A comparative study of a progestin-only oral contraceptive versus non-hormonal methods in lactating women in Buenos Aires, Argentina

Effectiveness and efficacy rates of progestin-only pills: A comprehensive literature review

OBJECTIVES

To synthesize published literature on POP effectiveness and efficacy.

STUDY DESIGN

We searched PubMed Central, PubMed, and the Cochrane library through March 07, 2022. We included articles written in English reporting a Pearl Index or life table rate for pregnancy. We excluded articles only assessing formulations that: were never marketed globally, are only sold in combination with estrogen, are currently sold only for noncontraceptive purposes, or were not given to participants continuously. Four researchers independently extracted data and two analyzed data using Excel and R.

RESULTS

We included 54 studies. Among studies at low or moderate risk of bias, the median Pearl Index rate (the failure rate during typical use) was 1.63 (range 0.00-14.20, IQR 4.03) and the median method failure Pearl Index rate (the failure rate during perfect use) was 0.97 (range 0.40-6.50, IQR 0.68). Excluding the newer formulations, Desogestrel and Drospirenone, which are closer to combined oral contraceptives in that they prevent pregnancy by inhibiting ovulation, the median Pearl Index rate is 2.00 (range 0.00-14.12, IQR 2.5) and the median method failure Pearl Index rate is 1.05 (range 0.00-10.90, IQR 1.38).

CONCLUSIONS

Among studies at low or moderate risk of bias, the median Pearl Index rate during typical POP use was much lower than currently estimated (7.00), while the median perfect use rate was similar to current estimates.

IMPLICATIONS

Future research should investigate the possibility that POPs may be much more effective during typical use than currently believed.

A review of the effectiveness of a progestogen-only pill containing norgestrel 75 µg/day

OBJECTIVES

To review published data on the effectiveness of a progestogen-only pill containing norgestrel 75 µg/day which should be under consideration by the FDA in 2022 for sale over the counter in the US.

STUDY DESIGN

A literature search in MEDLINE, EMBASE, and COCHRANE REVIEWS using specified search terms and adding related cross-references.

RESULTS

We identified a total of thirteen relevant studies of women using norgestrel 75 µg/day. None were reported with the rigor characteristic of trial reporting today. Nevertheless, six studies provided data on 3,184 women who were not breastfeeding, followed for over of 35,000 months and reported a range of overall failure rates during typical use of norgestrel 75 µg/day from 0 to 2.4/hundred woman-years giving an aggregate Pearl Index of 2.2. Seven additional studies involved 5,445 women some of whom were breastfeeding for at least part of the period of follow-up. More than 36,000 months of use yielded 12-month life table cumulative pregnancy rates for norgestrel 75 µg/day ranging from 0 to 3.4. We were unable to calculate an aggregate Pearl Index for the breastfeeding studies because of lack of crucial data.

CONCLUSIONS

The data support that norgestrel 75 µg/day is highly effective in clinical use, with similar estimates of failure in breastfeeding and non-breastfeeding women, providing support to the case for approval without the need to see a healthcare provider.

Progestogen-only contraceptive use among breastfeeding women: a systematic review

BACKGROUND

Postpartum women need effective contraception. Concerns have been raised that use of progestogen-only contraceptives (POCs) may affect breastfeeding performance and infant health outcomes.

OBJECTIVES

We investigated the clinical outcomes of breastfeeding duration, initiation of supplemental feeding and weaning, as well as infant outcomes including infant growth, health and development among breastfeeding women using POCs compared with breastfeeding women not using POCs.

SEARCH STRATEGY

We searched the PubMed database for all articles published from database inception through December 2014.

SELECTION CRITERIA

We included primary research studies of breastfeeding women of any age or parity who received POCs, including progestogen-only pills, injectables, implants or hormonal intrauterine devices (IUDs). The main outcomes were breastfeeding performance (as measured by initiation, continuation, frequency and exclusivity of breastfeeding) and infant health (as measured by growth, development or adverse health effects).

RESULTS

Forty-nine articles reporting on 47 different studies were identified that investigated the use of POCs in breastfeeding women and reported clinically relevant outcomes of infant growth, health or breastfeeding performance. Studies ranged from poor to fair methodological quality and generally failed to show negative effects of the use of POCs on breastfeeding outcomes or on infant growth or development. One randomized controlled trial (RCT) raises concerns that immediate insertion of the levonorgestrel IUD postpartum may be associated with poorer breastfeeding performance when compared with delayed insertion, although two other RCTs evaluating early etonogestrel implants compared with delayed initiation of implants or depot medroxyprogesterone acetate failed to find such an association.

