Devalia V, Hamilton MS, Molloy AM; BCSH. Guidelines for the diagnosis and treatment of cobalamin and folate dis-orders. Br J Haematol 2014;166:496–513.
Pavord S, Myers B, Robinson S, Allard S, Strong J, Oppenheimer C; BCSH. UK guidelines on the management of iron defi-ciency in pregnancy. Br J Haematol 2012;156:588–600.
Key References
1. WHO. Nutritional Anaemias. Technical Report Series.
Geneva: WHO, 1972.
2. WHO. Iron Deficiency Anaemia, Assessment, Prevention, and Control: A guide for programme managers.
Available from: www.who.int/reproductive-health/docs/
anaemia.pdf.
3. Centers for Disease Control. Current Trends: CDC criteria for anaemia in children and child-bearing age women. Morb Mortal Wkly Rep 1989;38: 400–4.
4. Ramsey M, James D, Steer P. Normal Values in Pregnancy.
2 edn. London: WB Saunders.
5. Finch CA, Cook JD. Iron deficiency. Am J Clin Nutr 1984;39:471–7.
6. Scholl TO, Hediger ML. Anemia and iron deficiency anemia: compilation of data on pregnancy outcome.
Am J Clin Nutr 1994;59 (Suppl):492S–501S.
7. Walter T. Effect of iron-deficiency anaemia on cognitive skills in infancy and childhood. Baillière’s Clin Haematol 1994;7:815–27.
8. Hallberg L, Bengtsson C, Lapidus L, Lindstedt G, Lundberg PA, Hultén L. Screening for iron deficiency:
an analysis based on bone-marrow examinations and
serum ferritin determinations in a population sample of women. Br J Haematol 1993;85:787–98.
9. Pavord S, Myers B, Robinson S, Allard S, Strong J, Oppenheimer C; BCSH. UK guidelines on the man-agement of iron deficiency in pregnancy. Br J Haematol 2012;156:588–600.
10. Reveiz L, Gyte GML, Cuervo LG. Treatments for iron deficiency anaemia in pregnancy. Cochrane Database Syst Rev 2007;2:CD003094.
11. SHOT Annual Report 2000/2001. London: Serious Hazards of Transfusion Steering Group, 2002.
12. Breymann C, Major A, Richter C et al. Recombinant human erythropoietin and parenteral iron in the treat-ment of pregnancy anemia: a pilot study. J Perinat Med 1995;23:89–98.
13. Watson F. Routine iron supplementation – is it necessary?
Modern Midwife 1997;7:22–6.
14. Pena-Rosasa JP, Viteri FE. Effects of routine oral iron supplementation with or without folic acid for women during pregnancy. Cochrane Database Syst Rev 2006;3:CD004736.
15. Lumley J, Watson L, Watson M, Bower C. Periconceptual supplementation with folate and/or multivitamins for preventing neural tube defects. Cochrane Database Syst Rev 2001;3:CD001056.
16. Elwood JM. Can vitamins prevent neural tube defects?
Can Med Assoc J 1983;129:1088–92.
17. Devalia V, Hamilton MS, Molloy AM; BCSH. Guidelines for the diagnosis and treatment of cobalamin and folate disorders. Br J Haematol 2014;166:496–513.
Chapter 22 Abdominal pain
Clare L Tower
INTRODUCTION
Abdominal pain is an extremely common complaint in pregnant women, with a majority of women experiencing it at some point during pregnancy. The vast majority is benign and self limiting. However, an approach to abdominal pain in pregnancy must enable identification of serious pathology to allow successful treatment to be implemented. There are many pitfalls in the assessment of pregnant women with abdominal pain and sadly several are found in the triennial maternal mortality report.1 In particular, diagnosis of the
‘acute abdomen’, often defined as a collection of symptoms and signs of intraperitoneal disease best treated with surgery,2 is notoriously difficult. The commonest surgical causes of the acute abdomen in pregnancy are appendicitis and cholecystitis.3
HISTORY AND EXAMINATION
In the same way as outside pregnancy, a systematic approach to the history and examination of the abdominal pain is required.
