The Association of Maternal Age With Fetal Growth and Newborn Measures: The Mumbai Maternal Nutrition Project (MMNP)

Abstract

Background: Young maternal age is associated with poorer birth outcomes, but the mechanisms are incompletely understood. Using data from a prospective cohort of pregnant women living in Mumbai slums, India, we tested whether lower maternal age was associated with adverse fetal growth. Methods: Fetal crown-rump length (CRL) was recorded at a median (interquartile range, IQR) of 10 weeks’ gestation (9-10 weeks). Head circumference (HC), biparietal diameter (BPD), femur length (FL), and abdominal circumference (AC) were recorded at 19 (19-20) and 29 (28-30) weeks. Newborns were measured at a median (IQR) of 2 days (1-3 days) from delivery. Gestation was assessed using prospectively collected menstrual period dates. Results: The sample comprised 1653 singleton fetuses without major congenital abnormalities, of whom 1360 had newborn measurements. Fetuses of younger mothers had smaller CRL (0.01 standard deviation [SD] per year of maternal age; 95% confidence interval CI: 0.00-0.02 1 ; P = .04), and smaller HC, FL, and AC at subsequent visits. Fetal growth of HC (0.04 cm; 95% CI: 0.02-0.05; P < .001), BPD (0.01 cm; 95% CI: 0.00-0.01; P = .009), FL (0.04 cm; 95% CI: 0.02-0.06; P < .001), and AC (0.01 cm; 95% CI: 0.00-0.01; P = .003) up to the third trimester increased with maternal age. Skinfolds, head, and mid-upper arm circumferences were smaller in newborns of younger mothers. Adjusting for maternal prepregnancy socioeconomic status, body mass index, height, and parity attenuated the associations between maternal age and newborn size but did not change those with fetal biometry. Conclusion: Fetuses of younger mothers were smaller from the first trimester onward and grew slower, independently of known confounding factors.

The Influence of Maternal BMI on Adverse Pregnancy Outcomes in Older Women

“…In our study, at the same time, younger and older age was associated with higher adjusted odds ratios of PE, IUGR, and preterm birth <37th week, which is consistent with reports in the literature [17][18][19]32], but the number of PE (n = 24) and IUGR (n = 21) cases in our the cohort was small. PE and IUGR often coexist, and in their pathogenesis the role of placental ischemia in early pregnancy is taken into account.…”

“…Our core results (higher risk of pregnancy complications in older mothers, and associations of young age with some pregnancy outcomes) are consistent with several reports in the world literature [4,[17][18][19][20][21]28]. However, some studies have found no correlation between maternal age and pregnancy outcomes [2,22].…”

“…However, the results of the research available in the literature are debatable and controversial. Many studies have shown risks of adverse pregnancy outcomes and complications increasing along with maternal age [17][18][19][20][21]. However, other studies have not found these associations [2,22,23].…”

Analysis of individual-level and community-level effects on advanced maternal age pregnancy in Nigeria

“…This study examined individual and community effects on advanced maternal age pregnancy, a growing phenomenon with serious implications for maternal, neonatal and child morbidity and mortality [30,[16][17][18][19][20]. The study improved upon previous studies by examining the individual and contextual effects on AMA pregnancy which were largely ignored in most existing hospital-based studies [21-23, 25, 2, 26].…”

“…Two, the proportion of women delaying motherhood for the purpose of achieving education and career enhancement is steadily increasing in the country [15]. Irrespective of the reasons for AMA pregnancy across the world, AMA pregnancy is a safe motherhood issue worthy of further investigation because evidence abounds that AMA pregnancy elevates the risks of maternal, neonatal and child mortality [16][17][18][19][20]. In a number of countries, numerous studies have examined different aspects of AMA pregnancy [21][22][23][24][25][26].…”