Nausea and vomiting occur in 50 ~ 80% of pregnancies in the first trimester. Inability to keep down fluids or solids leads to weight loss (2 to > 5 kg), dehydration, electrolyte disturbances and vitamin B deficiency (polyneuropathy), and may very rarely lead to liver failure, renal failure and fetal or maternal death. (Br J Obstet Gynaecol 1993;8:708).
- CBC, Electrolytes, urine for ketones and TFT (see Hyperthyroidism)
- LFT and RFT if severe or prolonged (↓albumin, ↑transaminases, PTR normal)
- Social aspects of admission.
- Admission and IV fluids are usually sufficient by themselves to reduce nausea and should be the only initial management.
- The patient should eat a little often.
- Antiemetics may be used only if the vomiting is not settling. No antiemetics are licensed for use in pregnancy. There is an unquantified, but probably very low, risk of teratogenesis:
If the vomiting is prolonged, severe and unresponsive to standard management, consider prednisolone 20 mg PO BID or TID or ondansetron 8 mg PO BID. Also consider enteral feeding (or TPN) and vitamin B supplementation. Abnormal LFT respond rapidly to correction of dehydration and malnutrition.
- metoclopramide 10 mg IM/IV TID
- domperidone 30 mg PO TID
- chlorpromazine 100 mg suppository QID (may lead to jaundice and extrapyramidal side-effects in the fetus).
The incidence of bulimia and anorexia nervosa in pregnancy is less than in the non-pregnant population.
- Bulimia: Bulimics tend to improve in later pregnancy and often become worse again after delivery. There may be a slightly greater incidence of fetal anomaly.
- Anorexia nervosa: Anorexics may become worse as pregnancy advances. The incidence of low-birth-weight infants is increased, particularly if ovulation induction has been used to assist conception. The perinatal mortality is also greater. Delay ovulation induction until the weight is >45 kg.