Injectable contraception: what should the longest interval be for reinjections?
BACKGROUND
Progestin-only injectable contraceptives continue to gain in popularity, but uncertainty remains about pregnancy risk among women late for reinjection. The World Health Organization (WHO) recommends a "grace period" of 2 weeks after the scheduled 13-week reinjection. Beyond 2 weeks, however, many providers send late clients home to await menses.


METHODS
A prospective cohort study in Uganda, Zimbabwe and Thailand followed users of depot-medroxyprogesterone acetate (DMPA) for up to 24 months. Users were tested for pregnancy at every reinjection, allowing analysis of pregnancy risk among late comers.


RESULTS
The analysis consists of 2290 participants contributing 13,608 DMPA intervals. The pregnancy risks per 100 women-years for "on time" [0.6; 95% confidence interval (CI), 0.33-0.92], "2-week grace" (0.0; 95% CI, 0.0-1.88) and "4-week grace" (0.4; 95% CI, 0.01-2.29) injections were low and virtually identical.


CONCLUSIONS
Extending the current WHO grace period for DMPA reinjection from 2 to 4 weeks does not increase pregnancy risk and could increase contraceptive continuation.
Steiner
Markus J
MJ
Family Health International, Research Triangle Park, NC 27709, USA. msteiner@fhi.org
Kwok
Cynthia
C
Stanback
John
J
Byamugisha
Josaphat K
JK
Chipato
Tsungai
T
Magwali
Thulani
T
Mmiro
Francis
F
Rugpao
Sungwal
S
Sriplienchan
Somchai
S
Morrison
Charles
C
D000328:Adult; D015331:Cohort Studies; D003268:Contraception Behavior; D003271:Contraceptive Agents, Female / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D008525:Medroxyprogesterone / Q000008:administration & dosage*; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D013785:Thailand; D016896:Treatment Outcome; D014454:Uganda; D015030:Zimbabwe
D003271:Contraceptive Agents, Female; D008525:Medroxyprogesterone