CONCLUSION

The preponderance of evidence fails to demonstrate adverse breastfeeding outcomes or negative health outcomes in infants such as restricted growth, health problems or impaired development. Evidence newly added to this review was largely consistent with previous evidence.

Lactation and contraception

PURPOSE OF REVIEW

This review examines evidence relevant to the effect of hormonal contraception on breastfeeding; and compares global and US recommendations for contraceptive initiation and use. Breastfeeding and use of postpartum contraception have high public health priority, making research in this area critical for optimizing guidance.

RECENT FINDINGS

High quality evidence remains limited with only a small number of well-conducted randomized controlled trials of hormonal methods and breastfeeding/neonatal growth outcomes. More evidence supports early initiation of progestin-only methods. Evidence on early initiation of combination hormonal methods is sparse.

SUMMARY

The WHO Medical Eligibility Criteria (MEC) differs from that of the US MEC. Generally, the WHO MEC is more restrictive, reflecting the potential greater impact on maternal child health if there is a negative impact from hormonal contraception on breastfeeding. Only well conducted clinical trials will further elucidate such an impact.

VIDEO ABSTRACT

http://links.lww.com/COG/A15.

Progestin-only pills for contraception

BACKGROUND

The introduction of a new progestin-only oral contraceptive in Europe has renewed interest in this class of oral contraceptives. Unlike the more widely used combined oral contraceptives containing an estrogen plus progestin, these pills contain only a progestin (progestogen) and are taken without interruption. How these pills compare to others in their class or to combined oral contraceptives is not clear.

OBJECTIVES

This review examined randomized controlled trials of progestin-only pills for differences in efficacy, acceptability, and continuation rates.

SEARCH METHODS

Through October 2013, we searched the computerized databases MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), POPLINE, and LILACS for studies of progestin-only pills. We also searched for current trials via ClinicalTrials.gov and ICTRP. Previous searches also included EMBASE.

SELECTION CRITERIA

We included all randomized controlled trials in any language that included progestin-only pills for contraception.  We incorporated any comparison with a progestin-only pill; this could include different doses, other progestin-only pills, combined oral contraceptives, or other contraceptives.

DATA COLLECTION AND ANALYSIS

The first author abstracted the data and entered the information into RevMan 5. Another author performed a second, independent data abstraction to verify the initial data entry.We attempted to extract life-table rates (actuarial or continuous) and used the rate difference as the effect measure. Where life-table rates were not published, we used the incidence rate ratio (ratio of Pearl rates). Where only the crude number of events was published, we calculated the Peto odds ratio with 95% confidence interval (CI) using a fixed-effect model. For continuous variables, the mean difference (MD) was computed with 95% CI. Because of disparate exposures, we were not able to combine studies in meta-analysis.

MAIN RESULTS

Six trials met the inclusion criteria. We have not found any new studies since the initial review. In the trial comparing the desogestrel versus levonorgestrel progestin-only pill, desogestrel was not associated with a significantly lower risk of accidental pregnancy; the rate ratio was 0.27 (95% CI 0.06 to 1.19). However, the desogestrel progestin-only pill caused more bleeding problems, although this difference was not statistically significant. The trial comparing low-dose mifepristone versus a levonorgestrel progestin-only pill found similar pregnancy rates. In the trial comparing ethynodiol diacetate versus a combined oral contraceptive, irregular cycles occurred in all women assigned to the progestin-only pill (odds ratio 135.96; 95% CI 7.61 to 2421.02). In a trial comparing two progestin-only and two combined oral contraceptives, the progestin-only pill containing levonorgestrel 30 μg had higher efficacy than did the pill containing norethisterone 350 μg. An early trial found megestrol acetate inferior to other progestin-only pills in terms of efficacy. A study of the timing of pill initiation after birth found no important differences, but high losses to follow up undermined the trial.

AUTHORS' CONCLUSIONS

Evidence is insufficient to compare progestin-only pills to each other or to combined oral contraceptives.

Progestin-only pills for contraception

BACKGROUND

The introduction of a new progestin-only oral contraceptive in Europe has renewed interest in this class of oral contraceptives. Unlike the more widely used combined oral contraceptives containing an estrogen plus progestin, these pills contain only a progestin (progestogen) and are taken without interruption. How these pills compare to others in their class or to combined oral contraceptives is not clear.

