Early pregnancy and obesity

Obesity has become a major health problem worldwide and it’s an independent risk factor for adverse pregnancy outcome. The World Health Organization classifies obesity into class I BMI (body mass index) 30.0–34.9, class II 35.0–39.9, and class III 40 or greater.

The prevalence of obesity in the general population in the UK has increased markedly since the early 1990s. The prevalence of obesity in pregnancy has also been seen to increase, rising from 9%–10% in the early 1990s to 16%–19% in the 2000s. In England, where the prevalence of obesity in women is among the highest in Europe, one in five women of reproductive age are now obese (BMI ≥30 kg/m ² ).

Pregnant women who are obese are at greater risk of almost all of early pregnancy-related complications compared with women of normal BMI, including;

• Maternal Complications:

  • Infertility: threefold higher in obese than in nonobese due to ovulatory dysfunction and decreased insulin sensitivity.

  • Maternal morbidity and mortality: 30% of maternal death were obese and 22% were overweight (2015 MBRRACE)

  • First trimester miscarriage (OR 1.2)

  • Recurrent miscarriage (OR 3.5)

  • Venous thromboembolism: higher risk of pulmonary embolism (OR 14.9) than DVT (OR 4.4)

  • Preeclampsia (risk doubled with each 5–7 kg/m ² increase in prepregnancy BMI)

  • Gestational hypertension (OR 2.5–3.5)

  • Gestational diabetes (OR 2.6–4.0)

  • Maternal infections (UTI OR 1.17, genital tract OR 1.24)

  • Anaesthetic complications (25% of cardiac arrest in pregnancy is caused by anaesthesia, of those 75% are obese)

  • Wound infection (OR 1.27)

  • Depression (obese, 33.0%; overweight, 28.6%; normal weight 22.6%)

  • Anxiety and eating disorder (OR 1.4)

  • Serious mental illness

• Fetal Complications:

  • Congenital anomalies (NTD OR 1.7 for obese, 3.11 for morbidly obese), other anomalies; hydrocephaly, cardiovascular, and limb reduction abnormalities

  • Stillbirth (OR 3.8)

  • Prematurity (<32 weeks OR 0.73)

  • Macrosomia (>4000 g OR 1.7–1.9) (>4500 g OR 2.0–2.4)

  • Neonatal death (OR 3.4)