National Women's Health Policy

Risk factors in pregnancy

Page last updated: 07 February 2011

There is a need to consider the range of social and cultural factors contributing to obesity in pregnancy, nutrition and women’s tobacco and alcohol use during pregnancy.

Obesity in pregnancy has tripled in the past decade and the implications are significant for women and their babies. Any pregnancy in an obese woman is high risk, requiring higher levels of obstetric and paediatric support, with much greater health care costs.263 Obese women are more likely to miscarry, to have still births and to have pregnancy complications.
Babies of obese mothers are likely to have heavier birth weights and impaired foetal development.264 Table 4 outlines some of the implications of obesity at various stages of pregnancy.

Table 4: Implications of obesity in pregnancy265

Stage of pregnancy Obesity-related problem
Preconception Mentrual disorders, infertility, polycystic ovarian syndrome
Early pregnancy Miscarriage, foetal abnormalities, difficult ultrasound
Antenatal Hypertension, pre-eclapsia, gestational diabetes, thrombosis
Delivery Induction of labour, caesarean section, should dystocia, perioperative complications
Postpartum Haemorrhage, infection, thrombosis
Foetal Macrosomia, foetal distress, perinatal morbidity and mortalitiy, birth injuries

Maternal nutrition during pregnancy and in the peri-conception period is a key modifier of health outcomes for both mother and child in the long term. The Australian Longitudinal Study on Women’s Health research has demonstrated that, while women appear to make alterations to their diets while pregnant, many still do not obtain the nutrients they require. Australian studies indicate that the folate, fibre, iodine and iron intake of pregnant women does not meet national recommended levels.266 267 268 Many women need to increase their intake of specific nutrients before, during and after pregnancy.269

Smoking during pregnancy has many detrimental effects for both the mother and infant. There is strong evidence that smoking is associated with low birth weight, intrauterine growth restriction, prematurity, birth defects of extremities, perinatal mortality and sudden infant death syndrome.270 271 The numbers of women who smoke during pregnancy continue to be high. In 2006 about 17 per cent of pregnant Australian women smoked.272

At least half of women who were smokers before pregnancy quit smoking during pregnancy, but 30 per cent or more did not.273 The rate of pregnant women who smoke was significantly higher for teenage pregnancies at 42 per cent and 52 per cent for Aboriginal and Torres Strait Islander women’s pregnancies.274 Women with low socioeconomic status, less education and who are unmarried are more likely to smoke during pregnancy. Aboriginal and Torres Strait Islander women are more likely to smoke during pregnancy and are less likely to access antenatal care in first trimester, when many risk factors could be addressed.275 276

Prior alcohol intake has a strong effect on alcohol intake during pregnancy277, with some 50 per cent of women having reported drinking alcohol at some time during their pregnancy.278 The Australian Longitudinal Study on Women’s Health found more than half of the women who—before pregnancy—were drinking at levels considered risky for pregnant women stopped drinking at those levels during pregnancy. Over one-third or more did not.279 In contrast, women with higher education attainment, and older women, are less likely to consume alcohol while pregnant.280