Obesity poses increased health risks for women not only before pregnancy but also puts these women and their babies at various adverse outcomes during pregnancy.
These women and their offspring are at increased long-term risks of weight retention, with significantly increased likelihood of long-term obesity and metabolic syndrome when compared with normal BMI mothers.
According to Public Health England, adult overweight and obesity is predicted to reach 70% by 2034.
Health professionals involved in the care of pregnant women should receive education on maternal nutrition and its impact on maternal foetal and child health.
Women (and health practitioners) may not be aware of all the risks. These risks also include effects on future offspring and should be appropriately shared in a sensitive manner during the prepregnancy counselling consultation by an appropriately trained health professional. Women should be supported to lose weight before pregnancy.
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Women should be counselled as regards increased risks related to their reproductive performance.
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Information should be provide about the effects of maternal obesity on the offspring.
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They should be informed that working towards a healthy weight will significantly reduce these risks:
Prepregnancy risks:
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Infertility and prolongation of the time to get pregnant (due to hyperandrogenaemia causing decrease in gonadotrophin secretion as well as the association of obesity with polycystic ovarian disease and anovulation).
Metabolic syndrome and Type 2 diabetes:
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This risk incrementally increases with higher BMI.
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Women with obesity have increased insulin resistance as well as their dietary patterns may increase that risk.
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More than 80% of type 2 diabetes can be associated with obesity.
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Metabolic syndrome during pregnancy is associated with higher risk of gestational diabetes, hypertension of pregnancy and thromboembolic disease.
Disorders of lipid metabolism:
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Elevated serum cholesterol, low density lipoprotein, and very low density lipoprotein, as well as reduction in serum high density lipoprotein (HDL).
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These effects and especially the lower levels of serum HDL cholesterol may increase the risk of coronary heart disease.
Folic acid deficiency:
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There are low serum folate levels in obese women.
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Additionally, obese women are less likely to have adequate folate intake in their diet or take nutritional supplements containing folate.
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Folic acid needs to be started 1–3 months before pregnancy and aspirin is usually started at 12 weeks.
Vitamin D deficiency:
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Obese women have lower levels of serum vitamin D concentrations.
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It is unlikely that the requirements in pregnancy are met by diet alone.
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Furthermore, in countries with less exposure to sunlight at the appropriate wavelength, this deficiency can be more marked, as vitamin D synthesis depends on skin exposure to sunlight.
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COVID-19: Obesity increases the morbidity and mortality from Coronavirus-19 disease and this seems independent of other risk factors.
Antenatal risks
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Miscarriage.
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Increased congenital abnormalities as neural tube defects, spina bifida, cleft lip and palate, anorectal atresia, hydrocephaly, cardiovascular, septal anomalies, and limb reduction abnormalities.
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Hypertensive disorders of pregnancy as preeclampsia. Difficulty in measuring blood pressure, therefore use of an appropriate sized cuff is recommended.
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Metabolic syndrome including gestational diabetes.
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Venous thromboembolism (VTE). The risk increases with BMI >30 kg/m 2 and is higher with increasing obesity. This risk is throughout the pregnancy and lasts 6 weeks postpartum.
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Foetal macrosomia.
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Increased mental health problems as depression, antenatal and postpartum anxiety.
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Increased induction of labour.
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Death. In the UK 60% of pulmonary embolism-related deaths (2003–2008) occurred in women who had BMI >30 kg/m 2 as opposed to 20% prevalence.
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Difficulty in assessing foetal size and external foetal heart tracing
Intrapartum risks
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Dysfunctional and prolonged labour.
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Foetal macrosomia increases shoulder dystocia with its sequalae as brachial plexus injury.
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Difficulty in palpating the presenting part, foetal size and external foetal heart rate tracing.
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Caesarean section.
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Less rates of successful vaginal birth after caesarean section.
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Difficult venous access.
Anaesthetic complications:
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Obese women are at higher risk of anaesthesia-related complications. The higher the BMI, the greater the complications.
