Abstract: Progesterone only methods are often prescribed for breastfeeding women. The main halachic concern with progesterone only preparations is their propensity to cause spotting  . This often, but not always, causes the woman to become niddah. Patients should be aware of what to anticipate prior to starting this method. Patients should be counseled to consult with their rabbis before abandoning this method because of spotting, as halachic solutions can sometimes be found
Progesterone only preparations (POPs) have several mechanisms of action  .
- Suppression of ovulation
- Suppression of midcycle gonadotropin peaks
- Alteration of cervical mucus: POPs reduce cervical mucus volume, increase its viscosity, and alter its molecular structure. The result is a "hostile," or "blocked," cervical mucus that decreases the possibility of sperm penetration.
- Alteration of the endometrium: POPs may interfere with the cyclic development of the uterine lining, making it unsuitable for ovum implantation. POP progestins appear to reduce the number and size of endometrial glands and inhibit the synthesis of progesterone receptors in the endometrium.
- Alteration of the fallopian tubes: POPs may affect cilia in the fallopian tubes, decreasing the intensity and frequency of their action. The result may be a slowing effect on the rate of ovum transport.
Progesterone only methods are most commonly available as the various brands of "minipill." Injections are also available; capsules are no longer used. These methods are generally prescribed for women for whom estrogen use is not desired. This includes breastfeeding women, as progesterone only preparations are less likely to have a negative impact on milk supply.
The efficacy of the minipill is approximately 93% . It is important that the pill be taken at the same time each day, as the protection starts to diminish after 20 hours  . Therefore, if more than three hours have passed from the usual time taken, a backup method (spermicide in the case of the halacha observant women) should be added . Varying the time taken may also increase the chance of breakthrough bleeding.
The main concern with this method is unanticipated bleeding. According to a 1982 randomized, double-blind trial by the World Health Organization (WHO), during the first three months of use, an average of 53% of users reported frequent bleeding, 22% reported prolonged bleeding, and 13% reported irregular bleeding. All of these patterns can lead to extended periods when the couple cannot have relations. Although the frequency of these effects decreased by cycle 12, one-quarter of POP users in the study discontinued because of bleeding disturbances . Halacha observant women are likely to abandon the method sooner, as these effects are more than just a nuisance.
However, sometimes this spotting may not be of halachic consequence and therefore, a woman should consult her rabbi before precipitously abandoning the method. She should also be counseled that it takes time for the body to adjust to the new hormonal environment. Spotting may improve after the first month or two of use, and she should be prepared to test the method for this period of time before abandoning it.
Care should be taken prior to recommending the depot method of administering progesterone. Not only is spotting a concern, but this method is typically associated even more than the minipill with very irregular, erratic, and unpredictable bleeding . Furthermore, the drug remains in the woman's body for a number of months. Therefore, there is little that can be done to help alleviate the situation. Return to fertility after depot formulation is also generally longer than after oral adminimistration  .
Although rarely used today, capsules under the skin do not constitute a barrier to mikveh immersion.
Implications for Patient Care:
Progesterone only contraception is a common request in the halacha observant population.
Patients should be counseled by the physician as to the expected frequency of irregular bleeding and spotting. They should be advised to consult with their rabbis as how to best avoid unnecessary periods of being niddah.
Depot preparations should be used with great caution in this patient population.
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