A detailed outline of this can be found in many undergraduate textbooks. The gravid uterus and the physiological changes in pregnancy can mask some of the typical findings seen
outside pregnancy. For example, the location of the appendix becomes displaced upwards as gestation increases. Therefore, whereas the appendix may lie at McBurney’s point in the first trimester, by the late third trimester it may become located in the right hypochondrium, or be located behind the pregnant uterus. The enlarging uterus also separates the intra-abdom-inal organs from the parietal peritoneum with increasing gestation. Therefore, signs of peritonism may be masked as the inflamed abdominal organ no longer irritates the parietal peritoneum. Furthermore, many associated symptoms and signs can also be those common in a normal pregnancy, for example nausea and vomiting. A thorough but focused his-tory and examination will usually suggest a short list of likely differential diagnoses (Table 22.1), thus guiding further investigation. Causes can be considered as either obstetric or non-obstetric, then within a systems review, e.g. gastrointest- inal, renal and other. Involvement of other specialists, such as gastroenterologists, urologists or surgeons, may be indicated.
INVESTIGATIONS AND IMAGING
The list of possible differential diagnoses will guide suitable and targeted investigations (Table 22.1). Knowledge of how biochemical and haematological markers differ from the non-pregnant state is imperative in order to understand the significance of the results. White cell counts are typically increased during pregnancy, as is alkaline phosphatase due to placental production. Biochemical markers such as urea and creatinine fall. A summary of the variations seen in the commoner investigations performed during pregnancy is given in Table 22.2.
There has been much debate about the suitability of varying imaging modalities during pregnancy, largely due to concerns about the effect on the fetus. Ultrasound is considered safe and widely used, and can be useful in the diagnosis of, for example, appendicitis and renal tract obstruction. It is widely available, cheap and does not require the use of contrast medium or ionising radiation. However, the accuracy can be operator dependent and it may produce inconclusive results.
Diagnosis of renal tract obstruction is a common exam-ple of how pregnancy causes difficulties in interpretation of
MRCOG standards
There is no specific established standard for this topic, but we would suggest the following points for guidance. Several of the many causes of abdominal pain can be found in core module 9, Maternal Medicine.
A detailed discussion of every cause of abdominal pain in pregnancy is both impractical and cumbersome, and many of the disorders are discussed elsewhere in detail. Thus, this chapter aims to give an overview of the approach to abdominal pain in pregnancy, with a focus on differential diagnoses, and aspects of the approach that are specific to pregnant women.
ANTENATAL OBSTETRICS Table 22.1 Differential diagnoses, key findings and investigations
Disorder Key clinical features Specific investigations Management Obstetric – early pregnancy
Miscarriage Pain and bleeding USS, hCG and progesterone
levels
Expectant, medical or surgical
Ectopic pregnancy Pain followed by a small amount of bleeding, peritonism, shoulder tip and rectal pain; may present with diarrhoea
USS, hCG and progesterone levels
Expectant, medical or surgical
Ruptured corpus luteal cyst
Signs of peritonism USS Analgesia ± laparoscopy
Adnexal torsion Twisting pain, peritonism Commoner in first trimester and postpartum
USS Analgesia ± laparoscopy
Obstetric – late pregnancy
Round ligament pain Bilateral, stitch like None Analgesia and reassurance
Braxton Hicks Painful/painless tightenings not causing cervical dilatation
Vaginal examination to exclude labour
Reassurance
Labour Painful contractions Vaginal examination, CTG, etc. Consider tocolysis and steroids if preterm
Placental abruption Constant pain, rigid uterus, sometimes frequent and short-lasting contractions
± bleeding
Fetal assessment, bloods Resuscitation, delivery
Pre-eclampsia Epigastric, right upper quadrant All pte-eclampsia investigations
Treat blood pressure, consider delivery
Polyhydramnios Tight, distended abdomen, difficult to feel fetal parts
USS, exclude diabetes, infection (TORCH)
Detailed fetal scan, consider amnio-drainage
Adnexal torsion Twisting pain, peritonism USS Analgesia ± laparoscopy
Fibroid degeneration Constant localised pain, over the fibroid USS to confirm fibroids;
degenerative cystic changes may be present
Analgesia
Uterine rupture Sudden-onset constant pain,
haemodynamic collapse, vaginal bleed, haematuria
All bloods, cross-match, CTG Resuscitate and surgery
Acute fatty liver Epigastric/right upper quadrant pain, often associated with malaise, nausea and vomiting; may be jaundiced and have ascites
All pre-eclampsia investigations – may have hyperuricaemia, hypoglycaemia, deranged LFTs.
