When it comes to the best age for having children, there is a Goldilocks zone of nine for women.
That’s according to a study of more than 31,000 births that found women aged 23 to 32 had the lowest risk of birth defects.
Teenage mothers and women in their early 20s were more likely to give birth to children with central nervous system defects affecting, for example, brain and spine development, while adult pregnancies were most associated with deformities of the head, neck, eyes, etc. ears were connected.
New mothers are often unprepared for pregnancy and have to deal with unhealthier lifestyle factors such as drug and alcohol use, the researchers said.
Older women have long been exposed to environmental stressors such as air pollution, which the scientists believe could contribute to their risk of various birth defects.
According to researchers, the window of time for a baby to be born safely is quite narrow, and the risk factors for various birth defects vary by mother’s age
The 10-year period of lowest risk was between 23 and 32 years, and lower and higher birth ages were almost equally risky
Men now give birth to their first child at an average age of 26.4 years, and women give birth to their first child at 23.7 years. Both have increased significantly over the past two decades
The study comes at a time when the average age of new mothers in America is reaching its highest level on record.
American women today give birth at an average age of 30, up from 27 in 2000 and 24 in 1970.
The increasing age of new mothers is attributed to a myriad of factors, including social and cultural changes delaying marriage and spending more time on leisure and travel, better prospects for women in the labor market, and financial constraints.
Scientists from Semmelweis University in Hungary analyzed data from 31,128 pregnancies with confirmed non-chromosomal birth defects collected as part of the Hungarian Case Control Surveillance of Congenital Anomalies between 1980 and 2009.
They compared this data to more than 2.8 million births registered with the Hungarian Central Statistical Office over the same 30-year period.
Overall, the risk of non-chromosomal birth defects increased by about one-fifth when giving birth to women under the age of 22. In women over the age of 32, the risk increased by about 15 percent.
The most common and life-threatening complications involved the fetal circulatory system and the central nervous system in mothers under 20 years of age.
Younger mothers were 25 percent more likely than older mothers to develop defects in their babies’ central nervous system.
Women born before their 20s saw an even greater risk of developing central nervous system abnormalities due to brain and/or spinal cord development problems in the developing fetus, leading to serious conditions such as spina bifida.
Older mothers, on the other hand, had a 100 percent higher risk of having a child with eye, ear, face and neck deformities caused by the infant’s skull or facial bones fusing together prematurely or in an abnormal manner.
This can result in a baby having ears that are unusually low on their head, eyes that are medically small, or vocal cord paralysis.
Women on the older end of the spectrum also had more heart defects and more urinary system abnormalities.
And older mothers are significantly more likely to give birth to a child with a cleft lip and palate—45 percent—while younger mothers are nine percent more likely.
While the risk of birth defects in the digestive system was higher in younger mothers than in older mothers – 23 percent and 15 percent, respectively – older mothers had a slightly higher risk of fetal genital malformations.
dr Boglárka Pethő, an assistant professor at Semmelweis University and first author of the study, said: “We can only speculate why non-chromosomal birth anomalies are more common in certain age groups.”
“For young mothers, it may be primarily due to lifestyle factors (e.g. smoking, drug or alcohol use) and the fact that they are often unprepared for pregnancy.”
“In mothers of advanced age, the accumulation of environmental influences such as exposure to chemicals and air pollution, deterioration of DNA repair mechanisms and aging of the oocytes and endometrium may also play a role.”
Previous research has confirmed that older maternal age also increases the risk of having a child with Down syndrome, an example of a genetic disorder. However, there is less research on nongenetic abnormalities
The number of American women with at least one child has fallen to just 52.1 percent, while the number of men in 2019 fell to 39.7 percent
The report was published in BJOG: an International Journal of Obstetrics & Gynecology.
During the baby boom of the mid-20th century, an average woman gave birth to three to four children. Today there are only 1.6 children – the lowest level since the data was first collected in 1800.
In women who become pregnant after the age of 35 and give birth to a child, the pregnancies are usually more dangerous. Older mothers may be at increased risk of miscarriage, high blood pressure, gestational diabetes and difficult labour.
The results concerned non-genetic birth defects that are not influenced by the mother’s genes.
Previous research has confirmed the link between older maternal age and certain genetic disorders, most notably Down syndrome, in which the risk increases from about 1 in 1,250 for a woman conceiving by age 25 to about 1 in 100 for one Woman getting pregnant at age rises 40.
Prof Nándor Ács, Director of the Department of Obstetrics and Gynecology at Semmelweis University, said: “Non-genetic birth disorders can often result from mothers’ long-term environmental exposure.”
“As the childbearing age has been pushed back extremely in the developed world, it is more important than ever to respond appropriately to this trend.”
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