A preliminary report on the contraceptive use of subdermal implants containing norethindrone

Contraception with subdermal ST-1435 capsules: side-effects, endocrine profiles and liver function related to different lengths of capsules

One Silastic capsule of 15 mm, 20 mm or 30 mm length was inserted subcutaneously into the ventral aspect of the left forearm or upper arm of 28 healthy women during menstrual bleeding or not later than on the seventh day of the menstrual cycle. A new capsule of the same length was inserted after six months and both capsules were removed twelve months after the first insertion. Side-effects, including changes in body weight, blood pressure, menstrual bleeding and liver function test results, were registered. Blood samples were taken from selected subjects twice a week during the 1st, 2nd, 3rd, 6th, 7th and 12th month of use. Plasma concentrations of ST-1435 were measured by radioimmunoassay and the effects of treatment on pituitary and ovarian function were determined by assaying plasma concentrations of LH, FSH, estradiol and progesterone. There were no differences in hormonal side-effects between subjects who had a 30 mm capsule or subjects who had 20 mm or 15 mm capsules, but subjects who had 20 or 15 mm capsules had significantly longer bleeding or spotting periods in comparison with subjects who had a 30 mm capsule. There were no changes in blood pressure, body weight or liver function test results in comparison with pre-insertion values. The plasma level of ST-1435 was not significantly higher during the use of 30 mm capsules than during the use of 20 or 15 mm capsules. During the use of the shorter ST-1435 capsules, plasma estradiol elevation and slightly suppressed FSH were seen, while the use of longer capsules resulted in a slight suppression of LH. Progesterone concentrations during monitored cycles indicated anovulation. No pregnancies occurred during the study period of one year. The continuation rate at one year was 71% in the 30 mm capsule group and 57% in the 20 and 15 mm capsule groups taken together.

Menstrual blood loss with contraceptive subdermal levonorgestrel implants

Six Silastic capsules each containing 30 mg of levonorgestrel were inserted subcutaneously in the left forearms of 13 volunteer women for contraceptive purposes. Quantitative determinations of menstrual blood loss were performed during a control cycle and during a 1-month period at the 1st, 6th, and 12th months of treatment. Days on which bleeding and spotting occurred were recorded and hemoglobin concentrations were determined. No changes were found in the amount of menstrual blood loss between the control cycles and the treatment cycles. The mean number of bleeding days during each of the three recorded treatment periods was significantly greater than that in the control cycles. No changes in hemoglobin concentration were found. None of the patients became pregnant during the study.

Contraception with subcutaneous capsules containing ST-1435. Pituitary and ovarian function and plasma levels of ST-1435

An RIA for a new progestin, ST-1435, was developed. Plasma concentrations of this steroid were measured in three women having three subcutaneous capsules, each containing 40 mg of ST-1435. Pituitary and ovarian functions were assessed by measuring plasma levels of LH, FSH, estradiol and progesterone. Plasma profiles of ST-1435 were characterized by high and irregular peaks all the way through the study period of 7-9 months. Concentrations below 100 pg/ml were not observed, whereas the highest peaks reached concentrations of 10.1 ng/ml. Plasma estradiol concentrations remained uniformly suppressed below 100 pg/ml, thus indicating a suppression in follicle development. As judged by constantly suppressed progesterone concentrations, no ovulations occurred during the treatment. Plasma FSH concentrations remained at the upper limit of the follicular phase, and those of LH at the lower limit of the luteal phase of the normal menstrual cycle. No midcycle gonadotropin peaks were observed.

Plasma levels of norethindrone and effect upon ovarian function during treatment with silastic implants containing norethindrone

The study was made to evaluate the effect upon the ovarian steroid pattern during treatment with subcutaneously implanted silastic rods containing norethindrone. Four rods, each containing 37 mg norethindrone (NET), were implanted subcutaneously in five women and left in place for 135--200 days. Plasma levels of NET, estradiol and progesterone were determined by radioimmunoassays. After an initial peak found in all subjects, the plasma level of NET declined. Great day-to-day variations of NET were found. Ovulations were suppressed during treatment in three subjects. One subject had regular ovulations throughout treatment and in one subject a single ovulation was recorded. Peaks of estradiol without subsequent ovulation were found in two subjects. The bleeding pattern was irregular; three subjects had varying degrees of spotting and bleeding, two subjects were amenorrheic. The average daily release rate was 300/micrograms, calculated from the amount of steroids lost from the removed rods. This study indicates that the release of steroid from four NET rods is high enough only initially to completely inhibit ovulation.

Contraceptive and sterilization practices and extrauterine pregnancy: a realistic perspective

Comparative data on the incidence of ectopic pregnancy among accidental pregnancies associated with failure of a contraceptive or sterilization procedure are shown in Table 16. The practical clinical significance of the data in this review is predicated upon a number of related factors. One of the most important of these is the realistic failure rate (or success rate) of each contraceptive or sterilization method. The reported efficacy of various contraceptive methods has such a wide range that we have not attempted to calculate the likelihood that a woman may experience an ectopic pregnancy within a particular time period while using a specific method. The success or failure rate of each method is influenced by such variables as (1) the conscientiousness and ability of the patient to follow instructions, (2) the true failure rate of the method itself, (3) the experience of the clinician prescribing a method or performing a surgical procedure, and (4) other factors less clearly defined. Because of these many variables, the data shown in Table 16 were calculated on the basis of the number of reported accidental pregnancies which occurred coincidentally with, or subsequent to, a specific contraceptive or sterilization modality. (formula: see text). These data do not reflect the actual rate of occurrence of ectopic pregnancy with respect to woman-months of experience. We recognize the significant influence that age, race, gravidity, and socioeconomic factors have upon the incidence of ectopic pregnancy, but were unable to control for these factors in the data presented in this review. These data reprresent only what has occurred under specific circumstances and cannot logically be extrapolated to any specific future case or study series. It is important to emphasize the necessity of constant awareness by the medical and paraprofessional personnel of the potentially increased risk to the patient of an extrauterine pregnancy should one or another of these contraceptive or sterilization procedures fail. Complacency or a false sense of security on the part of responsible medical personnel concerning women who are "protected against conception" can quickly lead to a life-threatening situation in case of an ectopic pregnancy. Prompt diagnosis and definitive treatment of the extrauterine pregnancy is vital for the successful management of this serious complication of conception.