To evaluate the feasibility of chamas, we analysed group attendance rates, GISE participation, membership retention, and continuation of the groups beyond the one year. To evaluate the effect of chamas, the investigators compared data from a prospective cohort of women in chamas with a group of controls who did not belong to a chama, matched for age, parity, and location of prenatal care. To evaluate the acceptability of chamas, FGDs were carried out with chama and non-chama participants, health providers and community health workers.