New research suggests new mothers over the age of thirty are at risk for adverse pregnancy outcomes. Karolinska Institute in Stockholm, Sweden and the University of Bergen in Norway examined the link between advanced maternal age and adverse pregnancy outcomes and compared the risks related to advanced maternal age with those related to smoking and being overweight or obese.
For the study researchers examined data from a population-based register study that included all women without offspring, aged 25 years and older with single pregnancies at 22 weeks of gestation or greater who gave birth in Sweden and Norway. The study examined 955,804 women in each national sample.
Adjusted odds ratio of very preterm birth, moderately preterm birth, small for gestational age, low Apgar score, fetal death, and neonatal death in women aged 30-34 years (319,057), 35 to 39 years (94,789) and 40 years and older (526,545) and were compared to women 25 to 29 years (526,545).
In the Swedish sample, the number of additional cases of each outcome associated with maternal age 30 years or older, smoking, and overweight or obesity, respectively, was estimated in relation to a low-risk group of nonsmokers of normal weight and aged 25-29 years.
The results showed for women in their early thirties (30 – 34yrs) had a one-fifth higher risk of premature birth or stillbirth during their 22nd to 34th week of pregnancy. There was also a higher risk that the child’s growth would be restricted and fetal death.
In the Swedish sample, the number of additional cases of each outcome associated with maternal age 30 years or older, smoking, and overweight or obesity, respectively, was estimated in relation to a low-risk group of nonsmokers of normal weight and aged 25-29 years.
Maternal age 30 years or older was associated with the same number of additional cases of fetal deaths (251) as overweight or obesity.
In their conclusion the researchers write “For the individual woman, the absolute risk for each of the outcomes was small, but for society, it may be significant as a result of the large number of women who give birth after the age of 30 years.”
Ulla Waldenström, PhD, Professor of Nursing at the Department of Women’s and Children’s Health at the at Karolinska Institute commented “We were surprised that the risk for certain outcomes increased at such a relatively early age. For women individually, the risk is small, but for society at large there will be a significant number of ‘unnecessary’ complications with so many women having children just after 30.”
Professor Waldenström adds” biologically the best time is probably 20 to 30.”
She adds physiological effect of aging on the womb and placenta was likely to explain the higher rates of complications.
This study appears in Obstetrics & Gynecology.
