Vancouver: 8th June. New research shows that women who had a low birth weight when they are born are more at risk of hypertension in pregnancy – such as eclampsia and pre-eclampsia – when they themselves have a baby. This in turn this may be passed on to the next generation. In addition, women who were themselves born prematurely have a greater risk of subsequent hypertension problems in pregnancy.
Low birth weight is a common condition, increasingly associated with a number of problems which can manifest themselves in later life. Now a group of Japanese scientists have found that women who suffered from low birth weight are more prone to develop potentially life-threatening conditions such as pre-eclampsia.
A research team led by Dr Takumi Kurabayashi (Niigata, Japan) carried out an analysis on 17,278 nurses enrolled on the Japan Nurses’ Health Study (JNHS), with the objective of clarifying the association between Hypertensive Disorder of Pregnancy (HDP – which is very high blood pressure when pregnant, as is found with pre-eclampsia) and birth weight. They also looked at the relation between HDP and gestational age (gestational age is the time from a woman’s last period to the current date: it indicates how far along the pregnancy is).
They found that women who weighed less than 2kg at their own birth had a 1.62 greater chance of suffering hypertension problems in pregnancy than women who had normal range birth weight. They also found that women who were premature babies, defined as a gestational age of less than 37 weeks at birth, had a 1.26 greater chance of suffering hypertension problems when they themselves fell pregnant *(see below for data).
According to Dr Kurabayashi
“Hypertension is one of the main problems faced by women in pregnancy. Worldwide, around 1 in 10 pregnancies encounter hypertension issues such as pre-eclampsia, and in some countries this is much higher. For example, in the USA is between 5 and 10% of pregnancies have hypertension problems, and in Japan this is around 7-10%. Unfortunately, the problem seems to be increasing. What we have done shows that hypertension problems in pregnancy are associated both with low birth weight and with premature birth.
One thing to note about our work is that we looked at babies with a birth weight of under 2kg, whereas the low birth weight statistics collected by the WHO and OECD takes less extreme births. According to the OECD, in developed countries, around 6% to 8% of children are born with low birthweight in developed (OECD) countries, but this rises to around 1 in 6 children globally. Of course, in some countries the figures are higher still”.
We believe that clinicians should ask pregnant women about their own birth weight, and they should make sure that their diet and body weight are managed during pregnancy. In addition, at-risk women probably need to undergo regular check-up after delivery, even into old age”.
Commenting, Nick Panay (Imperial College, London, and HonoraryDirector of Conferences, RCOG) said:
"High blood pressure is associated with a variety of problems including increased heart diseaseand stroke and as such is a serious public health risk. The study raises the possibility of identifying women who are at higher risk of high blood pressurein pregnancy, if they (themselves)were a very low birthweight baby. These women also appear to be more likely to pass this high blood pressure susceptibility to their babies.
Having this is information is of critical importance, as it will facilitate healthcare professionals to advise women on potential preventive measures.Practicalmeasures which could help to reduce risk include avoiding smoking, minimising alcohol consumption, reducing stress, and optimising diet and exercise to control body weight”.
Mr Panay was not involved in this work.
*Age-adjusted Odds Ratio (OR)s for hypertensive disorder of pregnancy (HDP) were 1.62 [95%CI: 1.20–2.19] for birth weight <2000g). Age-adjusted ORs for HDP were 1.27 [95%CI: 1.04–1.54] for <37 weeks of gestational. Note that these figures are Odds Ratios, not relative risk.
The JNHS baseline survey was supported in part by a Grant-in- Aid for Scientific Research (B: 14370133, 18390195) from the Japan Society for the Promotion of Science, and by grants from the Japan Society for Menopause and Women’s Health.
The 16th World Congress on Menopause takes place in Vancouver, Canada, from 6-9th June 2018, see http://www.imsvancouver2018.com/. This is the world’s pre-eminent international congress on menopause and midlife health. The world congress is organised by the International Menopause Society, http://www.imsociety.org/ .The next congress takes place in Melbourne, Australia, in 2020.