CHIPS-Child was a follow up study to the CHIPS (Control of Hypertension In Pregnancy Study) randomised controlled trial.
There is now solid evidence that a reduced rate of growth before birth is associated with adult cardiovascular disease (like heart attack or stroke). The information comes from different populations around the world, and is true even when babies are born with normal birth weights. At present, the ‘Developmental Origins Hypothesis’ provides the best explanation. In response to decreased nutrition in the uterus, changes are made to the activity of fetal genes (the 'code' that determines our health and traits, like height). These changes to gene activity are permanent, and after birth, set up the child’s metabolism in a way that may be harmful in the long-term (e.g., predisposal to diabetes or high blood pressure).
The CHIPS-Child sub-study was designed to find out whether the way a mother’s blood pressure is managed during pregnancy could affect her baby’s(ies’) potential for growth before birth, and as a result, have long-lasting effects on the child, such as diabetes or cardiovascular disease (or alternatively, such as high blood pressure, heart attack, and stroke in adulthood).
We followed up with a total of 626 children in this sub-study.
What participation involved
Participation involved a Study Visit when the CHIPS mother's child was 12 months old (+/- 2 months). The visit involved the following**:
- Basic body measurements of the child (eg. weight, height, head and waist circumference).
- 4 painless swabs from inside the cheek to look at genes and gene activity.
- Hair sample from the back of the child’s head to measure a hormone called ‘cortisol’. Being born smaller than anticipated can cause stress and increased production of the stress hormone cortisol. It is thought that chronic production of cortisol may predispose us to medical conditions such as diabetes, high blood pressure and heart attacks.
- Completion of a maternal questionnaire about the mother's background, emotional well-being and how her baby is fed. For example, if her child fed from her breast, a bottle, or a cup.
** In the event that the child was not able to attend the Study Visit or the basic body measurements were not obtained at the Study Visit and a repeat visit was not possible, the local CHIPS-Child Team attempted to obtain the measurements from the child’s medical records (please see 'Limited Participation' below).
At (or after) the 12 month Study Visit, the local CHIPS-Child Team gave (or sent) the child a birthday card, CHIPS-Child Measurement Postcard, CHIPS-Child Measuring Tape, and a CHIPS-Child wall growth chart. From the child’s second birthday (based on corrected post-gestational age), the child's height, weight and waist circumference were to have been recorded annually by the parents on a CHIPS-Child Measurement Postcard that was mailed to them for this purpose; the parents then sent back the Postcard to the local CHIPS-Child Team (which also maintained contact with the family at two additional times during the year). Postcards were mailed to families annually and contact was maintained throughout years 3-5 (as in year 2) in order to confirm the family’s contact details.
What limited participation involves
For CHIPS mothers who either did not wish to attend, or were not able to attend the Study Visit, LIMITED PARTICIPATION was a possibility. This included consent to contact the child’s physician to obtain the basic body measurements taken in the doctor’s office as close as possible to 12m corrected post-gestational age. Parents were sent the CHIPS-Child wall growth chart, Measuring tape, and Measurement Postcard on which they were to record the child’s height, weight and waist circumference; they then returned the Postcard to the local CHIPS-Child Team (which also maintained contact with the family at two additional times during the year). Pre-stamped and addressed Measurement Postcards were mailed to families annually, and contact was maintained throughout years 3-5 (as in year 2) in order to confirm the family’s contact details.