Oral Contraceptives and Neutropenia: A Population-Based Cohort Study

Yael Shalev Rosenthal, Gabi Chodick, Adam Rosenthal, Varda Shalev, Hila Shalev Ram, Gideon Koren

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Background: Oral contraceptives (OCs) are one of the most commonly used classes of drugs worldwide. A case of neutropenia and associated infections in a young woman using OCs that settled after discontinuation and reappeared upon re-challenge, has led us to investigate a potential association between oral contraceptives and neutropenia. Objectives: To compare rates of neutropenia among women receiving OCs to a matched control group of women not exposed to the “pill”. Patients and Methods: In this population-based cohort study we used a large computerized database of a health fund, comparing women prescribed OCs and a control group not using the pill. We selected a cohort of 51,394 OC users aged 16–40 years who purchased their first monthly pack of OCs between 2010 and 2018. Controls included all non-pregnant women aged 16–40 years for whom OC was not dispensed (n = 140,932). Neutrophil count before and during OC were compared. Results: Prior to OC exposure, 1.3% of the women were neutropenic, compared to 1.6% after exposure to OC (RR 1.22; 95% CI 1.1–1.35). Mean neutrophil count changed from 3.87 × 103 to 3.82 × 103 mm3 (p < 0.001). In the control group (n = 140,932) no difference was seen in the proportion of neutropenic women between the first complete blood count (1.7%) compared to the second (1.8%) count (p = 0.305). In all severity levels, neutropenia was significantly more common in the OC group. The relative risk was higher for severe (RR 1.63) than for mild neutropenia (RR 1.13) (p = 0.034 for trend). Conclusions: There is a significant increase in the proportion of neutropenic women after initiating OCs. More research is needed in order to evaluate the effect of neutropenia in this group of women.

Original languageEnglish
Pages (from-to)927-930
Number of pages4
JournalClinical Drug Investigation
Issue number10
StatePublished - 1 Oct 2019


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