In rural Nepal, factors affecting the risk of death in early infancy vary with an infant's age, according to a study conducted among women and their infants in one district.1 For infants in the first week of life, those whose mothers had had better nutritional status during pregnancy were more likely to survive, whereas those whose mothers had had a previous miscarriage were less likely to do so. Among infants in the first week and the second through fourth weeks of life, the risk of death was reduced by maternal tetanus vaccination during pregnancy and increased by severe maternal illness in the last trimester. Any parental education and assistance during delivery were associated with a reduced risk of death at age 4-24 weeks; maternal vaginal bleeding in the last trimester and the previous death of a sibling were associated with an elevated risk. In all age-groups up to 24 weeks, infants' odds of dying were reduced if they had been born at an older gestational age or if their mother had had at least one previous live birth, but were sharply elevated if their mother had died.
To identify risk factors for early infant mortality that might be amenable to intervention, researchers analyzed data from women of childbearing age from the Sarlahi district of Nepal who were participants in a trial of nutritional supplements and who gave birth to a live singleton infant between 1994 and 1997. During interviews conducted in the second and third trimesters of pregnancies and at three and six months after delivery, the women were asked about demographic and socioeconomic factors, prior pregnancy history, exposures and illnesses during their pregnancy, and characteristics of their labor and delivery. Multivariate analyses were used to assess the association of these factors with an infant's odds of dying 0-7 days, 8-28 days and 4-24 weeks after birth.
Analyses were based on 14,323 women and their infants. Twenty percent of the women were aged 19 or younger, and the birth was a first live birth for 22%. Fourteen percent of mothers and 45% of fathers had had some formal education. For the large majority of couples (about 80%), farming was the main occupation. During pregnancy, 28% of women smoked, about 9% drank alcohol and a similar proportion had night blindness (a sign of vitamin A deficiency). Nine percent had a severe illness during the last trimester of pregnancy, most commonly fevers (half of the illnesses) and diarrhea or dysentery (one-fifth). Nearly all women gave birth at home with the help of family members or traditional birth attendants; only 3% and 2% gave birth in a hospital or under the care of a doctor, respectively.
Among infants who were alive at the beginning of each age period, the death rates at 0-7 days, 8-28 days and 4-24 weeks after birth were 29, 17 and 22 per 1,000 infants, respectively. The cumulative death rate was 66 per 1,000 infants.
At all three ages, compared with infants who had been born at a gestational age of 28-31 weeks, those who had been born at 36-39 or 40-42 weeks had reduced odds of dying (adjusted odds ratios, 0.2-0.5), with the greatest reduction during the first week of life. In addition, a gestational age of 32-35 weeks was protective for infants in the first week of life (0.4), while one of 43 weeks or older was protective during both the first week and weeks 4-24 (0.2 and 0.4, respectively). Similarly, compared with infants whose mothers had not previously had a live birth, infants whose mothers had had at least one were consistently less likely to die (0.2-0.8); the reduction in odds was again greatest in the first week of life. In contrast, during all three age periods, infants whose mothers had died had sharply elevated odds of dying thereafter, and those odds increased dramatically with infant age (6.4, 11.7 and 51.7, respectively).
In the first week of life, infants' likelihood of dying was elevated if their mother had experienced a miscarriage in a previous pregnancy (adjusted odds ratio, 2.0) but was reduced if the mother's nutritional status during pregnancy, as assessed by the circumference of her upper arm (0.9 with each centimeter increase), had been better. Infants' odds of death were elevated in both the 0-7-day and 8-28-day periods if their mother had experienced a severe illness in the last trimester of pregnancy (2.7 and 1.9, respectively), whereas their risk was reduced during these periods if their mother had received a tetanus vaccination during pregnancy (0.7 for each).
Infants were less likely to die 4-24 weeks after birth if their mother or father had had some education (adjusted odds ratios, 0.3 and 0.6, respectively) and if their mother had been assisted during delivery (0.5); the type of assistant (relative, friend, traditional or trained birth attendant, or doctor) did not matter. However, infants' odds of dying during this period nearly doubled if their mother had previously had a child who died (1.9) and more than tripled if she had experienced vaginal bleeding during the last trimester of pregnancy (3.4). Compared with their female counterparts, male infants had higher odds of dying in the first week of life (1.4) but lower odds of dying in weeks 4-24 (0.7).
The researchers note that maternal and newborn care has been improving in the study district because of programs providing iron folate supplements, tetanus vaccines, deworming and safe birthing kits. To further reduce the rate of early infant death, they recommend that interventions focus on increasing women's access to basic prenatal and obstetric care, identifying and treating serious third-trimester illnesses and ensuring that women have sufficient calories and protein in their diet.
1. Katz J et al, Risk factors for early infant mortality in Sarlahi district, Nepal, Bulletin of the World Health Organization, 2003, 81(10):717-725