USS/CT or MRI of liver
Stabilise and deliver
Urinary retention (retroverted uterus)
Unable to pass urine, palpable and uncomfortable bladder
Catheter; USS will help exclude other causes
Conservative management; usually resolves after 12 weeks
Physiological obstruction of ureters
Renal angle tenderness USS to assess renal pelviectasis (2 cm normal)
Usually conservative; if significant, may require nephrostomy Chorioamnionitis Tender uterus, offensive discharge,
systemic signs of sepsis, usually preceded by ruptured membranes
Blood cultures, inflammatory markers, speculum, CTG
Intravenous antibiotics, resuscitate and deliver
(continued) Investigations and imaging 169
170 Abdominal pain
ANTENATAL OBSTETRICS
Disorder Key clinical features Specific investigations Management Symphysis pubis
dysfunction
Suprapubic tenderness, over bone;
worse on movement and standing on one leg
Full physiotherapy assessment Physiotherapy, analgesia
Rectus abdominis rupture
Sudden-onset pain, usually precipitated by cough or vomit; rare and usually in multiparous women; may have associated haematoma
Exclude other causes of abdominal pain
Analgesia; expanding haematoma may require surgical exploration
Non-obstetric Renal tract causes Urinary tract infection
Dysuria, frequency of micturition Urine dipstick, urine for culture Increase oral intake of fluid, antibiotics
Pyelonephritis Loin pain (renal angle tenderness), radiating round to abdomen and into groin, rigors
Blood cultures, urine dipstick and culture, renal USS
Antipyretics, IV antibiotics, IV fluids
Renal calculi Loin pain (renal angle tenderness), radiating round to abdomen and into groin, often colicky in nature
Urine dipstick (microscopic haematuria), urine for culture, renal USS
Conservative management with fluids and analgesia; involve urologists
Gastrointestinal tract causes Constipation
Constant or colicky abdominal pain;
infrequent, hard stools
Dietary advice, stool softeners
Gastritis/peptic ulcer disease
Epigastric pain, often constant or burning; duodenal ulcers relieved by food, gastric ulcers made worse by food; may be associated with nausea, vomiting, haematemesis
Gastroscopy if severe; involve gastroenterologists
Antacids and ulcer-healing drugs – H2-receptor antagonists/proton-pump inhibitors
Appendicitis Pain, not always localised to right iliac fossa, especially in third trimester;
signs of peritonism; associated anorexia, nausea, vomiting and pyrexia
Inflammatory markers (white blood cell count, C-reactive protein); USS of abdomen;
pyuria may be present
Involve general surgeons, surgical management
Bowel obstruction Colicky abdominal pain, associated with vomiting and nil passed per rectum; high-pitched or absent bowel sounds; usually have risk factors;
perforation will cause signs of peritonism
Abdominal X-ray; involve general surgeons; colonoscopy
Conservative management – IV fluids, nasogastric tube; may require surgery
Cholecystitis/
cholelithiasis
Epigastric or right upper quadrant pain (colicky or stabbing); may radiate through to back and be associated with nausea and vomiting; intolerance of fatty food; tenderness and guarding
USS of gallbladder/liver, LFTs Conservative management – analgesia, fluids, antibiotics if infected; surgery may be indicated (see text)
Pancreatitis Epigastric pain, radiates through to back; associated with nausea and vomiting
USS of upper abdomen, CT scan, LFTs, amylase and lipase three times normal, calcium low, high blood glucose
Involve surgeons, conservative management; use of prognostic scoring systems
Gastroenteritis Generalised, usually crampy abdominal pains, associated with diarrhoea and vomiting
Stool sample Fluids; manage at home if possible
Hepatitis Right upper quadrant/epigastric pain;
may be associated with jaundice
USS of liver, LFTs, hepatits screen
Involve hepatologist, depends on underlying cause
Strangulated hernia Peritonism, may be associated with bowel obstruction
Involve surgeons Involve surgeons, treat bowel obstruction
Table 22.1 Differential diagnoses, key findings and investigations (continued)
(continued)
ANTENATAL OBSTETRICS
scan findings. Physiological dilatation of the renal collecting system occurs in pregnancy due to a combination of compres-sion and smooth muscle relaxation secondary to progesterone.
