'Biological clock'? The realities of pregnancy and childbearing for women above 40

A lot is said about the right age for childbearing. Is younger better? Is older harder? 

The fear around 40 is partly justified and also partly exaggerated.

The risks that are increased with advancing maternal age at pregnancy include: miscarriage, chromosomal conditions such as Down syndrome, gestational diabetes, pre-eclampsia and other hypertensive disorders, placental abruption, stillbirth, preterm birth, low birth weight, and increased operative delivery (caesarean delivery).

 But "the above 40" rarely acts alone.

In our setting, age is accompanied by additional factors such as: high parity (a woman of 42 may be carrying her seventh pregnancy), pre-existing chronic medical conditions such as thyroid disorders, heart conditions, autoimmune diseases (such as Systemic Lupus Erythematosus- SLE, Rheumatoid Arthritis), hypertension, diabetes, obesity, anaemia, fibroids, or prior uterine surgeries such as myomectomies.

These work in synergy to increase the risks of pregnancy with advancing age.

These multi-factorial factors, layered onto the “three delays” in reaching and receiving quality care, drive poor outcomes more than the woman’s birthday itself.

The honest message is this: a woman of 40 in good health, who enters pregnancy with preconception assessment and optimization receives consistent and quality 8 ANC contacts, and has her childbirth attended to by a skilled health care provider in a health facility well equipped to handle any emerging obstetric emergency, can and often does have a healthy pregnancy and baby.

Age raises the stakes; it does not condemn the outcome.

But is conception after 40 a problem? Or sustaining a pregnancy?

The answer is both, and they compound each other.

Conception becomes harder because both the number and the quality of eggs (oocytes) decline with advancing age.

The chance of conceiving in any given cycle falls from one in four (25%) or five (20%) in the mid-20s to under one in ten (10%) by 40, and continues dropping steeply toward 43 - 45.

Sustaining the pregnancy is the second hurdle: the risk of miscarriage increases to around 30 - 40% at age 40 and above, and half (50%) by 45, mostly because of chromosomal abnormalities in the egg (oocyte).

So, a woman over 40 may take longer to conceive and then faces a higher chance of early pregnancy loss, which is why time matters and early medical evaluation is advised for those desiring fertility.

Do older mothers experience longer or more complicated labour?

On average, yes. Studies consistently show higher rates of prolonged and dysfunctional labour, slower cervical dilation at labor, more frequent induction of labor, more malpresentation, and more instrumental and caesarean deliveries in older mothers.

Part of this reflects less efficient myometrial contractility with age; part reflects a lower clinical threshold for medical intervention.

Often, a long-awaited or assisted pregnancy in a woman with comorbidities will have her medical team understandably cautious. It is important to stress that this is a tendency, not a certainty: many women over 40 labour and have child births vaginally.

Are women above 40 capable of getting pregnant naturally, without assistance?

Yes, and this is a message with two edges. Natural conception over 40 is entirely possible and happens regularly, which is exactly why women in this age group who do not wish to conceive still need effective contraception; unplanned pregnancy at 40-plus is a real contributor to unmet family-planning need in Kenya.

At the same time, for the woman who is actively trying, the monthly odds are genuinely lower, so "possible" should not be heard as "easy." Both truths need to be held together during pre-conception counselling.

What fertility challenges are common among women above 40?

The dominant one is diminished ovarian reserve, fewer eggs of lower quality, with rising chromosomal abnormalities.

Cycles often become irregular or anovulatory as perimenopause approaches. On top of that sit conditions that are common in our population and independently affect fertility: fibroids (which can distort the cavity and impair implantation), endometriosis, and tubal damage from prior pelvic infection.

Male-factor contribution rises too, since partners are often older as well. Pre-existing medical conditions such as thyroid disorders, hypertension and diabetes add further weight. And the higher miscarriage rate means that even when conception occurs, a live birth is less assured.

When are women advised to undergo fertility testing?

The standard guidance scales with age. A woman under 35 is generally advised to seek evaluation after 12 months of unprotected, regular intercourse without conception; between 35 and 39, after 6 months.

At 40 and above, the advice is to seek assessment early. After about 6 months of trying, many specialists would say promptly, given the narrow time window.

That said, evaluation should be individualized and done sooner at any age in the presence of red flags: irregular or absent periods, a history of pelvic infection or surgery, known endometriosis or significant fibroids, or a known male-factor problem.

 The guiding principle over 40 is that time is the scarcest resource, so the threshold to investigate should be low.

The writer, Dr. Grace Kanyi, is a Kenyan Specialist Obstetrician and Gynecologist working at the intersection of clinical care, health policy, and rights‑based sexual and reproductive health (SRH) advocacy.