Although it is not part of routine antenatal care to weigh women every time they attend clinic (NICE 2008), many women do keep an eye on their own weight gain. There is a wide range of weight gain associated with normal outcome; however, average weight gain for mothers of full-term babies is 11–15kg (Stables & Rankin 2005). The pregnant woman has additional nutritional requirements, including increased calorific intake (300kcal daily), increased protein (6g daily), folate supplementation (400μg daily) and increased dietary calcium and iron (Coad 2001).

Severe dietary restriction can result in significant reduction in birthweight (Enkin et al 2000). The NICE guidance on improving nutrition for pregnant and breastfeeding mothers (NICE 2008) highlights the prevalence of malnutrition, particularly in low-income households, with one-fifth of adults having small meals or skipping them altogether. Women with low incomes are eligible for Healthy Start vouchers to enable them to buy fruit and vegetables (Department of Health 2004). A systematic review (Kramer 2000) found that dietary supplementation with both calories and protein resulted in both maternal weight gain and increased birthweight with a subsequent decrease in small for gestational age infants and lower perinatal mortality. The same review concluded that restricting the energy or protein intake of obese women may be harmful.

Obesity in pregnancy is associated with increased obstetric risk, including gestational diabetes, hypertension, operative intervention, anaesthetic complications, prolonged labour and shoulder dystocia (Frohlich 2002). There is also evidence that maternal obesity is associated with an increased risk of fetal abnormality (Watkins et al 2003). In the Confidential Enquiry into maternal death 2003–2005 (Lewis 2007) it was reported that over 50% of women who died were overweight, compared with 35% in the previous triennium (Lewis 2004). Although women are often advised not to lose weight in pregnancy (Food Standards Agency 2008a), this may be a time when they are receptive to nutritional advice (Richens 2008). A systematic review of the benefits of a low glycaemic diet in pregnancy to reduce the risks of gestational diabetes mellitus (Tieu et al 2008) concluded that although the results suggested this to be beneficial, the evidence was not strong enough to be conclusive. Claesson et al (2008) report on a case control intervention study of motivational talks and aquarobic exercise classes for obese women. Although the intervention was not associated with any difference between the groups for obstetric variables, the intervention group had significantly less weight gain during pregnancy than the control group. Women with a BMI over 30kg/m² should be referred for consultant care (Richens 2008) and screened for diabtetes (NICE 2008). Those women with a BMI over 35kg/m² should be considered for aspirin therapy, in the presence of additional risk factors for pre-eclampsia, and for thromboprophylaxis if they have additional risk factors for thromboembolic disease (RCOG 2007).

Women are faced with an increasing range of foods that they are advised not to eat when pregnant, because of the potential risk to the developing fetus. There are also many supplements available over the counter for women who are pregnant or considering pregnancy.

Midwives need to find ways to explore women’s alcohol consumption in a sensitive, non-judgmental way as it is thought that under reporting is widespread (RCOG 2006a). A consistently high consumption of alcohol is linked with a series of characteristics that together are known as fetal alcohol syndrome (FAS). They include mental retardation, microcephaly, small eyes, hearing disorders, large ears, shallow philtrum, small for gestational age, thin lips and congenital abnormalities (Seidel et al 1997). Binge drinking has been highlighted as being particularly harmful (RCOG 2006a). The Food Standards Agency recommend that women abstain from drinking alcohol throughout pregnancy, however, when women do continue to drink, consumption should not exceed one to two units once or twice a week (FSA 2008). A study (Kesmodel et al 2002) found an increasing risk of stillbirth with increasing moderate alcohol consumption.

Both professionals and members of the public are well aware that smoking is hazardous to extra-uterine and intra-uterine health (Tobacco Information Campaign 2002). However, despite this knowledge, many pregnant women and their partners continue to smoke. They need support to give up and there are many local initiatives designed to provide advice and encouragement. Access to services depends on the midwife identifying the need for support and using her interpersonal skills to discuss the topic in a non-judgmental manner. The midwife needs to be aware of her own feelings with regard to women who smoke. If she alienates her when she asks the first question, ‘Do you smoke?’ either by the tone of her voice or the look on her face, it may be very difficult to repair the damage. It is important not to push information on a woman who does not want to give up smoking; however, it is prudent to assess if the woman is aware of the dangers to both herself and the developing fetus, and to correct misinformation. Even if a woman does not choose to make changes based on the information she receives, she still has a right to informed choice about her health behaviour.

The consequences of maternal smoking on the baby continue to emerge. They include: low birthweight (Cnattingius & Haglund 1997), acute and chronic middle ear disease (Strachan & Cook 1998), respiratory illness (Fergusson et al 1980; Weitzman et al 1990), increased risk of sudden infant death syndrome (Haglund & Cnattingius 1990) and reduced breastmilk volume in the mother (Vaio et al 1991).

Pregnant drug users have a range of social, emotional and physical needs that require expert attention. This vulnerable group of women requires individualized care. The Confidential Enquiry into Maternal Deaths 1997–1999 (CEMD 2001) identified 11 deaths from accidental drug overdose. There were two deaths attributed to overdose of street drugs in the triennium 2003–2005, and 11% of all the women who died had a problem with substance abuse (Lewis 2007). There are many more women who do not die as a result of their drug dependency but who remain vulnerable because of their chaotic domestic circumstances. The babies of drug users are also at risk of a range of sequelae, depending on the type of drug and degree of abuse (Baston & Durward 2001).