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Obesity is associated with higher initial failure rate of epidural insertion, increased resite rates and failed intubation.
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Obesity is considered a significant risk factor to maternal mortality from anaesthetic complications.
Postpartum risks
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Postpartum haemorrhage
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Wound infections and wound separation
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VTE
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Lesser rates of initiation and maintenance of breast feeding
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Postpartum weight retention for the mother
Short- and long-term risks for foetuses and infants include:
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Stillbirth
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Prematurity
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Macrosomia
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More prone to develop obesity in childhood. Infants of obese mothers tend to have more body fat than mothers with normal BMI
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Increased risk of childhood asthma
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Metabolic disorders in childhood and later life
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Possible increased risk of autism spectrum disorders and developmental delays in childhood
Preconceptional counselling:
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Health behaviours stem before pregnancy. There will be limited potential to impact unhealthy eating or lifestyle habits to cause significant change after pregnancy has already occurred.
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Preconceptional counselling and contraceptive consultations provides an excellent opportunity to address obesity in the reproductive age women.
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A holistic approach is ideal and women planning to get pregnant should also be informed of risks of smoking, drugs, and alcohol, which may not only affect a healthy lifestyle but can hinder them from achieving it.
Smoking
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Smoking with obesity may amplify various health issues.
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The risk of VTE and coronary heart disease is increased.
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Women should be advised to stop smoking before embarking on pregnancy.
Alcohol
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Women should be informed that there is no “low safe limit” during pregnancy. The UK’s chief medical officer guideline advises not to drink at all during pregnancy.
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It is particularly important to limit alcohol intake while trying to lose weight for various reasons:
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Firstly, the calories in alcohol may offset any dietary caloric restrictions.
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Secondly drinking is associated with increased hunger and in turn will lead to more food consumption.
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There is an association with various nutritional deficiencies.
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Binge drinking can be associated with unprotected intercourse leading to unplanned pregnancy.
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Alcohol intake during pregnancy can cause various birth defects.
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Foetal alcohol spectrum disorder (FASD) is a blanket term comprising various abnormalities due to alcohol consumption in pregnancy.
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These include physical, mental or behavioural problems and these include lifelong learning disabilities.
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Foetal alcohol syndrome is the most severe form of FASD and includes facial abnormalities, growth restriction, and lifelong learning disabilities
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Chronic alcohol consumption may lead to various nutritional deficiencies: this includes deficiency in vitamins. Of particular importance is vitamin B9 (folic acid) which can occur in up to 80% of alcoholics.
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A combined effect of alcohol, folic acid deficiency and obesity may confound folate deficiency-related birth defects as microcephaly, neural tube defects, and facial malformations
Unplanned pregnancies
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45% of pregnancies are unplanned.
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Health education and losing weight before pregnancy are essential steps in managing obesity in pregnancy and the overall approach to the obesity pandemic.
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An unplanned pregnancy can represent various missed opportunities and has several effects on women and children including:
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Late antenatal care
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Late testing for various abnormalities, such as gestational diabetes
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Late start to implement various dietary modifications
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Late starting of various medications and supplements as folic acid and aspirin at the appropriate time. Missed opportunity to risk assess for thromboembolism: Some women with multiple risk factors need to start LMWH in the first trimester based on their risk scoring
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Reducing alcohol and giving up smoking before pregnancy
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Not being up to date with vaccinations before pregnancy.
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Performing sexual health checks including cervical screening before pregnancy.
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Antenatal and postpartum depression
Diagnostic challenges
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Difficulty in assessing the nuchal translucency measurements due to obesity.
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Less clarity in imaging of foetal structures at ultrasound scan to screen for structural anomalies. This can decrease accuracy of detection of structural anomalies in obese women.
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Amniocentesis and chorionic villus sampling can be technically challenging and associated with higher miscarriage rates.
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Noninvasive prenatal testing for trisomies can be less effective in obese women. It is worth noting that other serum biomarkers are not affected by obesity as they are adjusted by weight.
