World-leading pregnancy project celebrates its 2,000th research paper

The 2,000th research paper has been published from data collected in a unique health study spanning almost 30 years and involving three generations of participants.

More than 14,000 women from the South West of England were recruited to take part in the ground-breaking project, named Children of the 90s, between April 1991 and December 1992.

Research on the women, their partners and children remains the most detailed of its type in the world – with more than 1.2 million biological samples taken.

These include blood, urine, placentas and cord blood, meconium, breast milk, milk teeth, saliva and skin biopsies.

In 2012, the study was opened to the children of the original babies and there are now 900 participants in this new cohort, called the Children of the Children of the 90s.

The latest published paper – number 2,000 for the study – has taken a first look at differences between the original mothers recruited in the 90s and their children’s generation.

Data from women who were pregnant between 2012 and 2018 was compared to that taken from their mothers at the same age, between 19 and 26.

Key findings include that today’s generation of mothers are more educated and are less likely to smoke during pregnancy, but experience higher rates of depression.

Their children are more likely to be delivered by cesarean section, heavier at birth and breastfed.

Professor Deborah Lawler, scientific lead for the Children of the Children of the 90s, said: “Bristol’s Children of the 90s is particularly unique in that it engages with whole families from the start and is now the only study globally with detailed genetic, biological, lifestyle, social, cultural, educational and clinical data on three generations.

“Our profile illustrates how families are being shaped over generations and how the study is using new technology and tools such as continuous glucose monitoring, parent-child interactions filmed by head camera use at home, and unobtrusive digital sensors in smart watches and phones to capture life as it happens.”

The risk of antenatal depressive symptoms is 50% higher in women pregnant between 2012 and 2015, compared with their mother’s generation, the paper found.

  • Average percentage of pregnant mums smoking has dropped from 39% to 16%.

  • Average weight of newborns has increased from 7lb 6oz to 7lb 8oz.

  • Average percentage of caeserian sections has increased from 14% to 19.3%

Children of mothers who experienced high levels of such symptoms in the 1990s were over three times more likely to also experience them.

Preliminary analysis of the data suggests that the current generation of pregnant women are slightly younger – with an average age of 23 in the 1990s and 21 in the 2010s data.

Babies weighed an average 7lb and 6oz in the 1990s, while those being born in the latest generation weigh 7lb 8oz on average.

Today’s pregnant women are more educated than their mothers, with 54% educated to A-level or higher compared to 19% for the previous generation.

The number of mother’s smoking during pregnancy has been slashed from 39% to 16%.

Samples of human umbilical cord are dissected and prepared by a lab technician
Samples of human umbilical cord are dissected and prepared by a lab technician

In the 1990s, 14% of babies on the study were born by caesarian section, compared to 19.3% in the most recent births.

Breastfeeding rates have also increased from 67% for the mothers and 80% for their daughters.

Professor Nic Timpson, principal investigator for Children of the 90s, described the 2,000th paper as “an important milestone”.

“The next five to 10 years present a fascinating opportunity to learn even more about the important events around a new pregnancy and its impact on health,” he said.

Since the Children of the 90s project began, data has uncovered findings on a vast range of topics.

These include diet and fitness, parenting patterns, autism, allergies, self-harm and the impact of genes, environment and major life events on physical and mental health.

Professor Jean Golding
Professor Jean Golding

Future research will focus on the factors affecting the health of a new baby, comparisons of the health of mothers across generations and the implications of stress on families including fathers.

Parents and their children can be recruited to the study, or return to it, at any age though most join during pregnancy.

Their data is collected through infancy, childhood and adulthood through regular clinics, assessments at home and questionnaires.

Children of the 90s is funded by the Wellcome Trust, the Medical Research Council and the University of Bristol.