The associations of parity and maternal age with small-for-gestational-age, preterm, and neonatal and infant mortality: a meta-analysis

Abstract

BackgroundPrevious studies have reported on adverse neonatal outcomes associated with parity and maternal age. Many of these studies have relied on cross-sectional data, from which drawing causal inference is complex. We explore the associations between parity/maternal age and adverse neonatal outcomes using data from cohort studies conducted in low- and middle-income countries (LMIC).MethodsData from 14 cohort studies were included. Parity (nulliparous, parity 1-2, parity ≥3) and maternal age (<18 years, 18-<35 years, ≥35 years) categories were matched with each other to create exposure categories, with those who are parity 1-2 and age 18-<35 years as the reference. Outcomes included small-for-gestational-age (SGA), preterm, neonatal and infant mortality. Adjusted odds ratios (aOR) were calculated per study and meta-analyzed.ResultsNulliparous, age <18 year women, compared with women who were parity 1-2 and age 18-<35 years had the highest odds of SGA (pooled adjusted OR: 1.80), preterm (pooled aOR: 1.52), neonatal mortality (pooled aOR: 2.07), and infant mortality (pooled aOR: 1.49). Increased odds were also noted for SGA and neonatal mortality for nulliparous/age 18-<35 years, preterm, neonatal, and infant mortality for parity ≥3/age 18-<35 years, and preterm and neonatal mortality for parity ≥3/≥35 years.ConclusionsNulliparous women <18 years of age have the highest odds of adverse neonatal outcomes. Family planning has traditionally been the least successful in addressing young age as a risk factor; a renewed focus must be placed on finding effective interventions that delay age at first birth. Higher odds of adverse outcomes are also seen among parity ≥3 / age ≥35 mothers, suggesting that reproductive health interventions need to address the entirety of a woman’s reproductive period.FundingFunding was provided by the Bill & Melinda Gates Foundation (810-2054) by a grant to the US Fund for UNICEF to support the activities of the Child Health Epidemiology Reference Group.

Factors associated with low birthweight in term pregnancies: a matched case-control study from rural Pakistan

“…This finding is in agreement with previous meta-analyses (19) showing that nulliparous women are consistently more likely to have LBW babies compared to their multiparous and grand multiparous counterparts. Several hypotheses have been put forward to explain this association, including the biological immaturity of young mothers and maternal-fetal competition for nutrients in women still trying to achieve their own growth potential (20,21).…”

Study of obstetric factors in perinatal morbidity and mortality at a tertiary centre

“…11,12 Perinatal deaths were more in multigravidae compared to primigravidae as noted in other studies. 9,12 With increasing parity risk of anaemia increasing predisposing to various risk factors like pregnancy induced hypertension, abruptio placentae. Also chances of twin gestation increases with age, which in itself is a risk factor for increased perinatal loss.…”

“…12,13 Many other studies show similar association of other factors like hypertension, diabetes mellitus hypothyroidism, and antiphospholipid antibody syndrome with perinatal loss.…”

Socioeconomic, bio-demographic and health/behavioral determinants of neonatal mortality in Nigeria: a multilevel analysis of 2013 demographic and health survey

“…All of these findings are consistent with previous studies. 3,22 After making an adjustment for "breastfeeding status", maternal age less than 20 years became a significant risk factor for neonatal mortality. Teenage mothers are known to be vulnerable to physical, and physiological immaturity.…”