Weight loss before pregnancy can carry health benefits into pregnancy and future pregnancies. Weight management strategies before pregnancy include:
Diet
Various approaches to diet should be considered to achieve weight loss. Some of the basic principles are as follows:
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Involve a dietician.
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Health education about various types of diet and calories.
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A healthy diet does not necessarily mean it would be helpful in reducing weight.
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Women should be educated about both healthy and low-in-calories diets which would aid in weight loss.
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Calculate the total energy expenditure. This can be done by using the World Health Organization equations for calculating energy expenditure.
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Overall caloric intake should be reduced and less than expenditure, and this should be the basis for any weight loss intervention.
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Aim to reduce caloric intake by approximately 500 kcal/day. This should reduce the weight by approximately 0.5 kg/week
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In calculating the macronutrients in the reduced caloric diet, aim for a balanced diet for protein, carbohydrates, and healthy fats. It has been recommended that diet should include higher protein and lower carbohydrates.
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Avoid or reduce alcohol, sugary beverages, and simple sugars in diet.
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Aim for consistency as it will take time
Exercise
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Physical activity is very important in mental and physical overall health. This, however, is different from the exercise effects on losing weight.
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Contrary to common belief, on its own without diet modifications it can only lead to modest reductions in weight. In other words, it will be difficult to lose weight with exercise alone. It is difficult to “outrun” a bad diet .
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According to the World Health Organization guidelines, updated in 2020, there is a reaffirmation that physical activity is better than none.
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A combined aerobic and resistance training or muscle strengthening in addition to diet seems to be a reasonable approach.
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All adults should undertake weekly 150–300 minutes of moderate intensity exercise or 75–150 vigorous intensity exercise or an equivalents combination.
Behavioural therapy
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The statement from US Preventive Services Task Force did not make specific recommendations on initiating behavioural counselling in primary healthcare settings. The health benefits seem to be small.
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However, clinicians can selectively counsel patients’ readiness to embrace changes, explore barriers to change, and direct to social support services that can aid in behavioural changes.
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This however is different from behavioural counselling that is usually done by dieticians to promote nutritional change in behaviour by proper education and nutritional counselling with regard to the different types of diet and food.
Medications
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A number of medications for management of obesity have been used; these include Orlistat, Liraglutide, Phentermine-topiramate, and Bupropion-naltrexone.
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Little data exist on their effects on pregnant women and the manufacturers recommend that these medications are contraindicated in pregnancy.
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The British national formulary however suggests that Orlistat can be used with caution in pregnancy and is to be avoided during breast feeding.
Bariatric surgery
National institute of clinic excellence in the UK recommends bariatric surgery for women with BMI >40 kg/m 2 or >35 in the presence of other comorbidities. There are numerous bariatric surgeries. They decrease weight by three main ways:
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Restriction of caloric intake by decreasing stomach capacity (example sleeve gastrectomy)
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Malabsorption of nutrients by decreasing the absorption length of small intestine (example jujeno-ileal bypass)
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Combination of above (example Reux-en-Y gastric bypass)
Care of women after bariatric surgery :
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Inform women that following weigh loss they are at higher risk to get pregnant if they are not using contraception. Cycles may become regular and rate of anovulation decreases, thus improving fertility.
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Women should be advised to wait for 12–18 months before getting pregnant as this is the time where these women are usually actively losing most weight, so this time is ideal to optimise the success of weight loss. Additionally, it gives time to address nutritional deficiencies.
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Risk of various nutritional deficiencies including iron, folate, calcium, B12, vitamin D, fat-soluble vitamins, fats, and proteins, especially in procedures that lead to malabsorption such as gastric bypass. It is thus important to know which type of surgery was performed.
Breast feeding advice
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Women should be advised about the potential benefits of breast feeding.
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Women who breast feed can lose weight faster than those who do not breast feed.
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Breast feeding also reduces risk of developing Type 2 diabetes mellitus.
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Obese women may find it difficult to initiate and maintain breast feeding for various reasons.
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Delay in lactogenesis in obese women.
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Impaired prolactin response to suckling.
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