How does advanced maternal age affect pregnancy and birth?

Advanced maternal age (AMA) is a term that is used to describe pregnant women over a certain age bracket. Unfortunately the term is not clearly defined internationally and varies across healthcare providers and literature. It might be when you are over 35, 38¹ , 40² years or even 45³ years of age.

There has been a steady rise in women of AMA, across the states in Australia we can see a steady rise in the last 10 years⁴ alone of women becoming mum over the age of 35.

If you are finding yourself in this situation, I just wanted to say: Congratulations!

This can be the most exciting and transformative season in your life and there are many benefits to becoming a mum later in life and is associated with improved health in their children, including cognitive ability. Children of older parents have described benefits such as emotional and financial stability and devotion, patience and attention of their parents.⁵

In this blog my aim is to provide you with evidence-based information about how AMA can impact your pregnancy and birth, so you can make informed decisions in relation to your care, how you look after yourself and how you would like to give birth.

It is important to note that pregnancy and birth carry risks across all age groups, nothing is completely safe and that all age related concerns raise gradually and not all at once.⁶

The following information about AMA related risks should not be seen as a standalone but rather your overall health and wellbeing and many factors individually to you should be considered. A good care provider will take all this into account. Generally speaking, your overall health and wellbeing and many factors individually to you, need to be considered.

The following are some – not all – risks in pregnancy that are associated with advanced maternal age:

Chromosomal abnormalities such as down syndrome.

The risk increases from

1 in 1340 at age 25
1 in 939 at age 30
1 in 353 at age 35
1 in 85 at age 40
1 in 35 at age 45⁷

Depending on your age you may be offered noninvasive screening tests or more invasive diagnostic tests such as chorionic villus sampling or amniocentesis.

The risk of developing gestational diabetes can be higher in advanced maternal age. It is a condition where blood sugar levels become elevated during pregnancy. You are most likely advised to have early screening at 14- 16 weeks²instead of later on in pregnancy.

Miscarriage is defined as pregnancy loss before 20 weeks and the rate climbs gradually with age. The increased risk of miscarriage with age can be related to an increase to pre existing medical conditions and egg quality. A recent Norwegian study found that the risk of miscarriage was :

17% at <20 years
11% at 20-24 years
10% at 25-29 years
11% at 30-34 years
17% at 35-39 years
33% at 40-44 years
57% at >45 years

Stillbirth and neonatal mortality

Researchers don’t fully understand why there is an increased risk of stillbirth in pregnant people as they age.

Overall we can establish that there’s a small increase in risk of stillbirth (the loss of a baby before birth) and neonatal mortality (death of a newborn within the first 28 days) in older mums compared to younger ones.
A recent study from the Netherlands⁹ has examined many adverse pregnancy outcomes by maternal age, including stillbirth (occurring between 37 weeks + 0 days to 42 weeks + 6 days).

Here are the results:

People aged 18 to 34 had a stillbirth rate of 1.7 per 1,000, or 0.17%
People between 35 and 39 years old had a stillbirth rate of 2.2 per 1,000, or 0.22%
People 40 and older had a stillbirth rate of 3.0 per 1,000, or 0.30%

When you look at the data you could conclude that mothers over 40 have an almost 50% higher chance of having a still born baby compared to women aged 18 – 34, which is a really intimidating number and sounds quite scary.

However, looking at the absolute risk of women aged 40 and over, the chance of having a still born baby is “only” 0.30% which compared to 0.17% in the age group 18-34 doesn’t sound that high, does it?

Now that we have looked at some of the risks that AMA can have in pregnancy, let’s see how this can affect your birthing experience:

Induction

The number one reason for generally recommending an induction around 39-40 weeks to most women aged over 35 is to decrease the risk of having a still born baby as discussed above.

Induction of labour involves a series of procedures and interventions with the aim to artificially bring labour on.

However, induction carries its own risks and can sometimes lead to other interventions, or resulting in a caesarean section, which can result in the mother feeling dissatisfied about her birth.

There is not enough evidence showing that induction of labour for women in AMA reduces the risk of stillbirth as there have not been any randomised controlled trials undertaken.

Induction is a huge topic, if this is something you are offered or faced with I would encourage you to research the topic and read what Dr Rachel Reed and Dr Sara Wickham have to say. Both have excellent resources on their website and have written books about inductions.

Caesarean Section

C-section rates across Australia are at an all-time high with 1 in 3¹¹ women giving birth via c-section.

The table below shows the effect age has on women having a c-section compared to younger mums.

Maternal Age	2011	2021
25-29	28.4%	32.7%
30-34	34.2%	38.9 %
35-39	41.4%	45.9%
Over 40	48.8%	55.7%

Data source: AIHW

The data doesn’t tell us why c-sections were performed, whether elective or medically indicated, but it does show how much higher the percentage is of women having a c-section based on their maternal age.

C-section is a major abdominal surgery and is not without risks either. A study published in the Canadian medical association journal states that “Caesarean delivery is associated with a higher risk of severe acute maternal morbidity than vaginal delivery, particularly in women aged 35 years and older. Clinical decisions regarding delivery mode should account for this excess risk accordingly”.¹¹

Despite all the potential risks in pregnancy and birth discussed, many women in their late 30s and 40s have healthy pregnancies and give birth to healthy babies.

It is important that you are educated and well informed so you can take responsibility and make the best decisions possible for your individual circumstances, knowing that all choices carry consequences – good or bad. And remember – you can always change your mind and give or withdraw consent.

Having a care provider that respects your decisions, gives and explains to you evidence based information and treats you with dignity is crucial to maintain a sense of autonomy and empowerment.

A doula can be a beneficial addition to your support team and is a great way of receiving continuity of care, providing you with information and education, supporting you emotionally and helping you to release any fears. Evidence shows that women who received continuous support were more likely to have spontaneous birth, less interventions and less negative feelings around childbirth.¹³

Where to from here ?

Enjoy your pregnancy and look after yourself
Map out your wants and needs and what tests, interventions etc you are agreeing to. Remember you can change your mind, give and withdraw consent at any time.
Choose a care provider that supports your decisions and consider finding a new one, if your current provider is not supportive
Use BRAIN (Benefits, risks, alternatives, intuition, nothing) for decision making
Consider getting a doula

My name is Josephine Mear and I am a qualified doula who has trained at the Doula Training Academy. If you would like more information about my doula services, please contact me:

Phone:
0416 837 778

Email:
[email protected]

Facebook:
www.facebook.com/nurturedbyjosi

Instagram:
www.instagram.com/nurtured_by_josi

Website:
www.nurturedbyjosi.com.au

RESOURCES & REFERENCES

https://evidencebasedbirth.com/advanced-maternal-age/

https://www.sarawickham.com/research-updates/induction-for-advanced-maternal-age/

https://www.sarawickham.com/articles-2/questioning-induction-of-labour-in-older-women/

https://www.sarawickham.com/research-updates/no-evidence-that-early-induction-of-labour-makes-a-difference-in-older-women-3539-trial/

¹https://www.matermothers.org.au/mothers-news/mothers-blog/november-2018/are-you-an-advanced-maternal-age-mater-mamma

²https://www.seslhd.health.nsw.gov.au/sites/default/files/documents/advancedageoutcomesOct21.pdf