Comparative analysis of parenteral and oral contraceptives


Uncover the latest findings on contraceptive methods as researchers delve into the safety, efficacy, and compliance rates of parenteral and oral hormonal contraceptives.

Comparative analysis of parenteral and oral contraceptives | Image Credit: © methaphum - © methaphum -

Comparative analysis of parenteral and oral contraceptives | Image Credit: © methaphum - © methaphum -

Parenteral and oral contraceptives are both effective contraceptive methods, according to a recent study published in the Journal of Clinical Medicine.


  1. The study reveals that the efficacy of parenteral and oral contraceptives is comparable, dispelling concerns regarding the effectiveness of these methods.
  2. Patients using parenteral contraceptives exhibited higher compliance rates compared to those using oral administration, suggesting improved adherence with alternative delivery methods.
  3. Among various administration methods, patch contraceptives demonstrated significantly greater compliance than oral contraceptives, providing a potential solution for women facing challenges with daily pill intake.
  4. Parenteral combined hormonal contraceptives demonstrated safety comparable to oral counterparts, with minimal differences in adverse events such as breast discomfort, vomiting, and nausea.
  5. The study concludes that parenteral contraceptives may offer a viable option to decrease discontinuation rates, emphasizing their potential role in promoting sustained contraceptive use among women.

Oral hormonal contraceptives have been available for decades, and recently, alternative administration methods such as transdermal and vaginal administration have been developed to reduce side effects and hormone levels. These may be effective alternatives for women who experience difficulties when taking pills daily.

The efficacy of combined parenteral contraception has been proven, but there is a significant temporal gap in the data. This indicates a need for updated data comparing combined oral contraceptive pills to combined parenteral contraception. To compare these methods, investigators conducted a systematic review and meta-analysis.

The MEDLINE, Cochrane Library, Embase, and Scopus databases were evaluated for literature published from database inception to November 20, 2022. The search key used was: “(contraception or contraceptive) and (ring or patch or transdermal) and random.”

Eligible literature included randomized controlled trials in peer-reviewed journals with women of fertile age as participants, combined parenteral contraception as the intervention, and outcomes including efficacy, adverse events, and cycle control. Exclusion criteria included non-randomized studies, non-peer reviewed publication, insufficient data, a focus on specific health problems, and contraceptive use for specific disorders.

Articles were screened for titles and abstracts then for full texts by 2 independent authors. The Pearl Index was used to determine efficacy, defined as the number of pregnancies with a specific contraceptive method per 100 woman-years. Plasma steroid levels were measured to determine compliance.

There were 13 studies included in the final analysis, 6 of which were used to evaluate efficacy. Contraceptive efficacy did not differ between the parenteral and the oral administration groups, nor was a difference reported between the transdermal patch and the vaginal ring subgroups.

Compliance rates, evaluated across 9 studies, were improved in the parenteral group compared to the oral administration group, with an odds ratio (OR) of 1.5. Subgroup analyses were conducted during 5 studies and found that patients using patch contraceptives had significantly greater compliance vs those using oral contraceptives, with an OR of 2.32.

A difference in compliance was not observed between the ring and oral subgroups. However, the transdermal patch subgroup had significantly improved compliance compared to the ring subgroup.

The odds of breast discomfort, evaluated in 8 studies, were increased in the parenteral group, with an OR of 1.78. Vomiting was evaluated and 5 studies, and the parenteral group had an odds ratio of 0.71. The lowest odds were in the ring subgroup, with an OR of 0.23 across 2 studies.

For nausea, a significant difference in risk was not observed between the parental group and oral group. An increased risk was observed in the patch subgroup, while a decreased risk was observed in the ring subgroup, indicating significant subgroup differences.

Additional outcomes assessed included vaginal discharge, dysmenorrhea, and headache. While the risk of vaginal discharge was increased in the parenteral group with on OR of 2.15, dysmenorrhea and headache risks were not significantly different between the parenteral and oral groups.

These results indicated safety and efficacy from parenteral combined hormonal contraceptives, along with increased compliance. Investigators concluded parenteral contraceptives may be used to reduce discontinuation rates.


Vleskó G, Meznerics FA, Hegyi P, et al. Comparison of combined parenteral and oral hormonal contraceptives: A systematic review and meta-analysis of randomized trials. J. Clin. Med. 2024;13(2). doi:10.3390/jcm13020575

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