Table 1 Study characteristics
Study | Setting | Study design | Study population | Primary outcome | Inclusion/exclusion criteria | Systematic follow-up period | Methods for pregnancy surveillance | Study follow-up frequency in pregnancy | Methods for birth outcome reporting or identifying live births | Study follow-up frequency after birth outcome | Cohort type |
|---|---|---|---|---|---|---|---|---|---|---|---|
Asia | |||||||||||
India 2000 | Rural Tamil Nadu | RCT of newborn vitamin A supplementation | Recruitment of all pregnant women in study area | 6-month mortality | All women identified as pregnant in the study area were included | 6 months | Local data collectors identified pregnancies from a variety of sources, including community-based health workers, antenatal care clinics, and other development workers in the study area | Visited every 2 weeks in pregnancy and at least once or twice a week in the last month of pregnancy | Local data collectors reported births. Mothers and infants were visited on the day of birth or as soon as possible afterward | Birth visit < 48 h; every two weeks until 6 months | Open pregnancy cohort |
Nepal 1999 | Rural Sarlahi | Cluster RCT of multiple micronutrient supplementation | Recruitment of all pregnant women in study area | Fetal loss and infant mortality | Exclusion criteria: women currently pregnant, breastfeeding an infant aged 9 month, were sterilized, were menopausal, or whose husband had died | > 1 year | Household census to identify eligible women. Local data collectors conducted visits at home every 5 weeks for pregnancy surveillance | Only one baseline visit after positive pregnancy test | Local data collectors reported births. Mothers and infants were visited on the day of birth or as soon as possible afterward | Birth visit < 72 h; daily visits in first 10 days; weekly visits in first 3 months; 6-, 12- months; 8-year visit | Open pregnancy cohort |
Nepal 2011 | Rural Sarlahi | RCT of newborn mustard oil massage | Recruitment of all pregnant women in study area | Neonatal mortality | Inclusion criteria: married women 15–40 years of age | 28 days | Household census to identify eligible women. Local data collectors conducted visits at home every 5 weeks for pregnancy surveillance | Monthly visits in pregnancy after positive pregnancy test and visit at 32-weeks | Local data collectors reported births. Mothers and infants were visited on the day of birth or as soon as possible afterward | Birth visit < 72 h; visits on 1-, 3-, 7-, 10-, 14-, 21-, and 28- days | Open pregnancy cohort |
Philippines 1983 | Urban Cebu | Longitudinal health-nutritional study of infant feeding patterns | Population-based, random cluster sample of census of pregnant women | Infant feeding patterns, determinants, and outcomes | Inclusion criteria: women who lived in the study area and delivered a single live birth | > 1 year | Household census to identify eligible women | Only one baseline survey in 6th month of pregnancy | Midwives and traditional birth attendants working in the survey area were hired to report all births. Reports made were verified by the study staff | Birth visit on 3rd day after delivery (conducted even for infant deaths < 3 days); every two months from months 2 to 24 | Open pregnancy cohort |
Sub-Saharan Africa | |||||||||||
Burkina Faso 2004 | Rural Hounde | RCT of multiple micronutrient supplementation | Prospective, community-based cohort of pregnant women | Fetal growth outcomes | Exclusion criteria: plan to leave the area within the next 2 years | 1 year | Household census to identify eligible women. Local data collectors conducted visits at home every month for pregnancy surveillance | Daily visits in pregnancy | Local data collectors reported births | Birth visit < 24 h; monthly postnatal visits at clinic | Closed pregnancy cohort |
Burkina Faso 2006 | Rural Hounde | RCT of micronutrient fortified balanced energy–protein supplementation | Prospective, community-based cohort of pregnant women | Fetal growth outcomes | Exclusion criteria: plan to leave the area within the next 2 years | 1 year | Household census to identify eligible women. Local data collectors conducted visits at home every month for pregnancy surveillance | Daily visits in pregnancy | Local data collectors reported births | Birth visit < 24 h; monthly postnatal visits at clinic | Closed pregnancy cohort |
Kenya 1992* | Rural Western Kenya | RCT of insecticide treated nets | Prospective, community-based cohort of pregnant women | Under-five mortality | All resident pregnant women and their newborns were eligible for enrollment | > 1 year | Monthly censuses by trained village monitors and/or trained traditional birth attendants residing in the same village | Monthly visits in pregnancy; weekly visits in final month of pregnancy | Traditional birth attendants monitored birth outcomes and visited the household within 24 h after delivery | First visit < 24 h after delivery; end of week 1 and week 2, every 2 weeks until either 2 or 5 years of age | Open pregnancy cohort |
Zimbabwe 1997 | Urban Harare | RCT of maternal-neonatal vitamin A supplementation | Facility-based recruitment of live births from 14 maternity clinics and hospital | Infant mortality | Eligible participants: no acutely life-threatening condition in mother or infant; singleton infant with birth weight ≥ 1500 g; mother planned to stay in Harare after delivery | 1 year | N/A | N/A | Women were recruited in the clinic following delivery of a live born infant | First visit < 96 h after delivery; 6 weeks; 3-, 6-, 9-, 12- months. Some also visited at 15-, 18-, 21-, and 24-months | Closed live birth cohort |
Latin America | |||||||||||
Brazil 1993 | Urban Pelotas | Longitudinal birth cohort study | Facility-based recruitment of all births in Pelotas hospitals | Multiple maternal and child health indicators | Inclusion criteria: living in the urban area of Pelotas | > 1 year | N/A | N/A | All maternity hospitals in the city were visited daily to identify live births | Visits at birth; 1-, 3-, 6-, 12-, 48- months; 11-, 15-, 18-, 22- years | Closed live birth cohort |
Brazil 2004 | Urban Pelotas | Longitudinal birth cohort study | Facility-based recruitment of all births in Pelotas hospitals | Multiple maternal and child health indicators | Inclusion criteria: living in the urban area of Pelotas | > 1 year | N/A | N/A | All maternity hospitals in the city were visited daily | Visits at birth; 3-, 12-, 24-, and 48-months; 6-, 11-, 15-, 18- years | Closed live birth cohort |
Brazil 2015 | Urban Pelotas | Longitudinal pregnancy cohort study | Facility-based recruitment of pregnancies and all births in Pelotas hospitals | Multiple maternal and child health indicators | Inclusion criteria: living in the urban area of Pelotas | > 1 year | Pregnancies were identified through weekly visits to, or other contact with, 123 health facilities conducted by study staff | Study visit conducted between 16 and 24 weeks gestation | Research teams were stationed at the four largest hospitals where > 99% of births in the city occur; daily visits to the fifth hospital, where the remaining births take place, were conducted by a mobile team | Visits at birth within 1–2 days after delivery; 3-, 12-, 24-, and 48-months | Open pregnancy cohort |