daily, and since it is worn internally, it allows for sexual spontaneity And compared with oral contraceptives, NavaRing may reduce the incidence of early
breakthrough bleeding and spotting.
For all the research, none of the new products will likely solve the problem of
breakthrough bleeding, Dr.
Oral systemic progestins can cause depression and other side effects such as
breakthrough bleeding, whereas locally delivered progestins have the same efficacy with fewer side effects, he commented.
