• Editors' Summary
• Credits

1. Exploring the New Evidence
• Findings from the DHS Study
• Findings from the CLAP Study
• Why Are Longer Intervals Better?
2. Actual Versus Preferred Birth Intervals
3. Contraception for Spacing Births
4. Who Has Shorter Intervals?
5. How Programs Can Help Couples Space Births

• Figures
• Tables
• Side-bars
• Bibliography

• Why are longer intervals better?
• Spacing: A matter of choice
• How to measure intervals
• Women want longer intervals
• Demand for spacing is high
• Infant deaths shorten intervals
• Traditional practices can help
• Health programs can spread the message

• POPLINE
• Other reports
• To Order
• CCP Home Page

Published by the Population Information Program, Center for Communication Programs, The Johns Hopkins University Bloomberg School of Public Health, 111 Market Place, Suite 310, Baltimore, Maryland 21202, USA.

New findings from a 2000 study in Latin America provide evidence that birth intervals of 3 to 5 years are healthier for mothers, too (38). The study by the Latin American Center for Perinatology and Human Development (Centro Latinoamericano de Perinatología y Desarrollo Humano) (CLAP) is the largest study to assess how birth spacing affects mothers’ health, using data for more than 450,000 women. The study employs a variety of detailed maternal health indicators and accounts statistically for a large number of confounding factors. In previous research the health benefits for mothers of longer birth intervals have been less clear than the benefits for their children. Some studies found that intervals of less than 2 years risk mothers’ health (44, 101, 167, 173). Other studies did not (55, 154).

The CLAP study pooled and analyzed data collected from hospital records between 1985 and 1997 in 19 countries of Latin America and the Caribbean. The data cover a variety of indicators, including mothers’ sociodemographic characteristics, their reproductive history, the health care they received during pregnancy and delivery, and their health and survival after delivery. The study is hospital-based and represents less than 2% of all births in Latin America and the Caribbean. Although data came from a variety of hospitals and were collected by numerous health care providers, data collection was standardized by a data clerk in each hospital who entered the data into a database and checked data problems immediately with the attendant physicians or nurses (38).

Another study by CLAP reinforces the findings of the DHS study about birth spacing and newborn health (36, 39). Using data on over 1 million pregnancies between 1985 and 2000 from the same hospital records, the study looked at how pregnancy intervals can affect health from 28 weeks gestation through the first week of life. The study accounted statistically for women’s demographic and socioeconomic characteristics as well as the health and survival of their previous children.

The CLAP study reports data for interpregnancy intervals—the time between delivering a baby and becoming pregnant again—rather than for birth intervals, as in the DHS study. Since the CLAP study focuses on pregnancies rather than births, it accounts for pregnancies that end in miscarriage or induced abortion. Adding 9 months to an interpregnancy interval makes the data comparable to data on birth intervals. Population Reports has converted these interpregnancy intervals to birth intervals to be consistent throughout this report. The CLAP study also reported data in months, rather than years, a convention that is retained in this report. Both the study of mothers and the study of infants compared birth intervals of 27 to 32 months with shorter and longer intervals (36, 38).

Maternal survival and health. Women who have their babies 27 to 32 months after a previous birth are more likely to survive pregnancy and childbirth than women who give birth after either very short intervals (9 to 14 months) or very long intervals (69 months or longer). These women are also healthier during and just after pregnancy (see Table 3).

Women with birth intervals of 27 to 32 months are less likely than women who have their next birth just 9 to 14 months later to experience third-trimester bleeding, including placenta previa (when the placenta is in the lower uterus and bleeds) and placental abruption (when the placenta bleeds, regardless of location), premature rupture of the membranes (tearing of the amniotic sac surrounding the fetus), anemia, and puerperal endometritis (infection of the uterus after pregnancy). Also, women with birth intervals of 27 to 32 months are less likely than women with birth intervals of 69 months or longer to experience pre-eclampsia (pregnancy-induced hypertension and high levels of protein in urine), eclampsia (convulsions or seizures with pregnancy-induced hypertension and high levels of protein in urine), and gestational diabetes mellitus (high levels of glucose in the blood during pregnancy).

Hugh Rigby for JHU/CCP

As with this family in Kenya, birth spacing can improve chances for survival and good health for the children and their mother, and result in more resources for the family.

Although the difference is not statistically significant, women with birth intervals of 27 to 32 months appear less likely to experience eclampsia than women with 9- to 14-month intervals. They also may be less likely than women with intervals of 69 months or more to die during pregnancy or delivery, or to experience third-trimester bleeding and gestational diabetes mellitus. Women with birth intervals of 27 to 32 months seem more likely than women with 9- to 14-month intervals or women with intervals of 69 months or more to experience postpartum hemorrhage (bleeding after delivery) (38).

Perinatal survival and health. Children born 27 to 32 months after a previous birth are more likely to survive the perinatal period, defined as 28 weeks gestation through the first week of life, than children born at 9- to 14-month intervals. Although the difference is not statistically significant, they also appear more likely to survive the perinatal period than infants born at 15- to 20-month or 21- to 26-month intervals. Infants born 27 to 32 months after a previous birth also are more likely to survive the perinatal period than infants born after 69 months or more (36, 39) (see Table 4).

The study estimates that, if women spaced their births a minimum of 27 to 32 months apart, perinatal mortality in Latin America could decline by as much as 14%—from 39 deaths per 1,000 births to roughly 34 deaths per 1,000 births. The total number of perinatal deaths could fall by 60,500 per year.

Newborns are also healthier at birth when born at 27- to 32-month intervals than when born either at 9- to 14-month or 15- to 20-month intervals. They are less likely to be low in weight (<2500 grams) or very low in weight (<1500 grams) at birth, to be born preterm (before 37 weeks gestation) or very preterm (before 32 weeks gestation), to be small for their gestational age, or to have a low Apgar score five minutes after birth. The Apgar score is a composite index of a newborn’s status. It reflects respiration, heart rate, muscle tone, reflex response, and skin color at birth.

Also, newborns born after an interval of 27 to 32 months are healthier than those born after a longer interval, particularly those born after 69 months or more. They are less likely to be low or very low in weight at birth, premature, or very premature (36).