OBJECTIVES

This review examined randomized controlled trials of progestin-only pills for differences in efficacy, acceptability, and continuation rates.

SEARCH STRATEGY

We searched the computerized databases MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), POPLINE, LILACS, and EMBASE for studies of progestin-only pills. We also searched for current trials via ClinicalTrials.gov and ICTRP.

SELECTION CRITERIA

We included all randomized controlled trials in any language that included progestin-only pills for contraception. We incorporated any comparison with a progestin-only pill; this could include different doses, other progestin-only pills, combined oral contraceptives, or other contraceptives.

DATA COLLECTION AND ANALYSIS

The first author abstracted the data and entered the information into RevMan 5. Another author performed a second, independent data abstraction to verify the initial data entry. Because of disparate exposures, we were not able to combine studies in meta-analysis.

MAIN RESULTS

Six trials met the inclusion criteria. In the trial comparing the desogestrel versus levonorgestrel progestin-only pill, desogestrel was not associated with a significantly lower risk of accidental pregnancy; the rate ratio was 0.27 (95% CI 0.06 to 1.19). However, the desogestrel progestin-only pill caused more bleeding problems, although this difference was not statistically significant. The trial comparing low-dose mifepristone versus a levonorgestrel progestin-only pill found similar pregnancy rates. In the trial comparing ethynodiol diacetate versus a combined oral contraceptive, irregular cycles occurred in all women assigned to the progestin-only pill (odds ratio 135.96; 95% CI 7.61 to 2421.02). In a trial comparing two progestin-only and two combined oral contraceptives, the progestin-only pill containing levonorgestrel 30 mug had higher efficacy than did the pill containing norethisterone 350 mug. An early trial found megestrol acetate inferior to other progestin-only pills in terms of efficacy. A study of the timing of pill initiation after birth found no important differences, but high losses to follow up undermined the trial.

AUTHORS' CONCLUSIONS

Evidence is insufficient to compare progestin-only pills to each other or to combined oral contraceptives.

Safety of the etonogestrel-releasing implant during the immediate postpartum period: a pilot study

BACKGROUND

The effects of etonogestrel (ETG)-releasing contraceptive implant during the immediate postpartum period on maternal safety are unknown.

STUDY DESIGN

Forty healthy women exclusively breastfeeding were randomized to receive either ETG-releasing implant 24-48 h after delivery (n=20) or depot medroxyprogesterone acetate (DMPA group; n=20) at the sixth week postpartum. We measured blood pressure, maternal and neonatal weight, body mass index (BMI; kg/m(2)), waist circumference (WC), complete blood count, C-reactive protein, interleukin-6, tumor necrosis factor (TNF-alpha), lipid profile, fasting serum glucose and maintenance of exclusive lactation up to the 12th week postpartum.

RESULTS

Decreases in mean maternal weight, BMI (kg/m(2)) and WC were significantly greater in the ETG-releasing implant group than in the DMPA group during the first 6 weeks postpartum (-4.64+/-2.71 kg vs. -2.6+/-2.45 kg mean+/-SD, p=.017; -1.77+/-1.06 kg/m(2) vs. -0.97+/-0.95 kg/m(2), p=.026; -15.3+/-6.72 cm vs. -9.05+/-5.84 cm, p=.003, respectively). In addition, total cholesterol and HDL, were lower in DMPA users, and TNF-alpha and leukocytes were higher in DMPA users compared to in the implant group, between 6 and 12 weeks after delivery. The newborns of implant users showed a trend towards gaining more weight, as compared with the infants of the DMPA mothers during the first 6 weeks of life (implant group: +1460.50+/-621.34 g vs. DMPA group: +1035.0+/-562.43 g, p=.05). The remaining variables, including the duration of exclusive breastfeeding, were similar between the groups.

CONCLUSION

The insertion of ETG-releasing contraceptive implant during the immediate postpartum period was not associated with deleterious maternal clinical effects or with significant maternal metabolic alterations or decreased infant weight gain.

Impact of early postpartum administration of progestin-only hormonal contraceptives compared with nonhormonal contraceptives on short-term breast-feeding patterns

OBJECTIVE

The purpose of this study was to identify the impact on breast-feeding patterns of early postpartum initiation of progestin-only birth control methods compared with nonhormonal methods.

STUDY DESIGN

A prospective, nonrandomized trial was performed comparing progestin-only contraceptive methods administered before hospital discharge with nonhormonal methods on breast-feeding continuation rates, exclusive breast-feeding, and supplementation at 2, 4, and 6 weeks after delivery.

