Table 4 Schedule A (Data collection before any detection of a menstruation delay)

Abstraction from clinical record

Sampling phase

Search clinical records to identify potentially eligible subjects

FA00

Introduction to study

First contact with subject (in person or by phone)

-Verify potential eligibility

FA00

-Verify subject address and contact information

FA01

-Introduce potential subject to the study

-Explain study purpose and subject responsibilities

-Answer any questions that potential subject may have

-Check willingness of potential subject to participate

Screening

Directly or within a week period after introduction into study

Screen subject for eligibility

FA02

Enrollment

Directly or within a week period after screening

-Obtain informed consent

FA03

-Obtain blood sample from subject

-Inform subject of process of study drug dispensing and next follow-up

Verification of B12 and pregnancy test results, randomization, dispensing study pills, and baseline contact

Within 1–2 weeks days after enrollment

-Verify blood test results (mainly B12 levels)

FA04

Randomize subjects who have no B12 deficiency and are not pregnant and dispense folic acid pills

Refer subjects who have B12 deficiency to hematology service

Follow-up onward

Every 2 months (about 8 weeks)

-Dispense and confirm receiving folic acid pills

FA05

-Complete follow-up visit form

Follow-up when blood sampling is due

(Once every 12 months after enrollment.

-Schedule an in person follow-up for blood sampling

FA05

-Dispense folic acid pills

FA16

-Complete follow-up visit form