A physiological dilatation of up to 2 cm is considered ‘accept-able’, and is often greater on the right. In physiological dilata-tion, the ureter will taper to a normal calibre as it crosses the pelvic brim, but, in pathological dilatation, this is lost. Also, ure-teric ‘jets of urine’ entering the bladder can be seen in physio-logical dilatation, a phenomenon that is also lost in pathophysio-logical dilatation.4
If ultrasound produces inconclusive findings, further imag-ing may be needed. Investigations involvimag-ing ionisimag-ing radiation have often been avoided during pregnancy due to concerns about the radiation effect on the fetus in terms of teratogen-esis, pregnancy loss and future malignancy. However, the overall risks are very small. Fetal risks, thought to be maximal with exposure between 8 and 15 weeks, are not increased by exposures <5 rad. Risks of subsequent carcinogenesis are also small. It is estimated that a 1 to 2-rad exposure may increase the risk of leukemia from 1:3000 to 1:2000.5 Table 22.3 gives Disorder Key clinical features Specific investigations Management
Inflammatory bowel disease
Generalised pain, associated diarrhoea, mucus and rectal bleeding, vomiting, weight loss
Inflammatory markers, sigmoidoscopy, colonoscopy
Involve gastroenterologists, steroids, mesalamine, other immune modulators such as azathrioprine
Other
Abdominal bleeding
Very rare; ruptured liver capsule, splenic artery aneurysms, aortic aneurysms, cause haemorrhagic shock and abdominal pain
FBC, cross-match, assess fetal wellbeing with CTG
Resuscitate, surgical management
Pelvic vein thrombosis Often thrombosis of right/left iliac vein, causing groin tenderness, leg swelling, sometimes pyrexia
Doppler ultrasound, venogram, thrombophilia screen
Anticoagulation using LMWH, involve haematologists; may require filter in inferior vena cava Systemic causes, e.g.
DKA, increased calcium, sickle cell crisis
Generalised abdominal pain, associated with being systemically unwell
Urea, electrolytes, blood glucose, bone profile
Treatment dependent on cause;
involve the general physicians
Trauma – remember domestic violence
Associated with bruising; domestic violence commonly results in abdominal trauma during pregnancy
Assessment of fetal wellbeing, Kleihauer’s test, particularly if rhesus negative; check for other injuries
Ensure safety, specialist midwifery service, social input
Pneumonia Right lower-lobe pneumonia may cause right upper quadrant pain; associated with respiratory symptoms
Chest X-ray, blood gases, inflammatory markers, sputum cultures
Antibiotics, may require oxygen and high-dependency support if severe
TORCH, toxoplasmosis, rubella,cytomegalovirus, herpes simplex and HIV; USS, ultrasound scan.
Table 22.2 Biochemical and haematological variations in pregnancy
Investigation Non-pregnant Pregnant Notes
Haemoglobin (g/dL) 12–15 11–14 Haemoglobin falls, to lowest at around 32 weeks
White cell count (x 109/L) 4–11 6–16 White cells increase; further increases in response to steroids when given for lung maturity, and in labour
Platelets (x 109/L) 150–400 Can fall by around 10% in pregnancy C-reactive protein (g/L) Does not vary in pregnancy
Urea (mmol/L) 2.7–7.5 <4.5 Falls with increasing gestation
Creatinine (µmol/L) 65–100 <75
Amylase Generally unchanged in pregnancy
Uric acid (urate) (mmol/L) 0.18–0.35 Generally considered as 0.1 x no. of weeks’ gestation, e.g. 0.35 at 35 weeks AST/ALT (IU/L) <40 Both usually lower in pregnancy, with 30 as upper limit of normal
Alkaline phosphatase (IU/L) 30–130 Increases with gestation, up to around 400 Table 22.1 Differential diagnoses, key findings and investigations (continued)
Investigations and imaging 171
172 Abdominal pain
ANTENATAL OBSTETRICS
approximate radiation doses of various types of investigation.
For comparison, these are much lower than a long-haul inter-continental flight that provides a 15-mrem dose of radiation, and a short-haul flight that provides 6 mrem.6 Thus, fetal risks are minimal and should not prevent an important investi-gation in pregnancy. However, CT scanning is uncommonly used, with the main indications for its use being trauma and renal stone pathology in the second and third trimesters.7 There is growing interest and expertise in the use of MRI for the investigation of non-obstetric abdominal pain in preg-nancy.8 This is considered safe although there remains debate about the use of the usual MRI contrast agent, gadolinium.9 This agent crosses the placenta and there are few data relat-ing to safety in human pregnancy. Hence MRI in pregnancy should be without the use of intravenous contrast, although some authors consider oral use acceptable.8