RESULTS

Three hundred nineteen women provided complete data until hospital discharge. The hormonal group had higher risk factors for not breast-feeding, but there was no difference among any of the subgroups in breast-feeding continuation rates except at week 4. Supplementation or perception of insufficient milk production did not differ between groups. By week 6, 23.5% of women discontinued breast-feeding, and 64.5% of those breast-feeding were supplementing.

CONCLUSION

This study demonstrates that there is no detectable adverse impact on breast-feeding attributable to progestin-only contraceptive methods initiated within the first 3 days post partum.

Premature introduction of progestin-only contraceptive methods during lactation

Experts on contraceptive technology concur that progestin-only methods can be used safely during lactation. However, very few studies exist of the effects on lactation of the introduction of progestin-only methods prior to the sixth postpartum week. Since progesterone withdrawal is the likely stimulus that initiates lactogenesis, it appears necessary for natural progesterone levels to decline to baseline before a progestin-only contraceptive is initiated. Therefore, the use of such contraceptive methods should be delayed for at least 3 days after the birth. Non-hormonal methods remain the first choice category of contraceptive methods for breastfeeding women, since there is no possibility that they will interfere with lactation. Progestin-only methods comprise a viable and often desirable next choice category, although the timing of their commencement must be determined with care in order to support lactation.

Hormonal contraception and lactation

Hormonal contraceptive measures can be used immediately postpartum if the patient so desires. Progestin-only contraceptives are preferable to estrogen-containing methods if initiated during the first six months after delivery. Progestin only contraceptives do not appear to affect milk volume, composition, or to cause deleterious effects in the infant. Ideally for women who desire a form of contraception in addition to lactation-induced amenorrhea, progestin-only methods should be started at six weeks postpartum if the woman is fully breastfeeding. Since contraception protection is provided by lactation amenorrhea, the six week delay will decrease infant exposure to exogenous hormones and decrease the incidence of irregular postpartum bleeding. Milk volume may decrease with the use of estrogen; however, no detrimental effects have been shown on infant growth or development. For women who are planning to gradually wean their infant, use of COCs may provide an easier transition to bottle-feeding. COCs should be used with caution by women who are not able to obtain supplemental milk. A decrease in milk volume can lead to earlier discontinuation of the hormonal contraceptive in an attempt to increase milk quantity. Supplementation is often needed, and then the woman ovulates again, possibly resulting in an unintended pregnancy. Many women are motivated immediately postpartum to accept contraception. For other women, lack of access to health care may provide barriers in obtaining adequate contraception later. In either case, there are adequate data to show no detriments of starting progestin-only contraceptives within days of delivery. Therefore, the best method for the patient should be employed to ensure adequate contraception while preserving optimal lactation.

Effectiveness of lactational amenorrhoea in prevention of pregnancy in Manila, the Philippines: non-comparative prospective trail

OBJECTIVE

To determine the contraceptive efficacy of the lactational amenorrhoea method.

DESIGN

Non-comparative prospective trial.

SETTING

Urban Manila, the Philippines.

SUBJECTS

485 lower income, educated women with extensive experience of breast feeding.

INTERVENTION

Women were offered all available contraceptives for use after birth. Those who chose the lactational amenorrhoea method were taught the method, screened for the study, and followed for 12 months to determine the risk of pregnancy when the method was used.

MAIN OUTCOME MEASURES

Life table pregnancy rates during correct and incorrect use of the method, censored monthly in the event of sexual abstinence or the use of another contraceptive method.

RESULTS

The lactational amenorrhoea method was 99% effective when used correctly (that is, during lactational amenorrhoea and full or nearly full breast feeding for up to six months). At 12 months the effectiveness during amenorrhoea dropped to 97%.

CONCLUSIONS

The lactational amenorrhoea method provided as much protection from pregnancy as non-breast feeding women experience with non-medicated intrauterine devices and barrier methods. The contraceptive effect of lactation cannot be attributed to lactational or postpartum abstinence.

