Late pregnancy: what are the risks? - Featured

2023-05-19 10:24:36

May 19, 2023

Late pregnancies concern pregnancies from the age of 40 and over. Increasingly frequent, they often involve closer medical monitoring to limit the risks. Explanations.

Virginie Efira has just formalized her pregnancy. At 46, the Belgian actress, in a relationship with comedian Niels Schneider, is expecting her second child. Since the 1980s, so-called “late” fertility, at age 40 or over, has continued to increase. Thus, in 2019, according to INSEE figures, 10.2 children per 100 women were born to mothers aged 40 and over. Late fertility was thus 3.4 times higher in 2019 than in 1980.

These pregnancies after the age of 40 expose the mother and/or the baby to increased risks. We take stock.

The risk of miscarriage

The risk of miscarriage increases with age. According to Medicare, the risk of spontaneous termination of pregnancy is 12% at age 25 and rises to 50% at age 42. This high figure is largely explained by the aging of the oocytes, the quality of which is altered with age. “The embryo would present chromosomal abnormalities which would stop its normal development and lead to its expulsion”explains Ameli.fr.

The risk of chromosomal abnormality

For the same reason as the risk of miscarriage, the risk of a chromosomal abnormality – abnormal structure or number – increases with the age of the mother. Thus, according to the Vidal medical dictionary, “the risk of trisomy 21, estimated at one birth in 1,000 when the mother is 30 years old, rises to one birth in 50 in mothers aged 42 years”. The mother may have recourse to an amniocentesis to find out if the fetus carries a chromosomal abnormality, but this is an examination which leads to a miscarriage in one out of ten cases.

The risk of gestational diabetes

From the age of 35, the risk of developing gestational diabetes during pregnancy increases. The Diabetic Federation thus explains that “in women over the age of 35, the prevalence reaches 14.2%”. For the mother, this represents an increased risk of caesarean section, anxiety and a recurrence of diabetes in a future pregnancy. For the baby, there is a risk of fetal macrosomia – weight over 4 kg – which can make delivery long, difficult and, sometimes, put the baby in danger. Gestational diabetes can also lead to hypoglycaemia in the child, which must be corrected at birth.

The risk of high blood pressure

A pregnant woman’s blood pressure is normal when it is below 140/90 mmHg – the first number expresses the systolic blood pressure, the second the diastolic blood pressure. Beyond these values, it is too high and requires reinforced monitoring. The older the mother, the more common hypertension.

It can be responsible for preeclampsia which can progress, if not treated, to eclampsia. The lives of the mother and the fetus are then at stake. “These are convulsive seizures, potentially fatal, caused by intracranial arterial hypertension in the mother”note Ameli.fr.

The other complications are cerebral hemorrhage, kidney failure, placental abruption and Hellp syndrome – syndrome of hemolysis, hepatic cytolysis and thrombocytopenia – serious liver damage in the mother, however very rare.

“Gestational diabetes and pregnancy-induced hypertension, more frequent after 40 years, sometimes lead to malformations, premature births or death in utero”adds the Vidal.

What follow-up for a late pregnancy?

For all these reasons and depending on the risk factors identified in the mother, the medical follow-up of a late pregnancy is tighter. There will also be more ultrasounds for mothers over 40 – three are normally scheduled. According to the recommendations of the High Health Authority, beyond the age of 35, the opinion of a gynecologist-obstetrician is recommended. For pregnancies without a risk situation, regular monitoring can be provided by “a midwife or a doctor (general practitioner, medical gynecologist or gynecologist-obstetrician) according to the choice of the woman”.

Source : Ameli.fr, HAS, Vidal, Federations of diabetics, Insee
Written by : Dorothée Duchemin – Edited by Charlotte David