Table 5.

School and class attendance at baseline and endline among nested cohort participants, by period day status

No (N)	Term 3 2017 (baseline) 99 girls		Term 2 2018 (endline) 81 girls
	Non period day	Period day*	Non period day	Period day
No of days	2625	554	4111	838
N (%) not attending full day of school	8.5	14.6	12.7	14.8
APR (95% CI)† APD (95% CI)†	1.84 (1.46 to 2.31) 7.1% (3.1% to 10.2%) p<0.001		1.16 (0.97 to 1.38) 2.1% (−0.5% to 4.6%) p=0.10
N (%) not attending all classes	11.4	19.9	18.2	20.6
APR (95% CI)† APD (95% CI)†	1.79 (1.47 to 2.17) 8.9% (5.4% to 12.5%) p<0.001		1.15 (0.99 to 1.32) 2.7% (−0.3 to 5.6%) p=0.07

*Includes days of menses plus day prior to menses (results similar when restricted to days of menses) obtained from daily diaries for 9 months.

†Obtained from random-effects logistic regression adjusting for age and school, allowing for within-girl clustering.

APD, adjusted prevalence difference; APR, adjusted prevalence ratio.