Effects of a progestogen-only pill (Exluton) and an intrauterine device (Multiload Cu250) on breastfeeding

The objective was to compare the effects of Exluton with those of Multiload Cu250, in an open-label, bi-center, randomized study in breastfeeding women. Subjects were randomized to one of the treatment groups 6 weeks after delivery. Women and their infants returned to the study site monthly and follow-up data regarding qualitative and quantitative characteristics of the breast milk, infant growth and infant and maternal health were obtained. There were no statistically significant differences between groups with regard to: (1) amount of milk drunk, amount of milk production, and number of daily breastfeedings; (2) mean milk concentrations of nutritional constituents (except higher milk levels of calcium and magnesium with Exluton during the first month); (3) infant anthropometric parameters. There were no between-group differences with regard to systolic or diastolic blood pressure. During the study, the mean maternal body weight in the Exluton group was significantly lower than in the Multiload Cu250 group. There were no differences between groups with regard to child or maternal health, except a lower incidence of child illness after 6 months in the Exluton group. This study confirms that both Exluton and Multiload Cu250 are acceptable and safe contraceptive methods in breastfeeding women.

Some methodological considerations of a progestin-only oral contraceptive study from a programmatic perspective

Among the limited number of reports on progestin-oral contraceptives (POCs), noncomparative studies conducted at family planning clinics have been the most often reported. This research trend will probably continue. Generally, noncomparative studies address a number of practical issues on POC use, and such studies have made important contributions to the understanding of this contraceptive modality. However, some studies have presented results that are either difficult to extrapolate for potential users or conflict with other findings. This article reviews several studies and suggests ways to improve the study methodology. Well-conceived, -executed, and -analyzed noncomparative studies can cost-effectively address a number of practical issues of POC use that have not been adequately addressed. Additional topics with programmatic utility, such as the effect of local background variables on POC acceptability, and the place of POCs in the ever-increasing contraceptive spectrum, are also discussed.

The safety and efficacy issues of progestin-only oral contraceptives--an epidemiologic perspective

Progestogen-only oral contraceptives (POCs) are generally considered a good contraceptive choice for brestfeeding women and for women who want to use an oral form of contraception, but are not suited for, or cannot tolerate the side effects of, estrogen-containing preparations. However, a number of POCs' safety, efficacy and other related issues remain to be addressed. This paper reviews recent literature and evaluates these issues from an epidemiologic perspective. The small number of users imposes severe limitations in designing epidemiologic studies to address POCs' long-term safety issues, but available information suggests POCs are at least as safe as, if not safer than, COCs. Compared to COCs, POCs are more likely to cause menstrual disturbances which, in turn, could affect their acceptability and lead to poor compliance and hence higher pregnancy rates. POCs' efficacy has been estimated to be between 1.4 and 4.3 pregnancies per 100 woman-years of use. Lower pregnancy rates approaching those of COCs have been reported in centers with good counseling. POCs' benefits outweigh their risks. However, more studies are needed to further address POCs' safety and efficacy issues.

A multicenter clinical trial of a progestin-only oral contraceptive in lactating women

A non-comparative study of a progestin-only oral contraceptive (POC) containing 75 micrograms norgestrel was conducted at 22 sites in 14 countries. This study was designed to evaluate safety, contraceptive efficacy, and the overall acceptability of a POC in breastfeeding women. A total of 4,088 women entered the study over a three-year period and 29,399 woman-months of experience was gathered. Women had follow-up visits at 2, 6, and 11 months after admission. Headaches and vaginal discharge were the medical complaints most commonly reported by women, both prior to and after admission. Menstrual problems were reported by 59% of the women after admission. Of the 3,714 women who returned for at least one follow-up visit, 1,101 (29.6%) discontinued through month 11. The 11-month total discontinuation percentage, including those lost to follow-up (25.3%) was 51.6%. The most common reason given for discontinuation was a woman's desire for a change in contraceptive method. Only 4.9% discontinued pill use for menstrual problems, a percentage far below those generally reported for POCs. Twenty-nine unintended pregnancies occurred through 11 months giving a gross cumulative life table rate of 1.2 per 100 women (Pearl Index = 1.4). The POC appears to be a safe, effective and acceptable contraceptive option for postpartum breastfeeding women.

The progestin-only oral contraceptive--its place in postpartum contraception

The progestin-only oral contraceptive (POC) is not a widely-used method of contraception, possibly due to competition from other contemporary contraceptive methods or misunderstanding and prejudices among clients and/or service providers. Because of its underuse, the POC, as a contraceptive method, is under-studied. This article evaluates the general merits of the POC and its disadvantages relative to combined oral contraceptives (COCs) and other contraceptive methods, specifically during the postpartum period and particularly for breastfeeding women. We find that the POC appears to be a safe and acceptable contraceptive method for postpartum women who are fully or nearly fully breastfeeding at six months postpartum or when menstruation returns. The POC could be considered for use at any time by non-breastfeeding postpartum women. The need for empirical studies of the POC is also discussed.