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Pregnancy after 35: What you should know about advanced maternal age

Woman playing with her baby on a big bedWomen are increasingly delaying pregnancy until later in life, especially in larger Canadian cities. The average age at first childbirth has seen a steady increase since the 1960s, and according to Statistics Canada's latest data, it is now just over 29 years old.

"Advanced maternal age is considered 35 years old and over," says  Dr. Yolanda Kirkham, gynecologist at Women’s College Hospital and obstetrician, affiliated with St. Joseph’s Health Centre Toronto. "Our eggs are as old as we are, and over time they decrease in quantity and quality. Although most women will have a healthy pregnancy, it’s good to keep this in mind."

With the birth rates for women between 35 and 39 years of age now higher than for those in their early 20s, Dr. Kirkham says it’s important for anyone considering pregnancy to understand their fertility and risks they may face down the road.

"There is a drop in fertility around age 33 to 35 when chance of pregnancy per month becomes 1 in 5; then it starts to fall rapidly.  By age 40 the chance of pregnancy is about 1 in 20," says Dr. Kirkham. "At the same time the rate of miscarriage goes up to 1 in 3 by age 40."

"Celebrity news about very late pregnancies in late 40s may make you think that it’s easy to get pregnant at that age, but people are not always aware that they likely had assistance with IVF or even used a previously frozen egg or donor egg," says Dr. Kirkham.

Benefits of having children later

There are some benefits to having children later in life. Having financial stability and established relationships and social networks can improve the social and financial supports for mom and baby. Having an older mom can also benefit the child’s socio-emotional development – one recent study showed that children with older moms were more likely to have fewer social, emotional and behavioural problems.

If you’re thinking of delaying pregnancy, consider your individual situation and priorities. Meet with your healthcare provider for preconception counselling to identify any potential issues early, especially if you have pre-existing medical conditions.

"Pre-pregnancy counselling will give you time to tee yourself up for the best chances of getting pregnant but also getting your lifestyle in order and being in the best health," says Dr. Kirkham.

Risks of advanced maternal age

Risks related to fertility and pregnancy increase around age 35 and are higher for women over 40. These complications include:

  • taking longer to get pregnant or needing assistance
  • miscarriages, especially before 12 weeks
  • genetic abnormalities
  • preterm labour
  • gestational diabetes
  • preeclampsia (high blood pressure in pregnancy)
  • needing a c-section or an emergency intervention during childbirth
  • having a baby with low birth weight (when baby is not growing well)

"It’s easy for people to see the list and think ‘it won’t happen to me,’ but a lot of these necessitate early delivery, and having a preterm baby comes with inherent risks such as needing to stay in neonatal intensive care (NICU) and having medical problems," Dr. Kirkham says. "While most women will be okay, these are just things to be aware of."

"Women should know that end game is around 42 to 43 years old. Conception rates after that are minimal," adds Dr. Kirkham. "There is no perfect time to get pregnant, it’s individual; but at the same time earlier is better, because of all the unforeseen circumstances that can come into play."

"The majority of people will be fine, and it may be easy to get pregnant, but it’s important to be informed and know the risks because you never know until you try," says Dr. Kirkham. "It’s disappointing to find out later that you waited too long."


This information is provided by Women’s College Hospital and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition. This document was last reviewed on: April 25, 2019.

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  • Women's College Hospital