Pregnancy past 35 puts first-time moms and babies at increased risk: study
Unlike previous generations, women are delaying first-time pregnancy until much later in life.
Now, a new study from the Canadian Institute for Health Information (CIHI) confirms the risk to mother and baby significantly increases with maternal age.
First-time mothers over 35-years-old are at a higher risk of experiencing pregnancy-related complications, compared to women between the ages of 20 and 34.
The risk of adverse birth outcomes in newborns also increases with maternal age, the study suggests.
The study looked at how age is associated with risks of pregnancy and labour complications, medical or surgical assistance during labour for safe delivery and poor birth outcomes and birth defects in newborns.
The findings are based on an analysis of more than one million hospital births from 2006-07 to 2008-09, the largest population-based study of its kind in Canada to measure the impact that advanced maternal age can have on both mothers and their babies.
Risks to baby
While many women have successful, uncomplicated pregnancies and deliveries at 35 years and over, first-time mothers over 35 are at an increased risk of pre-term births, delivering babies born before 37 weeks.
The risk of delivering babies with any birth defect was four times higher for older mothers, compared to their younger cohorts.
The study’s authors considered nervous system, circulatory, respiratory, digestive, urogenital, musculoskeletal and chromosomal defects such as Down syndrome.
Premature babies have not had the chance to develop fully in the womb and are more likely to face medical complications, ranging from difficulty breathing, vision problems and intestinal problems to neurological issues, such as cerebral palsy.
Risks to mom
First-time mothers 35 and over have the highest rates of many labour complications, compared to first-time moms 20- to 34-years-old.
The data suggests women over 35 have a higher risk of experiencing serious pregnancy conditions such as pre-existing hypertension and developing hypertension and pre-eclampsia, a condition in which high blood pressure and protein in the urine develop after the 20th week of pregnancy.
Mothers 35-to 40-years-old doubled their risk of developing diabetes during pregnancy, compared to first-time mothers age 20 to 34. For those over 40, the risk tripled.
Older first-time moms were also at higher risk of experiencing placenta previa, a complication in which the placenta may block the cervix.
Women 35 and over were 28 per cent more likely to have an assisted delivery.
Caesarian delivery rates were 44 per cent higher compared to first-time moms between the ages of 20 and 34.
One in three mothers 40 and over had a Caesarian delivery; the risk of miscarriage can be as high as 40 or 50 per cent for women over 45-years-old.
“One of the things that is very true about women over 40 who get pregnant is that their underlying health is very, very important. If you start a pregnancy in excellent health and you’re fit, you’ll have a healthy pregnancy,” said Dr. Jan Christilaw, president of BC Women’s Hospital and Health Centre.
But Christilaw warns, “even if you’re a perfectly healthy person, there will be an increased risk of complications and interventions.”
“Mothers over 40 stay in the hospital a little longer, as you age it takes a little longer to recover, you may be a little more fatigued,” Christilaw said.
Assisted vaginal deliveries, such as those requiring forceps or vacuum extraction, were also more common for older mothers with single births.
About a third of first-time mothers in their 40s had an assisted delivery, compared with one-quarter of first-time mothers aged 20 to 34.
